ML15238A492
| ML15238A492 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/18/1981 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Parker W DUKE POWER CO. |
| References | |
| NUDOCS 8201070312 | |
| Download: ML15238A492 (7) | |
Text
DISTRIBUTION:
HOrnstein Docket File PWagner NRC PDR L PDR Dockets Nos. 50-269, 270 & 287 TERA NSIC ORB#4 Rdg Mr. William 0. Parker, Jr.
OELD Vice President - Steam Production AEOD Duke Power Company IE-3 P. 0. Box 33189 ACRS-10 422 South Church Street GVissing Charlotte, North Carolina 28242 SHanauer Gray File
Dear Mr. Parker:
EBlackwood RIngram We have reviewed your "60 day" response dated October 20, 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 committed to provide its recommendations for further actions regarding PTS to the Commission in the Spring of 1982, it is 'inportant that your."150-day" response to our August 21 letter provide twosignificant pieces of informa tion. First, you must provide your basis for continued operation, pending completion 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.
Second1j1y, your response should fully adress the information addresse 4.
He have prepared Enclosure 2 to provide amplification t" ie "150-day" information request of the August 21, 1981 letter.
The additional information requested by the letter should be provided in accordance with 10 CFR 50.54(f) of the Commission's regulations.
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, Thomas M. Novak, Assistant Director
-0f0 3 -1 _D8f! 24 i for Operating Reactors PRAcCK00 PDA)
Division of Licensing
Enclosures:
- see previous 318 for
- 11.
Evaluation of the "60-day" concurrence OFFICt
~
Response to 8/201/61 Ltr.
ORB#4:DL ORB#4:DL FCE
- a... of ".5.,
SURNAME to 8/.1..1.
t..8/21......12/1 7/Ltr..12/./.
NRC FORM 318 (1o.WR6A~opage OFFICIAL R ECO RD COPY USGPO: 1981-335-960
-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.
(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 warm prestressing for some event sequences, include your justification and analyses showing that such events will follow a pressure-temperature path way for which warm pre-stress is effective.
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, Thomas H. Novak, Assistant Director for Operating Reactors Division of Licensing
Enclosure:
Evaluation of 60 Day Response to 8/21/81 URC ltr. on PTS &
Request for Additional Information cc w/enclosure:
See next page ORB 4:DL B#4:D DST AD:OR:DL OFFICE SURNAME.
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/81
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N.C. 0 OFFICIA RECORD COPY 980 NRC FORM 318 (10-80) NRCM 0240 OFF IC IAL RE CORD COPY USGPO. 1981-335-960
0 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 December 18, 1981 Dockets Nos. 50-269, 270 & 287 Mr. William 0. Parker, Jr.
Vice President - Steam Production Duke Power Company P. 0. Box 33189 422 South Church Street Charlotte, North Carolina 28242
Dear Mr. Parker:
We have reviewed your "60 day" response dated October 20, 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 committed to provide its recommendations for further actions regarding PTS to the Commission in the Spring of 1982, it is important that your "150-day" response to our August 21 letter provide two significant pieces of informa tion. First, you must provide your basis for continued operation, pending completion 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 amplification to the "150-day" information request of the August 21, 1981 letter.
The additional information requested by the letter should be provided in accordance with 10 CFR 50.54(f) of the Commission's regulations.
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, Thomas M. Novak, Assistant Director for Operating Reactors Division of Licensing
Enclosures:
- 11.
Evaluation of the "60-day" Response to 8/21/81 Ltr.
- 2. Amplification of "150-day" Requests to 8/21/81 Ltr.
cc w/enclosures:
see next page
Duke Power Company cc w/enclosure(s):
Mr. William L. Porter Duke Power Company P. 0. Box 33189 422 South Church Street Office of Intergovernmental Relations Charlotte, North Carolina 28242 116 West Jones Street Raleigh, North Carolina 27603 Oconee County Library 501 West Southbroad Street Walhalla, South Carolina 29691 Honorable James M. Phinney County Supervisor of Oconee County Walhalla, South Carolina 29621 Regional Radiation Representative EPA Region IV 345 Courtland Street, N.E.
Atlanta, Georgia 30308 William T. Orders Senior Resident Inspector U.S. Nuclear Regulatory Commission Route 2, Box 610 Seneca, South Carolina 29678 Mr. Robert B. Borsum Babcock & Wilcox Nuclear Power Generation Division Suite 220, 7910 Woodmont Avenue Bethesda, Maryland 20814 Manager, LIS NUS Corporation 2536 Countryside Boulevard Clearwater, Florida 33515 J. Michael McGarry, III, Esq.
DeBevoise & Liberman 1200 17th Street, N.W.
Washington, D. C. 20036
ENCLOSURE (1)
EVALUATION OF THE DUKE POWER COMPANY 60 DAY RESPONSE TO THE NRC LETTER DATED AUGUST 21, 1981 CONCERNING PRESSURIZED THERMAL SHOCK (PTS) AND REQUEST FOR ADDITIONAL INFORMATION OCONEE UNIT 1 DOCKET NO. 50-269
- 1.
RNT Values
-- NDT-K us We have reviewed your letter dated October 20, 1981, and accept your values of initial RTNDT, current RTNDT and current fluence at the critical longi tudinal weld.
- 2. Rate of Increase of RTNDT You have provided a rate of increase in fluence per EFPY at the peak loca tion and at the critical weld location, which takes account of a recent change in fuel management. We accept these values.
- 3. & 4. RT Limit and Basis for the Limit LDT Since the "60 day" response stated that you do not consider a limit on RTNDT to be an appropriate basis for continued operation, the staff needs to develop a quantative criterion for continued operation that, if implemented, would assure maintenance of an acceptable low risk of vessel failure from PTS event for the near-term, pending longer term results of more detailed analysis or research. We will be developing this criterion considering recommendations that you may provide in your "150 day" response.
- 5. Operator Actions The extent to which the overall concern of thermal shock is being emphasized at Oconee Unit 1 has been the subject of discussions between staff personnel (Project Manager and Resident Inspector).
From these discussions we recognize that PTS has received some emphasis in briefings, training and procedures and the operators are sensitive to thermal shock considerations. However, we cannot determine from your "60 day" response to our letter of August 21, 1981, the
Oconee 1
-2 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 dis cussion of what steps have been taken to ensure that your operators have a firm grasp of this issue and can be expected to cope with the events which serve to initiate PTS.
ENCLOSURE (2)
AMPLIFICATION OF THE "150-DAY" REQUEST TO THE AUGUST 21, 1981 LETTER (1) Identification of the PTS events that were considered in reaching your conclusions, and a justification for PTS events that you did not consider. You should include 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 inittal crack size, copper content, fluence, and initial reference temperature at welds.
(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 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 effective.