IR 05000289/1999005
| ML20209G606 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 07/09/1999 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20209G591 | List: |
| References | |
| 50-289-99-05, 50-289-99-5, NUDOCS 9907190204 | |
| Download: ML20209G606 (17) | |
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U.S. NUCLEAR REGULATORY COMMISSION REGION 1 Docket No: - 50-289 License No: DPR-50 Report No: 50-289/99-05 Licensee: GPU Nuclear,Inc. (GPUN)
Facility: Three Mile Island Station, Unit 1 Location: P. O. Box 480 Middletown, PA 17057 l Dates: May 10,1999 through May 28,1999 Inspectors: ' Aniello L. Della Greca, Senior Reactor Engineer
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Ram S. Bhatia, Reactor Engineer Gregory V. Cranston, Reactor Engineer Approved by: Lawrence T. Doorflein, Chief Engineering Programs Branch Division of Reactor Safety
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9907190204 990709 PDR ADOCK 05000289 G PDR t'
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EXECUTIVE SUMMARY Three Mile Island Nuclear Power Station Report No. 50-289/99-05 i
- During the period between May 10 and May 28,1999, the NRC conducted an engineering team inspection at the Three Mile Island Station, Unit 1. The objective of the inspection was to assess the effectiveness of the engineering functions in providing for the safe operation of the plan The results of this inspection are described below:
Enaineerina The design change process was acceptably implemented. The design change documents accurately described the purpose of the modifications and the intended results. When appi; cable, the modifications were supported by appropriate calculations. The safety evaluations reasonably concluded that the modifications did not involve an unreviewed safety question. (E1.1)
The licensee's review for consistency of the Updated Final Safety Analysis Report (UFSAR), the Technical Specification bases, the System Design Basis Documents (SDBD), and the as-built drawings was appropriate. The content of the SDBDs reviewed was comprehensive with interim system disign changes properly posted against the SDBD. The referencing of supporting documents was acceptable. (E1.2)
The engineering calculations reviewed were sufficiently detailed, consistent with their intended purpose, and act,aptably controlled. The revised calculation procedure provided sufficient guidance for the correct administration and control of the calculation results. (E1.3)
Evaluation of plant events was acceptable. The threshold for problem identification and the timeliness for resolving engineering issues were also acceptable. However, the licensee's review of the extent of condition and the bases for the problem resolution and operability determinations were sometimes limited or not well documented. The electronic task tracking system was effectively used to track action items. Communication among engineering and plant organizations was good. (E2.1)
The design change modification procedure was acceptable and contained sufficient guidance for the correct implementation of plant modifications. (E3.1)
The engineering self-assessment and the Nuclear Safety Assessment audits were an effective element of the TMI self-assessment process. They were broad in scope and addressed most engineering prc, grams. Recommendations were appropriate for the findings. Management was actively involved in ensuring that the findings and recommendations were addressed in a timely manner. (E4.1)
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The battery surveillance test procedure incorrectly specified the minimum battery voltage at the end of the duty cycle to be 105 Vdc. As identified in the battery sizing calculation, this voltage would not be sufficient to ensure. operability of the inverters. Based on the results of an earlier test and the available battery load capability margin, the licensee declared the inverters operable, but did not provide sufficient justification. The licensee confirmed operability by calculation during the inspection. However, the incorrect surveillance test procedure acceptance criteria resulted in a non-cited violation. (E8.1)
' The licensee's assessment of the TMl environmental qualification program was a comprehensive effort and provided a good insight on the qualification status of the equipment evaluated.' Also, the licensee's review and resolution of the identified findings was acceptabl The licensee planned to issue a Corrective Action Process (CAP) report to address extent of condition. (E8.2) _
The licer.see was proactively addressing relay coil failures in the Engineered Safety Features System and had engaged an independent laboratory to conduct a root cause analysis of the failure. Potentially defective relays were being conservatively replaced. (E8.3)
