ML20198B310

Safety Evaluation Re Util 831108 & 840201 Responses to Generic Ltr 83-28 Concerning Salem ATWS Event.License Complied W/Actions 3.1.1.3.1.2,3.2.1,3.2.2,4.1 & 4.5.1 of Ltr

ML20198B310
Person / Time
Site:	Three Mile Island
Issue date:	10/28/1985
From:	NRC
To:
Shared Package
ML20198A910	List: ML20198A905 ML20198B310
References
GL-83-28, NUDOCS 8511060416
Download: ML20198B310 (6)

Text

4 SAFETY EVALUATION GENERIC LETTER 83-28, ITEMS 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1 AND 4.5.1 GPU NUCLEAR CORPORATION THREE MILE ISLAND NUCLEAR STATION, UNIT 1 DOCKET NO. 50-289 1.0 Introduction On February 25, 1983, both of the scram circuit breakers at Unit 1 of the Salem Nuclear Power Plant failed to open upon an automatic reactor trip signal from the reactor protection system. This incident occurred du' ring the plant startup, and the reactor was tripped manually by the operator e about 30 seconds after the initiation of the automatic trip signar. The failure of the circuit breakers has been determined to be related to the sticking of the undervoltage trip attachment. Prior to this incident, on February 22, 1983,~at Unit 1 of the Salem Nuclear Power Plant, an auto matic trip signal was generated based on steam generator low-low level'(

during plant startup. In this case, the reactor was tripped manually by the operator almost coincidentally with the automatic trip.

Following these incidents, on February 28, 1983, the NRC Executive Direc-tor for Operations (EDO), directed the staff to investigate and report on the generic implications of these occurrences at Unit 1 of the Salem Nuclear Power Plant. The results of the. staff's inquiry into the generic implications of~the Salem unit incidents are reported in NUREG-1000,

" Generic Implications of ATWS Events at the Salem Nuclear Power Plant."

As a result of this investigation, the Director, Division of Licensing, Office of Nuclear Reactor Regulation requested (by Generic Letter 83-28 dated July 8, 1983) all licensees of operating reactors, applicants for an operating license, and holders of construction pemits to respond to ,

certain generic concerns. These concerns are categorized into four areas: l (1) Post-Trip Review, (2) Equipment Classification and Vendor Interface,

.(3) Post-Maintenance Testing, and (4) Reactor Trip System (RTS) Reliabi-lity Improvements. Within each of these areas various specific actions

.were delineated.

This safety evaluation (SE) addresses the following actions of Generic Letter 83-28: l

-- 3.1.1 and 3.1.2, Post Maintenance Testing (Reactor Trip System Components) 3.2.1 and 3.2.2, Post Maintenance Testing (All Other Safe,ty-Related Componen ts) 4.1, Reactor Trip System Reliability (Vendor-Related Modifications) kD PDR p.

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2 4.5.1, Reactor Trip System Reliability (System Functional Testing)

By letters dated November 8,1983, and February 1,1984, GPU Nuclear Corporation (GPUN or the licensee) described their planned or completed actions regarding the above items for Three Mile Island Nuclear Station, Unit 1 (TMI-1). Subsequently, certain of these actions were reviewed during a Region I inspection conducted on February 4-7, 1985, as described in Inspection Report 50-289/85-07.

2.0 Evaluation 2.1 General Generic Letter 83-28 included various NRC staff positions regard,irig the specific actions to be taken by operating reactor licensees ~and operating license applicants. The Generic Letter 83-28 positions and discussions of licensee compliance regarding Actions 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1 and 4.5.1 for TMI-1 are presented in the sections that follow.

2.2 Actions 3.1.1 and 3.1.2, Post-Maintenance Testino (Reactor Trip System Components)

Position Licensees and applicants shall submit the results of their review of test and maintenance procedures and Technical Specifications to assure that post-maintenance operability testing of safety-related components in the reector trip system (RTS) is required to be con-ducted and that the testing demonstrates that the equipment is capable of performing its safety functions before being returned to service.

Licensees and applicants shall submit the results of their check of vendor and engineering recommendations (regarding safety-related components in the RTS) to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications, where required.

Discussion The licensee has identified and reviewed the test and maintenance procedures and Technical Specifications that assure post maintenance operability testing of safety related components in the RTS as required. Their review also examined whether the testing demons-trates the capability of equipment to perform its safety function before being returned to service. .

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3 The results of their review indicated that two procedures required revision to meet the above requirement. These procedure changes were completed and in effect as of February 1,1984.

In 1981, the licensee recognized the need to develop a program to control and maintain vendor manuals. The program established by GPUN evaluates and incorporates vendor infonnation into appropriate docu-ments (i.e., procurement, storage, preventive and corrective mainte-nance, inspection and test) for reactor trip system equipment, com-ponents and activities. This program also provides engineering evaluation to develop procurement specifications, receipt inspection testing, storage conditions and preventive maintenance action, when-ever vendor information is lacking.

