ML14192A301
| ML14192A301 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 12/18/1981 |
| From: | Novak T Office of Nuclear Reactor Regulation |
| To: | Jackie Jones Carolina Power & Light Co |
| References | |
| NUDOCS 8201250233 | |
| Download: ML14192A301 (6) | |
Text
DISTRIBUTION:
SHanauer Docket File /
GVissing NRC PDR CParrish L PDR Gray File Docket No. 50-261 TERA NSIC ORB#l Rdg Mr. J. A. Jones OELD ED Senior Vice President AEOD Carolina Power and Light Company DEisenhut JAN 51982> 8 336 Fayetteville Street IE-3 US OMAOUwcoalssa Raleigh, North Carolina 27602 ACRS-10
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Dilmemiff JAENRa WRoss
Dear Mr.. Jones:
SVarga We have reviewed your "60 day" response dated October 26, 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. Sincethe staff is.committed to provide its recommendations for further actions regarding PTS to the Commission in the-Spring of 1982, it is rmportant _-Lat your "15idy" 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, 8201250233 811218 Thomas M. Novak, Assistant Director PDR ADOCK 05000261 PDRAOK0006 for Operating Reactors P
PDR Division of Licensing
Enclosures:
3 for
- 1. Evaluation of the "60-day" coeeupreiou 12//V8 Response to 8/21/81 Ltr.
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NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY USGPO: 1981-f3o5-96
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) Your assessment of the sensitivity of your analyses to uncertainties in\\input values, such as initial crack size, copper content, fluence, and in ital.reference temperature at welds.
(4) A i'st of assumptions relied upon in reaching your conclusions.
- a. I this list includes "credit" for operator actions, describe the ba'i-c instructions given the operators (for example, if a "sub cooli nq" band is used, describe it).
Submit the procedures the operat6 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'\\equences, include your justification and analys'es showing that such events will follow a pressure-temperature path way for which warm re-stress is effective.
The reporting and/or recordkeepy g requirements of this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
>incerely, Thomas M. ovak, Assistant Director for Opera ing Reactors Division of Licensing
Enclosure:
Evaluation of 60 Day Response to 8/21/81 NRC 1tr. on PTS &
Request for Additional Information cc w/enclosure:
See next page OFFICE
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NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COP Y USGPO: 1981-335-960
Mr. J. A. Jones Carolina Power and Light Company cc: G. F. Trowbridge, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.
Washington, D. C. 20036 Hartsville Memorial Library Home and Fifth Avenues Hartsville, South Carolina 29550 U. S. Nuclear Regulatory Commission Resident Inspector's Office H. B. Robinson Steam Electric Plant Route 5, Box 266-1A Hartsville, South Carolina 29550 Michael C. Farrar, Chairman Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Richard S. Salzman Atomic Safety and Licensing Appeal Board.Panel U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Dr. W. Reed Johnson Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission Washington, D. C. 20555
ENCLOSURE (1)
EVALUATION OF THE CAROLINA POWER AND LIGHT COMPANY 60 DAY RESPONSE TO THE NRC LETTER DATED AUGUST 21, 1981, CONCERNING PRESSURIZED THERMAL SHOCK (PTS) AND REQUEST FOR ADDITIONAL INFORMATION H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261
- 1. RTNDT Values We intend to use the initial RTNDT values as provided in your letter dated October 26, 1981.
You have indicated that your current RTYDT values are based on ASTM trend curves. There are no "ASTM trend curve as yet. The draft standard that is about to be balloted by the Task Group of ASTM Subcommittee E 10.02 has only a mean curve and a figure showing the scatter in the data. The upper limit curves recommended by the Metal Properties Council (MPC) report (which appear to be the curves referred to in your letter) were not accepted by the ASTM Task Group. Therefore, we cannot accept the figure of 242oF which was given for RT (and also for the shift since the initial RT was zero). The value TARTNDT given by Reg. Guide 1.99 Rev. 1 and al8T by some new, tentative trend curves based on PWR surveillance data for high nickel material is 2900 F. In arriving at the current RT value for the longitudinal welds you indicated that the values wereNUrived based on high copper, high nickel weld materials. Yet you indicated that the welds actually contain low nickel. This should be verified if at all possible and your RTNnT values adjusted accordingly. We are developing low-nickel trend curv that predict a lower shift for low nickel material.
Please address these discrepancies in our estimates of ARTNDT, in your 150 day response. We have no disagreement with your current fluence values.
- 2. The Rate of Increase of RTNDT We have no disagreement with your response to Item 2 but should point out that although the 10 year average change in RTNDT is 70F, the change in one EFPY from today is 110 F, based on MPC trend curves. In addition, please provide the expected rate of fluence increase per EFPY taking into consideration any contemplated changes in core configuration.
3 and 4. RTNDT Limit and Basis for the Limit You have indicated in your letter dated September 21, 1981, that the response to Item 3 & 4 of the August 21 letter will be provided in the 150 day response. Since the "60-day" responses from other licensees stated that PWR owners generally do not consider a limit on RTNDT to
-2 be an appropriate basis for continued operation, the staff needs to develop a quantitative criterion for continued operation that, if implemented, would assure maintenance of an acceptably low risk of vessel failure from PTS events for the near-term, pending longer term results of more detailed analyses or research. We will be developing this criterion, considering recommendation that you may provide in your 150 day response.
- 5. Operator Actions The extent to which the overall concern of thermal shock is being empahsized at Robinson 2 has been the subject of discussions between staff personnel (Project Manager and Resident Inspector).
From these discussions it is not apparent to us that this issue has received the emphasis we consider advisable, especially in informing and retraining the operators at the H. B. Robinson station. Also, 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 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 initial 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.