ML20093K889
| ML20093K889 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 10/16/1995 |
| From: | Jackie Cook ILLINOIS POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-95-07, GL-95-7, JGC-429-95, L30-95(10-16)LP, NUDOCS 9510250077 | |
| Download: ML20093K889 (4) | |
Text
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Chnton Power Station P.O. Box 678 Chnton. IL 61727 Tel 217 935-5623 Fax 217 935 4632 John G. Cook Vice President IL*LIN 915 u-co2506 PSMR L30-95(10- 16)LP 8G.120 JGC-429-95 October 16, 1995 Docket No. 50-461 Document Control Desk Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Illinois Power's (IP's) Response to Generic Letter (GL) 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-Ooerated Gate Valves"
Dear Sir:
GL 95-07 requests that licensees perform or confirm they have previously performed evaluations of safety-related power-operated gate valves for susceptibility to pressure locking an_d/or thermal binding and to take appropriate corrective actions to ensure that these valves are capable of performing their required safety functions. The GL provides a two-step approach:
1)
Within 90 days of the GL, perform a screening evaluation of operational configurations of all safety-related power-operated gate valves for pressure locking / thermal binding and document the basis that potentially susceptible valves are operable. If operability cannot be supported, licensees are expected to take appropriate Technical Specification actions.
2)
Subsequently, within 180 days, licensees are to perform a more detailed evaluation and implement corrective actions (or justify longer schedules) for the valves determined to be susceptible to pressure locking or thermal binding.
The generic letter requires that licensees submit within 60 days of GL 95-07 issuance, a written response indicating, "If the addressee intends to implement the requested action (s), provide a schedule for completing implementation." Clinton Power Station (CPS)is providing this letter to fulfill the 60 day reporting requirement. Listed below are actions taken by CPS prior to GL 95-07 issuance, actions to be taken as part of the Generic Letter 95-07 analyses, and a schedule for corrective actions to be taken for GL 95-07. These actions are intended to fulfill GL 95-07 requirements.
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Page 2 The subsequent sections list a chronology of actions that have been completed since 1993, are underway, or planned to meet the requirements of GL 95-07, Actions Taken as a Result of NRC Information Notice 92-26 Based on information provided in NRC Information Notice 92-26, " Pressure.
Locking of Motor Operated Flexible Wedge Gate Valves," issued April 2,1992, CPS modified the High Pressure Core Spray (HPCS) injection valve IE22F005 to prevent potential pressure locking. This modification was implemented during the fourth refueling j
outage (RF-4) which started in March 1993, and was a portion of a larger modification j
being implemented to support GL 89-10, " Safety-Related Motor-Operated Valve Testing and Surveillance," requirements.
Actions Taken for CPS's 89-10 Program In May 1994, CPS completed design basis evaluations for susceptibility to pressure locking and/or thermal binding of Probabilistic Risk Assessment (PRA) safety significant valves { safety significant valves}. Emphasis was placed on the safety significant valves because low PRA safety significant valves { low safety significant valves} collectively, contribute less than 0.01% of the power operated valve (POV) contributions to core damage frequency, failure to isolate containment, provide for containment heat removal, 4
i containment venting and containment / reactor pressure vessel flooding.
As a result of these design basis evaluations, CPS determined that the Emergency Core Cooling System (ECCS) injection valves were potentially susceptible to pressure locking under design basis conditions. CPS then modified the Low Pressure Core Injection (LPCI) "A", "C", IE12F041 A, C and Low Pressure Core Spray (LPCS) injection IE21F006 valves during RF-5 (March 1995) to alleviate any pressure locking concerns for them. As such, Divisions I, II, and III have injection valves modified to alleviate any pressure locking concerns.
The LPCI "B" valve IE12F041B is scheduled for modification during RF-6 (scheduled for October 1996). An operability evaluation in accordance with GL 91-18, "Information to Licensees Regarding Two NRC Inspection Manual Sections on Resolution of Degraded and Nonconforming Conditions and on Operability," was performed for the LPCI "B" valve. This evaluation determined that the LPCI "B" valve is operable.
Evaluations for low safety significant valves commenced after the safety significant valve evaluations were complete. These design basis event evaluations on low safety significant valves will be completed within the 90 day period requested in GL 95-07. Any i
actions regarding these valves will be addressed under CPS's GL 95-07 resolution.
a U-602506 Page 3 Generic Letter 95-07 Analyses The CPS scope of the POVs in the GL 95-07 analyses are safety-related gate POVs having an active safety function to open. This is consistent with industry /NRC discussions and feedback regarding GL applicability. In addition to the design basis event evaluation stated previously, POVs in the GL scope are being analyzed for operational configurations, bounded by the design basis, which could result in pressure locking or thermal binding. If any of the POVs are determined to be susceptible, the POV's operability evaluations will be documented, or actions taken in accordance with CPS Technical Specifications, if necessary. This activity will be completed within the 90 day period request-d in the GL.
In GL 95-07, the NRC suggested that the schedule for corrective actions may be based upon risk significance. CPS will prioritize corrective actions in accordance with a POV's safety significance. Listed below is the schedule for corrective act >ns.
L Schedule of Corrective Actions Susceptible safety significant POVs will be modified or other appropriate measures taken by completion of the next refueling outage (RF 6). Corrective actions for low safety POVs will be completed by RF-7 (scheduled for April 1998). However, an operability evaluation in accordance with GL 91-18 will have been performed for these valves to support their operability until such time they are modified or other appropriate measures taken. Procedural changes associated with pressure locking / thermal binding concerns will be completed prior to RF-6.
Further Reports CPS will submit another written response within 180 days from the date of GL 95-07 issuance with the additional information requested in the generic letter. provides an affidavit supporting the facts set forth in this letter.
Sincerely yours, d
.u. Cook Vice President JSP/csm Attachment cc:
NRC Clinton Licensing Project Manager NRC Resident Oflice, V-690 Regional Administrator, Region III, USNRC Illinois Depanment ofNuclear Safety
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c to U-602506-i J. G. Cook, being first duly sworn, deposes and says: That he is Vice President of the Nuclear Program at Illinois Power; that this letter supplying information for Generic Letter 95-07 has been prepared under his supervision and direction; that he knows the contents thereof; and that to the best of his knowledge and belief said letter and the facts contained therein are true and correct.
I This /b day ofOctober 1995.
Date:
Signed:
J.G. Cook STATE OF ILLINOIS l SS.
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Subscribed and sworn to before me this Mday of October 1995.
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(Notary Public)