1 '- ·i.~· · 2019. 7. 31. · hot spot fluid temperature (4 inch) core power ... 1975...

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11-_p,f.ERGENCY CORE COOLING SYSTEM ANALYSIS

REQU:RED BY 10 CFR 50.46

·1,

I I I 1-

SEPTEMBER 1, 1974 REVISED APRIL 11 2 1975

REVISED JUNE 5, 1975

SURRY ~OWER STATION UNIT NOS. 1 AND 2

DOCKET NOS. 50-280 AND 50-281 LICENSE NOS. DPR-32 AND DPR~37

•THE ATTACHED FILES ARE OFFICIAL RECORDS . ·Of THE OFFICE OF REGULATION; THEY HAVE -

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·~·.··~··DEADLINE REfoRNDATE · . .5Q-2 .. 86/z~ . t=· f.cc I ( k/J,l,,. rid ::J 0 lo- fo ~ 1 f nm -z ~~----:~r------'V"".'

_:~,P MARY JINKS.,..CHJEF . - ·'1" ."' NTRAL RECORDS STATION

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y

I I I I I I I I I I I I I I I I I

!I .. ,

I.

IL

III.

IV.

v.

VI.

TABLE OF CONTENTS

List of Tables - Small Break List of Figures - Small Break List of Tables - Large Break List of Figures - Large Break

Introduction

Loss of Reactor Coolant From Small Ruptured Pipes or From Cracks in Large Pipes Which Actuate the Emergency Core Cooling System

Major Reactor Coolant System Pipe Ruptures (Loss of Coolant Accident)

Conclusions

References

Proposed Changes to the Technical Specifications

Page No.

i ii

.. iii iv

1

5

25

77

78

I I LIST OF TABLES

SMALL BREAK

I TABLE NO. TITLE

I II-1 TIME SEQUENCE OF EVENTS

I II-2 RESULTS AND ASSUMPTIONS

I I I I I I I I I I I I I I i

/

I I I I I I I I I I I I I I I I I I -,

FIG. NO.

II-1

II-2

II-3

II-4

II-5

II-6

II-7

II-8

II-9a

II-9b

II-lOa

II-lOb

II-lla

II-llb

LIST OF FIGURES SMALL BREAK

TITLE

Safety Injection Flowrate

Reactor Coolant System Depressurization Transient (4 inch)

Core Mixture Height (4 inch)

Clad Temperature Transient (4 inch)

Core Steam Flowrate (4 inch)

Rod Film Coefficient (4 inch)

Hot Spot Fluid Temperature (4 inch)

Core Power

Reactor Coolant System Transient (3

Reactor Coolant System Transient (6



Clad Temperature Transient (3 inch)

Clad _Temperature Transient (6 inch)

ii

inch)

inch)

I I 'LIST OF TABLES

LARGE BREAK

I TABLE NO. TITLE

I III-1 TIME SEQUENCE OF EVENTS FOR DOUBLE ENDED COLD LEG GUILLOTINE BREAK (DECLG)

I III-2 ASSUMPTIONS AND RESULTS FOR DOUBLE ENDED COLD LEG GUILLOTINE BREAK (DECLG)

I III-3 CONTAINMENT DATA

I I I I I 'I I I I I I I -,.

iii

I I I I I I I I I I 'I I I I I I I I I

FIG. NO.

III-la

III-lb

III-le

III-2a

III-2b

III-2c

III-3a

III-3b

III-3c

III-4a

III-4b

III-4c

III-Sa

III-Sb

III-Sc

III-6a

III-6b

II1-6c

III-7a

III-7b

III-7c

III-Sa

III-Sb

III-Sc

LIST OF FIGURES LARGE BREAK

DOUBLE-ENDED COLD LEG GUILLOTINE BREAK (DECLG)

TITLE

Fluid Quality - DECLG (CD= 1.0)

Fluid Quality - DECLG (C = 0.6) D

Fluid Quality - DECLG (CD= 0.4)

Mass Velocity - DECLG (CD= 1.0)

Mass Velocity - DECLG (CD= 0.6)

Mass Velocity DECLG (CD= 0.4)

Heat Transfer Coefficient - DECLG (CD= 1.0)



Core Pressure - DECLG (CD= 1.0)

Core Pressure DECLG (CD= 0.6)

Core Pressure DECLG (CD= 0.4)

Break Flow Rate DECLG (CD= 1.0)

Break Flow Rate - DECLG (CD= 0.6)

Break Flow Rate - DECLG (CD= 0.4)

Core Pressure Drop - DECLG (CD= 1.0)



Peak Clad Temperature - DECLG (CD= 1.0)

Peak Clad Temperature DECLG (CD 0.6)

Peak Clad Temperature DECLG (CD 0.4)

Fluid Temperature - DECLG (CD= 1.0)



iv

I I I ,. I I

I I· I I 1· I I I I I I

FIG. NO.

III-9a

III-9b

III-9c

III-lOa

III-lOb

III-lOc

III-lla

III-llb

III-llc

III-12a

III-12b

III-12c

III-13a

III-13b

III-13c

III-14

III-15

TITLE

Core Flow - Top and Bottom - DECLG (CD= 1.0)

Core Flow - Top and Botton - DECLG .(CD= 0.6)

Core Flow - Top and Bottom DECLG (CD = 0.4)

Reflood Transient

Reflood Transient

Reflood Transient

DECLG (CD = 1.0)

DECLG (CD= 0.6)

DECLG (CD= 0.4)

Accumulator Flow (Blowdown) DECLG (CD = 1.0)

Accumulator Flow (Blowdown) - DECLG (CD= 0.6)

Accumulator Flow (Blowdown) - DECLG (CD= 0.4)

Pumped ECCS Flow (Reflood) - DECLG (CD= 1.0)

Pumped ECCS Flow (Reflood) DECLG (C = 0.6) D

Pumped ECCS Flow (Reflood) DECLG (CD 0.4)

Containment Pressure - DECLG (CD = LO)

Containment Pressure DECLG (CD= 0.6)

Containment Pressure DECLG (CD= 0.4)

Unit No. 1, Cycle 2, Maximum Peaking Factor .vs. Axial Core Height (+6, -9 Delta Flux Band)

Unit No. 2, Cycle 2, Maximum Peaking Factor vs Axial Core Height (+6, -9 Delta Flux Band)

V

I I I I I I I I I I I I I I I I I I

! I

I. INTRODUCTION

The re-evaluation of ECCS cooling performance as required by the

Order for Modification of License for Surry Power Station, Unit Nos. 1

and 2, issued by the Atomic Energy Commission on December 27, 1974, and

as specified by 10 CFR 50.46, 1 "Acceptance Criteria for Emergency Core

Cooling Systems for Light Water Reactors" is presented herein. This

analysis was performed with the March 15, 1975 version of the Westing

house evaluation model which includes modifications as specified by the

Regulatory Staff in Reference 8. The implementation of these modifications

in the evaluation model is described in Reference 13. The analytical

techniques utilized in the analysis are in compliance with Appendix K to

10 CFR 50, and are described in the topical report, "Westinghouse ECCS

Evaluation Model-Summary," WCAP 8339, 2 dated July 1974. The Nuclear

Regulatory Commission Staff acceptance of the "Westinghouse ECCS Evaluation

Model" is presented in Reference 14. The results of the analysis show

that the calculated cooling performance of the emergency core cooling

system (ECCS) following postulated loss-of-coolant accidents conforms to

the criteria set forth in paragraph b of 10 CFR 50.46.

A loss-of-coolant accident may result from a rupture of the reactor

coolant system or of any line connected to that system up to the first

closed valve. Ruptures of very small cross section will cause explusion

of coolant of a rate which can be accommodated by the charging pumps.

Should such a small rupture occur, these pumps would maintain an opera

tional level of water in the pressurizer, permitting the operator to

execute an orderly shutdown. A moderate quantity of coolant containing

J ..

I I I I I I I I I I I I I I I I I I I

such radioactive impurities as would normally be present in the coolant,

would be released to the containment.

Should a larger break occur, subcooled fluid is expelled from the

break rapidly reducing the pressure to saturation. Depressurization of

the reactor coolant system causes fluid to flow to the reactor coolant

system from the pressurizer, resulting in a pressure and level decrease

in the pressurizer. For a postulated large break, reactor trip is ini

tiated when the pressurizer low pressure setpoint is reached, while the

safety injection system (SIS) is actuated by coincident pressurizer low

pressure and low level. A high containment pressure signal serves as a

backup by initiating a safety injection signal which in turn trips the

reactor. The consequences of an accident are limited two ways:

1. Reactor trip and borated water injection supplement

void formation in causing rapid reduction of the

nuclear power to a residual level corresponding to

delayed fissions and fission product decay.

2. Injection of borated water also ensures sufficient

flooding of the core to prevent excessive clad

temperatures.

The safety injection system, even when operating on emergency power,

limits the cladding temperature to below the melting temperature of

Zircaloy-4 and below the temperature at which gross core geometry dis

tortion, including clad fragmentation, may be expected. In addition,

the total core metal-water reaction is limited to less than one (1) per

cent. This is valid for reactor coolant piping ruptures up to an in

cluding the double ended rupture of a reactor coolant loop. Conse

quences of these ruptures are well within .those for the hypothetical

-2-

I I I I I 1: I I I I I I I I I I I I I

accident and are, therefore, well within the limits of 10 CFR 100.

Before the break occurs the unit is in an equilibrium condition,

i.e., the heat generated in the core is being removed via the secondary

system. During blowdown, heat from decay, hot internals and the vessel

continues to be transferred to the reactor coolant system. The heat

transfer between the reactor coolant system and the secondary system

may be in either direction depending on the relative temperatures. In

the case of continued heat addition to the secondary, secondary system

pressure increases and the main safety valves may actuate to reduce the

pressure. Make-up to the secondary side is automatically provided by

the auxiliary feedwater system. The safety injection signal stops nor

mal feedwater flow by closing the main feedwater control valves, trips

the main feedwater pumps and initiates emergency feedwater flow by

starting the auxiliary feedwater pumps. The secondary flow aids in the

reduction of reactor coolant system pressure. When the reactor coolant

system depressurizes to 600 psia, the accumulators begin to inject water

into the reactor coolant loops. The reactor coolant pumps are assumed

to be tripped at the initialization of the accident and effects of pump

coastdown are included in the blowdown analyses.

The water injected by the accumulators cools the core and subsequent

operation of the low head safety injection pumps supply water for long

term cooling. After the contents of the refueling water storage is

emptied, long term cooling of the core is accomplished by switching to

the recirculation mode of core cooling, in which the spilled borated

water is drawn from the containment sump by the low head safety injection

pumps and returned to the reactor vessel.

-3-

-------..

I I I. I 'I I I I I I I I I I I I I I I

The containment spray system and the recirculation spray system

operate to return the containment to subatmospheric pressure.

-4-

I I I I I I I I I 1--I I I I I I I I I

II. LOSS OF REACTOR COOLANT FROM SMALL RUPTURED PIPES OR FROM CRACKS IN LARGE PIPES WHICH ACTUATE THE EMERGENCY CORE COOLING SYSTEM

Methods of Analysis

For breaks less than 1 ft 2 the WFLASH10 digital computer code is

employed to calculate the transient depressurization of the reactor.

coolant system, as well as to describe the mass and enthalpy of flow

through the break.