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TABLE OF CONTENTS EXECUTIVE SUM MARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ji i
Il l . Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 E1 Conduct of Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 E1.1 Safety-Significant Design Modifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 E1.2 Control of Design Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
. E1.3 Control of Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 E2 Engineering Support of Facilities and Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 E2.1 Engineering Support of Site Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 E3 Engineering Procedures and Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 E3.1 Design Modification Process . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . 5 E4 Engineering Staff Knowledge and Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 E Review of Self Assessment Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 E8 Miscellaneous Engineering issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 E8.1 Adequacy of Inverter input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 E8.2 Environmental Qualification Program Assessment . . . . . . . . . . . . . . . . . . . . . 9 E8.3 ESAS Relay Failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Management Meetings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 X1 Exit Meeting S um mary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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Report Details Summary of Plant Status During the period between May _10 and May 28,1999, the NRC conducted an engineering team inspection at the Three Mile Island Station, Unit 1. The objective of the inspection was to assess the effectiveness of the engineering functions in providing for the safe operation of the plan .The plant remained at or near full power throughout the inspection perio lil. Engineering E1 Conduct of Engineering E Safetv-Sionificant Desian Modifications a, inspection Scope (37550)
The team reviewed permanent and temporary design change packages (DCPs) to assess the quality of engineering analyses and to verify that the design change process complied with the plant procedure and NRC regulatory requirements. The team also conducted physical inspection of selected plant modifications to confirm that installation conformed with design document Observations and Findinas J
The team selected 16 safety-significant design change packages for review. Of these, ten involved permanent plant modifications and the other six pertained to temporary changes. Most of the permanent design changes had been recently installed and two had been designed, but scheduled for implementation during the upcoming refueling outag The inspectors found that in each case the design changes correctly addressed the concems for which the design modifications had been prepared and that the applicable analyses accurately described the purpose of the modification and the intended result The licensee had appropriately considered the original design basis requirements, performed acceptable safety evaluations, and confirmed that the changes did not involve an unreviewed safety question. As applicable, the system calculations and design documents, including design drawings and vendor manuals, had been updated to reflect the design ch.?nges. The installations physically inspected by the team conformed with the design drcwings and had undergone acceptable post-modification testing prior to being declared operationa For example, Modification MD-G973-001, dated May 7,1999, was issued to address the recently changed normal operating position of valves DH-V-0001 and 0002 and to resolve pressure locking concems regarding these valves. The team's review of the associated DCP found it to be complete and in conformance with the current procedur The team also determined that Engineering had correctly addressed the pressure locking and thermal binding issues discussed in Generic Letter 96-0 _-
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2- Conclusions The design change process was acceptably implemented. The design change documents accurately described the purpose of the modifications and the intended results. When applicable, the modifications were supported by appropriate calculation The safety evaluations reasonably concluded that the modifications did not involve an unreviewed safety questio E1.2 Control of Design Bases Inspection Scope (37550%
~ To address the licensee's control of the design bases, the team reviewed the scope and activities related to the UFSAR Update Project, three System Design Basis Documents 1
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. The team also reviewed selected modifications and calculations.
