ML20079L424
| ML20079L424 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 10/31/1991 |
| From: | Beard P FLORIDA POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9111060277 | |
| Download: ML20079L424 (3) | |
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%9 Florida Power CDMPORATeON crydal Eswv Uriit 3 DuaLa4 Na W302 October 31, 1991 3fl091 01 U.S. fluclear Regulatory Commission Attention: Document Control Desk Washington, D.C.
20555
Subject:
Revised Response to Generic l.etter 89-04 Guidance on Developing Acceptable Inservice Testing Programs
References:
A.
fPC to llRC - tetter dated October 3, 1989 B.
IPC to I4RC - Letter dated April 4, 1991
Dear Sir:
This letter is provided to inform the f1RC of florida Dower Corporation's (IPC) intentions to perform an alternate method for closure verification testing of the Borated Water Storage larik (BWST) to Decay Heat Removal Suction check valves OliV-33 and DliV-36. The method described herein is consistent with the provisions of Generic Letter 89-04, " Guidance for Developing Acceptable Inservice Testing Programs". The following discussion consists of a section with background information and an explanation of the short and long term actions being pursued to adequately test these valves.
BACKGROUND:
DHV-33 and DHV-36 are currently considered Category C valves whose safety function in the closed position is to prevent backflow from the Reactor Building Sump to the BWST in the event that the suction beader motor operated gate valves located upstream should fail to close. The Inservice testing requirements for Category C valves are specified in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Subsection IWV-3522.
Cuidance relative to meeting these requirements is provided in Attachment I to Generic letter 89-04.
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$tShk 500 A Florida Progress Company
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3fl091 01 page 2 JACKGROUND(Continued)
Reference A provided f PC's response to Generic letter 89 04.
lhls letter informed the NRC staff of IPC's plans for modifying the Decay lleaf System to provide the capability for closure verification of DilV 33 and DHV 36. leftrence B informed the NRC that the modification was studied and it was determined it would not provide the desired result. FPC stated we would evaluate additional alternatives and inform the NRC of our proposed resolution and schedule for its implementation.
IPC has evaluated several options for closure verification testing of DHV-33 and DilV-36.
The options considered required more extensive modifications of the Decay lleat pipirg than originally anticipated.
The review of the design of these valves and associated piping revealed that there was no existing external means (e.g.
position indicator) for the purpose of providing closure verification (indicating the valve disk on the seat). It would also be very difficult to achieve the appropriate conditions for identifying a pressure drop across the valves. Non-intrusive testing was performed on these valves during Refuel 7 as part of the CR-3 Check Valve Reliability Program, the results showed no degradation or abnormal characteristics of wear. Additionally, the valves are full stroke exercised once every three months during normal plant operatlon.
Generic letter 89-04 accepts disassembly and inspection as an acceptable method for demonstrating closure capabilities when used as a verification of seating contact and not to take the place of leak testing. NRC's position on the issue of acceptability of disassembling as a positive way of verifying closure of check valves has also been discussed and documented in NUREG/CP-Olll, " Proceedings of the Symposium on Inservice Testing of pumps and Valves". Therefore, FPC considers this method of testing meets the criteria of ASME Section XI, Subsection IWV 3522.
TPC has also evaluated this l
alternative testing against the criteria provided in Generic letter 89-04 (Page 3) and is satisfied that this method ts adequate for detecting valve degradation.
SHORT TERM ACTIONS:
DilV-33 and OliV-36 will be disassembled and inspected during Refuel 8 (8R) as an interim measure. This action was not added to the Mid Cycle Outage (8M) because more appropriate conditions such as having the BWST drained, the vessel defueled, etc.
I will occur in BR.
Also, the decision for using this method of inspection was reached af ter the BM scope had been completed and a new activity would have disturbed the outage schedule. The inspection will verify that the valve disk has freedom of movement, capability of a full stroke and seating contact. Additionally, the general condition of the valve internals will be checked for structural degradation including the presen:e of any loose parts, debris and abnormal or excessive corrosion products, wear and erosion.
The results of all the inspections performei by this alternative test method will become part of the history file for these valves, and any discrepancies noted during the preceding inspection will be monitored during the next inspection. The maintenance history for these valves has been compiled and reviewed, and it has l'een determined that the procedures to be used for the inspection adequately monitor for the recurrence of problems.
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3fl091 01 Page 3 OTHER ACTION $t FPC is investigating the option of replacing DHV-33 and DHV-36 with valves provided with external position indicators. This option is being evaluated because of IPC's comit ment to reliability enhancement and to reduction of personnel radiation exposure.
IPC is also reviewing DHV 33 and DHV-30 against recently published Information Notice (lN) 91-56 " Potential Radioactive Leakage to Tank Vented to Atmosphere". If it is determined that these valves should be re classified as Category A instead of Category C the valves may need to be replaced to facilitate leak testing.
FPC's initial assessment of the IN recognizes some significant differences between CR-3's design and the design of Palisades and fort Calhoun Nuclear Plants.
The Pump and Valve Program will be revised to incorporate disassembly and inspection as the interim method for closure verification of DHV-33 and DHV-36.
Sincerely, c{'m~ h
.)
/
t-t--et w lV P. M. Seard, Jr.
Senior!Vice President Nuclear Operations PMB:LVC xc:
Regional Administrator, Region 11 NRR Project Manager Senior Resident inspector
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