The WFLASH program used in the analysis of the small break loss

of coolant accident is an extension of the FLASH-4 code developed at

the Westinghouse Bettis Atomic Power Laboratory. The WFLASH program

permits a detailed spatial representation of the reactor coolant system.

The reactor coolant system is nodalized into volumes interconnected

by flowpaths. The broken loop is modeled explicitly with the intact

loops lumped into the second loop. The transient behavior of the system

is determined from the governing conservation equations of mass, energy

and momentum applied throughout the system.

The use of WFLASH in the analysis involves, among other things,

the representation of the reactor core as a heated control volume with

the associated bubble rise model to permit a transient mixture height

calculation. The multi-node capability of the program enables an ex

plicit and detailed spatial representation of various system components.

In particular it enables a proper calculation of the behavior of the

loop seal during a loss of coolant transient.

Safety injection flow rate to the reactor coolant system as a

function of the system pressure is used as part of the input. The

-5-


safety injection system was assumed to be delivering borated water to

the reactor coolant system 25 seconds after the generation of a safety

injection signal.

For these analyses, the safety injection delivery considers pumped

injection flow which is depicted in Figure II-1 as a function of reactor

coolant system pressure. This figure represents injection flow from the

safety injection pumps based on performance curves degraded five (5)

per cent from the design head. The twenty-five (25) seconds delay in

cludes time required for the emergency diesel generator to assume its

load. The effect of low head safety injection pump flow is not considered

since their shutoff head is lower than reactor coolant system pressure

during the time portion of the transient considered. Minimum safeguards

emergency core cooling system capability and operability has been assumed

in these analyses.

Peak clad temperature analyses are performed with the LOCTA-IV4 code

which determines the reactor coolant system pressure, fuel rod power

history, steam flow past the uncovered part of the core and mixture

height history.

Results

The results of the limiting break size-are given in Table II-2.

The worst break·size (small break) is a 4 inch diameter break. The

depressurization transient for this break is shown in Figure II-2. The

extent to which the core is uncovered is shown in Figure II-3.

-6-

\


During the earlier part of the small break transient, the effect of

the break flow is not strong enough to overcome the flow maintained by

the reactor coolant pumps through the core as they are coasting down

following reactor trip. Therefore, upward flow through the core is

maintained. The resultant heat transfer cools the fuel rod and clad to

very near the coolant temperatures as long as the core remains covered

by a two phase mixture.

The maximum hot spot clad temperature calculated during the transient

is 1898 degrees Fahrenheit including the effects of fuel densification

as described in Reference. 11. The peak clad temperature transient is

shown in Figure II-4 for the worst break size, i.e., the break with the

highest peak clad temperature. The steam flow rate for the worst break

is shown on Figure II-5. When the mixture level drops below the top of

the core, the steam flow computed in WFLASH provides cooling to the upper

portion of the core. The rod film coefficients for this phase of the

transient are given in Figure II-6. The hot spot fluid temperature for

the worst break is shown in Figure II-7.

The core power (dimensionless) transient following the accident

(r~lative to reactor scram time) is shown in Figure II-8.

The reactor shutdown time (3.4 sec) is equal to the reactor trip

signal time (1.2 sec) plus 2.2 sec for rod insertion. During this rod

insertion period the reactor is conservatively assumed to operate at

rated power.

-7-


Additional Break Sizes

Additional break sizes were also analyzed. Figures ll-9a and ll-9b

present the reactor coolant system pressure transient for the three (3)

inch and six (6) inch breaks, respectively, and Figures 11-lOa and II-lOb

present the volume histroy (mixture height) for both breaks. The peak

clad temperatures for both cases are less than the peak clad temperature

of the four (4) inch break. The peak clad temperatures for both cases

are given in Figures 11-lla and 11-llb.

The time sequence of events for all small breaks analyzed is shown

in Table 11-1 and Table 11-2 presents the assumptions and results for

these analyses.

The results of several sensitivity studies are reported in WCAP-8342. 12

These results are for conditions which are not limiting in nature and

hence, are reported on a generic basis.

-8-

----~---------~----

I I.O I

TABLE II-1

TIME SEQUENCE OF EVENTS FOR SMALL BREAKS

BREAK SIZE (INCHES)

EVENT

.Start of LOCA

Reactor Trip Signal

Top of Core Uncovered

Accumulator Injection Begins

Peak Clad Temperature Occurs

Top of Core Covered

3

TIME AFTER START

0.0

21.2

690

971

992

1011

4 6

OF LOCA (SECONDS)

o.o 0.0

13.4 8.0

333 108

530 265

574 276

853 315

-------------~~----

I ...... 0 I

TABLE II-2

ASSUMPTIONS AND RESULTS FOR SMALL BREAKS

Results

Peak.Clad Temp. (°F)

Peak Clad Location (Ft.)

Local Zr/H2

0 Rxn (max) (%)

Local Zr/H2

0 Location (Ft.)

Total Zr/H20 Rxn (%)

Hot Rod Burst Time (sec)

Hot Rod Burst Location (Ft.)

Calculation

NSSS Power MWt 102% of

Peak Linear Power Kw/ft 102% of

Peaking Factor

Fuel region analyzed (Most Limiting)

Unit No. 1

Unit No. 2

3 IN

1702

11. 0

1.17

11.0

<0.3

N/A

N/A

Region

3

3

4 IN

1898

11.0

1.66

10.5

<0.3

N/A

N/A

2542

14.44

2.32

6 IN

1559

10.5

0.91

10.5

<0.3

N/A

N/A

--- -

\

I I I I

FIGURE II,-1

SAFETY INJECTION FLOWRATE

I 2500

I r,

I 2000 ,_

I -<(

en· 0... - 1500 -

I LI.I 0::: :::::, en en LI.I 0:::

I 0...

en (.)

1000 -

0:::

I 500 -

I I

. -- r 'I I

500 0

0

I II

100 200 300 SI FLOW {LB/SEC)

I

~00

I I I I I I I

,J. .\ 1: ..

I I I I I I

....--

I <t rr., c.. -UJ

I et:: ::::) rr., C1) UJ et:: c..

I rr., (...) a::

1. I I I I I I I I I

FIGURE II-2

RCS DEPRESSURIZATION TRANSIENT (4 inch)

2500

2000

1500

1000

500

0

0 250 500 Tl ME (SECONDS)

-·-···- - ·- -- - . -- - - ·- -- ------ .. _ --- ... -

750 I 000

I I

I


FIGURE II-3

CORE MIXTURE HEIGHT (4 inch)

20

16 i

-f-,-u.. 12 -f-,-::c C!J

LU ::c

LU a:: 8 0 c:...>

0 0 250 500 750

TIM~ (SECONDS)

------------·~- ------ -- .. ~ --··-------------

'

1000

; I


-LL 0 -Cl) UJ IX :::, ..... ~ IX UJ Q. :::E UJ ..... Q ~ ...J (.)

FIGURE II-4

. CLAD TBMPDATUBES TRANSIBliT ( 4 inch)

2000

1500

1000

500

300 ~00 500 600 700. 800 '900

Tl!ME (SECONDS)

' .... llji:., •


-u UJ Cl) -al ....I -UJ I-<( cc:

3 0 ....I LL

::E <( UJ I-Cl)

~00

300

200

I 00

0

-100

-200

-300

-~00 0

FIGURE II-5

STRAM FLOW ( 4 inch)

-·

250 500

TIME (SECONDS)

750 I 000

; • .-- ~.!""-I'~--- -

/

------- .. --·--------·-

-LL. 0

I CN I-LL.

I cc: :c -:::, I-al -I-z: w

.. \ c..:>

I ., .. ·..=.,· . LL.

°' ·- --~

f?.: ,. w

~ ·-· 0 J-:;,- c..:>

.. _ .. X _J

LL.

Q 0 cc:

I 03

8

6

lj.

2

102

8

6- --- I

'

lj.

2

10 1

300 .. ~00 500 600

TIME (SECONDS)

..:~~1L .. r·- -

ROD r)lti!1tmrit~ er,·~~)

800 900

I I I I I I I I

'I I I ·I I I

-1 I I I I

-LL 0 -LU cc: ::,

~ cc: LU ~ ::E: LU I-

C

::, ....J LL

I-0

-~ Cl)

I-0 :c

FIGURE II-7

HOT SPOT FLUID TEMPDATUBE (4 inch)

2000

1500.

1000

500

0 300

' : j .

-- ifoo · · · · ·· --s-oo-··· -· Boo- 100

Tl~E (SECONDS)

--.-· .... - '·- ·-~. -·.

,. r.

___ , __

-------------------

I I-' Q:) I

e::::

I oo 8 6

lj.

2

UJ 10-1 ~ 8 0...

I< II<( 3: -en I-

6

lj.

2

i IO-~ 6

lj.

2 '

tQ-1 2 4- 6 s I o0 2

TOTAL RESIDUAL HEAT (WITH 4-% SHUTDOWN)

4- 6 s to 1 , I

2 4- 6 s 102 2 4- 6 8 I 03

TIME AFTER SHUTDOWN ( SECONDS)

FIGURE II-8

CORE POWER

I I

\ \

I FIGURE II-9a

RCS DEPRESSUJUZATION T&ANSIEBT (3 inch)

I I 2500

I 2000

! I -<(

Cl)

I a.. -L&J 0:::

1500

=> Cl)

I Cl)

L&J 0::: a.. 1000 Cl) (..)

I 0:::

500

I I

0 200 4-00 600 800 1000 1200

I TIME (SECONDS)

I I I I I I -19-

I I I FIGURE 1I-9b

I RCS DEPRESSURIZATION TRANSIENT (6 inch)

I 2500

I I -

2000

<(.

I Cl) c.. - 1500 UJ a:::

I ::::, Cl) Cl) UJ a::: c.. 1000

I Cl)

u a:::

I 500

I ·o - .

I 0 500 600 100 200 300 ~00

TIME (SECONDS)

I I I I I I -20-

--- -~---

' I I I FIGURE II-lOa

I CORE MUTUBE HEIGHT ~3 inch)

I 20

I I

16

I -I-LL 12 -I-

I :c c:,

UJ :c

UJ 8

I 0.::: 0 c..>

I 4-.

I 0

.I 0 200 4-00 600 800 IOOO 1200 TIME (SECONDS)

I I I I I I --21-

I I I FIGURE II-lOb

CORE MIXTURE HEIGHT (6 inch)

I I 1· 16

I -I

I-LL. -I-

12

:::c <:!'

I LU :::c LU

8 0::: 0

I (.)

I I 0

·o .100 200 300 4-00 500 600

I TIME (SECONDS)

I I I I I I -22-


-LL 0 -LJ.J 0:: ::, I-<( 0:: LJ.J 0...

i:fi I-a <( _J (.)

FIGURE II-lla

CLAD TEMPERATURE TRANSIENT (3 inch)

2000

1500

1000

500

600 700 800 900 1000 1100 1200

TIME (SECONDS)

-23-

I I I I I I I I I ·I I I ·1 I I I I I I

u. 0 -w 0:::: => I-< 0:::: w Q.. :::: '

w I-

0 < _J c:..:,

FIGURE II-llb

CLAD TEMPB2ATURE TRANSIENT (6 inch)

2000

1500

1000

500

0 -~· --- .