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b. ~ Observations and Findma The licensee was in the final phase of the UFSAR Update Project. This phase involved the review of the UFSAR Chapter 14 Accident Analysis section for acceptability. The review also included a comparison between applicable UFSAR sections, the Technical Specification Design Bases, SDBDs, and design drawings to assure consistency within the design bases documents and between these and the as-built design document The team's review of the licensee's activities in this area found that the project was proceeding satisfactorily, and that discrepancies were clearly described and entered into the Corrective Action Process (CAP) for evaluation and disposition. A major UFSAR update had been made in 1997 during the biennial revie The team's review of three SDBDs found their scope and content to be comprehensive, with clear references to the supporting documentation and consistent with the UFSAR descriptions. Design basis changes, such as modifications and calculations, that had been recently implemented, had been properly posted against the SDBD for ease of interim retrievability and for incorporation into the SDBD at the next update. No discrepancies were identified by the team between the SDBDs, the supporting documents, and the UFSAR description Conclusions The licensee's review for consistency of the UFSAR, the Technical Specification bases, the System Design Basis Documents (SDBD), and the as-built drawings was appropriate. The content of the SDBDs reviewed was comprehensive with interim system design changes properly posted against the SDBD. The referencing of supporting documents was acceptable.-
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E1.3 Control of Calculations Inspection Scope (37550)-
The team reviewed selected calculations to evaluate their scope and content and to determine whether the results were properly used in the affected design document The review also included selected portions of the applicable calculation control procedure, Observations and Findinas The team selected for their review several calculations that related primarily to design
. modifications. The team found that the scope and content of the calculations were consistent with their intended purpose and that sufficient details had been provided by the licensee regarding the methods used and the intended results. The team also found i that the newer calculations had been prepared and controlled in accordance with the current engineering procedure EP-006, " Calculations," dated February 9,199 The revised calculation "ocedure itself was well written and provided appropriate j
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administrative guidance for the control of the engineering calculations and for the correct processing of the calculation results. The team also found that when discrepancies or concems were identified by the preparer, the issues were entered in the corrective action process for appropriah resolution.- i Conclusions The engineering calculations reviewed were sufficiently detailed, consistent with their intended perpose, and acceptably controlled. The revised calculation procedure j provided sufficient guidance for the correct administration and control of the calculation '
result E2- Engineering Support of Facilities and Equipment E Enoineerina Support of Site Activities Insnar* ion Scooe (37550) -
The team evaluated Engineering's support of plant activities by reviewing their involvement in the technical resolution of plant issues, including selected 1999 Licensee Event Reports (LERs), Corrective Action Process reports, operational experience 1 reviews (OER), Electronic Task Tracking System (ETTS) items, justifications for continued operation (JCOs), and use of Probability Risk Assessment (PRA). The team also observed communications at site plan-of-the-day meetings and at plant schedule meetings.
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-4- Observations and Findinas The team reviewed three recent LER's. The review addressed the iicensee's evaluation of the condition as well as the engineering involvement in the resolution of the issue The team found the evaluation of the event-specific issues to be sufficient and their resolution acceptable. However, the engineering evaluation of the extent of condition and impact on other systems was not well documented. For example, the licensee's review of LER 1999-003-00, dated May 7,1999, determined that the manual balancing damper failure that resumed in Control Room Habitability being outside the design basis, was caused by lack of a period % maintenance and failure to recognize the importance of the manual damper in the design basis of the plan Discussions with engineering p3rsonnel indicated their understanding that the condition might be applicable to other plant ventilation systems and that they had conducted further evaluation. However, in Section Vil of the LER, " Corrective Actions Taken," the immediate, long and short term actions specified by the licensee only addressed the Control Building Ventilation Syste The team's review of a variety of CAP reports found that the CAP was being effectively used by engineering to identify and correct problems and that the threshold was appropriately low. However, the team observed that the issue resolution documented in the " Corrective Action" did not always include the supporting evidence of how the conclusion had been reached. Operability determinations similarly lacked details of the reasoning used by Engineering to support their conclusion, as in the inverter input voltage evaluation discussed in Section E8.1, belo The team also found that problem resolutions were sometimes narrow in scope. For example, consistent with the statements of the above LER regarding the control building ventilation system manual damper, CAP T1999-0235 had only addressed the control building issue. Other examples were the CAP entries resulting from the environmental qualification program self-assessment, as discussed in Section E8.2 below. Despite the limited documentation, when the issues were pursued with the responsible engineer, the team found that good bases existed for the conclusion and that a broader extent of condition review had been don .
