ML20205B259

Safety Evaluation Accepting Licensee Position on Generic Ltr 83-28 Items 4.2.1 & 4.2.2 Re Reactor Trip Sys Reliability

ML20205B259
Person / Time
Site:	Calvert Cliffs
Issue date:	07/10/1985
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20205B081	List: ML20205B076 ML20205B259
References
GL-83-28, NUDOCS 8509110136
Download: ML20205B259 (4)

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4** UNITED STATES NUCLEAR REGULATORY COMMISSION 5 E WASHINGTON. D. C. 20555

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' SAFETY EVALUATION BY THE 0FFICE OF NUCLEAR REACTOR.REGULATins

! CALVERT CLIFFS NUCLEAR POWER PLANT. UNITS 1 AND 2 REACTOR TRIP SYSTEM RELIABILITY l ITEMS 4.2.1 AND 4.2.2 0F GENERIC LETTER 83-28 1

1. INTRODUCTION On July 8,1983, the Nuclear Regulatory Commission (NRC) issued

_ Generic Letter (GL) 8'-28. 4 This letter addressed intermediate-term actions

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to be taken by licensees'and applicants aimed at assuring that a comprehensive progfam of preventive maintenance and surveillance testing is implemented for the reactor trip breakers (RTBs) in pressurized water reactors. In particular, Item 4.2 of the letter required the licensees and applicants to submit a description of their preventive maintenance and

f surveillance program to ensure reliable reactor trip breaker operation.

The description of the submitted program was to include the following:

GL, Item'4.2.1 A planned program of periodic maintenance, including lubrication, housekeeping, and other items recommended by the equipment supplier.

GL, Item 4.2.2 Trending of parameters affecting operation and measured during testing to forecast degradation of operation.

Baltimore Gas and Electric, the licensee for Calvert Cliffs 1 and 2, submit'ted responses to the Generic Letter on November 5, 1983, February 29, 1984, and January 18, 1985. This report presents an evaluation of the  !

adequacy of those responses and of the licensee's preventive maintenance l And surveillance programs for RTBs.

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2. EVALUATION CRITERIA 2.1 Periodic Maintenance program The primary criteria for an acceptable periodic maintenance program are contained in Maintenanca Instruction GEI-50299EI*, Power Circuit l

Breakers, Types AK-2/2A-15, AK-2/3/2A/3A-25, AKU-2/3/2A/3A-25," and Service  !

Advice 175-9.35 and 175-9.20, by Generel Electric. The NRC Staff, Equipment Qualification Branch, has reviewed these item; and endorsed the maintenance program they describe. The criteria include those items in the General Electric instructions and advisories that relate to the safety function of the breaker, supplemented by those measurements which must be taken to accumulate data fcr trending. Those items identified for maintenance at six month intervals that should be included in the licensee's RTB maintenance program are:

1. Verification of breaker cleanliness and insulation structure; all foreign materials, such as paint, dust, or oil, should be removed to prevent electrical breakdown between points of different potential;

. 2. Verification of breaker: physical condition, including wiring insulation and termination, all retaining rings, pole bases, arc quencher, stationary and movable contacts, and tightness of nut's i and bolts;

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3. Verification of proper manual operation of the breaker, including checks for excessive' friction, trip bar freedom, 1stch engagement, operating mechanism alignment and freedom, and undervoltage1 trip (9VT) device armature freedom; l

4. Verification cf the optimum freedom of the armature as specified in General Electric Service Advice 175-9.35, Item #S1;

5. Verification of proper trip latch engagement as specified in Service Advice 175-9.35, Item #52.

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'- 6. Verification of undervoltage pick-up setting, as specified in Service Advice 175-9.35, Item #S3, and dropout voltage; i

7. Verification that the trip torque required on the trip shaft is less than 1.5 pound-inches, as specified in Service Advice 175-9.35, Item #S4; "Before" and "After" maintenance torque values should be recorded;

8. Verification of positive tripping by checking the adjustment between the UVT device and trip paddle as specified in Service Advice 175-9.35, Item #55;

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9. Verification of proper trip response time as specified in Service Advice 175-9.35, Item #56;

10. Shunt Trip Attachment (STA) operation verification; 1

11. Examination and cleaning of breaker enclosure;

12. Functional test of the breaker prior to returning it to service.

2.2 Trending of Parameters Generic Letter Item 4.2.2 specifies that the licensee's preventative maintenance and surveillance program is to include trending of parameters affecting operation and measured during ?.esting to forecast degradation of operation. The parameters measured during the maintenance program described above which are applicable for trending are undervoltage trip attachment dropout voltage, trip torque, and breaker response time for undervoltage trip. The staff position is that the above three parameters in addition to the breaker insulation resistance are acceptable and

, recommended trending parameters to forecast breaker operation degradation or failure. If subsequent experience indicates that any of these parameters is not useful as a tool to anticipate failures or degradation, the licensee may, with justification and NRC approval, elect to remove that parameter from those to be tracked.

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3. EVALUATION 3.1 Evaluation of the Licensee Position on Item 4.2.1 The licensee states that his preventative maintenance program for RTB's is being revised and by March 31, 1985, will contain all the elements i detailed in Section 2.1 of this SER; however, the licensee performs maintenance on the breakers annually. The licensee states that the j extended interval is justified based on the GE recommendation that maintenance be performed at least annually, with a hostile environment or severe load condition warranting more frequent maintenance. The staff

.__ finds this justification adequate and the licensee position on Item 4.2.1 to be acceptable.

3.2 Evaluation of the Licensee's Position on Item 4.2.2

The licensee has committed to performance of trend analysis of trip

, torque, breaker response time, undervoltage trip dropout voltage and

, insulation resistance. The Itcensee has identified the organization which will perform trend analysis, how often it will be performed and how the information derived from the analysis will be used to affect periodic maintenance. The staff finds the licensee position on Item 4.2.2 to be acceptable.

4. CONCLUSIONS -

Based on a review of the licensee responses, the staff finds the licensee positions on Items 4.2.1 and 4.2.2 of Generic Letter 81-28 to be i acceptable.

Principal Contributor:

N. Romney, DE INEL Date: July 10,1985 i

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