nrc ouestions (9/14/79) o. 1/2

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November 21, 1979

Trojan Nuclear PlantDocket 50-344License NPF-1

Director of Nuclear Reactor RegulationATTN: Mr. A. Schwencer, Chief

Operating Reactors Branch #1Division of Operating Reactors

- U. S. Nuclear Regulatory CommissionWashington, D. C. 20555

Dcar Sir:

Attached are 40 copies of Licensee's responses to several of the NRCStaff questions of September 19, September 28 and October 2,1979.

Sincerely,

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DJB/LWE/4sa6A24Attachments

c: Mr. R. H. Engelken, Directorl'. S Nuclear Regulatc ry Commission |j()q J.;74Region V

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Mr. Lynn Frank, DirectorState of OregonDepartment of Energy \

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NRC Ouestions (9/14/79)

O. 1/2 Page 1 of 2

1. Provide a detailed description of how the equivalent dia-

meter was determined which was used in computing the penetra-

tion of the dropped washer into the steel cover plate for

cable trays.

2. Provide a drawing which illustrates the projected area

used for computing the equivalent diameter.

Answer:

An evaluation of the postulated drop of a plate washer on the

steel cover trays was provided in Licensee's response dated

September 5, 1979 to Systems Branch Question No. 11. In the

equation used, the term "D" is the diameter of the missile .

For an irregularly shaped missile, such as the corner of the

plate washer, an equivalent diameter must be used in the

analysis.

The equivalent diameter is taken as the diameter of a circle

with an area (A) equal to the circumscribed contact area or

projected frontal area of the noncylindrical missile. (Refer-

ence: page 2-4, Bechtel Topical Report BC-TOP-9A, Rev. 2).

The contact area (A) is the plate thickness (T) times the arc

length (L) of the rounded portion of the plate washer.

The arc length (L) is the length of the rounded edge, or one

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0.1/2 Page 2 of 2

fourth the circumference of a circle of that radius (R).

Plate Washer thickness (T) 2.375 in.=

Radius of rounded corner (R) = 1.5 in.

L = 2n R = 2n (1. 5 ) = 2.36 in4 4

5.6 in.2A = TL = (2.375)(2.36) =

D= 4A 4(5.6) = 2.67 in,

w n

The attached Fig. 2-1 shows the projected area used for compu-

ting the equivalent diameter of the plate washer impact.

I394 342

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NRC Questions (9/14/79)

Q. 4 Page 1 of 4

For the cable trays ABA401, ABA010, and AEA380, which may

be exposed to a drop of a plate washer in excess of 3 feet,

you have stated that suitable guides or alterr; ate protection

will be provided. Describe the guides or alternate protec-

tion and show pictorially how the protection will work..

Answer:

This answer discusses Mie methods which Licennee will use to

assure that all cable trays in the Cable Spreading Room will

be procected against any drop of a plate washer. As indicated

in Licensee's respo:.se dated September 5, 1979 to NRC Systems

Branch Question No. 10(c), cable trays ABA401, TBA010, and

ABA380 may be exposed to a drop of a plate wasner in excess of

thr ee (3) feet. If the present bolt hole locations were to be

changed, cable trays ABA595, ABA285, or NPA206 penetrating the

R line wall might also be exposed to such a drop. The cable

trays located near the R line wall in the Cab;e Spreading Room

which might be exposed to a drop of a plate washer while the

washers are being installed on the R line wall are shown in

attached Figures 4-1 and 4-2.

.

In order to provide protection to the cable trzyn passing

through or near the R line wall which could be exposed

to a drop of a plate washer, and to facilitate installa-

tion of the plate washers, Bechtel plans to erect

tubular scaffolding with nominal 2" thick timber planking

in the Cable Spreading Room. The scaf folding is E tandard

construction equipment, and will be bolted together

i394 344,

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Q. 4 Page 2 of 4

from 2-3 inch diameter steel pipes. It is light weight mate-

rial without sharp edges and does not present a risk of damage

to either cables or cable trays.

As shown in Figures 4-1 and 4-2, the timber planking will be

perpendicular to and flush against the wall directly beneath

each applicable plate washer location. It will be placed so

that the maximum height a washer can fall onto it is 3 feet.

An on-site test will be performed by dropping a steel washer

from 3 feet onto the planking. If the washer penetrates, or

significantly deforms, the planking, another layer will be

added.

The planking will be cut to the length required to protect the

cable trays below it. Though for the most part the length of

the planking will be seven feet, the maximum length in some

instances will be determined by the space available. In all

cases the length of the planking will be sufficient to prevent

a plate washer from falling more than 3 feet onto a cable tray.