The method used by the licensee for planning and scheduling work activities, and for tracking and dispositioning engineering items not required to be entered into the CAP
- was the Electronic Task Tracking System. The team found that the licensee made effective use of this tool. However, in some instances, this was also the method they used to address extent of condition items. Although propar tracking existed for these items, the team believed that, because the items were not also included in the CAP action item list, they would not receive proper management visibility and, hence, their resolution might be deferre :
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-5-The team reviewed selected Justifications for Continued Operation reports to evaluate the reasonablene a of the licensee's conclusions. The team found that the JCOs were typically detailed and included the necessary bases for the justification. PRA was also used as appropriate to provide the technical bases for the JCO )
Regarding operational experience, the team determined that Engineering had established a process for reviewing the data received and for evaluating its impact on the plant performance. The review involved both intemal and extemal information, including information obtained from visits to otherjob sites, and/or received at conference Observations by the team at different licensee meetings, such as plant plan-of-the-day and plant schedule meetings, indicated good preparation by Engineering and active participation in the issue discussion Conclusions Evaluation of plant events was acceptable. The threshold for problem identification and the timeliness for resolving engineering issues were also acceptable. However, the licensee's review of the extent of condition and the bases for the problem resolution and operability determinations were sometimes limited or not well documented. The electronic task tracking system was effectively used to track action item Communication among engineering and plant organizations was goo {
l E3 Engineering Procedures and Documentation '
E Desian Modification Process Inspection Scope (37550)
The team reviewed selected portions of the current administrative procedure to evaluate the adequacy of the guidance available to Engineering for the development, installation, and testing of plant design modification Observations and Findinas Procedure EMP-002T, " Modification," issued on January 18,1999, delineated the current guidelines and requirements for preparation, review, and approval of design modifications. The team's review of this procedure determined that it acceptably addressed essential areas of the design change process, such as the review of existing design and licensing bases, preparation of a safety evaluation to ensure that the change did not involve an unreviewed safety question, and the development of applicable testing requirement The procedure also included appropriate guidance for the evaluation, review, and approval of technical issues including fire hazards, environmental qualification of electrical components, electrical loads, corrosion control, and human factors, as applicable, and for the development of post-modification testing. Relevant procedures
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6- Conclusions The design change modification procedure was acceptable and contained sufficient guidance for the correct implementation of plant modification {
E4 Engineering Staff Knowledge and Performance E Review of Self Assessment Activities Insoection Scope (37550)
The team reviewed the results of self-assessments conducted by the engineering personnel and the Nuclear Safety Assessment (NSA) organization, and interviewed responsible personnel to evaluate the effectiveness of the licensee's self-assessment programs related to engineering activities, Observations and Findinos As documented in NSA audit Report S-TMI-97-04, dated August 25,1997, weaknesses in various engineering program areas, including safety evaluations and control of design changes and calculations, resulted in GPUN management initiating several actions to <
evaluate and address these programs. To improve the self-assessment process, GPUN designated full-time self-assessment coordinators and updated Corporate Procedure ,
1000-ADM-1291.03,"Self-Assessment Program Guide. The revised procedure reflects !
current industry practices and provides the guidelines necessary for GPUN personnel to identif/ program weaknesses and areas for improvement and to set high standards of .
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In the engineering self-assessment area, the team's review of assessment reports !
completed between 1997 and 1999 found them to be of good quality and effective in j identity,. g weaknesses. The reports included appropriate recommendations to improve !
the processen. For example, in the area of nuclear safety-related material quality classification and safety evaluation documentation accuracy, the engineering personnel had completed two self-assessments (E270-MO-97-09, dated July 14,1997, and E440- j MO-98-04 dated December 23,1998). The team's review of these reports determined !
that an adequate quantity of sample documentain had been reviewed, the identified corrective actions (CAPS T1999-00204 and T 1998-1102-1) were appropriate, and the 1 recommendations had been implemente In the area of design changes, Engineering performed three evaluations. The team's j review of the applicable reports found that the licensee had compared the design changes against the enhariced implementing procedure and identified several issues related to the preparation of bills of material (BOM), due to conflicts between the modification and the BOM procedure .
