ML20093K862
| ML20093K862 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/16/1995 |
| From: | George Thomas DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-95-07, GL-95-7, NUDOCS 9510250049 | |
| Download: ML20093K862 (4) | |
Text
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eeaver vaiiev Power station Shipp ng rt PA 15077-0004 (412) 643-8069 FAX GEORGE S. THOMAS October 16, 1995 Division Vice President Nuclear Services Nuciear Power Divissort U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001
Subject:
Beaver Valley Power Station (BVPS), Unit No. I and No. 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 i
Sixty-Day Response to Generic Letter 95-07
Reference:
"NRC Generic Letter 95-07: Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," dated August 17,1995.
The referenced letter requested that certain actions be taken by utilities regarding the susceptibility and evaluation of power-operated gate valves to the phenomena of pressure locking and thermal binding. The purpose of this submittal is to provide Duquesne Light Company's (DLC's) 60-day response to GL 95-07.
The generic letter has two requested actions. First, within 90 days, perform a screening evaluation to identify the power-operated gate valves which are potentially susceptible to pressure locking or thermal binding, and, for those found susceptible, document a basis for operability. Second, within 180 days, identify power-operated gate valves susceptible to pressure locking or thermal binding, and perform further analysis and take needed corrective actions to ensure that susceptible valves are capable of performing their intended safety function under all modes of plant operation.
The responses required by the generic letter are a 60-day response providing the extent ofintended implementation of the requested actions, or alternate course of action as appropriate, and a 180-day response documenting the second requested action by providing the following information:
1.
Description of susceptibility evaluations, additional analysis, and the susceptibility criteria used.
2.
Evaluation results, including a list of susceptible valves.
3.
Corrective actions with associated schedules, and, where appropriate, justifications of operability.
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9510250049 951016 PDR ADOCK 05000334 I
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Be&ver Valley Power Station Units No. I and No. 2 d
. 60-Day Response to Generic Letter 95-07 Page 2 To complete the response to GL 95-07, DLC is participating in a program developed through the Westinghouse Owners Group (WOG).
The program will establish a common set of criteria which can be applied in the screening and evaluation of the pressure locking and thermal binding phenomena. Most of the Nuclear Steam l
Supply Systems (NSSSs),'as well as many of the valves in those systems, are common i
among the various Westinghouse plants. Thus, it is beneficial and cost effective, to both the WOG members and the NRC, to utilize the combined expertise of the member i
utilities and Westinghouse to develop a consistent, effective, and comprehensive set of screening and evaluation criteria that can be used by all WOG plants. To this end, a WOG task team of members has been formed as a part of this effort and is in the process of developing the criteria.
A set of screening criteria will be defined to identify valves susceptible to pressure locking or thermal binding, taking into account both component and system considerations. Criteria and methodology are also being developed to assist in the evaluation of each valve determined to be susceptible to pressure locking or thermal binding. Once the criteria have been established, each utility can apply the criteria to its own population of safety-related, power-operated gate valves. As susceptible valves are identified, the evaluation criteria and methodology will be used to determine the need for additional analysis and/or valve modifications.
Because of the imponance in completing the evaluations which determine what effect pressure locking or thermal binding may have on valve operability, it is believed that resources should be focused on meeting the requested 180-day actions. A WOG Task Team has established an aggressive schedule for criteria development for valves susceptible to pressure locking and thermal binding. If, at any time, the evaluation identifies a valve as being susceptible to either pressure locking or thermal binding, and corrective actions have not been taken, an operability assessment will be made and a basis for continued operability developed. If operability cannot be demonstrated, the applicable technical specification actions will be followed.
t Evaluations of BVPS gate valves for pressure locking and thermal binding were performed in response to INPO SOER 84-7, " Pressure Locking and Thermal Binding of Gate Valves," and GL 89-10. Examination of 60 valves at BVPS Unit I and 77 valves at BVPS Unit 2 resulted in either the modification or the confirmation of bonnet relief capability of 10 valves at each BVPS Unit. While the total scope of GL 95-07 extends the boundaries of these evaluations, it is believed that the evaluations and modifications already performed at BVPS satisfies the intent of the 90-day actions of GL 95-07 by significantly reducing the potential of safety related valves not performing their safety related functions due to these phenomena. Moreover, a preliminary review of BVPS power-operated gate valves, for potential susceptibility to the types of phenomena to be e
considered under the guidelines of GL 95-07, indicates that most of the valves that may t
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l Be&ver Volley Power Station Units No. I and No. 2
',60-Day Response to Generic Letter 95-07
. Page 3 4
need further evaluation are motor-operated. Because motor-operated gate valves' were the focus of the previous evaluations at BVPS, additional confidence is provided for believing that there is the reduced potential of pressure locking or thermal binding preventing significant safety functions from being performed. Based on the evaluations previously performed at BVPS, the WOG effort already in progress, and the aggressive schedule to identify and evaluate the operability of valves as they are identified, DLC plans to waive the requested 90-day action.
The actions and responses specified in the 180-day required response will be complied with. These include completion and documentation of the following:
Screening criteria.
List of susceptible valves.
Description of evaluations.
j Susceptibility evaluation results.
l Corrective actions completed or scheduled.
J Bases for continued operability, as needed.
These actions will be completed and the responses provided within 180 days of the date of Generic Letter 95-07.
If there are questions regarding this letter, please contact Roy K. Brosi, Manager, Nuclear Safety Department at (412) 393-5210.
Sincerely, Y
~3 George S. Thomas c:
Mr. L. W. Rossbach, Sr. Resident Inspector Mr. T. T. Martin, NRC Region I Administrator Mr. D. S. Brinkman, Sr. Project Manager
COMMONWEALTH OF PENNSYLVANIA)
) SS:
COUNTY OF BEAVER
)
Subject:
Beaver Valley Power Station (BVPS), Units No. I and No. 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 60-Day Response to Generic Letter 95-07 Before me, the undersigned notary public, in and for the County and Commonwealth aforesaid, this day personally appeared George S. Thomas, to me known, who being duly sworn according to law, deposes and says that he is Division Vice President, Nuclear Services of the Nuclear Power Division, Duquesne Light Company, he is duly authorized to execute and file the foregoing submittal on behalf of said Company. and the statements set forth in the submittal are true and correct to the best of his knowledge, information and belief.
i hj George S. Thomas Subscribed and sworn to before me on this/6'I ay of hdhikb NW d
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