ML19341D226
| ML19341D226 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/30/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19341D223 | List: |
| References | |
| NUDOCS 8103050176 | |
| Download: ML19341D226 (3) | |
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UNITED STATES 7)c(
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s E WASHINGTOPi, D. C. 20555
$e SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 53 TO PROVISIONAL 0"ERATING LICENSE NO. DPR-19 DOCKET NO. 50-237 INTRODUCTION By letter dated December 23, 1980, Commonwealth Edison Company (CECO) requested that the effective date of the February 21, 1980 NRC Con-firmatory Order which had previously amended the license to require installation of a recirculation pump trip, be extended from December 31, 1980 to January 4,1981 for Dresden Nuclear Power Station, Unit No. 2.
BACKGROUND Over the past eleven years the subject of anticipated transients without scram (ATWS) events and the manner in which they should be considered in the design of nuclear power plants has been discussed extensively i
i between the Nuclear Regulatory Comission (NRC) Staff and the nuclear 1
industry.
In April 1978, the Staff published a report on " Anticipated Transients Without Scram for Light Water Reactors," NUREG-0460, Volumes 1 and 2, which sumarized technical considerations related to ATWS and made recomendations.
Following additional investigations by the Staff and by the ACRS, the Staff issued Volume 3 of NUREG-0460, in December 1978.
Although final detennination of all the design changes to nuclear power plants which may be necessary to respond to ATWS events has not yet been reached, the Staff has concluded that the addition of a Recirculation Pump Trip (RPT) in boiling water reactors (BWRs) would significantly limit the imediate consequences of an ATWS event. Therefore, letters dated January 9,1979 were sent to the BWR licensees who did not have installed RPTs. These letters:
described the reasons for requiring an RPT at this time,
- described two alternative ways to provide an acceptable RPT, and requested that licensees provide an RPT implementation schedule which would provide for installation within two years.
In response to the letter of January 9,1979, and additional discussions with the Staff, the CECO comitted, by letters dated March 29, and November 30, 1979, and February 4,1980, to installation of an RPT 18103050/7s..
o' before reactor operation during calendar year 1981.
On February 21, 1980, the NRC formalized CEC 0's comitment by issuing a Confirmatory Order requiring that RPT installation be completed no later than December 31, 1980.
The licensee's request for a four-day extension cited the low probability ~
of an ATWS event as one basis.
In additico, the licensee indicated that at cower levels less than about 80',',
the recirculation pump trip feature is not r'equired to keep peak vessel pressures below the 1500 psig limit during an ATWS event. As noted below, the Dresden Unit 2 reactor power level is about 45% and decreasing.
EVALUATION The Staff has reviewed CECO's proposed extension of the date of compliance with our February 21, 1980 Confirmatory Order. The licensee has requested four additional days of operation of Unit 2, to permit more efficient use of Ceco's manpower during the end of year holiday seasca.
Based on our review, we have determined that a four day extension will result in an insignificant risk contribution to the health and safety of the public.
There will be no change in the operating mode of Cresden Unit 2 in the four-day period of operation af ter December 31, 1980.
Additionally, because Dresden Unit 2 is at the end of its operating cycle, the reactor power level is restricted by fuel burn-up consider-ation to less than 45Y. power. Therefore, the results of an Anticipated Transient without Scram event will be further reduced during the four day period of additional operation allowed by this amendment. We conclude that the additional four-day operation is an insignificant risk contributor to the health and safety of the public and is acceptable.
ENVIRONMENTAL CONSIDERATIONS We have determined that this amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significsnt environmental imoact. Having rade this determination, we have further concluded that this amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR 551.5(d)(4) that an environmental impact statement, or negative declaration and environmental-impact appraisal need not be prepared in connection with the issuance of this amendment.
CONCLUSION We have concluded: (1) because of the amendment does not involve a significant increase in the probability of consequences of accidents previously considered and does not. involve a significant decrase in
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a safety margin, the amendment does.not-involve a significant hazards J'
l consideration, (2).there is reasonable assurance that the health and safety of the public will not be endangered by operation'in the proposed manner, and (3) such activities vill be conducted in ccepliance i
with the Comission's' regulations and the issuance of this. amendment will not be inimical to the common defense and security or to the health
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and safety of the public.
i Date:
December 30, 1980 t
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