.. 0 100 200 300 ~00 500 600

TliME (SECONDS)

-24-


III. MAJOR REACTOR COOLANT SYSTEM PIPE RUPTURES (LOSS OF COOLANT ACCIDENT)

Method of Thermal Analysis

The description of the various aspects of the LOCA analysis is

given in WCAP-8339. 2 This document describes the major phenomena modeled,

the interfaces among the computer codes and features of the codes which

maintain compliance with the Acceptance Criteria. The SATAN-IV, WREFLOOD,

COCO, and LOCTA-IV codes used in their analysis are described in detail

in WCAP-8306, 3 WCAP-8171, 5 WCAP-8326 6 and WCAP-83054 , respectively. The

containment parameters used in the containment analysis code to determine

the ECCS backpressure are presented in Table III-3.

Results

Table III-2 presents results for the double ended cold leg break for

three (3) large break sizes (discharge coefficients (CD)). This range of

discharge coefficients was determined to include the limiting case for

peak clad temperature from sensitivity studies reported in WCAP-8356. 7

The analysis of the loss of coolant accident was performed at 102 per

cent of 2542 megawatts thermal. The peak linear power and core power used

in the analyses are given in.Table III-2. The equivalent core peaking

factor at the license application power level (2441 MWth) is also shown

in Table III-2.

The limiting power peaking envelope applicable to this analysis,

along with the actual power peaking values expected during operation of

-25-


each Surry unit, are shown in Figures III-14 and III-15. The actual

power peaking values were determined using the procedures described

in WCAP-8385 9 assuming a +6, -9 per cent delta flux (~I) band. The

limiting envelope was determined on the basis that:

1.

2.

3.

Extensive sensitivity studies presented in WCAP-83567

and WCAP-8472 15 have shown that the cosine is the

worst power shape as long as the change of FQ with

elevation is maintained as shown on Figures III-14

and IIi-15 in the region from 0.0 feet to 11.0 feet.

The computed peak clad temperature does not exceed

2200°F for the case of a cosine power shape with

FQ = 2.10.

The location of the line segment between 11.0 feet

and 12.0 feet is the same as that presented in

WCAP-8356. 7 This line segment was confirmed by the

small break results presented in Section II of this

report.

For results discussed below, the hot spot is defined to be the

location of maximum peak clad temperature. This location is given in

Table III-2 for each of the three (3) discharge coefficients used for

the double-ended break.

The time sequence of events for the three (3) discharge coefficients

used in the large break analysis is shown in Table III-1.

Figures III-1 through III-13 present the transients for the principal

parameters for the double ended cold break for the three (3) discharge

coefficients used. Each of these parameters is enumerated below:

-26-

------

I I

1.

I I I

2.

I I I 3.

I I I

4.

I I 5.

I I I 6.

I I I

Fluid Quality - Figures III-la, band c show the fluid

quality at the clad burst and hot spot locations

(location of maximum clad temperature) on the hottest

fuel rod (hot rod) for the three (3) discharge co-

efficients used.

Mass Velocity - Figures III-2a, band c show the mass

velocity at the clad burst and hot spot locations on

the hottest fuel rod for the three (3) discharge co-

efficients used.

Heat Transfer Coefficient - Figures III-3a, b ~nd c

show the heat transfer coefficient at the clad burst

and hot spot locations on the hottest rod for the

three (3) discharge coefficients used. The heat

transfer coefficient shown was calculated by the LOCTA

IV code.

Core Pressure - Figures III-4a, band c show the cal

culated pressure in_the core for the three (3) dis

charge coefficients used.

Break Flow Rate - Figures III-Sa, band c show the

·calculated flow rate out of the break for the three (3)

discharge coefficients used. The flow rate out the

break is plotted as the sum of both ends for the guillo-

tine break cases.

Core Pressure Drop - Figures III-6a, band c show the

cal~ril~ted core pressure drop for the three (3) dis

charge coefficients used. The core pressure drop

-27-

I '·


7.

shown is from the lower plenum, near the core, to the

upper lenum at the core outlet.

Peak Clad Temperature - Figures III-7a, band c show

the calculated hot spot clad temperature transient and

the clad temperature transient at the burst location for

the three (3) discharge coefficients used.

8. Fluid Temperature - Figures III-Sa, band c show the

calculated fluid temperature for the hot spot and burst

locations for the three (3) discharge coefficients used.

9. Core Flow - Figures III-9a, band c show the calculated

core flow, both top and bottom, for the three (3) dis


10. Reflood Transient - Figures III-lOa, band c show the

calculated reflood transient for the three (3) dis


11. Accumulator Flow - Figures III-lla, band c show the

accumulator flow for the three (3) discharge co

efficients used. The accumulator delivery during blow

down is discarded until the end of bypass is calculated.

Accumulator flow, however, is established in refill re

flood calculations. The accumulator flow assumed is the

sum of that injected in the intact cold legs.

12. Pumped ECCS Flow (Reflood) - Figures III-12a, band c

show the calculated flow of the emergency core cooling

system for the three (3) discharge coefficients used.

-28-


13. Containment Pressure - Figures III-13a, band c show

the calculated pressure transient for the three (3)

discharge coefficients used. These pressure transients

are based on the data given in Table III-3.

The clad temperature analysis is based on a total peaking factor

of 2.10. The hot spot metal reaction reached is 5.6 per cent, which is

will below the embrittlement limit of 17 per cent, as required by 10

CFR 50.46. In addition, the total core metal-water reaction is less

than 0.3 per cent for all breaks as compared with the 1 per cent criterion

of 10 CFR 50.46.

The results of several sensitivity studies are reported in WCAP-8356. 7

These ~esults are for conditions which are not limiting in nature and

hence are reported on a generic basis.

-29-

----~--------------

I w 0 I

TABLE 111-1

TIME SEQUENCE OF EVENTS FOR DOUBLE ENDED COLD LEG GUILLOTINE BREAKS (DECLG)

DISCHARGE COEFFICIENT (CD)

EVENT

Start of LOCA

Reactor Trip Signal

Safety Injection Signal

Accumulator Injection

End of Blowdown

Pump Injection

Bottom of Core Recovery

Accumulator Empty

(GD=l.O) (CD=0.6)

TIME AFTER START OF LOCA

0.0 p.o

0.63 0.65

1.43 1. 78

11.5 14.4

23.9 23.3

26.5 26.8

37.3 36.9

43.4 45.8

(CD=0.4)

(SECONDS)

0.0

0.66

2.2

· 18. 0

30.6

27.2

40.99

: 49. 6

- - - - - - - - - - - - - - - - - - ·-

I (.;.) I-"' I

TABLE III-2

ASSUMPTIONS AND RESULTS FOR DOUBLE ENDED COLD LEG GUILLOTINE BREAKS (DECLG)

Results

Peak Clad Temp. (OF)

Peak Clad Location (Ft.)

Local Zr/H2o Rxn (max) (%)

Local Zr/H2o Location (Ft.)

Total Zr/H2o Rxn (%)

Hot Rod Burst Time (sec)

Hot Rod Burst Location (Ft.)

Assumptions

Power. (MWt) 102% of

Peak Linear Power (Kw/ft) 102% of

Peaking Factor Used

Accumulator Water Volume (Ft3)

Fuel region analyzed (Most Limiting)

Unit No. 1

Unit No. 2

DECLG ( CD= 1. 0)

1986

7.5

3.90

7.5

<0.3

48.2

6.0

Cycle

2

2

DECLG (CD=0.6)

1995

7.00

4.19

7.25

<0.3

32.4

6.00

2542

13.12

2.10

975.0

Region

4

4

DECLG (CD=0.4)

2090

6.75

5.60

7.0

<0.3

27.2

5.75

I I I I I I I I I I I I I I I I I I I ~

TABLE III-3

CONTAINMENT DATA

NET FREE VOLUME

INITIAL CONDITIONS Pressure Temperature RWST Temperature Service Water Temperature Outside Temperature

SPRAY SYSTEM I Number of Pumps Operating Runout Flow Rate (each) Actuation Time

SPRAY SYSTEM II RECIRCULATION SPRAY FROM SUMP

Number of Pumps Operating Runout Flow Rate (each) Actuation Time Heat Exchanger UA (per pump) Service Water Flow (per exchanger)

-32-

1.863 X 106 ft3

9.35 psi 75 40 35.0 9.0

2 3200

20.0

2 3500

125 3.5

6100

OF oF OF OF

gpm secs

gpm secs

x 106 BTU/hr-°F gpm


STRUCTURAL HEAT SINKS

Thickness (In)

Concrete 6.

Concrete 12.

Concrete 18.

Concrete 24.

Concrete 36.

Carbon Steel 0.375 Concrete 54

Carbon Steel a.so Concrete 30.

Concrete 24.

Carbon Steel 0.366

Stainless Steel 0.426

TABLE III-3

CONTAINMENT DATA

Area (Ft 2 ),

-33-

including uncertainty

6972

57,960

40,470

10,500

4410

46,887

25,075

11,284

167,165

3399

I I ·1 ·1 I I I I I I I I I I ·1

I I I I

, .... 18111

1--

-0 •r- . JISOII '.:l

..--LL

4-. C

>. +-' •,-r-/Cl ::I O'

. 2500G

o.,

0 ••

6.oc/

8 8 -

FIGURE III·- la

(J\t lrnllct-;l ru'-'1 rud)

8 8 C\,I

Time (Sec)

8 8 .. ..

I I 'I I I I t ·-

I t.nal

I ··-I ·o ......

~ r--LL

I· 4--0

>, +->

I •.-,--<t.l :::s c::r

I .... I •••

I I .I I I 1·

f.H:UI!E l'Ti-· lh

FL C TD c, !J /o.i, T' 1 'Y ·-· ·--·· -· - ... ~ . - ..... .

(At hottest fll(~l rod)

...... _._.. ........ ~-------+-------+------c---·-+---------11

I-toll-------:-+----------- --·-·-· ·-·------..J....------~ ------~ 6.oo--' y-_ I

~7.00 . ,

t--------+-·---------~- ~- ----·-·-------·--'-·--- ---1--------- .

-------,---+------·------· -----------·-------..--------

•• •-8 8 ....

Time (Sec)

DECLG ( c1r·O. G)

. -35-

8 8 -a i ' I

I I ·1 I .I I I I I -c

.,.-::; r-Li..

I I 4-. C

>, .:-, •,-

I

I r-res ::I er

I I· I I I I I I

, ....

., ... .1'50IO

,,..

...

ff.PJD _quM,I'l'i'

(At hottest fuel rod)

. '

' lt--------+------.._----------t-------l~-----1

. .

..__ _____ . --+-·----···•' --·-----·--····-! -. -·· --·---------t----------+-------t !

' . I . I ! _j_

'-------+-·----. -·-·-1-· -------·· . -------+------1

. I I . •• ~

I Ii ..

L. . I i

Time (Sec)

-36-

I • ' I

I· I I I 1. I (.)

CJ (/)

IN~ 1::: .c ,... ..

I ---~ t·· •r·

(._l

I 0

r-· C..!

> (/)

I (,1

C1J =~

I I I I 1·

I i I I I

nG DO

ICI0,00 ----1~. ---1-----1-----t------

100,DO

D.0

-tao oo

-200,00

-no.oo

----·-······---·- -- -· ...... ----·· . . l-.·--· f

··-----·--- ---··---·-··-·---- ~·-----t

----------·--·--· -·-·-··--···-·- ·-····------- ~----·----·-------t

V 7.50 1

v6.co'

-----------·-- ------- r----·----------------

• • 8 8 ...

Time (Sec)

T' ''('- (' , (' 1 ()) J.L:..,L .. ~·1/"'···.

