Experience of the implementation of post-Fukushima measures at Ukrainian NPPs

Vienna

March 27-29, 2017

VIKTOR PROKHOROV

Nuclear Power of Ukraine Today

Energoatom – is the operator of 4 NPPs in

operation with total capacity of 13 835 MW

NNEGC “Energoatom” is generating more then half of electricenergy in Ukraine.

Now it is about 60%

National Nuclear Energy

Generating Company “Energoatom”

was established on

17-th October 1996

2

3

SE NNEGC “Energoatom”15 power units

VVER-440/213RNPP - №1, 2 VVER-1000/302

VVER-1000/338SU NPP - №1, 2

VVER-1000/320(11 power units)▪ ZNPP №1,2,3,4,5,6;▪ KhNPP №1, 2;▪ RNPP №3, 4;▪ SU NPP №3

PWR type. 2 circuits. Primary circuit:VVER-1000 – 4 loops (6 for VVER-440)

Reactor – water-cooled water-moderated power reactor

Steam generators – horizontal

Safety trains - 3

НАЦИОНАЛЬНАЯ АТОМНАЯ ЭНЕРГОГЕНЕРИРУЮЩАЯ КОМПАНИЯ

МИНИСТЕРСТВО ЭНЕРГЕТИКИ И УГОЛЬНОЙ ПРОМЫШЛЕННОСТИ УКРАИНЫ

Power units of Ukrainian NPPs

In 2011 the “stress-tests” were performed by the Energoatom

The “stress-tests” wereperformed in accordancewith the ENSREG methodology.

(13/05/2011, Declaration of ENSREG, Annex 1 «EU “Stress-test”specifications»).

In the framework of the “stress tests”Energoatom analyzed in detail external extreme natural events/combinations of events

Actions taken in Ukraine after the Fukushima

Accident

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Earthquake

Fire

Flooding

Storm

Tornado

Temperature

Snow

Icing

Safe Design

Emergency Preparedness and Response System

Initiating Events

Methodology of “stress-test”

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Analyzing external extreme natural events/

combinations of events

The initiating event

Loss of electrical power

Loss of ultimate heat sink

Severe accident

management

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Sequence of events that occurred at Fukushima Daiichi NPP is practically impossible at Ukrainian NPP

No new safety issues were revealed, which were unknown before the stress tests.

Power units have safety margins for all extreme natural hazards and their combinations

Additional measures were recommended, now being implemented within the existing safety upgrade program

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General Conclusions on Stress-tests

National Action Plan basedon the outcomes of “stress-tests”

Comprehensive(Integrated) Program of SafetyImprovement of Ukraine NPP PowerUnits as approved by the Cabinetof Ministers of Ukraine

Program of Works on Severe Accident Analysis

and SAMG Development, as endorsed by the

State Nuclear Regulatory Inspectorate of

Ukraine (SNRIU)

Background to perform the Post-Fukushima measures

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COMPREHENSIVE (integrated) SAFETY UPGRADE PROGRAM FOR POWER UNITS OF NUCLEAR POWER PLANTS

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▪ After the Fukushima accident, the CiSUPstatus was raised to the governmentallevel.

▪ The CiSUP is approved by the Ordinanceof the Cabinet of Ministers of Ukraine dd.07.12.2011 №1270

▪ Implementation period – 2011-2020

▪ Total cost ~ EUR 1.4 bln

(Internal Energoatom funds - about 800 mln EUR

and International EBRD/EA loans - 600 mln EUR)

Prevention of severe accidents

➢ emergency electrical power supply in case of SBO

➢ steam-generators make-up in case of SBO

➢ SFP make-up and cooling in case of SBO

➢ operability of service water consumers in case of dewatering of spray ponds / failure of service water system

➢ ensure seismic robustness 0.1 g PGA (0.12g –SUNPP, 0.15g -ZNPP)

➢ additional seismic investigations and monitoring on sites

➢ BDBA monitoring of 1st circuit parameters

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Management of severe accidents

➢ SAMG for operation and shutdown states

➢ filtered containment venting system (VVER-1000)

➢ hydrogen concentration reduction in the containment

➢ PAMS inside containment (including H2 concentration)

➢ prevent early containment bypass

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The status of the‘Post-Fukushima’ measures

0

50

100

150

200

250

В-320В-302/338

В-213

45 25 8

156

10 18

Nu

mb

er

of

measu

res

осталось

выполнено

0

50

100

150

200

250

В-320 В-302/338 В-213

4525

8

156

1018

Nu

mb

er

of

measu

res

осталось

выполнено

Total - 262 the‘Post-Fukushima’ measures for 15th units

Today - 78 measures was implemented

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List and cost of Post-Fukushima measures № Code Measures

Apr. cost,

mln EUR

without VAT

Additional equipment and systems 165,4

1 13307 Steam-generators make-up in case of SBO (mobile pumping station-MPS)

322 13511 Functionality of group A equipment in case of the loss of service water system (MPS)

3 11305 SFP make-up and cooling (MPS)

