ML20056H578
| ML20056H578 | |
| Person / Time | |
|---|---|
| Issue date: | 07/13/1993 |
| From: | Rosalyn Jones Office of Nuclear Reactor Regulation |
| To: | Charemagne Grimes Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20056C697 | List: |
| References | |
| RTR-NUREG-1430, RTR-NUREG-1431, RTR-NUREG-1432, RTR-NUREG-1433, RTR-NUREG-1434 NUDOCS 9309100112 | |
| Download: ML20056H578 (2) | |
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ENCLOUSRE 6-eno ug'o UNITED STATES NUCLEAR REGULATORY COMMISSION -
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July 13,1993 i
MEMORANDUM FOR:
Christopher I. Grimes, Chief 4
Technical Specification Branch l
Division of Reactor Support l
FROM:
Robert C. Jones, Chief Reactor Systems Branch Division of Systems Safety and Analysis
SUBJECT:
TECHNICAL SPECIFICATION (TS) ON BWR SHUTDOWN COOLING REQUIREMENTS e
In response to your memo to me dated May 12, 1993, the Reactor Systems Branch (SRXB) has_ reviewed the BWR Owners Group comments j
on NUREG 1433 and 1434, Standard Technical Specification for BWR/4 and BWR/6, regarding shutdown cooling requirements.
We have the following recommendations:
1.
Standard Technical Specifications (STS) during Modes 4 and 5 i
require one RHR shutdown cooling subsystem in operation to-i ensure accurate reactor coolant temperature monitoring.
The BWR Owners Group considers this as an operational issue and suggests that this requirement is eliminated from the LCO of STS.
However, we consider that this requirement is important to safety by ensuring accurate reactor coolant temperature monitoring during shutdown modes.
Thus, we' recommend that this part of STS remain unchanged.
2.
STS during Modes 4 and 5 require two RHR shutdown cooling subsystem operable.
The BWR Owners Group suggests that if l
heat losses to ambient are sufficient to maintain temperature below the limit (e.g.,
extended refueling outage or significant portion of core unloaded), there should be no requirement to maintain a shutdown cooling subsystem operable or in operation.
When fuel is subsequently loaoed i
in the reactor such that there is no longer assurance that the temperature limits will not be exceeded, the LCO will i
again be applicable.
We believe that the requirement of two RHR shutdown cooling f
subsystems be operable may be exempted for purposes of maintenance during shutdown when heat losses to ambient are sufficient to maintain reactor water temperature below its limit provided that plant conditions are clearly specified
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Contact:
C. Liang, SRXB/DSSA 504-2878
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Christopher I. Grimes in the TS (e.g.,
time period into refueling outage, percent of core remaining in the reactor etc.) which reflects a decay heat level so low that there is no need for the RHR system to be in operation.
These plant conditions should be demonstrated from the results of actual testing in typical BWR/4 and BWR/6 plants.
Without actual plant tests to demonstrate under which conditions decay heat is sufficiently low to eliminate the requirement that two RHR shutdown cooling subsystem be operable, the current STS in this regard should remain unchanged.
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two Robert Jones, Chief Reactor Systems Branch Division of Systems Safety and Analysis cc:
A. Thadani T.
Collins M. Weston o
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