ML19305C075
| ML19305C075 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 03/19/1980 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-79-27, NUDOCS 8003250554 | |
| Download: ML19305C075 (3) | |
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U March 19, 1980 Mr James G Keppler Office of Inspection and Enforcement Region III US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - CONSUMERS POWER COMPANY RESPONSE TO IE BULLETIN 79-27: LOSS OF NONCLASS 1-E INSTRUMENTATION AND CONTROL POWER SYSTEM BUS DURING OPERATION Consumers Power Company's response *o IE Bulletin 79-27 (Loss of Nonclass 1-E Instrumentation and Control Power System Bus During Operation), dated November 30, 1979, is as follows:
ltem 1 Review the class-1-E and non-class 1-E buses supplying power to safety and non-safety related instrumentation and control systems which could affect the ability,to achieve a cold shutdown condition using existing procedures or procedures developed under item 2 below. For each bus:
a) identify and review the alarm and/or indication provided in the control room to alert the operator to the loss of power to the bus.
l b) identify the instrument and control system loads connected to the bus and evaluate the effects of loss of power to these loads including the ability l
to achieve a cold shutdown condition.
i c) describe any proposed design modifications resulting from these reviews and evaluations, and your proposed schedule for implementing those l
modifications.
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. Response to Item 1 Big Rock Point Plant personnel have examined the Class 1-E and Nonclass 1-E buses supplying power to safety-and nonsafety-related instrumentation and control systems which could affect the ability to achieve'a cold shutdown condition.
It was found that existing Big Rock Point Plant procedures and systems are adequate to deal with a loss of instrumentation and control system loads and achieve a cold shutdown condition in all cases of loss of a bus supplying the instrument and control system loads.
Item 2 Prepare emergency procedures or review existing ones that will be used by control room operators, including procedures required to achieve a cold shutdown condition, upon loss of power to each class 1-E and non-class 1-E bus supplying power to safety and non-safety related instrument and control systems. The emergency procedures should include:
a) the diagnostics / alarms / indicators / symptom resulting from the review and evaluation conducted per item 1 above, b) the use of alternate indication and/or control circuits which may be powered from other non-class 1-E or class 1-E instrumentation and control buses.
c) methods for restoring power to the bus.
Describe any proposed design modification or administrative controls to be implemented resulting from these procedures, and your proposed schedule f',r implementing the changes.
Response to Item 2 Although all procedures and systems examined per Item #1 were found adequate (as discussed in Item #1), two procedures were recommended to the Plant Review Committee for revision. The procedures where:
Loss of station power: This procedure does not address loss of individual on-site a-c buses. Although loss of instrumentation and control functt ns would not occur, this procedure is being revised to include corrective action upon loss of certain motor control buses, including load shifting necessary to l
achieve a cold shutdown condition.
Loss of d-c power system: This procedure is being revised to address the possibility-of a reactor trip during a loss of d-c power to instrumentation and control systems which would compound the ability to achieve a cold shutdown.
These revisions will-be implemented by the end of April 1980.
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3 Item 3 Re-review IE Circular No. 79-02, Failure of 120 Volt Vital AC Power Supplies, dated January 11, 1979, to include both class 1-E and non-class 1-E safety related power supply inverters. Based on a review of operating experience and your re-review of IE Circular. No. 79-02, describe any proposed design modifications or administrative controls to be implemented as a result of the
're-review.
Response to Item 3 Not applicable to Big Rock Point Plant.
David P Hoffman (Signed)
DarO. P Hoffman Xoclear Licensing Administrator CC Lf rector, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement f
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