ML20039G827
| ML20039G827 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 12/18/1981 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Groce R Maine Yankee |
| References | |
| NUDOCS 8201190188 | |
| Download: ML20039G827 (6) | |
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L PDR IE 3 ocke TERA ACRS-10 DEC 181981 DR HISC BRequa Docket No. 50-30@RB#3 Rdg PKreutzer-3
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TNovak Mr. Robert H. Groce RECEIVED Senior Engineer - Licensing g7 Maine Yankee Atomic ~ Power Coupany DEC2at h rn 1671 Worcester Road
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Framingham, Massachusetts 01701 88"p m
Dear Mr. Groce:
We have reviewed yout "60 day" re:ponse dated Novecher 2,1981, to our letter dated August 21, 1981, concerning Pressurized Thermal Shock (PTS). to this letter identifies additional information needed as a result of our review of your response. We request that the additional information identified in Enclosure 1 be provided with your "150-day" response to our August 21 letter.
In addition, we have been assessing what information will be provided in the "150-day" responses due in January 1982 and the information expected to be supplied from the PWR Owners' Group. Since the staff is comnitted to provide its reco.waendations for further actions regarding PTS to the Coniaission in the Spring of 1982, it is important that your "150-day" response to our August 21 letter provice two significant pieces of informa-tion. First, you nost provide your basis for continued operation, pending conpletion of any longer term studies. We emphasize that continued opera-tion of your facility, without any immediate modifications to your facility or its operation, will be dependent upon our evaluation of your response.
Secondly, your response should fully address the information addressed in.
We have prepared Enclosure 2 to provide anplification to the "150-day" information request of the August 21, 1981 letter.
The additional information requested by this letter should be provided in accordance with 10 CFR 50.54(f) of the Commission's regulations.
l The reporting and/or recordkeeping requirements of this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely, Original signed by:
139oggg Thomas M. Novak, Assistant Director
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P ADOCM o 2228 for Operating Reactors PD ooh Division of Licensing D:DS SHa a er
Enclosures:
- See previous 318 for concurrence.
12//g/81 l
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E 2-(3) Your assessment of the sensitivity of your analyses to uncertainties in input values, such as initial crack size, copper content, fluence, and inital reference temperature at welds.
L (4) A list of assumptions relied upon in reaching your conclusions.
a.
If this list includes " credit" for operator actions. describe the basic instructions given the operators (for example, if a "sub-cooling" band is used, describe it). Submit the procedures the operator will follow, and describe the training being given to establish operator readiness to cope with PTS events, b.
If the list includes credit for the effects of wam prestressing for some event sequences, include your justification and analyses stming that such events will follow a pressure-temperature path-way for which wam pre-stress is effective.
The reporting and/or recordkeeping requirevaents of this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
Sincerely, Thomas fl. Ilovak, Assistant Director for Operating Reactors Division of Licensing
Enclosure:
Evaluation of 60 Day Response to 8/21/81 11RC ltr. on PTS &
Request for Additional Information cc w/ enclosure:
See next page s
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_-_______-________A
' Maine Yankee Atomic Power Company CC:
E. W. Thurlow, President Mrs. L. Patricia Doyle, President Maine Yankee Atomic Power Company SAFE POWER FOR MAINE Edison Drive Post Office Box 774 Augusta, Maine 04336 Camden, Maine 04843 Mr. Donald E. Vandenburgh First Selectman of Wiscasset Vice President - Engineering Municipal Building Yankee Atomic Electric Company U. S. Route 1 20 Turnpike Road Wiscasset, Maine 04578 Westboro, Massachusetts 01581 Mr. Gustave A. Linenberger John A. Ritsher, Esquire Atomic Safety and Licensing Board Ropes & Gray U.S. Nuclear Regulatory Commission 225 Franklin Street Washington, D. C.
20555 Boston, Massachusetts 02110 David Santee Miller, Esq.
l Mr..Rufus E. Brown 213 Morgan Street, N. W.
j Deputy Attorney General Washington, D. C.
2Q001 State of Maine Augusta, Maine 04330 Mr. Paul Swetland
' Resident Inspector / Maine Yankee Mr. Nicholas Barth c/o U.S.N.R.C.
Executive Director P. O. Box E Sheepscot Valley Conservation Wiscasset, Maine 04578 Association, Inc.
P. O. Box 125 Mr. Cha'rles B. Brinkman Alan, Maine 04535 Manager - Washington Nuclear Operations Combustion Engineering Inc.
Wiscasset Public Library Association 4853 Cordell Avenue, Suite A-1 High Street Bethesda, Maryland 20014 Wiscasset, Maine 04578 Mr. John H. Garrity, Director Mr. Torbet k Macdonald, Jr.
