ML20212N701

Forwards Viewgraphs for 860827 CRGR Briefing Re Current Discussions of Possible BWR Containment Backfits to Ensure Adequate Performance in Severe Accidents

ML20212N701
Person / Time
Issue date:	08/27/1986
From:	Bernero R Office of Nuclear Reactor Regulation
To:	Sniezek J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
Shared Package
ML20209E138	List: ML20209E134 ML20209G637 ML20210B280 ML20210B759 ML20210B807 ML20210C592 ML20210G952 ML20210J028 ML20210L538 ML20210V255 ML20211K137 ML20211K492 ML20211K505 ML20211K519 ML20211N756 ML20211N761 ML20212F264 ML20212N701
References
FOIA-87-10 NUDOCS 8608290127
Download: ML20212N701 (20)

Text

,

4

. et .

4 W

MG27 Q MEMORANDUM FOR: James H. Sniezek i Deputy Executive Director for Regional Operations & Generic Requirements FROM: Robert M. Bernero, Disector Division of BWR Licensing Office of Nuclear Reactor Regulation .

SUBJECT:

CRGR BRIEFING ON BWR CONTAINMENT PERFORMANCE As we agreed, I will brief the CRGR on August 27, 1986 about current discussions of possible backfits of BWR containments to ensure adequate performance in severe accidents. Attached are two sets of slides, the first set includes the ones I will use in the August 27 briefing. The second set is the one I used in a public meeting with the BWR Owners Group on June 16, 1986; they are for the Committees information and I would be pleased to discuss them as well.

erisiantSiamed3rs

.Sehert & Beamesp Robert M. Bernero, Director Division of BWR Licensing Office of Nuclear Reactor Regulation Attachments:

As stated cc: E. L. Jordan D. F. Ross, Jr.

C. J. Heltemes J. Scinto R. Cunningham J. Zerbe W. Schwink , , , .

Z. Rosztoczy J. Murphy

~

Distribution H. Denton R. Vollmer U/S.

.#. W. Houston R. Barnero Central Files DBL R/F OFC : BL  :  :  :  :  :  :

...... g....................................................................................

NAME do $ $ $ $

DATE //J//86 -

I

,~ --

0FFICIAL RECORD COPY g

VPP

. o .

q,-

'h - .~..-,-%._ _ , .

SAFETY OBJECTIVES e THE LIKELIHOOD OF SEVERE ACCIDENT (CORE DAMAGE OR CORE MELT) SHOULD BE VERY LOW AND .

e IF A SEVERE ACCIDENT OCCURS THERE SHOULD BE SUBSTANTIAL ASSURANCE THAT THE CONTAINMENT WILL ,

MITIGATE ITS CONSEQUENCES

~

en g s

4 a

'J

.r e *s

,,,9e- g ,+grw *wwa.-.erm.

• __,4 ..- -e

, ,7 7 ,

V '; " ,

CONTAINMENT ISSUES e EARLY REACTORS LOW POWER / BIG CONTAINMENTS -

COULD MEET CONTAINMENT OBJECTIVE e EVOLUTION OF DESIGN MUCH HIGHER POWER FOCUS ON PREVENTION OBJECTIVE CONTAINMENT GOOD FOR FISSION PRODUCTS BUT g, QUESTIONS ABOUT HEAT AND GAS e REACTOR SAFETY STUDY (1975)

BIGGER REACTORS .

1 PWR (SURRY) 1 BWR (PEACH BOTTOM)

BWR RESULTS' INDICATED LOWER PROBABILITY BUT P00R CONTAINMENT 4

O l

b o .-

US BWRS

(

" 4. - e 2 SMALL UNITS WITH LARGE CONTAINMENTS e 24 BWR 2/3/4 WITH MARK I CONTAINMENT (ALL LICENSED) e 9 BWR 4/5 WITH MARK II CONTAINMENT (7 LICENSED)

)

. O

!( et 4 BWR 6 WITH MARK III CONTAINMENT (3 LICENSED)

.e-i 4

g I

t k

l l.

l l

i t -

.c -

Io. .-

. BWR CONTAINMENT IN SEVERE ACCIDENTS

- SINCE TMI e TMI ACTION PLAN I.C

- LETTERS OF SEPT-NOV, 1979 ON PROCEDURES

- BWR EPG, REV 1, REV 2, REV 3, REV 4 o IDCOR ANALYSIS IDCOR FOUNDED DECEMBER 1980 STILL DELIBERATING ANALYSIS WITH NRC e NRC/ CONTRACTOR ANALYSIS SOURCE TERM STUDIES SARRP - WHAT WILL NUREG-1150 SAY?

BNL GUIDELINES AND CRITERIA e CHERNOBYL UNIT 4 HAD PRESSURE SUPPRESSION CONTAINMENT FEATURES -

= A STRIKING RESEMBLANCE?