The washers will be pulled across the floor of the Cable Spread-

ing Room, and lifted onto the scaffolding. The washers will

not be lifted over cable trays unless the planking is in place

and secured to protect the cable tray. Any cable tray which'

could conceivably be struck by a washer dropped while it is

being lifted to the scaffolding will be protected by the steel

cable tray covers described in Licensee's response, dated

Septemoer 5, 1979, to NRC Staff System Branch Question No. 11.

As discussed in that previous response, cable tray covers will

l394 545

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Q. 4 Page 3 of 4

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protect the cables from a plate washer drop of less than three'

feet. No plate washer will a s lif ted to the scaf folding in s

an area in which it is possible for it to fall more than

three feet onto an adjacent cable tray. After the plate

washer is lif ted onto the planking, it will be pulled across,

the planking to the R line wall where it will be lif ted

into position. The protection provided by the scaffolding andplanking, together with the cabic tray covers, assures that nounprotected cable tray will be exposEJ to the drop of a platewasher and that any such drop will be limited to 3 feet.

The scaf folding planks will be treated with the "Plamort-WC"fire retardant, as will be discussed in Licensee's response

to NRC Staff Question No. 3, dated September 14, 1979. The

amount of planking in the Cable Spreading Room at any onetime during the modification work will be limited so that

the resulting combustion loading in the room due to the plank-2

ing will be less than 1.0 lbs/f t compared with an existing2loading of 15.8 lbs/f t , (PGE-1012 Table 3-1). At all

times when the planking is in the cable Spreading Room, a

fire watch will inspect the area on an hourly basis.-

.

Protection will also be provided to the cable trays on the

vest side of the R-line wall during the modification program.

Potential hazards to those cable trays includo dropped hand

tools, bolts or nuts, and lumber cribbing for Plate 8 instal-

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Q. 4 Page 4 of 4

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lation*. Field inspection has established that the maximum

drop height for any of these items onto these cable trayt willnot exceed 3 feet. As explained in Licensee's redponse dated

August 13, 1979 to NRC Staff Structural Branch Question No. 11dated July 20, 1979, , cable tray covers will be used to protect

the cable trays on the west side of the R line wall from tools

and paterials to be used in that area.

* Protection of the cable trays from fire hazards of cutting

and welding is discussed in paragraph 6 of Affidavit of

E. W. Edwards, dated August 27, 1979, on Consolidated Inter-

venors' Contentions Nos. 2A and C.

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Q. 1

Verify that the installed Hexcel energy absorbing material

will be

(a) " stabilized" in order to ensure the edge material is

stabilized and therefore will absorb the anticipated

amount of energy should it be crushed by a falling

plate.

(b) "precrushed" in order to eliminate the peak load shown

in Figure V-2 of Hexcel catalog #TSB-120.

Answer:

(a) The Hexcel energy absorbing material will be " stabilized"

by bonding a plate on the top and bottom of the material.

(b) The Hexcel energy absorbing material will be "precrushed"

in order to eliminate the peak load shown in Figure V-2

of Hexcel catalog #TSB-120.

I394 350


Q. 2

Previous responses have indicated, in response to the control

of dust, grit and debris, that the work area may be isolated.

In this regard, the staff believes a small portable enclosure

should be employed on the east and west inside walls of the

Control Room and the electrical auxiliaries room when drilling

holes in the walls. This box shall be capable of containing

and collecting any dust, dirt, debris and water that may enter

the room as the drill penetrates the wall.

Verify that such a small enclosure and collection means will

be provided in order to preclude the release of this material

inside the rooms.

Answer:

A small enclosure will be used on the inside of the walls as

outlined in the above question. It will be constructed so

as to collect and contain any dust, dirt, debris and water

incidental to the drilling. It will also be constructed

such that a workman can hold the enclosure against the wall

with his hands, and at the same time be able to see the wall.

to determine when and where the drill bit is penetrating.-

The enclosure will have approximate dimensions of l' x l' x

3" and will weigh approximately five (5) pounds. Such an

enclosure will not pose a threat to electrical cables or

equipment in the event that the enclosure would be dropped.

Additional measures to control dust, grit and debris are

described in Licensee's response to Question No. 7 of this

set.

I394 351

NRC Questions (5,28/79)

Q. 4 Page 1 of 2

The Trojan response of September 5, 1979 to Systems Branch

question 10 is confusing in that it speaks of areas externalto Category 1 equipment. The staff believes that a fire

_watch patrol should be established to perform hourly inspec-

tions for areas where a fire could affect safety related

cables or equipment in which non-fire retardant wood will beused for concrete forms or other purpcses.

The person while assigned as a fire watch patrol should have

no other duties. This fire watch patrol should be instituted

when the non-fire retardant wood is taken into any of these

areas and continue until it is removed. The fire watch patrol

would not be necessary during the times when a continuous

fire watch has been established in an area for other reasons.

