ML20246D050

Commission Response to J Bates Subcommittee on Energy & Power Question 12 from

ML20246D050
Person / Time
Site:	San Onofre
Issue date:	05/11/1989
From:	Zech L NRC COMMISSION (OCM)
To:	Bates J HOUSE OF REP.
Shared Package
ML20246C933	List: ML20246C943 ML20246C952 ML20246C956 ML20246C990 ML20246C995 ML20246D002 ML20246D017 ML20246D024 ML20246D033 ML20246D042 ML20246D047 ML20246D050 ML20246D080
References
BATES-890511, CCS, NUDOCS 8907110225
Download: ML20246D050 (1)

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QUESTION 12 How can it be assumed that this reactor can operate safely with a damaged thermal heat. shield since Edison has not yet installed the proper equipment to facilitate monitoring of adequate reactor core cooling?

ANSWER As noted in our response to Question 11, the licensee is required to install a reactor vessel water level instrument to facilitate monitoring of adequate reactor core cooling by 1991. However, the instrumentation has no connection with operation with the degraded thermal shield. The reactor vessel water level instrument provides useful information to the operators in situations involving loss of coolant (water) from the reactor coolant system but does not provide the necessary thermal shield monitoring for safe operation.

Information on the NRC staff's basis for interim operation is provided in License Amendment No. 127 and the associated Safety Evaluation (attached to Question 3). The necessary operational monitoring of the degraded thermal l shield is provided by a neutron noise monitor and a loose parts monitor system. These systems were required to be in service prior to restart.

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