ML20137B092
| ML20137B092 | |
| Person / Time | |
|---|---|
| Site: | River Bend, LaSalle, 05000000 |
| Issue date: | 09/16/1985 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| Shared Package | |
| ML20136E841 | List: |
| References | |
| FOIA-85-668 NUDOCS 8511260179 | |
| Download: ML20137B092 (2) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION
, /[, i WASHINGTON, D. C. 20555 vf#
September 16, 1985 s
f l
MEMORANDUM FOR: Robert D. Martin Regional Administrator Region IV FROM:
C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
SUBJECT:
POTENTIAL FOR HPCS SYSTEM RELIEF VALVE FAILURES AT RIVER BEND UNIT 1 Prompted by several High Pressure Core Spray (HPCS) System relief valve failures reported at LaSalle Units 1 and 2, AE0D initiated a review of these events and an evaluation of the potential for similar failures at other BWRs with HPCS systems. The enclosed Engineering Evaluation Report provides the From our review, we have concluded that a potential
[s)resultsofourstudy. exists for similar relief valve failures at River Bend Unit 1.
C/
Our investigation found that the relief valve failures at LaSalle were caused by excessive back pressure on the discharge port of the relief valve. At LaSal.le, back pressure on the valve port occurred whenever the HPCS system operated because the relief valve discharge was hard piped to the HPCS minimum flow line. The minimum flow line operates at relatively high internal pressure when the HPCS pump is running. Special tests performed at LaSalle showed that the back pressure at the HPCS pump discharge relief valve reached approximately 100 psi. However, the Crosby relief valve involved in the failures have a back
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pressure rating of only 90 psi. The consequences of the valve failure were significant valve leakage into the HPCS compartment and a loss of containment integrity. At LaSalle, the excessive back pressure problem was corrected by routing the relief valve discharge to the reactor building equipment drainage system.
From our review of the HPCS system flow diagrams and the relief valve designs for each of the other potentially affected BWRs, we have concluded that River "e
Bend Unit 1 is the only other plant with a potential for relief valve failures 1,;;-
of the type which occurred at LaSalle.
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SHOLLY85-668 PDR
.At River Bend, the HPCS pump discharge line relief valve is also manufactured
)ytheCrosbyValveCompanyandhasadischargewhichishardpipedto
!the HPCS minimum flow line.
In view of the similarities between the two plant
- designs, we would suggest that Re: ion IV request the licensee to evaluate the l suitability of the HPCS system relief valve discharge piping design in light-
!of the failures which occurred at LaSalle.
Should you or your staff have any questions, require clarification or
! additional information, please contact Sagid Salah of my staff. He be reached lat FTS 492-4432.
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/ -
'M e
C. J.
temes, J.,
ector Office for Analysis and Evaluation of Operational Data
Enclosure:
As stated cc: w/ enclosure S. Stearn, NRR D. Chamberlain, Region IV E. Johnson, Region IV l
H. Denton, NRR H. Thompson, NRR T. Novak, NRR 9
o O
e 9
9 1. ps
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