IR 05000272/1987016
| ML18093A234 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 06/30/1987 |
| From: | Blumberg N, Finkel A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML18093A232 | List: |
| References | |
| 50-272-87-16, 50-311-87-19, NUDOCS 8707160851 | |
| Download: ML18093A234 (6) | |
Text
U.S. NUCLEAR REGULATORY COMMISSION
REGION I
50-272/87-16 Report N /87-19 50-272 Docket N DPR-70 License N DPR-75 Licensee:
Public Service and Gas Company 80 Park Plaza - 17C Newark, New Jersey, 07101 Facility Name:
Salem Generating Station Units 1 and 2 Inspection At:
Hancocks Bridge, New Jersey Inspection Conducted:
June 1-5, 1987 Inspector:
A. Finkel, Lead Reactor Engineer, DRS Approved by:
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' dat'e Inspe-ction Summary:
A routine, unannounced inspection conducted on June 1-5, 1987, (Report Nos. 50-272/87-16 and 50-311/87-19).
Areas Inspected:
Routine unannounced inspection of licensee's analysis, modification and testing of the vital bus record level undervoltage protection systems, quality assurances interface, surveillance test procedures, and electrical distributio~ system improvement stud Results:
No violation or deviations were identified.
DETAILS 1.0 Persons Contacted Public Service Electric and Gas Company (PSE&G)
L. Corleto, Principal Engineer H. Deano, Quality Control Inspection
- D. Dodson, Licensing Engineer
- M. Gray, Licensing Engineer M. Marrino, Engineer
- D. Perkins, Manager Station Quality Assurance L. Randel, Maintenance Supervisor G. Roggio, Licensing Engineer
- J. Ronafalvy, Technical Manager - Salem
- P. White, Maintenance Manager - Salem United States Nuclear Regulatory Commission
- T. Kenny, Senior Resident Inspector K. Gibson, Resident Inspector
- Denotes those present at the exit meeting on June 5, 1987.
The inspector also held discussions with managers, supervisors and other licensee employees during the course of the inspection, including operations, technical and administrative personne Modification of the Second Level of Undervoltage Protection System Based Power Technologies, Inc. (PTI) Study On August 26, 1986, Salem Unit No. 2 experienced a false loss of offsite power event in which the vital busses sensed an apparent loss offsite power and separated from the preferred offsite power sourc This was caused by a sensed undervoltage conditio As a result, two diesel generators started to supply electricity to the 4160 Kv vital bu However, there was not actual loss of offsite powe The voltage transient was caused by high in house loads concurrent with high offsite power deman NRC review of this event and subsequent licensee actions have been previously documented in inspection reports 311/86-26, 311/86-36, 311/87-08 and 272/87-0 As result of the incident, the licensee performed a detailed design revie This* review revealed that transient voltage analyses had not been performed on plant design changes subsequent to October, 1979, which added electrical load In order to better predict future transients, PT! has modeled the Salem electrical distribution system using their PSS/E computer software package to be able to predict transcient and steady-state voltage at the plant elect_rical buse The results of the PT!
computer models
_
prediction indicated that after the non-vital group bus fast transferred on Unit 2, the voltage dipped below the second level of undervoltage protection setpoints and did not reset in sufficient time for the logic to stop the start and load of the diesel generator PTI's review indicated that the present Technical Specification setpoint and allowable values did not provide sufficient margin to-preclude blackout operation even though voltages were accepabl A new setpoint of greater than 91.6% has been selected and implemented in design change package Nos. lEC-2271 and 2EC-2271 for Salems Units No. 1 and 2 which are the subject of this inspectio.1 Design Change Packages (DCP) Nos. lEC-2271 and 2EC-2271 The design change packages (DCP's) for Salem Units 1 and 2 described the following changes to be made to their relaying schemes:
Elimination of the 91% voltage vital bus transfer scheme and provision for three 91% undervoltage relays wired from each vital bus to its associated safeguards equipment cabinet (S.E.C) for a two out of three logic to start the diesel generato Wiring changes at each S.E.C. unit to accomplish the abov The equipment is located on the 64 1 elevation electrical switchgear room and the 100 1 elevation relay roo The existing 70%
undervoltage relays and S.E.C. interface remained unchange The inspector reviewed the Unit 1 and Unit 2 DCP packages to assure they were reviewed and approved in accordance with the Technical Specification (TS) and established QA/QC controls for this sit The following areas were verified by the inspector for compliance with the licensee's proposed TS changes and the requirements of the licensee's "Safety Evaluation for the Modification of the Second Level of Undervoltage Protection System Report", dated March 23, 198 The inspector verified that:
The issued design changes were controlled by established procedure Post modification test records were reviewed by the licensee and out of specification reading were a~ted on by the license The operating and surveillance ~rocedures have been changed to reflect the new values listed in _the Power Technologies, In (PT!) stud The as-built drawings for the DCPs listed in attachment 1 have been issued and reflect the DCP change.2
Test Program The testing of the Second Level of Undervoltage Protection System modifi~ation was performed using procedure M3T, Revision 15, titled 11 Undervoltage and Under Frequency Trip Check and Time Response Surveillance Test".