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-7-The team found tnat engineering self-assessments had addressed most engineering programs, including design calculation deveiopment, verification, and control; commercial grade dedication; drawing update program; engineering changes after the initial design, instrument error calculation; and setpoint determination. As indicated previously, the licensee had addressed all findings and observations and had either corrected them or placed them in their corrective action progra Audits of engineering programs were also conducted by the Nuclear Safety Assessment Department. The team's review of two NSA audits performed in the area of engineering support activities (S-TMI-97-04, dated August 25,1997, and S-TMI-98-04, dated May 5,1998) determined that NSA had observed noticeable improvements in most engineering areas, including procedure compliance; procedure update; design configuration control; OER; and calculation update and contro Other management activities to address the 1997 concerns included visits to other plants to identify good performance practices and the initiation of a continued safety assessment process to review management challenges at TMI and identify needed action Conclusions The engineering self-assessment and the NSA audits were an effective element of the TMl self-assessment process. They were broad in scope and addressed most engineering programs. Recommendations were appropriate for the finding Mana0ement was actively involved in ensuring that the findings and recommendations were addressed in a timely manne E8 Miscellaneous Engineering issues E Adenuacy of inverter Inout Voltaae _ Inspection Scope (37550)
Based on the results of a recently revised battery sizing calculation, the licensee identified that, at the end of the two-hour cycle, the minimum specified voltage at the battery terminals would not be sufficient to ensure operability of the associated inverter The team reviewed the calculation and associated documentation to evaluate the operability of the inverter Observations and Findinos Calculation No. C-1101-734-5350-003, "TMli Battery Capacity Sizing and Voltage Drops for DC System," was recently revised to address system load changes. Section 2.3.1 of Revision 3 of this calculation, dated April 27,1999, stated that the available de voltage at the inverter terminals would be less than the required 105 Vdc when the battery voltage drops to 105 Vdc at the end of the 2-hour battery loading cycle. Specifically, under the stated condition, the inverter calculated voltage would range between 102.73 for inverter
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-8-The NRC originally questioned the minimum voltage at the inverter terminals during the 1990 Electrical Distribution System Functional Inspection (Inspection Report N /90-81) because the minimum required voltage at the inverter (105 Vdc) was the same as the minimum voltage specified at the battery terminals in the battery sizing calculation. The use of the same voltage did not allow for a voltage drop between the battery and the inverter. At that time, because a voltage drop calculation was not available, the issue remained unresolved pending further NRC and licensee revie Subsequently, in 1993, the issue was incorrectly closed based on the NRC understanding that a Unit 2 diesel generator, assigned to support a Unit i station blackout (SBO), would be available within ten minutes to provide charging power to the connected battery and maintain the battery voltage above the required minimu The licensee's review of the revised calculation results, recognizing that the SBO diese!
generator did not meet the design criteria for the de system, questioned the design and licensing bases of the plant and issued a CAP to evaluate the finding. In the CAP the licensee addressed inverter operability and stated that the inverter input voltage was "not an operability and reportability problem at this time." The statement did not include any technical bases, but rather made reference to a conversation between the approving shift supervisor and the system engineer in the CAP, the only other comment was a reference to the inspection report in which the issue had been close The team's review of the UFSAR and Technical Specifications, identified no specific requirements for the inverters. Their operability, however, is predicated on the assumption that adequate voltage is available from their power sources, the batterie The minimum acceptable input voltage for the inverters is 106 Vdc. This is based on the !
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inverter shutdown setpoint that is regularly calibrated to actuate at 105 Vdc_* 1 Vd Regarding the batteries, Section 8.2.2.6 of the UFSAR states, in part that, "the capacity of each of the two redundant batteries is sufficient to feed its connected essential load for i 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> continuously and perform three complete cycles of safeguard breaker closures )
and subsequent tripping." Also, Technical Specification Section 4.6.2.d.(1) requires that i the battery be subject to a load test on a refueling interval basis to verify that the battery capacity can meet the design load Based on the above, the team believed that the periodic test of the battery should demonstrate that the voltage at the battery terminals at the end of the two-hour !
discharge period does not fall below 106 Vdc plus the voltage drop between the battery and the inverter terminals. Based on the latest calculation, for battery 1 A, the most j heavily loaded battery, this voltage drop is 1.5 Vdc. Therefore, the battery surveillance i test acceptance criterion should have been 107.5 Vde, not 105 Vde, as specified in the surveillance test procedur Based on the results of the most recent tests, actual rather than tested load values, and manufacturing data obtained from the licensee, the team estimated that, at the end of the two-hour discharge period, the minimum voltage at the battery terminals would be slightly above the minimum reouired by the current design. This was independently verified by the licensee who calculated that the battery capacity in 1997 was 90% versus the 80% required and, therefore, sufficient to support operability of the inverters. Based on this review, the licensee revised the operability determination and planned to reevaluate the design and licensing bases during their review of the CAP ite . .
