ML20154D799

Forwards Documents Re Background Info on Util Violation of 10CFR50.44,per Request

ML20154D799
Person / Time
Site:	Pilgrim
Issue date:	07/24/1981
From:	Robert Carlson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Wessman R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
Shared Package
ML20154D739	List: ML20154D737 ML20154D749 ML20154D775 ML20154D786 ML20154D799 ML20154D811 ML20154E181 ML20154E200 ML20154E235 ML20154E256 ML20195F929
References
FOIA-88-198 NUDOCS 8809160116
Download: ML20154D799 (6)

Text

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50-293 S:

F01004888 g g4 NOTE TO:

Richard Wessman. Chief. Enforcement Branch. IE FROM:

Robert T. Carlson. Director. Enforcement and Investigation Staff. R!

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SUBJECT:

BOSTON EDISON COMPANY - PILGRIM RECOMMENDED ESCALATED ENFORCEMENT ACTION The enclosed documents are forwarded per your request for background information on the Pilgrim violation of 10 CFR 50.44.

f Robert T. Car *1 son. Director Enforcement and Investigation Staff

Enclosures:

1.

SER 8/25/71 2.

BEco Itr to 00L. 6/13/74 I

3.

Ippolito ltr to Andognini. 3/14/79 4

Andognini Itr to Ippolito. 6/6/79 I

5.

Andognint Itr to Ippolito. 10/19/79 l

6.

Ippolito Itr to Andognini, 10/30/79 7.

LER 81-021/01X-0, 6/16/81 i

E.

Novak memo to Moris t. 6/26/81

10. RI Daily Rpt. 7/31/80

11. RI Daily Rpt. 9/9/80 i

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August 25, 1971 i

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SAFETY EVALUATION SY Tilt i

. DIVISION OF REACTO. R LICENSING _.

U.S. ATOMIC ENERCY COMMISSION, t

IN THE MATTER OF i

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50STON EDISON _COMPA Q eit.CRIM WUCLEAF. POWER STATION i

DOCKET NO. 50-293 i

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4.1.2 Co n t a,1,nfe,n,t,,A,t no s p h e,r e, C,o n t,r o 1, Fo11 ovine a loss-of-coolant accident (IDCA), (a) hydrogen pas could be menerated inside thn orteary containment f rom a chemical reaction between the fuel rod claddina and steam (metal-water reaction), and (e) both hydroedn and oxymen would be menerated as a rasult of redi-olytic decoeposition of recirculatine coolant solutions. If a sufft-cient ascunt of the hydroren is generated and oxyeen is asa11able in stoichiometric quantities, the subsequent reaction of hydrogen with U

C oxygen at rates rapid enouth to lead to significant over-pressure 3

could lead to f ailure of the containnent to maintain low leakare integrity.

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The applicant croposes ventint of the containwnt as the corrective 3

seasure if the monitored hydrocen concentration inside the containeent shows sips of so, 9achine the lover flamability limits. The proposed l

ventine involves ournina containaent atmosphere with air and ventine i

in a controlled manner through the standby Ras treatment sys'eu to the l

I stack.

We have concluded that a hydrogen control system should be provided.

La addition to the nurstne system pronosed be the apnitcant, to keen l

C the hydrogen content within safe limits:

1.e., less than 4 volum l

3 percent.

In its report on the Dresden 3 facility, the ACRS recosamended I

that a reasonable time period be allowed for the desten of such a system l

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and appropriate review by the reeulatory staf f.

Special Report No.14 l

subnitted for Dresden Unit 3 in response to our letter to Cosmnwealth l

Edison Company dated December 22, 1970 provided additional information on post-accident covbustible eas control for Dresden Unit 3.

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Special Raport provides a conceptual desien of a flamability control i

system and a containnent atmosehere nonitorine system. As was the case for the Dresden Unit 3 facility. installation of a corbustible I

eas control systers would require a chante in the desian of the Filaria f acility af ter the construction retnit had been issued, since we had not considered the problem of corbustibio sas can'.rol l

durine, our construction permit review of the Filaria aeotteation, we i

i evaluated this ratter in the lieht of 13 CTR 50.109 which states that 1

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the Comission may require the backfittine of a f acility if it finds that such action will provide substantial additional protection which is required for the public health and safetf. Our calculations in

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accordsace with AIC Safety Guide No. 7 on other similar plants has indicated that the production of hydrogen is auch that purains would be required within about 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> following a less-of-coolant accident.

I The radiolosteal consecuences from such releases usins the existine standby eas treateent system calculated by us for another sisitar plant i

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- 38 indicate that the incremental doses could be sienificant. Thus the capability to control the hydrogen concentration by pensures not requiring release to the environment with the present system would pro-vide a eubstantial reduction in the total offsite doses that mieht i

result from the accident.

L We have concluded that the backfitting of the Pilgrim facility in 1

I this regard will provide substantial additional protection required for i

the public health and sa fety, but that the desian and installation of a

the systen need not be coseleted prior to issuance of an operatint I

license. We believt this action to be consistent with the advice of l

the ACR$ as given on the Dresden 3 facility, i.e., that action should i

i be achieved on a reasonable time basis. We will require the applicant to submit the derailed desirn and schedule for the installation and testing of a cet inment atmosphere senitorina system and control system to meet the desipn basis riven in Safety Guide 7.

The prir.ary containment will be provided with an inert atmosphere of nitrogen durina reactor sever operation, keepine the containtient atm-sphere oxygen concent ration less than 5?. by weteht. in order to ministre I

t the possibility of the combustion of tydroten evolwd from a strcontum-I j

water reaction durine the first few minutes following a loss-of-coolant i

accident.

The inert atnoschere will also extend the time available to cope with the hedromen evolved fron radiolvsis of the ortmtv coolant.

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. 5 Ve recomise that inertinr makes insnection and repair of the orieary

.4 tysten core difficult and believe that it is erudent to permit short o

l t term personnel access to the drvve11 for leak inspections durine l

l startup/ hot standby periods when the primary systen is at or near rated l

l operatine temperature and pressure. Accordinely, a 24-hour transition l

I period is permitted to inert subsequent to inspections and the place-ment of the reactor in the Rm ?bde, and to deinert durine operation l

prior to a shutdown without stanificantly af fecting plant safety, j

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Containment inerting has been requirnd for all nrevious boilinr water reactor pressure suppression containwnts. We conclude that the inerting system for the Pilerim Station provides additional plant safety

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which outaeiphs the operational restrictions that may re s ul t.

l 4.1.3 teolation Valves The basic function of all primry containment isolation valves is to trovide containeent intenrity between the erinary coolant system stes-sure bondary or the containment atrosphere and the environs in the l

event of accidents or sin 11ar equionent failures. Where necessary the valves are provided with valve operators, and these valves are auto-matica11y closed when the sensors detect certain accident or faulted conditions. The consequences of ecstulated pipe f ailures both inside l

and outside the containment have been evaluated.

For exanole, the operational aspects of the main steam line isolation valves for a l

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