O

a WHAT ARE THE PROBLEMS AND SOLUTIONS e 5 ELEMENTS TO CONSIDER HYDROGEN SPRAYS PRESSURE CORE DEBRIS TRAINING 8 PROCEDURES e MANY CHANGES ARE ALREADY IN PLACE 4

9 e FINAL IMPROVEMENTS ARE NOW UNDER HIGH PRIORITY STUDY GENERIC ACTION WITH IDCOR AND BWROG GENERIC WORK BY NRC VER"'.NT YANKEE-STUDY PILGRIM PROGRAM

~

o, CHRONOLOGY e JUNE 16, 1986: MEETING WITH BWROG/IDCOR PROPOSED A GENERIC LETTER, PRESCRIPTIVE SOLUTION, BY BACKFIT e JUNE 30, 1986: VERMONT YANKEE COMMITS TO GOV, KUNIN TO DO A SPECIAL 60-DAY CONTAINMENT STUDY

-o JULY 25, 1986: BOSTON EDISON COMPANY BOARD DECIDES TO FIX PILGRIM CONTAINMENT e AUGUST 19, 1986: BWROG EXECUTIVES V0TE TO FUND AND CONTINUE DIALOGUE ON THIS WITH NRC, CONTACT NUMARC ABOUT BWR VS. PWR e SEPTEMBER 11, 1986: MEETING WITH BWROG TO COMPARE BACKFIT NOTES AND STRAWMAN GENERIC REQUIREMENTS e SEPTEMBER 11, 1986: MEETING WITH VERMONT YANKEE TO REVIEW CONTAINMENT STUDY e SEPTEMBER 23, 1986: NRC/IDCOR MEETING ON BWR/ MARK I ANALYSES e SEPTEMBER 23, 1986: ACRS SUBCOMMITTEE ON CONTAINMENT PERFORMANCE TO DISCUSS HARPERS FERRY WORKSHOP RESULTS AND BWR CONTAINMENT GENERIC APPROACH e SEPTEMBER 24, 1986: ACRS SUBCOMMITTEE ON CLASS 9 ACCIDENTS TO DISCUSS BWR/ MARK I ANALYSES AND SEVERE ACCIDENT PROGRAM e NOVEMBER 19, 1986: CRGR REVIEW 0F DRAFT GENERIC LETTER ON BWR CONTAINMENT REQUIREMENTS (T0 BE PUBLISHED FOR COMMENT) e DECEMBER 17, 1986: ISSUE DRAFT GENERIC LETTER ON BWR CONTAINMENT REQUIREMENTS FOR PUBLIC COMMENT e APRIL 1987: ISSUE FINAL GENERIC LETTER ON BWR CONTAINMENT REQUIREMENTS l

.O '

i.. -

DISCUSSION e BWR MARK I CONTAINMENTS APPEAR TO BE MOST VULNERABLE e ANALYTICAL PROCESS IS VERY SLOW 1-IDCOR/NRC DIALOGUE 2-IPE METHODOLOGY SUBMITTED 3-IPE METHODOLOGY APPROVED 4-IPE GUIDELINES AND CRITERIA DEVELOPED 5-IPE GUIDELINES AND CRITERIA APPROVED 6-PROGRAM REVIEW WITH COMMISSION 7-PLANT-BY-PLANT CONDUCT OF IPE 8-PLANT-BY-PLANT SUBMITTAL OF IPE RESULTS AND PROPOSED CHANGES 9-NRC REVIEW 0F IPE RESULTS AND PROPOSED CHANGES 10-NRC ORDER, AS REQUIRED, TO IMPLEMENT NEEDED CHANGES 11-IMPLEMENTATION I

l l

1

1. -

SLIDES FROM JUNE 16, 1986 MEETING WITH BWROG I

1 l

l

c.

.o ,

1 NRC SEVERE ACCIDENT POLICY e FUTURE PLANTS STANDARD .

CONVENTIONAL REVIEW PRA e EXISTING PLANTS THEY ARE SAFE EN0 UGH IDCOR PROCESS-IS NEEDED INDIVIDUAL PLANT EVALUATIONS GENERIC TREATMENT FOR GENERIC MATTERS i _

t

~- - , - - - - , , , - . - , , , , , , , . , . ,n ,, -

1

.o 2

s.

TWO ACTIVITIES e DEVELOPMENT OF EMERGENCY OPERATING PROCEDURES SCOPE: PREVENTION AND MITIGATION EPG > PGP > E0P NOW ON EPG REV. 4 e IDCOR IPE SCOPE: PREVENTION AND MITIGATION fiETHODOLOGY ---+ IPE PROGRAM >IPE METHODOLOGY BEFORE NRC e COMMON FACTORS ARE IMPORTANT SCOPE

= -

PLANT / EVENT ANALYSIS .