Identify each of the areas where such a fire watch patrol

would be necessary to monitor for fires in areas where a fire

could affect safety-related cables or equipment.

Answer:

~

The intent of Licensee's response dated September 5, 1979, to

Systems Branch Question No. 1G(i) was to indicate that, duringthe modification program describ?d in PGE-1020, Licensee willestablish a fire watch patrol when wood, whether fire-retardant

or not, is utilized in areas where a fire could affect safety-

related cables or equipment. The fire watch patrol will per-

form hourly inspections from the time any wood is brought intoany such area until it is removed, and will not be assignedother duties. The areas where such a fire watch patrol might

i394 352

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Q. 4 Page 2 of 2

be necessary will be identified in Licensee's response to

NRC Question 3 dated September 14, 1979.

1394 353

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Q. 5

In reference to the construction noise levels in the control

room, response 18 to the staff's July 20, 1979 questions, you

indicated that "Should it be determined by the plant operator

in the Control Room that excssive noise is being c'reated,lighter weight tools or other means of concrete removal will

be employed". The staff believes it is essential that if

either the NRC IE resident inspector or the plant operator

should determine that excessive construction noise is being

created, lighter weight tools or other means of concrete re-

moval will be employed.

Verify that the abov' "iditional control on control room noise

is acceptable and will be complied with.

Answer:

In the event that either the NRC IE Resident Inspector or the

Plant operator determines that excessive construction noise is

being created, lighter weight tools or other means of concrete

removal will be employed.

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Q. 6

Presently it is proposed to utilize a positive feed control

drill on the east and west control building outer walls. Fur-

ther a person will be stationed on the inside for the purpose

of detecting when the wall has been penetrated and notifying

the driller via radio communications or by sound or battery

powered telephones. Describe and discuss any other additional

measures that can and will be implemented to further provide

assurance the drill will not be allowed to penetrate to such

an extent as to damage equipment within, e.g., positive stops

or a paint strip on the core drill to alert the driller that

wall penetration is imminent.

Answer:

Conventional practice for such drilling operations includes

the use of marking on the core drill so that the drill operator

knows where his drill bit is located in relation to his planned,

penetration depth. Such a marking procedure will be used for

all concrete or masonry core drilling required for the modifi-

cation work. The type of marking used will be one that the

drill operator can easily see while operating the drill.-

Either a tape or painted stripe is the method which we would

plan to use.

1394 355

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Q. 9

Your June 29 response to question 3 and PGE-1020, Revision 2

indicates that the appropriate factor of safety for the Nel-

son studs is 2. Your June 22 response to question 22 indi-

cates that a factor of 3 was used in the design of the studs

and, therefore, may be more appropriate. Clarify this apparent

inconsistency.

Answer:

In PGE-1020 Section 3.2.4.3 and in Licensee's response dated

June 29, 1979 to NRC Question No. 3, it is stated that the

allowable design values for Nelson studs are one-half of the

values given in Table 15 of the Nelson Division of TRW, Inc.

publication, " Design Data 10 - Embedment Properties of Headed

Studs". A justification for the allowable design values is

presented in Licensee's response dated June 22, 1979 to NRC

Question No. 7

Licensee's response dated June 22, 1979 to NRC Question No. 22

indicates that the maximum calculated forces on the studs are

one-third of the values given in Table 15 of " Design Data 10 -

Embedment Proper ties of Headed Studs'; . Since the calculated

forces are less than the allowables, the design of the studs

is adequate.

I$Y4 356

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Q. 16

Your July 10 response to question 13 indicates that the

maximum vertical amplification factor is 16 percent whileyour September 5 response to question 15 indicates that it is

13 percent. Therefore, provide the correct maximum vertical

amplification factor.

Answer:

Licensee's response dated July 10, 1979, to NRC Question No.13 stated that the maximum vertical amplification factor is

16 percent. Licensee's response dated September 5, 1979, to

NRC Question No. 15 states that "the dead load was reduced13% to account for vertical motion". Thus, the 13% is the

reduction in dead load, and is not a value for vertical

amplification.

I394 3S/

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O. 18

In your September 5 responses to questions, the response toquestion 17 indicates that for the combination of dead, live

and SSE loadings, the maximum allowable stress in bending andtension is limited to 0.9 fy and the maximum allowable shear

stress is limited to 0.5 fy. Verify that this limitation was

imposed for the evaluations of steel elements discussed in the

responses to questions 18 and 25.

Answer:

In Licensee's responses dated September 5, 1979 to Structural

Branch Questions Nos. 18 and 25, the maximum allowable stress

in bending and tension of the steel elements was limited to

0.9 f and the maximum allowable shear stress was limitedyto 0.5 f for the load combinations referred to.y

l394 358.

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nrc ouestions (9/14/79) o. 1/2

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