-37-

8 i

8

' • •

,------

I I I I

I

I. I

I I I I .--..

u (1)

V1

I ~4J ll-......_ s:.-:

15 .--

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I 0 r-Q)

::-=-(()

Vi

I ct)

~

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••••

tcill .•

O.Q

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-mJ.IIO

FTCUHE U l···?h

~1/\.<:s v1,:1,nc1 TY -·-···- - -- --- .. . . ... - -

--------r---------· --·-···-···· ··--·--·--·----=-·--'--·--------.

1-------+---:·-----'-·-------'--~---··--·- - .. --------

.o •

,

8 8 -

1 . I.

----__ -_ . . ----_ ----T--

8 8 "'

Time (Sec)

-38-

8 8 4"'

8 8 •

8 i

I ·-.... I I

) I I I ....

... (.)

><I N

~

I I

til H

H

ol

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(Jc-JS _iJ/W

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ii~~OL

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0, ss-ew

---· --- ---·-· ---- -----

I I 1· I I~, Iii , ;u_

!\.) •. oo i r·J 400.00 I , ... ) 300.011 1'-i-

:.::SI ·.,.,I 1 .. .ais:: 200.00 ,-~

II QJ •,-u

•...-·

I 4- 50000 I;--a.i 40.000 0

u 30.000

. , s. . 20.000 OJ Lr-U)

s:.: <"u

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_/ V

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7.S'

' t=::1::::sc====::t:===-====-::~=---_-...:. .. =-·=---=-=-=-=-=-=-:--=-===t'-:.:.:· ============t============J

0 c:i

8 8 -

8 8 cu

Tirr.e (Sec)

1.wc1.r: cc"=--0 1.0) u

-40--

8 8 ""'

8 8 •

8 8 "'

- I _.,..

I-' I

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ro

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100

00

lD0.

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300.

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500.

00

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C fr·.

·'(b

,u

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111!

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!:!

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I ii. 'II

ill ii i!I

I g,

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11 1

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111r

I

i

I 1

11 i 1

!1 I

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I 11 I

I J

i :

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i ! . I

I .1

1 1 1

I I

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I' I

I I

' l

j l

I

- -· -

-

,,-.

.-

\-:

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-- -.

I I I

I .p s::: (\)

·,-

I I I I I I I I 1·

u

II -· -· .... I -... ·-I ..... .. -,._ ··-

M

• "

I

I -

I •

... , . . ,,·,:·:" (':lEi,-FIClF:~T lli ,\'l~ _l:_1'.'.·11·,,,_, t_ " ... ~-- ----·· . - ·-.

( ,\ L I H, l l , , , , l I t11. • I

--'

' l

b, 75' I

-- ~ /V

V .AL_

-- --6.7.s, ~ ----~

llttM

8 8 I • i i I i

Time (Sec)

·1i1·r·i (' (r, c.,(). L:) , ....... , l ' !J

-42-

I I I I FIGURE III-4a

I CORE PRESSURE

I I 25

I 2000

-I

<( - 1500 Cl)

0... ·-UJ

I c,::

. :::, Cl) 1000 Cl) UJ c,:: 0...

I 500

I I 0 5 10 15 20 25

TIME {SECONDS)

1· I DF.CLG (~•LO)

I ·1 ------------.L.-.------

I I -43-

--- --- -

~---

I I I I

FIGURE 1II-4b

I CORE PRESSURE

I I 2500

I 2000

I ......... < Cl) Ii.

1500

I -LU c:::: =::, . Cl)

1000

I Cl) LU c:::: Ii.

I 500,

I (}·

0 5 10 15 20 25

1· TI ME (SECONDS)

·1 I DECLG (CDa0.6)

I I I -44-

I I I I

FIGURE III-4c

I, CORE PRESSURE

I I

2500

I 2000

I -<(

1500 rr., a..

I LJ.J cc: :::, rr.,

1000 rr.,

I LJ.J cc: a..

I 500

I 0 -

I' 0 10 20 30 ~o TIME (SECONDS)

'I I DECLG (CD•0.4)

I I I -45..'.,

I I I I I I I I I I' I I I -, 'I I I I I

FIGURE III-Sa

BREAK FLOW RATE

1--,-,------_;_ __ ....;._ __ ~

r-

u 5 UJ Cl) -::E: ~ ij

5 10 15 20 25 TIME (SECONDS)

DECLG (~ml.O)

..;.46-

I I I I FIGURE III-Sb

I BREAK FLOW RATE

I 7 -

I 6

I, - 5 ::t" 0 -

I -u 4, UJ (/) -:=:: al

I ....J 3 -3: 0 ....J

I u,. 2 :=.::: <t UJ 0::: al

I 0

I 0- 5 10 15 20 25

I TIME. ( SECONDS)

'I I

DECLG (~•0.6)

I I I -47-

:I

I I I FIGURE III-Sc

I BREAK FLCN BATE

I 7

I 6

I <:j-

0

5 -(.)

I I.LI en -::E:

~ a:i ....J

I -3 0 ....J

3 LL

I ::..::: <( I.LI 0::: a:i

2

I .I

01

I .. 20 30 ~o 0 10

TIME (SECONDS)

I I DECLG (CD•0.4)

I I I

-48-

I I I I I I I I -

en c... -

I c... 0 a::: Cl

a::: c...

I UJ a::: 0 u

I I I I I I I I I

· FIGURE 111-6&

CORE PRESSURE DROP

50 -..---------------------

25

0

-25

-50

-75 · 0 5 10 15 20 25

TIME (SECONDS)

-49'-


-en c... -c... 0 0:: Cl

0:: c... UJ 0:: 0 u

0 5

FIGURE III-6b

CORE PRESSURE DROP

10 15

TIME (SECONDS)

DECLG (C -0.6) D

-50-

' - - ..... ; .

20 25

----- l ·1 I I I

FIGURE III-6c

I CORE PRESSURE DROP

I I 50

I I - 25

Cl)

0.. -~1 0..

0 0 0::: Cl

0::: 0..

I UJ 0::: 0 -25 (.)

I I

-50

0 10 20 30 lJO

TIME (SECONDS)

I I I

DECLG (~ca0.4)

I I I -51-

~---

I I I I I L-

I G)

'-· :::;

rv ;._ 1 · ~-E OJ f-

"CJ

I C

c-::

+-' ()

:!.::

I c .. r:: OJ

f--

OJ

I > < v ro .--

I L)

I I I I I I I I

DOD

2500.0

2000 0

tSOO.O

t000.08

500.00

o.a

0 0

8 8 -

Fl !.·::J::1: i l i- 7:.1

---·-------- --- - r-·- . i '

-Time (Sec)

DECLG (C ,0 J .O) D

-52-

-- ·-···---· -··~. --- --·--·- .... - . --·- --- --

8 8 ""

8 8 ..

8 8 "'

----

--

I Vl

w

I

-l

(./)

(1)

()

- o.o

HJ(

) 00

200

00

. 300

.00

-00

00

----

--.. ·

----

-!

,, ,:

)

', I

~

~ i

LJI

8 I?:

.... •

0 8

c,

0 C

) r:

, 0

0 ...

... c·

» ''"

..,, '"

i \

··--

··-

··--·

I I.

'"d

.t

~ >

rj

("')

H

~ (;

') ~ l:rj

t-3

~ H

H

H

§ I .....

.. o

'

! i ~

I l:

rj

I

i !

! .

·---· __

_j_

_, _

__

_

-+--

------

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------·-

-..

.J-.

__

__

__

..

' !

----

---

-

I lsl

.i,- 1

0

+,

Vl

rD

()

...

. .....

.... -·· .... -·

-· --

f"''

l,

1, ad

[\

'J.:~

T(

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I I

er, .. ~ ...

---

f·lc

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d I c

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re

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f_J.

E· Q! t-

I -u ...... :::; ,... ..

I.I ..

I I I I I I I I I I

JOOQ D

2500.0

t500.I

tCIDO,Ot

500.oe

D.I

-- J _____ _ . ··+· ..... - -·-··- -·-··--·-------- t---------·- -·· ---·· ... ----· -·-·····-·------/ 1

----l---- I

• • 8

!

· Time (Sec)

I , LC:1 C ( C . 0~ L O) . ll

-55-

8

i

.....

8 8 •

8 I

I I I I I I

LL. 0 ,. ...._.,,

c., s.~ ::J

. +.1 <O

I s.. C.' r:: .. f.: 11) f-

I ·o •r-· ::; r-LL

I I I I I

, .

I !

I I I I

311111 a

2SIIO.O

tsaa.a

SOD.GI

...

Fl\ll'l 'li'li'FP~T(JF'' ··-- ~ '. I • • . ,'" ·; - -~ ·! :_ ---· . ...l.:

f .. I ~~-c~= ..

------1-' ·- _ _j_ ____ --- -.. -----· -+-------t I ' I 1

i

l I ; I

---------'· ----·---- ;-------·-•-.. --- .. ----+-------··-----_ ----+------I I , I I

-?,00 I

' ~-~~ ..... ~..._---fl-- 6.oo--'-.--

0 • 8 8. ...

.. _~

8

i

Time (Sec)

-56-

8 8 •

8 i


~.o LL 0

' "-'

CJ $.... :'5 -.0

+J re >-C..1 D.. E: (lJ

I-

-0 •;--

:..::; ,. -l! •. -··

-·· ...

• "

8 i

FTCLKE l n--8c

r

Time (Sec)

-57-

8 i

i 5,75

I I • I

I I I I FIGURE II1-9a

I CORE FLOW - TOP AND BOTTOM

I 7500·

I 5000

I 2500 -(..) I LU

Cl) -::::E al

0 ....J

I -3: 0 ....J u. -2500

BOTTOM

I LU 0::: 0 (..) -5000

I -7500 -

I -10000

I 5 25 0> 10 15

TIME (SECONDS) 20

I I

DECLG (~•1.0)

I I

•• ~.-=. ...

I -58-

I I I I FIGURE III-9b

I CORE FLOW - TOP AND BOTT~

I 75

I .......... 50

N

I 0 ..... ..__. -u

LU 25

I en -::E: IJl .....J -

I 3: 0 .....J LL

0

LU 0::

I 0 u

-25

I -50

I -75 0 5 10 . 15 20 25

I TIME (SECONDS)

I I I I I -59-

-- - - -

I I I FIGURE III-9c

I CORE FLOW - TOP AND BOTTOM

I 7500

I 5000

I I

2500

-(..) I

UJ Cl) -::E CD

0 _J -

I 3: 0 _J

u... :-2500 UJ

I a::: 0 (..)

I -5000

I -7500 I

I -10000

I· 0 10 20

TIME (SECONDS)

30

·1 I I I

I I I I I

··- t'0.000

·I l WiC 17 ~00

I 3.0GOO 15 000

I r.sa ~ 12.:;oo

!5 u

I > ....