S

3

s. -

CONCERNS e E0P WHAT ARE THE E0P STRATEGIES?

WHAT ARE MINIMA TO TRANSFER FROM EPG --> PGP > E0P?

ARE REQUIREMENTS CLEAR?

e IDCOR IPE IS IT AN ASSESSMENT OR AN EVALUATION?

SHALL EACH OWNER ENTER THE IPE WITH A BLANK SLATE?

ARE THERE ANY. GENERIC SOLUTIONS OR STRATEGIES EVIDENT?

PRIORITIES?

6

- . = ~ , - ,, , ,- - , , , e- -

. . . 4

. RECALL WASH-1400 .

e BWR VS PWR PROBABILITY OF CORE MELT BWR <, PWR CONSEQUENCES OF CORE MELT BWR > PWR e BWR CHARACTERISTICS

-5 BWR-3 2 x 10 TC-g TW-7 .

i BWR-2 6 x 10-6 TW-/'

=

S

, . . _. =. _ _ -. _

5 -

-s . .

A 5 ELEMENT POLICY

1. HYDR 0 GEN

2. SPRAYS

3. PRESSURE 14 . CORE DEBRIS

5. TRAINING AND PROCEDURES l

l .

l l

6 i, .

- ELEMENT 1 - HYDROGEN OBJECTIVE: PREVENT HYDROGEN COMBUSTION CAUSED FAILURE REQUIREMENTS:

A. 0XYGEN CONTROL INERT TO START CONTROL INGRESS OF OXYGEN B. HYDROGEN CONTROL CONTROLLED BURNING EQUIPMENT SURVIVABILITY

ISSUES:

< 1. WHEN AND HOW LONG NOT INERTED

2. INDEPENDENT POWER FOR IGNITERS

3. SURVEILLANCE FOR IGNITERS l

l l

l

o:'

7

=

ELEMENT 2 - SPRAYS OBJECTIVE: SPRAY WATER T0:

1. LOWER PRESSURE

2. COOL VULNERABLE EQUIPMENT

3. QUENCH DEBRIS

4. SCRUB AEROSOLS REQUIREMENTS:

1. SPRAY IN DRYWELL

2. BACKUP WATER SOURCES AND PUMPS HOSE CONNECTIONS USE OF FIREMAINS

= ISSUES:

1. RISK OF IMPLOSION

2. RISK OF HYDROGEN COMBUSTION AFTER STEAM CONDENSATION

3. MANUAL ACTIONS AND TIMING

8 k *

~

ELEMENT 3 - PRESSURE OBJECTIVES: 1. AVERT UNCONTROLLED OVERPRESSURE FAILURE

2. CONTROL RELEASE PATH (SCRUBBING)

REQUIREMENTS:

1. SUBSTANTIAL CAPABILITY TO VENT WETWELL

2. REMOTE / RELIABLE CONTROL OF VENT VALVE

3. ABILITY TO RECLOSE VENT ISSUES:

1. DELIBERATE RELEASE OR RADI0 ACTIVITY

2. WHAT IS REMOTE / RELIABLE CONTROL?

3. IS DUCT BURST IN SECONDARY .

CONTAINMENT ACCEPTABLE?

4. WHAT IS APPROPRIATE ACTION PRESSURE?

. - . - . _ _-_m -

- ~ ^

. a. .

ELEMENT 4 - CORE DEBRIS ,

+

OBJECTIVE: REDUCE LIKELIHOOD OF FAILURE BY DIRECT ATTACK REQUIREMENTS:

1. USE PRACTICAL DEBRIS RETARDING BARRIERS.

2. CONSERVE SUPPRESSION POOL WATER AS A QUENCHING POOL ISSUE: WHAT IS PRACTICAL?

=

J

,v. ,

.g 10 ELEMENT 5 - TRAINING AND PROCEDURES .

OBJECTIVE: ENSURE OPERATORS ARE READY TO USE PLANT FEATURES TO BEST ADVANTAGE IN SEVERE ACCIDENTS REQUIREMENTS:

, 1. CLEAR SYMPTOM BASED STRATEGIES (INTEGRATED)

2. REMOVAL OF UNNECESSARY INHIBITIONS

3. TRAINING / PROCEDURES ISSUES:

1. COMPETING SAFETY REQUIREMENTS

2. DEGREE OF TRAINING

' 11 /

l'- ,

AN INSTITUTIONAL APPROACH .

e GENERIC LETTER - ADVANCED NOTICE OF PROPOSED REQUIREMENTS - TO SOLICIT COMMENT e COLLECTIVE PUBLIC REVIEW e GENERIC LETTER OF REQUIREMENTS e IMPLEMENTATION WITH IPE AND EPG REV. 4 IMPLEMENTATION 1

O h

- _ _ - _ . ._m.__ , --_.- . _._ . . ._._,