4 15103 Emergency electrical power supply (Mobile diesel-generator) 12

5 14101 Post accident monitoring system (PAMS) 33,4

6 16201 The hydrogen concentration monitoring system in case BDBA 7

7 16203 Passive autocatalitic recombiners (PARs) in the containment dome 15

8 16205 Containment filtered venting system (1st/2nd stage) 1,5 / 72

9 16101 Prevent early containment bypass 4

Qualification 62,85

10 10101 Qualification of the power unit elements 7,5

11 13501 Replacement of air conditioners for conditioners qualified for "hard" conditions and seismic 41,2

12 Qualification of internal crisis centers for seismic and SAC 0,15

13 18101 Seismic qualification 10

14 18102 Seismic monitoring system 4

Emergency procedures

15 19203 Improvement of Emergency instructions for eliminating accidents at low power and outage 1,3

16 19204 Severe accident management guidelines (SAMG )

Analytical

17 10102 The study of the necessity and the possibility of qualification for the conditions of SA

1,57

18 13308 Analysis of the need to make up the 1st circuit

19 19105 Analysis of the possibility of in vessel retention

20 19103 Taking into account the full spectrum of the initial events for reactor states and FP in PSA

21 - Handling of large amounts of radioactive water

22 - Investigation of emergency SA phenomena and improvement of calculated models

Others 0,7

TOTAL for all NPPs 241,8

Seismic qualification

Qualification is based on the values refined upon site seismic survey

Design-basis PGA Refined PGA value

NPP SL-1/OBE SL-2/SSE Refined SSE Qualification margin

Khmelnitsky

0.025g 0.05g

0.06g 0.1g

Rivne 0.06g 0.1g

South-Ukraine 0.093g 0.12g

Zaporizhe 0.115g 0.15g

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Progress in seismic qualification

- SUNPP-1,2, ZNPP-1,2 - completed (for SUNPP-1 2414 pieces of equipment, qualification of 1461 pieces was increased, 194 pieces of equipment were replaced)

- on-going for other units – till 2020

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Replacement of air conditioners for

conditioners qualified for "hard"

conditions and seismic

Apr. cost 3 mln EUR per unit

Progress in seismic qualification

Seismic monitoring system

- SUNPP site –completed

- ZNPP site – under completion:✓equipment for 6 points of seismic monitoring in ZNPP 25 km

✓drilling to install seismometers, protective structures

✓ trial operation planned in 2015

- RNPP and KhNPP –on-going ✓purchasing the equipment

✓mounting work

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Apr. cost 1 mln EUR per unit

General strategy for SBO/LUHS

- SG depressurization by steam dump to atmosphere (BRU-A or SRV)

- SG feed:✓ from mobile diesel-driven pump (MDP) connected to emergency feed water system (EFW) line (additional bunkered EFW for WWER-440)✓ passive dearator depletion (+ approx. 8.5 hrs to core damage)

- RCS boron injection by ECCS high pressure (powered from mobile DG)

- Spent fuel storage pool feed/cooling by MDP

- Support functions✓alternative power supply (0.4 kV/800kW MDG)✓essential service water (ESW) supply by MDP✓compressed air✓I&C (PAMS)

Additional equipment - 3 mobile diesel-driven pumps (SG feed, SFSP feed, ESW) and mobile DG / per power unit

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Mobile pumping station

− SUNPP-1,2, ZNPP-1,2, RNPP-3– completed (mobile

diesel-driven pumps 396 m3/h, 10 кgf/сm2 , procedure for alternative water supplyfrom the mobile pump to essential loads with water intake (SG, SFP, ESW) from anyalternative sources: tanks, water intake pools of ventilation cooling towers or waterchannel of the cooling pond)

− Schedule for others units:- ZNPP-3, KhNPP-2, RNPP-1,2 – 2017- remaining units – 2018

- Estimate cost per unite - 0,74 million Euros

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Pump Station NRS-110

Nominal features:

- Flow rate, m3/h – min 396;

- Discharge head, kgf/cm2 – min 10;

- Suction height, m – min 7.

Examples of completed modernizations

Arrangement for make-up of a SG,

SFP, ESW

Mobile diesel driven pumps (SUNPP-1 examples)

Mobile pump to feed SG/SFP Connection places installed for SFP water supply

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Alternative power supply in case of SBO(SUNPP-1 examples)

−0.4 kV/800 kW mobile DGs

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−SUNPP-1,2, ZNPP-1,2 – completed−Schedule for others units:

-ZNPP-3, KhNPP-2, RNPP-1,2,3 – 2017-remaining units – 2018

- Approximate cost per unite - 0,9 million Euros

SAMG implementation

• SAMG for operation at rated power - implemented at pilot RNPP-1, SUNPP-1 and ZNPP-

1 units, personnel trained

- developed and being revised for all non-pilot units (to be implemented in 2015)

• SAMG for low power and shutdown states/SFP

- developed and being revised for pilot units

- implementation schedule:- pilot units – 2015- non-pilot units - 2016

The conditions for transfer to SAMGs –temperature increase at core output above 450 С, SFP level under 430 cm, time without SFP cooling

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Containment filtered venting system