2.0000 ID 000

I t 5000 7 5000

I 1 0000 5.0000

I :,uc::J 2.5000

I 0 C o.o

I I I I I I

.r r I- l Oa

-----. -----------·---+·- ...... ·---·-·. ·-· "-·· ""l" ---- ---- .. ···--··-+-----····-··

i ! Do wNc.o~EK.. Le. VEL ' ··-------+-···------,-f-------+--:---~,;.__--,-1

........................ ~- ·-·- .............. _. _________ J ________ i--------1

I I -·---- --· ·--·-- - •. i I ! . t··"" ····-·· - ---- ._... . .. ..... +·· .. _ .... -----·--·· ·-· -i _ .. -------------

1 I

l i ... ----····1 ·--·· .... - ... j

-+ i --- , ....... -· - ............. i" !

i

! . ..• :... .. _____ ........ j ......... --------·--+-------.1

I ae.u LeveL ... ... .. J_ ·:=:=:::::_ -·==t--'==1

>---- I __ ,I.-' ---- , ... --~- ....... ·i--------·----+-------~ - I ,,....-- . . :.. I ~ ' ... . --~ r ----- --!- --:r,vdi-

1 VEU)e;,n·TV~· -.;;,=:;::=::;.::==j

1 j --~ -----

g r., <:>

<:) c, g ci 0

"'

Time (Sec)

-61-

C 0

g ...

·•"

8 8 •

I. i

I I I I I ,.ooao lO 000

I 3 5000 17 ~

I 3 OOJO 15 000

I 0

? 5000 .._ !2 soa

~ l . .i

-"' .....

I ? 0000 10 CCC

I . 5000 ''jOQO •

1 0000 5 0000

I 50000 ~ -5000

I o.o 0.0

I I I I I I I

V r ("lif! E IT I - l!)h

- -. -·

~~=-1=~----r--'.'-

j ~-----------+ Do~~ ~-~ LeieL --- .... ---- ......... --+---------------

' i

! f

--·-·;·-. ---- -- . --\ --- J ; ----------- r·------t-----_J

·--···--···--)----------+---_J I

, --- . ____ C.QKk / .. £.\JEL --rL_--·-::-::::·-:.::···.:;::'--=--t--====::j

·-------. ---- .... ~:-;". . -- -- ··----------- -t-··--------------1 -r-----_J tNL..E.T

------Ln·---; -' -- ~ ---·-t----1 ' l I I -

'

0 c-:, 0 0

·::l ,:_-, 0

-:., CJ C) '\·

Time (Sec)

DECLG ( Crt·O . r,)

-62.-

0 0

8 .., 8 g ,,,

8

i


z ;

··-3.5000

3.0000

Q Z.5000 ....

u ... 2 0000

,. 5000

1 onoo

. 50000

o.o

20 OOll

17 ~

15.000

tl'SOO

to.ooo

7.5000

5.onoo

l.5000

•••

• ci

FIGTHrn lJI--10c

Time (Sec)

DECLG (C ,·(). l1) . l)

