ML20009F263
| ML20009F263 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 06/11/1981 |
| From: | Vandenburgh D YANKEE ATOMIC ELECTRIC CO. |
| To: | Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML20009F259 | List: |
| References | |
| FCY-81-15, NUDOCS 8107300223 | |
| Download: ML20009F263 (4) | |
Text
r L. ' YANKEE AT0 TIC ELECTRIC COMPANY T-
&Gk 1671 Worcester Road, framingham, Masso<husetts 01701 f<y
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June 11, 1981 FCY 81-15 Mr. William J. Dircks Executive Director for Operations United States Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Dircks:
I was pleased to receive your letter of May 1,1980 suggesting that Vermont Yankee pursue an alternative to a pre-inerted containment. This is the first indication we have received that the NRC might entertain an alte rnative proposal.
The recent incident at Browns Ferry Unit III involving the leakage of many thousands of gallons of primary coolant into the primary containment over a relatively short period is particularly germane to the discussion of p re-i ne r ting. The incident, later determined to be caused by a Icaking valve packing, resulted in a site alert, a plant shutdown and, of course, some negative publicity. No radiation was released to the environment, and NRC officials were able to characterize it as being of minor importance. The fact that it took approximately 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> f rom the time excessive leakage was detected until the source of the leakage was identified seems anything but of minor importance to u.
Had the source been ident"fied, at the insipient stages the icak could have been reduced or stopped completely (eg. the valve backseated) and gross leakage could have been avoided.
Early diagnosis of problems is of inestimable benefit in planning subsequent actions.
Through numerous communications to the NRC, including presentations to the ACRS Subcommittee on the TMI Action Plan and to the Commissioners themselves, Vermont Yankee has stressed the fact that access to the primary containment significantly increases the operator's ability to monitor and control Icakage into the containment, thereby rede ing unnecessary plant shutdowns and the resultant thermal cycling.
It is a documented fact that, on several occasions, Vertuont Yankee operators have made drywell entries to investigate drywell leakage and have found packing leaks on similar valves to the one that caused this incident.
On these occasions, the Icakage was reduced to an acceptable level or entirely eliminated in a very short time because the containment was accessible. Thus, the potential for a more se rious incident was eliminated and a plant shudown cycle avoided.
8107300223 810714 DR ADOCK 05000 g,d Off. EDO, '
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',.*~t Mr. Willien J.. Dircks
. June 11, 1981 Page 2 The Browns Ferry ~ Ill incident is.-only one _ example of the many. significant countervailing safety disincentives 'to containment inerting which do' exist in the real world of everyday plant operation. We must again state tiIit we remain firmly convinced that, in the words of the NRC staff, "... [the] small
... decrease in-theo retical risk..." obtained through inerting is
- overwhelmingly _ outweighed by. the very real gains in operational safety available through operator action in an accessible containment.
- We~again
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strongly encourage you to seriously. reconsioer_ the NRC's position on the relative importance of the theoretical risk of pre-inerted operation and the
-documented gains in operational safety to be had by operating with a non-inerted containment.
With regard to your suggestion concerning, alternatives, we would be happy to initiate discussions with the Staff (NRR) in order to pursue more acceptable solutions to your hydrogen combustion concern. However, over the last. several months we have been under very heavy pressure from the NRC staff to prepare for mandatory containment inerting (via order o; an interim rule on degraded cores).. Recent informal contact with the stafr has shown that.there i
is essentially no serious interest in considering any alternative to i
pre-inerting. Before we could participate in activities relative to hydrogen control. that could possibly provide a viable alternative, we must receive some l
assurance from the commission that no precipitouu ar.d perhaps irreversible action would be _ taken that would foreclose: successful implementation of an alternate scheme. Such assurances must originate from your office or from the i
Commissioners themselves since the staff is uninterested.
i We believe an effort of this nature holds considerable potential for
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practical, industry-wide safety benefits. We await your response in this very l
Important matter.
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Very truly yours, 0*
D. E. Vandenburgh j
Senior Vice President s
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1 ACTION CONTROL DATES CONTROL NO.
FROM:
L "D. E.!Vandenburgh COMPL DE AOLINE 4/22/81 10360 Yankee Atomic Electric Company ACK N OWLE DGM E NT DATE OF DOCUMENT INTERIM REPLY g f pg fg]
TO; PREPARE F R SIGNATURF.
Chaiman Hendrie FIN AL REPLY FILE LOCATICN O ExECuT:Vi DIRECTOR
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DESCFilPT )N O LETTER OMEMO O REPORT OOTHER SPECIAL INSTRUCTIONS OR REMARKS Encourage the Commission to reconsider relative importance of theoretical risk and real risk before taking final action on the proposed interim requirements related 'to ' hydrogen control and certain degraded core considerations rule CLASSIFIED DATA DOCUMENT / COPY NO.
CL ASSIF IC ATION l NUMBER OF PAGES CATEGORY POSTAL REGISTRY NO.
O NSI O RD D FRD SECY-81-0448 ASSIGNED TO:
DATE INFORMATION ROUTING LEGAL REVIEW D FIN AL O COPY Minogue, RES 4/6/81 Shapar ASSIGNED TO:
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81-0448 Not L%png De*e 3/ 3 0/81 NRC sECRETARI AT TO:
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re the pro nla interim requirements related 1
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