ML19309F675

Forwards Response to IE Bulletin 79-27, Loss of Non-Class IE Instrumentation & Control Power Sys Bus During Operation. Equipment Necessary for Cold Shutdown Available

ML19309F675
Person / Time
Site:	Crystal River
Issue date:	04/25/1980
From:	Richard Bright FLORIDA POWER CORP.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-79-27, TAC-42664, NUDOCS 8004300331
Download: ML19309F675 (7)

Text

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. . e..r April 25, 1980 File: 3-0-3-a-3 Mr. J. P. O'Reilly Director Office of Inspection and Enforcement U.S. fluclear Regulatory Commission Suite 3100 101 Marietta Street Atlanta, GA 30303

Subject:

Crystal River Unit 3 Docket 50-302 Operating License fio. DPR-72 IE Bulletin 79-27

Dear Mr. O'Reilly:

Enclosed is Florida Power Corporation's response to I&E Eulle-tin 79-27. This submittal is based on our letter to you dated March 26, 1980.

The reviews submitted within were part of an overall review effort by Florida Power Corporation's Safety Task Force as a result of our February 26, 1980, transient. The recommendations of the Safety Task' Force included several items in the general area of the subject matter of IaE Bulletin 79-27 and the enclosed respon-ses are made in light of these recommendations.

A copy of the submittal, explaininc the actions to be taken by FPC prior to startup after this refuel;.ag outage, based upon the Safe-ty Task Force work, including an identification and description of these recomendations, will be forwarded to you.

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General Office 320s hivourm street soum . P O Boa 14042 St Petersburg Fonda 33n3 e 813 866 5151

Mr. J. P. O'Reilly Page Two April 25, 1980 If you require any further discussion of this matter, please con-tact this office.

Very truly yours, FLORIDA POWER CORPORATION Ronald M. Bri t Acting Manager Nuclear Support Services RMB(Bu179-27)ekc(DN-65) cc: Director Office of Inspection and Enforcement Division of Reactor Operations Inspection U.S. Nuclear Regulatory Connission Washington, DC 20555 I

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!&E Bulletin No. 79-27 ITEM 1 Review the class IE and non-class 1E buses supplying power to safety and non-safety-related instrumentation and control systems which could affect the ability to achieve a cold shutdown condi-tion 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.

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 to achieve a cold sinutdown condition.

c) describe any proposed design modifications resulting from these reviews and evaluations, and your proposed schedule for implementing those modifications.

RESPONSE 1 a) Florida Power Corporation has reviewed the buses supplying

, power to the instrument and control systems required to achieve cold shutdown. Included in this review are the sources of power, whether or not the sources of power are safety-related and the Control Room alann or indication re-ceived upon loss of power.

b) We have reviewed and identified, on a bus-by-bus basis, the equipment necessary for cold shutdown. We have also reviewed the effects of a power loss to this equipment and where power supplies are not redundant, alternate means of achieving the desired control results are identified, e.g., handwheel oper-ation.

Prior to our February 26, 1980, incident, we were also re-viewing our external power sources to the NNI and ICS instru-ments on control system, subsequent to the incident, we have impicmented a number of design changes as shown on our March 12, 1980, submittal to preclude a similar power failure from " blinding" the operators during operation.

, c) Based on our review, we have proposed no new design modifica-

tions based on this bulletin, however, Ib), above, refers to j modifications as a result of our February 26, 1980, incident.

I Prior to the issuance of Bulletin 79-27, Florida Power Corporation was in the process of designing to install static

IE Bulletin No. 79-27 (Continued)

RESPONSE 1 (Continued) switches to our vital bus inverters and we are taking into account the "les .ns learned" from Circular 79-02 in design-ing our protectivt relaying.

A static switch will be used for this purpose. Failure of the static switch prevents the transfer from the preferred source to the backup source. In the event that the static switch did fail and short the two buses together, only a single inverter would be lost. The remaining 3 inverters would still be available.

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IE Bulletin No. 79-27 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 1E and non-class 1E bus supplying power to safety and non-safety-related instrument and control systems. The emergency pro-cedures 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 1E instrumentation and control buses.

c) methods for restoring power to the bus.

Describe any proposed design modification or administrative con-trols to be implemented resulting from these procedures, and your proposed schedule for implementing the changes.

RESPONSE 2 At the time of the February 26, 1980, transient, we were in the process of reviewing our normal, emergency and abnormal operating procedures, to ensure that:

1. Adequate instructions were given for response to indica-tions and alarms identified in our response to paragraph 1.a.,

2. Appropriate steps were included to specify which indica-tions should be ignored on the loss of a particular bus and which should be utilized as alternate indication /

control circuits powered from other non-class IE buses, and,

3. Appropriate methods were outlined for restoration of power to the affected bus.

As a result of the transient, FPC established a Safety Task Force to perform an in-depth review of Crystal River Unit 3, including the above procedures and system designs. This Task Force was still in session at the time of our last correspondence regarding this bulletin (R. M. Bright to J. P. O'Reilly, dated March 26, 1980). As a result of their efforts, several areas were identi-fied which require input from the Babcock & Wilcox company.

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IE Bulletin 79-27 (Continued)

RESPONSE 2 (Continued)

At this time, we are working with 88W to develop operator guide-lines, regarding instrument power supplies. In accordance with the NRC's Confirmatory Order for Crystal River Unit 3, dated April 14, 1980, we have comitted to implement procedures and training to assure positive and safe manual response by the opera-tor in the event that competent instruments are unavailable. This commitment shall be met prior to restart of Crystal River Unit 3 from the current refueling outage.

In addition, proposed design modifications or administrative con-trols to be implemented, resulting from the above-referenced pro-cedure changes, which will be completed prior to unit startup, will be described in future correspondence.

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IE Bulletin No. 79-27 ITEM 3 Re-review IE Circular No. 79-02, Failure of 120 Volt Vital AC Pow-er Supplies, dated January 11, 1979, to include both class 1E and non-class 1E 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 adminis-trative controls to be implemented as a result of the re-review.

RESPONSE 3 We have re-reviewed IE Circular No. 79-02 and we have no design or administrative changes planned at this time, based on our re-review. As stated in 1.c above, our design of the protective re-laying scheme for our ne , static switches will preclude an event as occurred at Arkansas Nuclear One Unit 2 from occurring at Crystal River Unit 3.

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