-63-

DOWN<>( fYIER Lt\JE.L

8

! 8 I


~~~-~----

7000 -

6000

5000 -(..) UJ Cl) lJOOO -:::E in -' - 3000 3: 0 -' LL

2000

IOOO

FIGURE IIl-lla

ACCUMULATOR FLOW (ILOWOOWN)

5 I (j 15

TIME (SECONDS)

DECLG (~11:11.0)

-64-

20 25

(SONO:l3S) ll~ll

9l Ol 91 . 01 9

I.

0 ----0

0001

OOOl

000€

oooti

I ooog.

0009

-OOOL

"T1 r 0 :::e:

-r gJ

3:

-en IT1 (")

-


----

---

----

---

' i i I I '

li i: ll t' r! !l ii fl II '

·rt-

' i

FLOW

(LB

M/S

EC)

;~

1 I

1· i

o I

s:

-----

:---

----

--::

,---

--,-

,--"

'T""

'I'-

.;._

__

.. · .... --·--·

···----

--..-

----

-....

...1

I ,

• .

.,,..,

O: i '

~ ~ .....

~ __ .

..... __

____

...,. ___

____

____

___ ....

..,. __

_. ~

--

--

---

·---

--

-·-

--

--

--··

-

.

~·' T'

, "

r-j '"

' I ! R

,.. ~ . I

, \

I) r

'

!1. Q

--f'

'

1 .L

i:. !

::i '-

1\;1

.,.

"ct 1

'~uN

,.ucR

i-"

.,.!-J

"-

·I I I 1 . . J


FIGURE ITT-12a

PlJHPED ECCS FLO\~ - (REFLOOD)_

-67-


<..) LJ..I Cl) --"'t L~)~J;;~~~;

FIGURE III-12h

I

i, .

.JI

DECLG (CD"'0.6)

-68-


~-

<...) w C/) -M f-LL ..__

3': 0 _J

ll.

FIGURE III-12c

~,1t;+~tlj1~~~~1•~~~=iJ••,.~fi!~;is;~~ ···r 0···~1 ·*' ··· '[;-' I "'''\.="'j' .,,,,,y•· I

,,~0c,I. ·· · ···r, lr,·E,~·,·~ ,~- · i'iiCf -+· ·· I ·£ · 1'· · · · ·· ·. ·•

=····· ..... j .1.+1±1 Jf l-' "1···''·1~~~~1 +' .

·:_~JJ~4~lr[~~ff 4'.f~~\,Y~~: .. ~~~~f8 ··'"·~•L. ,.·. ·' +•·,, , ... , ..... '··t'M( (SEC)·•"""· l+··1 ~1 ~ . I ~~s-: ~~L.!~~ 1:~:-r=·T~:r.-:-~-l-::-::~ J :-.~---,-- :,-:)f~)~l:~~,:~~~ ::\r-~~n:;:~ ·:_::}~~-:: :=~~--~-·

DECLG (Cn"'0.4)

-69-

I I I

FlGUH.E lll-13a

I CONTA INW.C:NT PRESSURE ---- - - --·--------- -------·---

I I I j

0.. ..........

I Q) ~ ~ V)

t·1 (l)

I ~-

CL

I I I I I I ---

I I J

I -70-

J

I I I FH;Ulrn 111-Uh

I CO!\TAINMENT PRESSURE

I,

I I ct

•r-u,

CL .........

I Cl) s... ::l u, u, Cl)

I .S... CL

I I I I I I

. ---A_

I DECLG (Cn""0.6)

I I I ~

------

I I I

FICURE ll] -1 Jc

CON'l.'A rNNENT ]'lrn::smrn -------·-·-------~---- -·- ··--------

I I I I &:

•r-(./') • -· 1- •

0.. ...._~

I ClJ !... ::i (./') (./')

ClJ !...

I CL

I I I I I Time (Sec)

I -J\--

DECLG (C0==0.4)

I I I -72- ,

I

I I I I I I I I I I I ;-._

N -..J

O'

I ~

I I I I I I I

2.4

2.2

2.0

1. 8

1.6

1.4

1. 2

1.0

0.8

0.6

0.4

0.2

0.0

FIGURE III-14

SURRY 1, CYCLE 2 MAXIMUM PEAK.ING FACTOR vs AXIAL CORE HEIGHT

(+6, -9% Delta Flux Band)

::: : ': '. '. ::::::::;:!I !\J.' '. 111 :11J1·f H1J tli-L;\: rJt tlUT::lL11 iJ;-: ~:i;_1r:; __ lln !!.U. :;u ii~'. :: 1

: :··· c:..:_;_:_/---'...:..'..>-'-....;.:.'·-· i,•, -1·-···· ., i+111 r-,,,1+!1 --,--11--, rl:-t +l+W-1---ti11n1-1,:-r 1-:1---+:-r,+11-·-,'1-'·--d. !, ..• : - : 1 : ·:: i,: - , . , - .1,; L

1-J ,- I;!. 1 I 1J :1 t.i" 1-JrJ: _l:H_E- -1+1:1- Jffi':--'fH-H 1-1-1-1.:1 +-H, 1-1-+1 1 11-1- --,· u-11-H ,.1n '-+111- -1-1-1+ +,+• .. ·",

;lc\l .. , 1 ,1,! 1:1: ,

111 , , __ •• 1\-+J-'"-i',j·:ffi \+.J:l lt+H--f 1--t+!_! +j-r'.,:±:'.""t:\. •J··ti: ___ ._,·c+.t-~IJ41_]J"t'~-+T'Y~-:t_r:rJ·::·:.::;

:·! t •• , , :- i- . ; • i 1., i ., L i !-: k --,- 1.t..:L .... -·- J_,_~ ! ...1 _j_ 1i:t:11, _j r. -l -r..t t-t.., .. 1...!--+--J.I -1 .. ; .• _ .. rr. _, 1=-t r:1Jt ·-,·

0 2 4 6 8 10 12

CORE HEIGHT, ft.

-73-

I I I I I I I I I I

,....._ N 1:0

I I I I .I I I I

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

;;.11

FIGURE III-15

SURRY 2, CYCLE 2 MAXIMUM PEAKING FACTOR vs AXIAL CORE HEIGHT

(+6, -9% Delta Flux Band)

•11 i1: ,, ' 1i'- l!.1 1 11,1.·1. !I,!! ! l,r 11 1.1-,.1_11111-1-1- :t·-1+-- - 1-H + I -ill-+ -ij·-~-j+H-~lt-f: + -0 +1+ --1+~-.-rL_ •:t"·+ : __ i:_·,. 1,i._1'._ -!_::_·-.:_! .' .• !•.'.' _1 __ .1 .. · , -lj-1-- 11 -iT;.,:1Tl p: -,, _q:1_-1: 1:+:1:lit ++:H:t ·:rj.t!t .. ,:·1_::J=:[i.:LTJ

ill'···: ,. :.:., j;, -f-r-1--H-t i, fJ -r!--l--r1-Jlr-·· r-H~+f--/-!-,gi -rr~--h+--!-l--+ 13~--- :_::, :, :_]-:_--:.~,-----!_-_:_--~,--:. ~-·-_:,·. +--i-:..-:·-1-i~ii ~. / l ii:; j I iii-I ii =--IH-ll=\-"-1 - -lt ·:t+1,Hl 1+-. -tf:!1 :\ =i':: :l \:ttl·\+l-::·! t!j.· \±1-l:hlt lj:: . : , , : ; : :_ ~~ :::: .. ,_, -t: , 1 , : ; :±r tr --:1tttl:tt -· .tr·- - 1: :1:;. 11- :r: I · i i"t-F ~I :t :j~/:Ji::1~1:t-: · 1Ji.r. L--.r:rh:H- ~i "

0 2 4 6 8 10

CORE HEIGHT, ft.

-74-


IV. CONCLUSIONS

For breaks up to and in~luding the double ended severance of a

reactor coolant pipe, the emergency core cooling system meets the

Acceptance Criteria as presented in 10 CFR 50.46. Specifically,

1.

2.

3.

4.

s.

Peak ·Cladding Temperature

The calculated peak fuel element clad temperature

provides margin to the requQrement of 2200 degrees F. l

Cladding Oxidation

The clad temperature transient is terminated at a time

when the core geometry is still amenable to cooling.

The cladding oxidation limits of 17 per cent are not

exceeded during or after quenching.

Hydrogen Generation

The amount of fuel element cladding that reacts

chemically with water or steam does not exceed 1 per

cent of the total amount of Zircaloy in the reactor.

Coolable Geometry

The core remains amenable to cooling during and after

the break.

Long-term Cooling

The core temperature is reduced and decay heat is re

moved for an extended period of time, as required by

the long-lived radioactivity remaining in the core

by the safety injection system.

-76-

I I I I' I I I I

·1 I I I I I ·I I

I

V. REFERENCES

1. "Acceptance Criteria for Emergency Core Cooling Systems for Light Water Cooled Nuclear Power Reactors" 10 CFR 50.46 and Appendix K of 10 CFR 50. Federal Register, Volume 39, Number 3 January 4, 1974.

2. "Westinghouse ECCS Evaluation Model-Summary" WCAP-8339, Bordelon, F.M., Massie, H.W., and Zordan, T.A., July 1974.

3. Bordelon, F.M., et al., "SATAN-IV Program: Comprehensive Space-Time Department Analysis of Loss-of-Coolant," WCAP-8306, June 1974.

4. Bordelon, F.M., et al., "LOCTA-IV Program: Loss-of-Coolant Transient Analysis," WCAP-8305, June 1974.

5. Kelly, R.D., et al., "Calculational Model for Core Reflooding after a Loss-of-Coolant Accident (WREFLOOD Code)," WCAP-8171, June 1974.

6. Bordelon, F.~. and Murphy, E.T., "Containment Pressure Analysis Code (COCO)," WCAP-8326, June 1974.

7. Buterbaugh, T.L., Johnson, W.J. and Kopelic, S.D., "Westinghouse ECCSPlant Sensitivity Studies," WCAP-8356, July 1974.

8. Federal Register, "Supplement to the Status Report by the Directorate of Licensing in the matter of Westinghouse Electric Company ECCS Evaluation Model Conformance to 10 CFR 50, 'Appendix K, 111 ,November 1974.

9. Morita, T., et al., "Power Distribution Control and Load Following Procedures," WCAP-8385, September 1974.

10. Esposito, V.J., et al., "WFLASH-Computer Program for Simulation of Transients in a Multi-Loop PWR," WCAP-8261, July 1974.

11. WCAP-8219, "Fuel Densification Experimental Results and Model for Reactor Applications, ,i October 1973.

12. WCAP-8342, "Westinghouse Emergency Core Cooling System Evaluation Model-Sensitivity Studies," July 1974.

13. Bordelon, F .M., et al., "Westinghouse ECCS Evaluation ModelSupplemental Information," WCAP-8472, April 1975.

14. Letter from D.B. Vassallo of the Nuclear Regulatory Commission to C. Eicheldinger of Westinghouse Electric Corporation dated May 30, 1975.

15. WCAP-8472, "Westinghouse ECCS Evaluation Model, Supplementary Information."

-77-

I I I I I I ·1 I I 'I I 'I I I I ·1 I 'I I

VI. PROPOSED CHANGES TO THE TECHNICAL SPECIFICATIONS

The proposed Technical Specification changes contained herein

are designated as Change No. 29. The proposed changes are denoted by

a heavy black line in the righthand margin. The operation of Unit Nos.

1 and 2, Surry Power Station, in accordance with these specifications

will assure the validity of the ECCS analysis presented herein.

-78-

I I I I I I I 1· I I I 'I I I I I ·1 I ·1

L.

TS 1.0-7

Low Power Physics Tests

Low power physics tests are tests conducted below 5% of rated power

which measure fundamental characteristics of the reactor core and

related instrumentation.

(Deleted)

CHANGE NO. 29

I I I I I I I ·I I I I I I I I I ·1 ·1 I

TS 3.3-1

3.3 SAFETY INJECTION SYSTEM

Applicability

Applies to the operating status of the Safety Injection System.

Objective

To define those limiting conditions for operation that are necessary to

provide sufficient borated cooling water to remove decay heat from the

core in emergency situations.

Specifications

A. A reactor shall not be made critical unless the following conditions

are met:

1.

2.

3.

The refueling water tank contains not less than 350,000 gal. of

borated water with a boron concentration of at least 2000 ppm.

Each accumulator system is pressurized to at least 600 psig and

contains a minimum of 975 ft 3 and a maximum of 989 ft 3 of

borated water with a boron concentration of at least 1950 ppm.

The boron injection tank and isolated portions of the inlet and outlet

piping contains no less than 900 gallons of water with a boron con

centration equivalent to at least 11.5% to 13% weight boric acid solution

CHANGE NO I 29

I I I I I I I I I I I I I I I I I I 1

3.12 CONTROL ROD ASSEMBLIES AND POWER DISTRIBUTION LIMITS

TS 3.12-1 12-27-74

Applicability

Applies to the operation of the control rod assemblies and power distribution

limits.

Objective

To ensure core subcriticality after a .reactor trip, a limit on potential re

activity insertions from hypothetical control rod assembly ejection, and an

acceptable core power distribution during power operation.

Specification

A. Control Bank Insertion Limits

1. Whenever the reactor is critical, except for physics tests and

control rod assembly exercises, the shutdown control rods shall

2.

be fully withdrawn.

Whenever the reactor is critical, except for physics tests and

control rod assembly exercises, the full length control rod

banks shall be inserted no further than the appropriate limit

determined by core burnup shown on TS Figures 3.12-lA, 3.12-lB,

3.12-2, or 3.12-3 for three-loop operation and TS Figures 3.12-4A,

3.12-4B, 3.12-5, or 3.12-6 for two-loop operation.

CHANGE NOO 29

I I I I I I I I ·1 I I I I I I I I I I

3.

TS 3.12-2 12-27-74

The limits shown on TS Figures 3.12-lA through 3.12:-6 may be

revised on the basis of physics calculations and physics data

obtained during unit startup and subsequent operation, in

accordance with the following:

a,

b.

c.

The sequence of withdrawal of the controlling banks, when

going from zero to 100% power, is A, B, C, D.

An overlap of control banks, consistent with physics

calculations and physics data obtained during unit

startup and subsequent operation, will be permitted.

The shutdown margin with allowance for a stuck control rod

assembly shall exceed the applicable value shown on TS

Figure 3.12-7 under all steady-state operation conditions,

except for physics tests, from zero to full power, including

effects of axial power distribution. The shutdown margin

as used here is defined as the amount by which the reactor

core would be subcritical at hot shutdown conditions

(T >547°F) if all control rod assemblies were tripped, avg - .

assuming that the highest worth control rod. assembly re-

mained fully withdrawn, and assuming no changes in xenon,

boron, or part-length rod position.

CHANGE NO. 29

I I I I I I I

I I I I I I I I I I

4.

5.

6.

TS 3.12-3

Whenever the reactor is subcritical, except for physics tests,

the critical rod position, i.e., the rod position at which

criticality would be achieved if the control rod assemblies were

withdrawn in normal sequence with no other reactivity changes,

shall not be lower than the insertion limit for zero power.

Operation with part length rods shall be restricted such that

except during physics tests, the part length rod banks are with

drawn from the core at all times.

Insertion limits do not apply during physics tests or during

periodic exercise of individual rods. However, the shutdown

margin indicated· in TS Figure 3.12-7 must be maintained except

for the low power physics test to measure control rod worth and

shutdown margin. For this test the reactor may be critical with

all but one full length control rod, expected to have the highest

worth, inserted and part length rods fully withdrawn.

B. Power Distribution .Limits

1. At all times except during physics tests, the hot channel factors

defined in the basis must meet the following limits:

F (Z) < (2.10/P) x K(Z) for P > .5 Q

FQ(Z) < (4.20) x K(Z) for P < .5

F~H :5._ 1.55 (1 + 0.2(1 - P))

CHANGE NO. 29

I I I I I I I I I

I I I I I I I I I

2.

TS 3.12-4

where Pis the fraction of rated power at which the core is operating,

K(Z) is the function given in Figure 3.12-8, and Z is the core

height location of FQ.

Prior to exceeding 75% power following each core loading, and

during each effective full power month of operation thereafter,

power distribution maps using the movable detector system, shall

be made to confirm that the hot channel factor limits of this

specification are satisfied. For the purpose of this confirmation:

a.

b.

The measurement of total peaking factor, F~eas, shall be

increased by three percent to account for manufacturing

tolerances and further increased by five percent to account

for measurement error.

N The measurement of enthalpy rise hot channel factor, FliH'

shall be increased by four percent to account for measure-

ment error.

If either measured hot channel factor exceeds its limit specified

under 3.12.B.1, the reactor power and high neutron flux trip set

point shall be reduced until the limits under 3.12.B.1 are met.

If the hot channel factors cannot be brought to within the limits

FQ 2_ 2.10 x K(Z) and F~H ~ 1.55 within 24 hours, the overpower LiT

and overtemperature LiT trip setpoints shall be similarly reduced.

CHANGE NO. 29

I I I I I

II

I I I I I I I I I I I I I

3.

4.

TS 3.12-5

The reference equilibrium indicated axial flux difference (called

the target flux difference) at a given power level P0

, is that

indicated axial flux difference with the core in equilibrium

xenon conditions (small or no oscillation) and the control rods

more than 190 steps withdrawn. The target flux difference at

any other power level, P, is equal to the target value of P

multiplied by the ratio, P/P0 • The target flux difference shall

be measured at least once per equivalent full power quarter.

The target flux difference must be updated during each effective

full power month of operation either by actual measurement, or by

linear interpolation using the most recent value and the value

predicted for the end of the cycle life.

Except during physics tests, during excore detector calibration

and except as modified by 3.12.B.4.a., b., or c. below, the

indicated axial flux difference shall be maintained within a

+6 to -9% band about the target flux difference (defines the

target band on axial flux difference).