This procedure provided instructions for obtaining and documenting the undervoltage set points and time response data for all vital busses and the under frequency response data for all group busses associated with the DCP Nos. lEC-2271 Unit 1 and 2EC-2271 Unit The test procedure, M3T, defined such ~reas as purpose, scope, responses, precautions, limitations and actions, prerequisites, test equipment and inspection hold point In this test procedure each section of the procedure was listed as an inspection hold point and required witnessing before proceeding to the next line ite A review of the test procedures by the inspector verified that the inspection hold points were witnessed and signed by an independent observe The inspector also verified that the recorded data was within the required ranges as specified in the procedur The data for test procedure M3T was reviewed by the inspector and compared with the requirements of PSE&G report 11 Evaluation for the Modifica-tion of the Second Level of Undervoltage Protection System 11 dated March 23, 1987 and were found to conform to the report criteri.0 Quality Assurance (QA)
The quality assurance program requirements for this modification were defined in each DC QA review was to perform surveillance during the installation and test portion of the DC The quality assurance witnessing of the test program was documented in procedure M3T with the in-process surveillance of DCPs documented in the Station QA Surveillance Report The inspectors review of selected Station QA Surveillance Reports is listed in Attachment A review of the surveillance reports and discussions with the quality assurance personnel who performed the inspection indicated that the personnel were knowledgeable of the work being performed and were performing in compliance with the requirements outlined in the DCP package No violations or deviations were identifie.0 Surveillance Procedures The original >91% setpoint used by the licensee assumed that the class lE 4KV motors were rated.at 4000 volts and the 91% setpoint of the 4160 volt bus would provide 94.5% protection for 4000 volt rated motor The 4KV motors are rated at 4160 volt The minimum allowable value of >90% did not consider the voltage drop in cables from the 4KV switchgear to the motor termi~als nor did it consider the accuracy of the potential transformer which the undervoltage relay utilizes to monitor the bus
voltag The new setpoint of >91.6% was determined in accordance-with Regulatory Guide 1.105, 11 Instrument Setpoi,nts 11 and the calculations to justify their values are documented in --PSE&G Design Memorandum S.C.El30-CDM-0494-l, 11Second Level of Undervoltage Protection System,
dated March 29, 198 The new minimum allowable value of >91% considers the voltage drop in the longest cable run and the potential transformer accurac The inspectors independent calculations using licensee supplied data, indicated that the >91% setting is a conservative value for setting the relay Since the Technical Specification provides these setpoints with a greater-than sign and the new setpoint is more conservative, the values will be changed and controlled administratively until a license T.S. change has been finalized. The inspector verified that Technical Specification Table 3. 3-4 Attachment 11J 11 has been changed to reflect the new trip setpoints and is administratively controlle The inspector noted that the TS change requested by the licensee and implemented in the DCP 1 s is schedules to be sent to the NRC for evaluation by June 30, 198 No violations or deviations were identifie.0 Electrical Distribution System Improvement Study (EDSIS)
The licensee has established an engineering study group to reevaluate the electrical distribution system for the Salem Unit 1 and 2 plant In addition to analyzing system deficiencies/weaknesses and developing feasibility studies for system improvement, the study will perform a review and calculation of the system voltage and provide short circuit analysis, relay coordination, motor starting requirements, et The EDSIS program is scheduled for management evaluation during the 1st quarter of 198 The results of this study and the changes that may occur in the safety systems as a result of this study will be evaluated by the NRC during future inspection at this sit No violations or deviations were identifie.0 Exit Meeting The inspector met with licensee management representatives (see section 1.0 for attendees) at an exit meeting on June 5, 1987.
The inspector summarized the scope and findings of the inspection at that tim At no time during the inspection was material provided to the licensee by the inspecto The licensee did not indicate that any proprietary information was contained within the scope of this inspectio **
ATTACHMENT 1 ACNs and Drawings Advance Change Notice (ACN), Procedure M3T, Revision 14, ANC 4, 3, 2, & 1 -
UV and UF Trip Check and Time Response Surveillance Test, issued June 1, 198 No. 1 and 2 Units No. 11 and 21 Sta. PWR Transformer 13./4 KV Potential Transformer Drawings 203977 B 9937 pages 10, 11, 17 and 1 Station QA Surveillance Reports Report No.87-411 - No. lA, 4KV Vital Bus Control Cubicle, Unit 1 Report No. 87-0377 - Switchgear Room Elevation 64 1 Units 2 Report No. 87-0387 - Switchgear Room Elevation 64 1 Units 2 Report No. 87-0386 - Switchgear Room Elevation 64 1 Units 2 Report No. 87-0373 - Switchgear Room Elevation 64' Units 2 Report No. 87-0427 - Switchgear Room Elevation 64' Units 1 Design Change Modification Packages Unit No. 1 lEC-2271 FSAR Tables, Attachment 11J 11 and 11 K
Unit No. 2 2EC-2271 FSAR Table-s, Attachment 11J 11 and 11 K
Failure Mode Analysis Attachment 4, Final Safety Analysis Repor Design Documentation PSE&G Design Memorandum - S.C.E130-CPM-0494-1, Second Level of Undervoltage Protection System, March 23, 198 Salem Nuclear Plant Undervoltage Study, Power Technologies, Inc., Report No. R7-87, February 198 PSE&G Engineering Evaluation S-C-E130-CEE-0162-0, Engineering Evaluation of Verification and Validation of Power Technologies Inc. (PTI) PSS/E Software Package and Salem Electrical Model, January 26, 1987.