NRC Inspection 50-289/85-07 reviewed statio.n procedures and ver.i~fied

'that the licensee has implemented a cost-maintenance and modification testing program which includes: '

written procedures for initiating requests for post-maintenance testing; .- '

criteria and responsibilities for review and approval of post-maintenance testing; criteria and responsibilities for performing inspection of post-maintenance testing; methods for perfonning functional testing following maintenance and prior to returning to service; and, requirements for adequate documentation of the above reviews, approvals, inspections, and tests.

Based on the above, the licensee has complied with the NRC staff position for Actions 3.1.1 and 3.1.2 of Generic Letter 83-28.

2.3 Actions 3.2.1 and 3.2.2, Post-Maintenance Testing (All Other Safety Related Components)

Position Licensees and applicants shall submit a report documenting the extending of test and maintenance procedures and Technical Specifi-cations review to assure that post-maintenance operability testing of all safety-related equipment is required to be conducted and that the testing demonstrates that the equipment is capabla of perfonning its safety functions before being returned to service. ,

Licensees and applicants shall submit the results of their check of vendor and engineering recomendations (all other safety-related

4 components) to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifica-tions, where required.

Discussion The licensee perfomed a review of applicable administrative pro-cedures and Technical Specifications to assure that post-maintenance operability testing of all safety-related equipment is required to be conducted and that the testing demonstrates that the equipment is capable of performing its safety functions before being returned to service.

The licensee performed a review of plant corrective maintenance,. pre-ventive maintenance and surveillance procedures to ensure that a'ppro-priate post-mair.tenance testing is required. The licensee stated that the plant staff will review each maintenance procedure as part of the bi-annual review program and will pay particular attention t.o the post-maintenance testing section to assure operability. ,

The licensee has established a program to track, evaluate, and inc'or-r.

porate vendor information into appropriate documents (i.e., procure-ment, inspection and surveillance test, preventive and corrective maintenance) for safety-related equipment, components and activities.

This program and its administrative controls are described in GPUN Engineering Procedure EP-017 " Review of Industry /GPUN Operating Experience."

In addition the licensee's quality assurance personnel are active in efforts to identify further improvements in the vendor manual activi-ties. These efforts include a review of maintenance procedures for reference to appropriate vendor manuals, and reviews to assure that vendor manuals are maintained and controlled properly.

Based on the above, the licensee has complied with the NRC staff position for Actions 3.2.1 and 3.2.2 of Generic Letter 83-28. ,

i 2.4 Action 4.1, Reactor Trip System Reliability (Vendor-Related '

Modifications) l Position .

All vendor-recomended reactor trip breaker modifications shall be reviewed to verify that either: (1) each modification has, in fact, been implemented; or (2) a written evaluation of the technical reasons for not implementing a modification exists.

For example, the modifications recommended by Westinghouse in NCD-Elec-18 for the 08-50 breakers and a March 31, 1983, letter for the DS-416 breakers shall be implemented or a justification for not

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implementing shall be made available. Modifications not previously made.shall be incorporated or a written evaluation shall be provided.

Discussion The reactor trip circuit breakers at TMI-1 are General Electric, Type AK-2-25. There have been no vendor-recommended field modifications from either Babcock & Wilcox Company (B&W) or General Electric to the subject circuit breakers. This fact was supported in writing by a General Electric letter to Babcock & Wilcox Company dated September 7, 1983, in response to a request made by B&W on behalf of the B&W Owners Group.

Based on the above, the licensee has complied with the NRC staff .

position for Action 4.1 of Generic Letter 83-28.

2.5 Action 4.5.1, Reactor Trip System Reliability (System Functional

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Testing)

Position

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On-line functional testing of the reactor trip system, including independent testing of the diverse trip features, shall be performed on all plants. The diverse trip features to be tested include the breaker undervoltage and shunt trip features on Westinghouse, B&W and CE plants; the circuitry used for power interruption with the silicon controlled rectifiers on B&W plants; and the scram pilot valve and backup scram valves (including all initiating circuitry) on GE plants.

Discussion The licensee conducts on-line functional testing of the RTS on a monthly basis in accordance with Surveillance Procedure 1303-4.1,

" Reactor Protection System."

* Surveillance Procedure 1303-4.1 provides for tha independent testing of the control rod drive mechanism (CRDM) power feeder breakers' under-voltage trip devices. As of October 12,1983 a change to this procedure incorporated independent testing of the control rod drive control system silicon controlled rectifier trip circuit.

A second modification by the licensee provided the capability for tripping the CRDM power feeder circuit breakers via their shunt trip devices. This modification to the reactor trip system breakers and the revision to Surveillance Procedure 1303-4.1 was completed as of August 1984. ,

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Based on the above, the licensee complied with the NRC staff position for Action 4.5.1 of Generic Letter 83-28.

6 3.0 Conclusion Based upon the foregoing discussions, the staff concludes that the licensee has complied with Actions 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1, and 4.5.1 of Generic Letter 83-28.

Principal Contributor:

Thomas Silko, Division of Reactor Projects, Region I

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