a. At a power level greater than 90 percent of rated power,

if the indicated axial flux difference deviates from its

target band, the flux difference shall be returned to the

target band, or the reactor power shall immediately be

reduced to a level no greater than 90 percent of rated

power.

CHANGE NO. 29

i


b.

TS 3.12-6

At a power level no greater than 90 percent of rated power,

(1) The indicated axial flux difference may deviate from

its +6 to -9% target hand for a maximum of one hour

(cumulative) in any 24 hour period provided the flux

difference does not exceed an envelope bounded by -18

percent and +11.5 percent at 90% power. For every 4

percent below 90% power, the permissible positive flux

difference boundary is extended by 1 percent. For every

5 percent below 90% power, the permissible negative flux

difference boundary is extended by 2 percent.

(2) If 3.i2.B.4.b. (1) is violated then the reactor power

shall be reduced to no greater than 50% power and the

high neutron flux setpoint shall be reduced to no

greater than 55% power.

(3) A power increase to a level greater than 90 percent

of rated power is contingent upon the indicated axial

flux difference being within its target band.

c. At a power level no greater than 50 percent of rated power,

(1) The indicated axial flux difference may deviate from

its target band.

CHANGE .NO. 20

I I I I I I I I I I I I I I I

I I I

5.

TS 3.12-7.

(2) A power increase to a level greater than .50 percent

of rated power is contingent upon the indicated axial

flux difference not being outside its target band for

more than two hours (cumulative) out of the preceding

24 hour period. One half of the time the indicated

axial flux difference is out of its target band up to

50 percent of rated power is to be counted as con

tributed to the one hour cumulative maximum the flux

difference maximum deviate from its target band at a

power level less than or equal 90 percent of rated

power.

Alarms shall normally be used to indicate the deviations from the

axial flux difference requirements in 3.12.B.4.a and the flux

difference time limits in 3.12.B.4.b. If the alarms are out of

service temporarily, the axial flux difference shall be logged,

and conformance to the limits assessed, every hour for the first

24 hours, and half-hourly thereafter.

The allowable quadrant to average power tilt is

T = 2.0 + 50 (1.435/F - 1) < 10% xy

where F is 1.435, or the value of the unrodded horizontal plane xy

peaking factor appropriate to FQ as determined by a movable incore

detector map taken on at least a monthly basis; and Tis the per

centage operating quadrant tilt limit, having a value of 2% if

F is 1.435 or a value up to 10% if the option to measured F xy xy

is in effect.

CHANGE NO .. 29


6.

7.

TS 3.12-8

If the quadrant to average power tilt exceeds a value T% as

selected in 3.12.B.5, except for physics and rod exercise

testing, then:

a.

b.

c.

The hot channel factors shall be determined within 2 hours

and the power level adjusted to meet the specification of

3. 12. B. 1, or

If the hot channel factors are not determined within two

hours, the power and high neutron flux trip setpoint shall

be reduced from rated power, 2% for each percent of quadrant

tilt.

If the quadrant to average power tilt exceeds ±_10% except

for physics tests, the power level and high neutron flux

trip setpoint will be reduced from rated power, 2% for each

percent of quadrant tilt.

If after a further period of 24 hours, the power tilt in 3.12.B.6

above is not corrected to less than +T%:

a. If design hot channel factors for rated power are not

exceeded, an evaluation as to the cause of the discrepancy

shall be made and reported as an abnormal occurrence to the

Nuclear Regulatory Commission.

CHANGE NO. 29

L


,d,

C.

b.

c.

TS 3.12-9

If the design hot channel factors for rated power are exceeded

and the power is greater than 10%, the Nuclear Regulatory

Commission shall be notified and the nuclear overpower, over

power ~T and overtemperature ~T trips shall be reduced one

percent for each percent the hot channel factor exceeds the

rated power design values.

If the hot channel factors are not determined the Nuclear

Regulatory Commission shall be notified and the overpower ~T

and overtemperature ~T trip settings shall be reduced by the

equivalent of 2% power for every 1% quadrant to average power

tilt.

Inoperable Control Rods

1.

2.

3.

A control rod assembly shall be considered inoperable if the

assembly cannot be moved by the drive mechanism, or the assembly

remains misaligned from its bank by more than 15 inches. A full

length control rod shall be considered inoperable if its rod drop

time is greater than 1.8 seconds to dashpot entry.

No more than one inoperable control rod assembly shall be permitted

when the reactor is critical.

If more than one control rod assembly in a given bank is out of

service because of a single failure external to the individual rod

CHANGE NO. ,, ('I L .J

I I I I I 1·

I I I I I I I I I I I I I

4.

5.

6.

7.

TS 3.12-10

drive mechanisms, i.e. programming circuitry, the provisions of

3.12.C.l and 3.12.C.2 shall not apply and the reactor may remain

critical for a period not to exceed two hours provided immediate

attention is directed toward making the necessary repairs. In the

event the affected assemblies cannot be returned to service within

this specified period the reactor will be brought to hot shutdown

conditions.

The provisions of 3.12.C.l and 3.12.C.2 shall not apply during

physics test in which the assemblies are intentionally misaligned.

If an inoperable full-length rod is located below the 200 step

level and is capable of being tripped, or if the full-length rod

is located below the 30 step level whether or not it is capable

of being tripped, then the insertion limits in TS Figure 3.12-2

apply.

If an inoperable full-length rod cannot be located, or if the in

operable full-length rod is located above the 30 step level and

cannot be tripped, then the insertion limits in TS Figure 3.12-3

apply.

No ·insertion limit changes are required by an inoperable part

length rod.

CHANGE NO. 29


D.

8.

TS 3 .12-11

If a full-length rod becomes inoperable and reactor operation is

continued the potential ejected rod worth and associated transient

power distribution peaking factors shall be determined by analysis

within 30 days. The analysis shall include due allowance for non

uniform fuel depletion in the neighborhood of the inoperable rod.

If the analysis results in a more limiting hypothetical transient

than the cases reported in the safety analysis, the unit power

level shall be reduced to an analytically determined part power

level which is consistent with the safety analysis.

If the reactor is operating above 75% of rated power with one excore

nuclear channel out of service, the core quadrant power balance shall

be determined.

1.

2.

Once per day, and

After a change in power level greater than 10% or more than 30

inches of control rod motion.

The core quadrant power balance shall be determined by one of the

following methods:

1. Movable detectors (at least two per quadrant)

2. Core exit thermocouples (at least four per quadrant).

CHANGE NO ?.9


E.

F.

TS 3.12-12

Inoperable Rod Position Indicator Channels

1.

2.

If a rod position indicator channel is out of service then:

a.

b.

For operation between 50% and 100% of rated power, the position

of the RCC shall be checked indirectly by core instrumentation

(excore detector and/or thermocouples and/or movable incore

detectors) every shift or subsequent to motion, of the non

indicating rod, exceeding 24 steps, whichever occurs first.

During operation below 50% of rated power no special monitoring

is required.

Not more than one rod position indicator (RPI) channel per group

nor two RPI channels per bank shall be permitted to be inoperable

at any time.

Misaligned or Dropped Control Rod

1. If the Rod Position Indicator Channel is functional and the

associated part length or full length control rod is more than

15 inches out of alignment with its bank and cannot be realigned,

then unless the hot channel factors are shown to be within design

limits as specified in Section 3.12.B.1 within 8 hours, power

shall be reduced so as not to exceed 75% of permitted power.

CHANGE NO, 29


2.

Basis

TS 3;12-13

To increase power above 75% of rated power with a part-length or

full length control rod more than 15 inches out of alignment with

its bank an analysis shall first be made to determine the hot channel

factors and the resulting allowable power level based on Section

3.12.B.

The reactivity control concept assumed for operation is that reactivity changes

accompanying changes in reactor power are compensated by control rod assembly

motion. Reactivity changes associated with xenon, samarium, fuel depletion,

and large changes in reactor coolant temperature (operating temperature to

cold shutdown) are compensated for by changes in the soluble boron concentration.

During power operation, the shutdown groups are fully withdrawn and control of

power is by the control groups. A reactor trip occurring during power operation

will place the reactor into the hot shutdown condition.

The control rod assembly insertion limits provide for achieving hot shutdown

by reactor trip at any time, assuming the highest worth control rod assembly

remains fully withdrawn, with sufficient margins to meet the assumptions used

in the accident analysis. In addition, they provide a limit on the maximum

inserted rod worth in the unlikely event of a hypothetical assembly ejection,

and provide for acceptable nuclear peaking factors. The limit may be determined

on the basis of unit startup and operating data to provide a more realistic

limit which will allow for more flexibility in unit operation and still assure

compliance with the shutdown requirement. The maximum shutdown margin require-

CHANGE NO. 29


TS 3.12-14

ment occurs at end of core life and is based on the value used in the analysis

of the hypothetical steam break accident. The rod insertion limits are based

on end of core life conditions. Early in core life, less shutdown margin is

required, and TS Figure 3.12-7 shows the shutdown margin equivalent to 1.77%

reactivity at end-of-life with respect to an uncontrolled cooldown. All other

accident analyses are based on 1% reactivity shutdown margin.

Relative positions of control rod banks are determined by a specified control

rod bank overlap. This overlap is based on the consideration of axial power

shape control.

The specified control rod insertion limits have been revised to limit the

potential ejected rod worth in order to account for the effects of fuel

densification.

The various control rod assemblies (shutdown banks, control banks A, B, C, and

D and part-length rods) are each to be moved as a bank, that is, with all

assemblies in the bank within one step (5/8 inch) of the bank position. Position

indication is provided by two methods: a digital count of actuating pulses

which shows the demand position of the banks and a linear position indicator,

Linear Variable Differential Transformer, which indicates the actual assembly

position. The position indication accuracy of the Linear Differential Trans

former is approximately ±_5% of span (±_7.5 inches) under steady state conditions.

The relative accuracy of the linear position indicator is such that, with the

CHANGE NO. 29

I


TS 3.12-15

most adverse errors, an alarm is actuated if any two assemblies within a bank

deviate by more than 14 inches. In the event that the linear position indicator

is not in service, the effects of malpositioned control rod assemblies are

observable from nuclear and process information displayed in the Main Control

Room and by core thermocouples and in-core movable detectors. Below 50% power,

no special monitoring is required for malpositioned control rod assemblies with

inoperable rod position indicators because, even with an unnoticed complete

assembly misalignment (part-length of full length control rod assembly 12 feet

out of alignment with its bank) operation at 50% steady state power does not

result in exceeding core limits.

The specified control rod assembly drop time is consistent with safety analyses

that have been performed.

An inoperable control rod assembly imposes additional demands on the operators.

The permissible number of inoperable control rod assemblies is limited to one

in order to limit the magnitude of the operating burden, but such a failure

would not prevent dropping of the operable control rod assemblies upon reactor

trip.

Two criteria have been chosen as a design basis for fuel performance related

to fission gas release, pellet temperature and cladding mechanical properties.

First, the peak value of linear power density must not exceed 21.1 kw/ft for

Unit No. 1 and 20.4 kw/ft for Unit No. 2. Second, the minimum DNBR in the

core must not be less than 1.30 in normal operation or in short term transients.

CHANGE NO. 29


TS 3.12-16

In addition to the above, the peak linear power density must not exceed the

limiting Kw/ft values which result from the large break loss of coolant accident

analysis based on the ECCS acceptance criteria limit of 2200°F on peak clad

temperature. This is required to meet the initial conditions assumed for the

loss of coolant accident. To aid in specifying the limits on power distribution

the following hot channel factors are defined.

Fq(Z), Height Dependent Heat Flux Hot Channel Factor, is defined as the maxi

mum local heat flux on the surface of a fuel rod at core elevation Z divided

by the average fuel rod heat flux, allowing for manufacturing tolerances on

fuel pellets and rods.

FE, Engineering Heat Flux Hot Channel Factor, is defined as the allowance Q

on heat flux required for manufacturing tolerances. The engineering factor

allows for local variations in enrichment, pellet density and diameter, surface

area of the fuel rod and eccentricity of the gap between pellet and clad.

Combined statistically the net effect is a factor of 1.03 to be applied to

fuel rod surface heat .flux.

F~H' Nuclear Enthalpy Rise Hot Channel Factor, is defined as the ratio of the

integral of linear power along the rod with the highest integrated power to the

average rod power.

CHANGE NO. 29


TS 3.12-17

It should be noted that F~H is based on an integral and is us~d as such in

the DNB calculations. Local heat fluxes are obtained by using hot channel

and adjacent channel explicit power shapes which take into account variations

in horizontal (x-y) power shapes throughout the core. Thus the horizontal

power shape at the point of maximum heat flux is not necessarily directly

N related to F6H.

An upper bound envelope of 2.10 times the normalized peaking factor axial