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in a design basis event that includes a loss of offsite power and a single failure, it is l reasonable to assume that one set of batteries will be maintained in the charged state by j the associated battery charger and diesel generator and will be able to supply adequate l
voltage to the associated inverters. Therefore, the team did not believe this to be a l safely issue. However, the team did believe that the tests should either be revised to reflect the current design bases of the plant or the design bases should be revised to reflect design requirements. This non-repetitive licensee-identified Severity Level IV violation of 10 CFR 50, Appendix B, Criterion XI, Test Control, already entered in the licensee's corrective action program, is being treated as a Non-Cited Violation, consistent with Appendix C of the NRC Enforcement Policy. (NCV 50-289/99-05-01) Conclusions The battery surveillance test procedure incorrectly specified the minimum battery voltage
- at the end of the duty cycle to be 105 Vdc. As identified in the battery sizing calculation, this voltage would not be sufficient to ensure operability of the inverters. Based on the results of an earlier test and the available battery load capability margin, the licensee declared the inverters operable, but did not provide sufficient justification. The licensee confirmed operability by calculation during the inspection. However, the incorrect surveillance test procedure acceptance criteria resulted in a non-cited violatio E8.2 Environmental Qualification Proaram Assessment Inspection Scooe (37550)
Recently, a licensee consultant completed an evaluation of the Three Mile island environmental qualification program. As a result of this review, several CAPS were issued to address identified deficiencies. The team reviewed the results of the i evaluation to determine the significance of the findings and the adequacy of the ,
licensee's corrective action Observations and Findinos I
During the current inspection, the licensee issued Technical Data Report No.1241, 1
" Environmental Qualification Self-Assessment," dated May 1999. The assessment, conducted by a licensee's independant consultant, involved a vertical slice review of qualification status of the equipment required to mitigate certain design basis accident The assessment also evaluated the licensee's calculated environment at the mounting locations of the equipmen The team's review of selected portio".. of the report fou'nd the assessment effort to be comprehensive and to provide prxi insights in the qualification status of the evaluated safety-related electrical equipment. Although the findings did not result in any equipment being inadequately qualified for its intended safety function, the consultant's evaluation identified several issues that required further review and resolution by the licensee. The issues involved such concerns as, the accident environment was not up-to-date; the environmental qualification was based on bulk-temperature rather than that at the equipment location; the qualified life calculations were not always properly supported; and some equipment was not included in the master lis '
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-10-The licensee reviewed each of the consultant's findings and observations and provided justifications as to the reason why the components involved where either qualified or qualifiable. As appropriate, the licensee issued several CAPS. The team's comparison of the CAPS to the findings and observations contained in the report, determined that the specific issues had been correctly captured in the CAPS. However, a review of the findings to evaluate their impact on other equipment, mounting locations or other postulated accidents had not been addressed in the CAP Discussions by the team with responsible engineering personnel determined that most of the issues had been entered in the electronic task tracking system. Therefore, the team believed that ultimately extent of condition would be properly addressed. However, because the corrective actions required to address extent of condition had not been identified in the CAPS, the team also believed that those items would have not received the proper visibility and, hence, the required management attention. As a result of the team's discussions, the licensee stated that a CAP would be prepared to address the other areas requiring revie Conclusions The licensee's assessment of the TMI environmental qualification program was a comprehensive effort and provided a good insight on the qualification status of the equipment evaluated. Also, the licensee's review and resolution of the identified findings was acceptable. The licensee planned to issue a CAP to address extent of condition.
