ML20244D938
| ML20244D938 | |
| Person / Time | |
|---|---|
| Issue date: | 05/21/1986 |
| From: | Bernero R Office of Nuclear Reactor Regulation |
| To: | Speis T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20195F761 | List:
|
| References | |
| FOIA-87-714 NUDOCS 8606120635 | |
| Download: ML20244D938 (2) | |
Text
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l MEMORANDUM FOR: Themis P. Speis, Director Division of Safety Review and Oversight FROM: Robert M. Bernero, Director ( h' Division of BWR Licensing
SUBJECT:
PRIORITIZATION OF GENERIC ISSUE . VALVE INTERLOCKS TO PREVEN 1 VESSEL DRAINAGE DURING SHUTDOWN COOLING Attachment 1 is a memorandum from Region I recommending an evaluation of the need for valve interlocks and/or technical specifications on valve interlocks in order to minimize the likelihood that the reactor pressure vessel will be drained due to valve misalignment during normal shutdown cooling.
The concern arises from that fact that 22 event: have already occurred in I which reactor coolant was drained to the suppression pool as a result of RHR valve alignment errors. In some cases automatic isolations terminated the event, in other cases manual actions were required.
We have performed a preliminary review of the attachment and concluded that the concern is applicable to all jet pump BWRs. We recommend that a value-impact assessment of the need for valve interlocks to prevent inadvertent draining of the reactor vessel be performed. In addition to the Region I concerns, however, the evaluation should also account for the possibility that interlock failure might delay or prevent ECCS functions which use the suppression pool suction valves in question. The evaluation should also note that the decay heat rate even at the start of shutdown cociing is significantly lower than that immediately following a design basis LOCA.
I request that by December 31, 1986 the issue La evaluated by DSR0 and a priority assigned for the investigation. Attachment 1 is the Generic Issue Information required by NRR Office Letter No. 40 dated May 8, 1983.
ggg3rs khh noe & Por**85 W
bert M. Bernero, Director Division of BWR Licensing
Enclosures:
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H. D;nton W. Butler R. M. Bernero e ,f D tisenhut D. Muller G. Lainas ' k - (/ , ' s J. Zwolinski M. W. Hodges i /,
W. Minners F. Congel RSB Members T. Collins J ,,4 , '
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Contact:
T. Collins, RSB, x29463
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9 DFFICIAL RECORD COPY 860622 VlI;^JLJ, l,3
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l ATTACHMENT 1 1
! GENERIC ISSUE INFORMATION
- 1. ' Suggested Title of Proposed Generic Issue - Valve Interlocks to Prevent Vessel Drainage During Shutdown Cooling for BWRs 2a. Existing Deficiency - No Tech Spec requirement to verify RHR valve positions and no requirement for RHR valve interlocks to prevent drainage due to valve misalignment when-in the shutdown cooling mode of operation.
Applicable LERs are listed in Enclosure 2 to Attachment 2.
2b. Safety Requirement in Doubt - GDC 34 requires that a system be provided te remove residual heat and that the RHR system be provided with isolation capabilities to assure that the system safety function can be accomplished. We also note that SRP section 5.4.7 " Residual Heat Removal fystem" does not discuss the concern of valve misalignment while in shutdown cooling.
- 3. Description of Proposed Issueg - See Attachment 2.
4 Proposed New Solution - Valve interlocks and Tech Specs to prevent RPV water drainage due to valve misalignment.
- 5. Solution is likely to result in: Revised surveillance pro:edures and a No change to the circuit logic for the RHR and ECCS suction valves.
additional research, testing or rulemaking is required. Operational exposure may be very slightly increased due to surveillance requirements. Logic modifications would not extend a plant shutdown or refueling outage.
- 6. Value-Impact Study - We request DSR0 assessment.
- 7. Other Persons Currently Working On This - Loren Plisco, Region I (FTS l 8-717-542-2134); Jack Strosnider, Region I (FTS 488-1128).
- 8. Person Supplying Information - Richard Starostecki, Region I
- 9. References - See Attachment 2 i
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