1st stage (intermediate) - containment venting through existing exhaust

air ducts and further release of the steam-gas medium to atmosphere through the ventilation stack and treatment on available iodine and airborne filters

Completed for SUNPP-1,2, ZNPP-1,2 – replacement of air ducts, upgradingdischarge line

2nd stage – additional filtered venting:analytical justification for filters completed, technical specifications approved,

tender for SUNPP-1,2, ZNPP-1,2 is finishing (first two units – “dry” filter byWestinghouse, second two – “wet”, Areva technology)

Implementation schedule: SUNPP-1,2,4, ZNPP-1,2 – 2018,ZNPP-3,5, KhNPP-1, RNPP-3, SUNPP-3 – 2019,

remaining units – up to 2020

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- Estimate cost 1st/2nd

stage per unite -0,17/5,1 million Euros

Post accident monitoring system (PAMS)

1st stage: - software based I&C (upper level of

PAMS)

- emergency instrumentation of

coolant level in reactor

- connection of existing design based

sensors to upper level of PAMS

2nd stage:- implementation of emergency

instrumentations, qualified for severe

accident conditions;

- data transfer from PAMS to “black

box”

Уровень теплонос. в реакторе

Уровень теплоносителя в КД

Проектный и. п.

Монитор БЩУМонитор РЩУ

Сист. Блок

Коммутатор 1

Коммутатор 2

АВР 1 АВР 2

Шкафы верхнего

уровня

АБ СУЗ

АДГ

Осн. и.п.

СККВ АСРКАКНП

АВР

-/~СКУТ

ЧЯ

Внеш. КЦ Внут.КЦ

.

ИВС

Температура в петлях ГЦК

Температура дна корпуса реактора

ТС АКИП

Температура в ГО

Давление над активной зоной реактора

Температура в бассейне выдержки

Уровень в бассейне выдержки

Шкафы нижнего

уровня

АВР 1 АВР 2

Мощность дозы в ГО

Давление в ГО

Уровень воды в ПГ1 – ПГ4

Давление в ПГ1 – ПГ4

Уровень в приямках ГО

Температура на выходе из ТВС

Температура бетона шахты реактора

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Key measures (5/6)

Reflectometry radar-sensor by "AMICO kit" (Mykolayiv) to measure the level of liquids (including boiling) in spent fuel pool with temperatures up to 300 0C.

Measuring range 0 - 16 m.

Accuracy - 4 sm.

Measurement of temperature using platinum resistance thermometers and thermocouples made in Ukraine by “Thermoprilad” or “Omega”

Measurement of dose rate with BDRG-47R by “Technopole”, or upgraded GIM-206 by MIRION

Measurement of pressure in the primary circuit, pressure in the containment, the level in the pit GA201/1,2,3 used pressure sensors of PJSC "Manometer-Kharkiv"

PAMS Implementation progress

✓ SUNPP-1,2 - software based upper level PAMS designed and produced by Ukrainian manufacture “Westron” installed and put into trial operation, equipment purchased for providing information to emergency centers, in-core coolant level measurement improved

✓ ZhNPP-1,2 - software based upper level PAMS designed and produced by Ukrainian manufacture “Impuls” installed and put into trial operation

✓ For other units tender is ongoing ore preparing

List of monitored parameters for SAMG strategies:

1. The temperature of the fuel assembly outlet2. The level in the reactor3. The pressure above the core4. The temperature of the reactor vessel bottom5. The temperature in the containment6. The concentration of hydrogen

7. The gamma radiation dose rate in the containment8. The pressure in the containment9. Temperature in fuel pool10. The level in fuel pool11. The water level in the pit of containment

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Measures to protect containment integrity(SUNPP-1 examples)

Installation of passive autocataliticrecombiners (PARs) in the containment dome

Concrete barrier in the melt spreading area to avoid the containment bypass (WWER-1000/V-302 peculiarities)

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Внедрение пассивных рекомбинаторов водорода на ЮУАЭС

ПРИМЕРЫ ВЫПОЛНЕННЫХ МЕРОПРИЯТИЙ ПО ПОВЫШЕНИЮ БЕЗОПАСНОСТИ УКРАИНСКИХ АЭС (ПРОДОЛЖЕНИЕ)

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Good practices

▪ Measure is first implemented at pilot power units to cover reactorsof each design and then at other units taking into account theexperience gained from the pilot one (results, technical solutionsand findings). Application of the stage improvement.

▪ Site-specific SARs have been developed for each NPP to justifyeffectiveness of the complex strategy in case of SBO/LUHS withdifferent combinations of mobile equipment, operator actions,estimation of the time for delivery of mobile equipment to theconnection places, etc.

▪ Unification of Mobile pumping station for reservations of function

▪ Regulatory body monitors, in a systematic manner,implementation of the measures at open Board meetings andinspections.

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Challenges

▪The schedule for safety measures is affected by the technicalcomplexity of their development and implementation, and requiredscope of funding

▪Financial constrains due to the current political situation

▪The complicated tendering procedure

▪ For measures on severe accident management,analytical/experimental studies of relevant severe accidentphenomena are to be continued

THANK YOU FOR YOUR ATTENTION!