E8.3 ESAS Relav Failures Inspection Scope (37550)
The team's review of current CAPS observed several items pertaining to relay coil failures in the Engineered Safeguards Actuation System (ESAS). The team reviewed the actions being taken by the licensee to evaluate the failures and their impact on the system to which they were associate Observations and Findinas The ESAS logic is provided by Clark electro-magnetic relays consisting of a stationary assembly and a coil-movable contact arrangement (kit). The licensee, to satisfy the service life requirements, replaces the kits on a regular basis. Since their last replacement, approximately thr 3 years ago, the licensee noticed an increase in relay failures that resulted in the codacts not closing properly following re-energization. The relays are mostly normally-energized and perform their safety function when the coil de- i energize l During periodic tests of the relay logic, the relays are de-energized and then re-energized. Failure of the relay contacts to properly return to their energized state occurs '
at this time, indicating a potentially weak or aged coil, or a loss of freedom in the contact movement. The licensee has conducted several reviews of the failures, including a
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-11-Kepner-Tregoe failure analysis. The licenset as also contacted the vendor to evaluate potential manufacturing process changes. None of these efforts have provided the desired results and the licensee planned on removing an entire relay to conduct microscopic analysis and identify the potential root cause. In the mean time, the licensee was performing regular thermography of the relays to identify potentially defective coils before they failed. Overheated relays were immediately replace The team discussed the failures with the system engineer. Specifically, the team discussed seismic impact on potentially aged relays and safety functions during the re-energization phase of the relay. As stated previously, the system engineer indicated that the relays performed their safety function following de-energization. Therefore, the system engineer did not consider re-energization or relay chatter, during a seismic event, an issu Conclusions The licensee was proactively addressing relay coil failures in the Engineered Safety Features System and had engaged an independent laboratory to conduct a root cause analysis of the failure. Potentially defective relays were being conservatively replace V. Manaaement Meetinos X1 Exit Meeting Summary The team presented the inspection results to members of licensee management at the conclusion of the inspection in a meeting on May 28,1999. The licensee acknowledged th findings presented without comment The licensee did not indicate that any of the information presented at the exit was proprietar T
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PARTIAL LIST OF PERSONS CONTACTED
- GPU Nucleer A. T. Asenpota Manager Modification R. Barley Manager Component Engineering E. Fuhrer NSCC Staff C. Hartman Manager System Engineering
- M. G. Kapil Manager EP&l R. Knight Licensing Engineer J.Langenbach ' Vice President and Director TMI M. Press- NSA Lead Assessor S. Queen Manager System Engineering J. Schork PRG Chairman G. R. Skillman Director, Configuration Control J.Tesner System Engineer P. Walsh Director Equipment Reliability R. Warren IOSRG Enginear AmerGen J.B. Cotton Transition Team fLRQ W. Schmidt Sr. Resident inspector INSPECTION PROCEDURES USED IP 37550 \ Engineering ITEMS OPENED, CLOSED AND DISCUSSED anan 50-289/99-05-01 NCV Test Control - Inadequate Battery Test Acceptance Criteria Closed ,
50-289/99-05-01 NCV Test Control-Inadequate Battery Test Acceptance Criteria l
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LIST OF ACRONYMS USED
- AC or ac = Alternating Current BOM Bill of Material CAP Corrective Action Process CFR Code of Federal Regulations DC or dc Direct Current DCP . Design Change Package DRS - Division of Reactor Safety EDG Emergency Diesel Generator ESAS Engineered Safeguards Actuation System i ETTS Electronic Task Tracking System j GL' Generic Letter
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GPUN General Public Utilities Nuclear j JCO Justification for Continued Operation LER Licensee Event Report
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NR Nuclear Regulatory Commission NS Nuclear Safety Assessment
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OER Operating Experience Report PRA Probability Risk Assessment SDBD ' System Design Basis Document SBO Station Blackout ,
UFSAR Updated Final Safety Analysis Report V Volts '
-VDC or Vdc Volts Direct Current
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