dependent of TS Figure 3.12-8 has been determined from extensive analyses

considering all operating maneuvers consistent with the technical specifi

cations on power distribution control given in Section 3.12.B.4. The results

of the loss of coolant accident analyses are conservative with respect to the

ECCS acceptance criteria as specified in 10 CFR 50.46.

When an FQ measurement is taken, both experimental error and manufacturing

tolerance must be allowed for. Five percent is the appropriate allowance

for a full core map (~ 40 thimbles monitored) taken with the movable incore

detector flux mapping system and three percent is the appropriate allowance

for manufacturing tolerances.

In the specified limit of F~H there is an eight percent allowance for un

certainties which means that normal operation of the core is expected to.

result in F~H ..::_ l.55/1.08. The logic behind the larger uncertainty in this

case is that (a) normal perturbations in the radial power shape (e.g. rod

misalignment) affect F~H' in most cases without necessarily affect FQ, (b)

the operator has a direct influence on F through movement of. rods, and can Q

CHANGE NO. 29


TS 3.12-18

limit it to the desired value, he has no direct control over F~, and (c) - · LlH

an error in the predictions for radial power shape, which may be detected

during startup physics tests can be compensated for the FQ by tighter axial

control, but compensation for F~H is taken, experimental error must be allowed

for and four percent is the appropriate allowance for a full core map (2:_ 40

thimbles monitored) taken with the movable incore detector flux mapping

system.

Measurement of the hot channel factors are required as part of startup physics

tests, during each effective full power month of operation, and whenever ab-

normal power distribution conditions require a reduction of core power to a

level based on measured hot channel factors. The incore map taken following

core loading provides confirmation of the basic nuclear design bases including

proper fuel loading patterns. The periodic incore mapping provides additional

assurance that the nuclear design bases remain inviolate and identify operational

anomalies which would, otherwise, affect these bases.

For normal operation, it is not necessary to measure these quantities. Instead

it has been determined that, provided certain conditions are observed,

the hot channel factor limits will be met; these conditions are as follows:

1. Control rods in a single bank move together with no individual

rod insertion differing by more than 15 inches from the bank

demand position. An indicated misalignment limit of 13 steps

precludes a rod misalignment no greater than 15 inches with

consideration of maximum instrumentation error.

CHANGE NO. 29

I I I I I I I I I I I I

·1 I I I I I I

2.

~-

4.

TS 3.12-19

Control rod bariks are sequenced with overlapping banks as

shown in Figures 3.12-lA, 3.12-lB and 3.12-2.

The full length and part length control bank insertion limits

are not violated.

Axial power distribution control procedures, which are given

in terms of flux difference control and control bank insertion

limits are observed. Flux difference referes to the difference

in signals between the top and bottom halves of two-section

excore neutron detectors. The flux difference is a measure

of the axial offset which is defined as the difference in

normalized power between the top and bottom halves of the core.

The permitted relaxation in F~H with decreasing power level allows radial

power shape changes with rod insertion to the insertion limits. It has been

determined that provided the above conditions 1 through 4 are observed, these

hot cha~nel factors limits are met. In specification 3.12.B.1 Fq is

arbitrarily limited for P < .5 (except for physics tests).

The procedures for axial power distribution control referred to above are

designed to minimize the effects of xenon redistribution on the axial power

distribution during load-follow maneuvers. Basically control of flux

difference is required to limit the difference between the current value of

flux difference (~I) and a reference value which corresponds to the full

power equilibrium value of axial offset (axial offset= ~I/fractional power).

CHANGE NO. 29


TS 3.12-20

The reference value of flux difference varies with power level and burnup,

but expressed as axial offset it varies only with burnup.

The technical specifications on power distribution control given in 3.12.B.4

assure that the FQ upper bound envelope of 2.10 times Figure 3.12-8 is not

exceeded and xenon distributions are not developed which at a later time,

would cause greater local power peaking even though the flux difference

is then within the limits specified by the procedure.

The target (or reference) value of flux difference is determined as follows.

At any time that equilibrium xenon conditions have been established, the

indicated flux difference is noted with the full length rod control bank more

than 190 steps withdrawn (i'.e. normal full power operating position appropriate

for the time in life, usually withdrawn farther as burnup proceeds). This

value, divided by the fraction of full power at which the core was operating

is the full power value of the target flux difference. Values for all other

core power levels are obtained by multiplying the full power value by the

fractional power. Since the indicated equilibrium value was noted, no allowances

for excore detector error are necessary and indicated deviation of +6 to -9% ~I

are permitted from the indicated reference value. During periods where extensive

load following is required, it may be impractical to establish the required

core conditions for measuring the target flux difference every month. For this

reason, the specification provides two methods for updating the target flux

difference.

CHANGE NO. 29


TS 3.12-21

Strict control of the flux difference (and rod position) is not as necessary

'during part power operation. This is because xenon distribution control at

part power is not as significant as the control at full power and allowance

has been made in predicting the heat flux peaking factors for less strict

control at part power. Strict control of the flux difference is not

possible during certain physics tests or during required, periodic, excore

detector calibrations which require larger flux differences than permitted.

Therefore, the specifications on power distribution control are not applied

during physics tests or excore detector calibrations; this is acceptable

due to the low probability of a significant accident occurring during these

operations.

In some instances of rapid "unit power reduction automatic rod motion will

cause the flux difference to deviate from the target band when the reduced

power level is reached. This does not necessarily affect the xenon dis

tribution sufficiently to change the envelope of peaking factors which can

be reached on a subsequent return to full power within the target band, how

ever, to simplify the specification, a limitation of one hour in any period

of 24 hours is placed on operation outside the band. This ensures that the

resulting xenon distributions are not significantly different from those

resulting from operation within the target band. The instantaneous

consequences of being outside the band, provided rod insertion limits are

observed, is not worse than a 10 percent increment in peaking factor for the

allowable flux difference at 90% power, in the range +14.5 to -21 percent

(+11.5 percent to -18 percent indicated) where for every 4 percent below

rated power, the permissible positive flux difference boundary is extended

CHANGE NO. 20

I I I I

I I I I I I I I I I I I I I

TS 3.12-22

by 1 percent, and for every 5 percent below rated power, the ~ennissible

negative flux difference boundary is extended by 2 percent.

As discussed above, the essence of the procedure is to maintain the xenon

distribution in the core as close to the equilibrium full power condition

as possible. This is accomplished, by using the boron system to position

the full length control rods to produce the required indicated flux difference.

At the option of the operator, credit may be taken for measured decreases in

the unrodded horizontal plane peaking factor, Fxy· This credit may take the

form of an expansion of permissible quadrant tilt limits over tilt limits

over the 2% value, up to a value of 10%, at which point specified power re-

ductions are prudent. Monthly surveillance of F bounds the quantity because xy

it decreases with burnup. (WCAP-7912 L).

A 2% quadrant tilt allows that a 5% tilt might actually be present in the core

because of insensitivity of the excore detectors for disturbances near the core

center such as misaligned inner control rods and an error allowance. No

increase in FQ occurs with tilts up to 5% because misaligned control rods

producing such tilts do not extend to the unrodded plane, where the maximum

FQ occurs.

CHANGE NO. 29

I I

TS FIGURE 3.12-8

I HOT CHANNEL FACTOR NORMALIZED

I OPERATING ENVELOPE

SURRY POWER STATION

I UNIT NOS. 1 AND 2

I I

1.0

I I ,,..... .8

N '-'

O' Ii-<

I A ~ N H .6 i--l

I ~ 0 z

I ,,..... .4 N '-' ~

I . 2

I 0

I 0 2 4 6 8 10 12

CORE HEIGHT (ft.)

I I I I

(' 1 i ~ \"Cr NO, .,,0 .,,,. ri. j J .Jt


TS 4.10-1

4.10 REACTIVITY ANOMALIES

Applicability

Applies to potential reactivity anomalies.

Objective

To require evaluation of applicable reactivity anomalies within the reactor.

Specification

A.

B'.

Following a normalization of the computed boron concentration as a

function of burnup, the actual boron concentration of the coolant shall

be compared monthly with the predicted value. If the difference between

the observed and predicted steady-state concentrations reaches the

equivalent of one percent in reactivity, an evaluation as to the cause

of the discrepancy shall be made and reported to the Nuclear Regulatory

Commission per Section 6.6 of these Specifications.

During periods of power operation at greater than 10% of power, the hot

N channel factors, FQ and FL'IH' shall be determined during each effective

full power month of operation using data from limited core maps. If these

factors exceed values of

F Q (Z) < (2 .10/P) x K(Z) for p > .5

F (Z) < Q

(4. 20) x K(Z) for P < .5

FN < t,H - 1. 55 (1 + 0.2 (1 - P))

CHANGE NO. :29

I I I I I I I I I I I I I I I I ,I I I

TS 4.10-2

(where Pis the fraction of rated power at which the core is operating,

K(Z) is the function given in Figure 3.12-8, and Z is the core height

location of FQ), an evaluation as to the cause of the anomaly shall be

made.

Basis

BORON CONCENTRATION

To eliminate possible errors in the calculations of the initial reactivity

of the core and the reactivity depletion rate, the predicted relation between

fuel burnup and the boron concentration necessary to maintain adequate control

characteristics, must be adjusted (normalized) to accurately reflect actual.

core conditions. When full power is reached initially, and with the control

rod assembly groups in the desired positions, the boron concentration is

measured and the predicted curve is adjusted to this point. As power operation

proceeds, the measured boron concentration is compared with the predicted

concentration, and the slope of the curve relating burnup and reactivity is

compared with that predicted. This process of normalization should be completed

after about 10% of the total core burnup. Thereafter, actual boron concentration

can be compared with prediction, and the reactivity status of the core can be

continuously evaluated. Any reactivity anomaly greater than 1% would be· un

expected, and its occurrence would be thoroughly investigated and evaluated.

The value of 1% is considered a safe limit since a shutdown margin of at

least 1% with the most reactive control rod assembly in the fully withdrawn

position is always maintained.

CHANGE NO. 29


TS 4.10-3

PEAKING FACTORS

A thermal criterion in the reactor core design specifies that "no fuel

melting during any anticipated normal operating condition" should occur.

To meet the above criterion during a thermal overpower of 118% with additional

margin for design uncertainties, a steady state maximum linear power is

selected. This then is an upper linear power limit determined by the maxi

mum central temperature of the hot pellet.

The peaking factor is a ratio taken between the maximum allowed linear power

density in the reactor to the average value over the whole reactor. It is of

course the average value that determines the operating power level. The peaking

factor is a constraint which must be met to assure that the peak linear power

density does not exceed the maximum allowed value.

During normal reactor operation, measured peaking factors should be significantly

lower than design limits. As core burnup progresses, measured designed peaking

factors are expected to decrease. A determination of FQ and F~H during each

effective full power month of operation is adequate to ensure that core re

activity changes with burnup have not significantly altered peaking factors in

an adverse direction.

G HANGE NO. 29


-----------~--------------~

3.

4.

5.

6.

TS 5.3-2

Reload fuel will be similar•in design to the initial core. The

enrichment of reload fuel w.ill not exceed 3.60 weight per cent of

U-235.

Burnable poison rods are incorporated in the initial core. There

are 816 poison rods in the form of 12 rod clusters, which are

located in vacant control rod assembly guide thimbles. The burnable

poison rods consist of pyrex glass clade with stainless steel.

There are 48 full-length control rod assemblies and 5 part-length

control rod assemblies in the reactor core. The full-length control

rod assemblies contain a 144 inch-length of silver-indium-cadmium

alloy clad with stainless steel. The part-length control rod

assemblies contain a 36 inch-length of silver-indium-cadmium alloy

with the remainder of the stainless steel sheath filled with Al 2o3

.

The initial core and subsequent cores will meet the following per

formance criteria at all times during the operating lifetime.

a. Hot channel factors:

F (Z) < (2.10/P) x K(Z) for P > .5 Q

FQ(Z) < (4.20) x K(Z) for P < .5

N F~H _::_ 1.55 (1 + 0.2 (1 - P))

where Pis the fraction of rated power at which the core is

operating, K(Z) is the function given in Figure 3 .12.-8, and Z

is the core height location of FQ.

CHANGE NO. 29

--- fr

REGULATORY DOCICET_FILE COP:YJ_

!!REGULATORY DOCKET FILE COPY

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1 '- ·i.~· · 2019. 7. 31. · hot spot fluid temperature (4 inch) core power ... 1975...

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