Nuclear Engineering & Licensing Of fice of Energy Resources Maine Yankee Atomic Power Company State House Station #53 Edison Drive Augusta, Maine 04333 Augusta, Maine 04336 Robert M. Lazo, Esq., Chairman Atomic Safety and Licensing Board U.S. Environmental Protection Agency U.S. Nuclear Regulatory Commission-Region I Office Washington, D. C.
20555 ATTN:
Regional Radiation Representative JFK Federal Building Dr. Cadet H. Hand, Jr., Director Boston,, Massachusetts 02203 Bodega Marine Laboratory University of California Bodega Bay, California 94923 State Planning Officer Executive Department 189 State Street Augusta, Maine 04330 e
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EVALUATION OF THE MAINE YANKEE ATOMIC POWER COMPANY 60 DAY RESPONSE TO THE NRC LETTER DATED AUGUST 21, 1981 CONCERNING PRESSURIZED THERMAL SHOCK (PTS)
AND REQUEST FOR ADDITIONAL INFORMATION MAINE YANKEE ATOMIC POWER PLANT DOCKET 50-309 1.RTNDT values Your,responseo'fNovember2,1981,providedaninitklRTi4DTvalueof-300F for the weld metal, which we understand was for the surveillance weld and which matched the circumferential beltline. weld material. For the longitu-dinal beltline welds, which.are more critical for PTS events,.your letter dated October 27, 1981, provided an initial RTNOT value.of +10 F as estimated "
per branch technical position MTEB 5 2 Thi is the val e we nte d t use.unless you can support a lower value. basehontestso archevaSmakeria),
previously unreported. data from vessel vendor's records, or.a sound generic study of representative welds (in that order of preferencek We cannot determine
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1 if the vessel ID fluence of 5.4 x 10 8n/cm Se
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isthefluenceforthecriticallongitudinalsokds.ptkmber30 leaseverNJ.orprovide nl we the peak fluence at the critical longitudinal welds. When the above is pro-vided we.will then be able to verify your current RTNDT values.or determine another value which we will use in our independent assessments.
2.
Rate of Increasing RTNDT BeforewecanherifyyourendoflifeRTNDT values we must have the increase in fluence per EFPY at the critical longitudinal welds. This is particularly necessary if you contemplate changing core configurations. Also.we request the copper and nickel content of the critical longitudinal welds.
- 3. & 4.
RTNDT Limit and Basis for the Limit Since the "60 day" response stated that you do not consider a limit on RT to be an appropriate basis for continued operation, the staff needs to debopaquantitativecriterionforcontinuedoperationthat,.ifimplemented, would assure maintenance of an acceptable low risk of vessel failure from PTS l
events for the near-term, pending longer term results of more detailed anajysis or research. We.will be developing this criterion considering recommendations i
that you may provide in your "150 day" response.
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5.
Operator Actions The extent to which the overall concern of thermal shock which is being emphasized at Maine Yankee has been the subject of discussion between i
staff personnel (Project Manager and Resident Inspector), From these discussions we recognize that PTS has received some emphasis in training and procedures and operators at Maine Yankee are sensitive to thermal shock considerations. However, we cannot determine from your "60 day" response to our letter of August 21, 1981 the degree of emphasis which is currently placed on the need for changes in procedures, training and management involvement.
We request that you expand your response to provide us a more detailed discussion of what steps have been taken to ensure that your operators have a firm grasp of the issue and can be expected to cope with the events which serve to initiate PTS.
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ENCLOSURE (2)
AMPLIFICATION OF THE "150-DAY" REQUEST TO THE AUGUST 21, 1981 LETTER j
(1)
Identification of the PTS events that were considered in reaching your conclusions, and a justificatica for PTS events that you did not consider. You should ttclude a quantitative assessment of the probability of occurrence of the various PTS events considered and not considered and an accompanying assessment of the likelihood of vessel failure vs. EFPY for the events. The manner in which you considered multiple failures of systems, components, and those resulting from operator actions should be described in detail.
(2)
A description of the steps, if any, you are taking now or plan to take in the near future to delay the rate of further embrittlement of your vessel, and your assessment of the effectiveness of those steps.
(3)
Your assessment of the sensitivity of your analyses to uncertainties in input values, such as initial crack size, copper content, fluence, and initial reference temperature at welds.
(4)
A list of assumptions relied upon in reaching your conclusions, e.
If this list includes " credit" for operator actions, describe the basic instructions given the operators (for example, if a "sub-cooling" band is used, describe it). Submit the procedures the operator will follow, and describe the training being given to establish operator readiness to cope with PTS events.
b.
If the list includes credit for the effects of warm prestressing for some event sequences, include your justification and analyses showing that such events will follow a pressure-temperature pathway for which warm pre-stress is effcctive.
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