IR 05000272/1995011
| ML18101A759 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 05/25/1995 |
| From: | Cheung L, Ruland W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML18101A758 | List: |
| References | |
| 50-272-95-11, 50-311-95-11, NUDOCS 9506070609 | |
| Download: ML18101A759 (9) | |
Text
DOCKET/REPORT NO U.S. NUCLEAR REGULATORY COMMISSION
REGION I
50-272/95-11 50-311/95-lf FACILITY:
LOCATION:
Salem Nuclear Generating Station, Units 1 and 2 Hancocks Bridge, New Jersey DATES:
INSPECTOR:
APPROVED BY:
May 11 - 12, 1995 Leonar C eung, Sr. Re neer Electrical Section Division of Reactor Sa
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11al1iflRU and, Clef Electrical Section Division of Reactor Safety
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Areas Inspected: Announced inspection by regional inspectors to review the status of previously identified open items and to determine the adequacy of the licensee's corrective actions to resolve these issue,
Results:
The review of licensee.corrective actions for the four electrical items indicated that these corrective actions were adequat All items were close The four items reviewed were:
91-30-01 91-80-03 91-80-02 Title Status EQ of containment Closed isolation valve position switches (Violation) Failure Closed to implement corrective actions for 125 Vdc system (Violation) Failure Closed to implement design control measures for EOG calculations 9506070609 950530 PDR ADOCK 05000272 Q
PDR Discussed in Paragraph 2.1.3
93-82-10 High ambient temp in switchgear/
penetration areas i i Status Closed Discussed in Paragraph *
DETAILS PURPOSE AND SCOPE {2515/111)
The purpose of this inspection was to review and verify licensee corrective actions for inspection findings identified during the February 1993 electrical distribution system functional inspection (EDSFI) and the April 1991 safety system function inspection (91-80). This inspection also covered a review of management oversight for resolving ele~trical open item.0 STATUS OF PREVIOUSLY IDENTIFIED INSPECTION ITEMS
. (Closed) Unresolved Item 50-272/91-30-01 and 50-311/91-30-01 This item pertained to the ~nvironmental qualification (EQ) of 28 containment isolation valve position switches (for each unit) for Regulatory Guide 1.97 applicatio The licensee later re-clarified the locations for some of these valve position switches to be a non-harsh environment, and provided engineering justification for the rest of the valve position switches that were located in a harsh environmen This item was updated during the February 1994 EQ inspectio The engineering justification was reviewed by the NRC during that inspection, and was determined to be acceptabl However, the exemption request for these deviations was never documented in their submittal to the NR On June 27, 1994, the licensee formally documented the exemption request for these deviations in their letter, NLR-N94009, to the Office of Nuclear Reactor Regulation (NRR) of the NR This exemption request was reviewed by NRR and was determined to be acceptabl The results of NRR's reviews were documented in the Regulatory Guide 1.97 Safety Evaluation Report, dated April 27, 199 This item is close.2 (Closed) Violation 50-272/91-80-03 and 50-311/91-80-01 This violation pertained to inadequate corrective actions for underrated fuses for the 125 Vdc syste During the April 1991 safety system functional inspection (SSFI), the team identified.that the fuses used for the 125 Vdc
- system were not capable of interrupting the calculated fault current. There were six fuses involved for each unit, and each fuse was rated at 10,000 amperes de interrupting curren The calculated fault current was 20,408 ampere The team also identified that this problem had been known to the licensee for years and no corrective actions were taken by the license In addition, the team also identified the following deficiencies in the
- *licensee's short circuit calculation, S-C-EOOO-EDC-0129, Revision.
The calculation used* 120 V at the battery terminals even though the assumptions stated that the battery was considered to be in a fully-charged state. The correct terminal voltage should have been the system float voltage of 132-135 Vd The higher voltage results in a higher fault contribution from the batter.
The effects of higher-than-nominal individual cell temperatures were not considered. Higher-than-nominal temperatures increase the available fault contribution from the batter.
The calculation assumed an incorrect battery charger contribution during a fault condition. It assumed 220 amperes as the rated output current contrary to the actual rated output of 250 amperes, as stated on the charger nameplat However, the calculation did conservatively assume that two chargers are connected to the system at any one time even though only one is normally connecte The licensee did not contest this violatio In their July 12, 1991, response letter to the Notice of Violation, the licensee attributed the root cause of this violation to personnel error for not following ihe station procedure to correct the problem promptl The licensee alsd identified the corrective actions to be taken to resolve this issue, including:
1) replacing all 12 fuses; and 2) counselling all functional engineering personnel on handling nonconformance During this inspection, the licensee stated that the 12 fuses were not replaced because they were not underrate The licensee provided a letter dated August 17, 1993, from the fuse manufacturer, Cooper Bussmann, for the inspector's revie This letter indicated that the KRP-Cl200 fuse (installed at Salem) had been tested by the manufacturer for 50,000 amperes interrupting current for 344 Vdc application (the ac rating for this fuse is 200,000 amperes interrupting current). The licensee explained that the de rating of these fuses was assumed to be 10,000 amperes at the time of the SSFI, because a telecon from a contractor engineer indicated the 10,000 amperes ratin There were no other data available at that time. Since the calculated short circuit current was less than 25,000 amperes, the inspector agreed that the fuse would be capable of interrupting the fault current. The inspector reviewed the manufacturer's letter and technical manuals, condu~~ed a walk down of the installed fuses at Unit 2, and verified that the installed fuses were as specified. The inspector also reviewed the counselling records for the functional engineering groups, and a memo (ELE-91-0635, dated October 31, 1991) entitled, 11 1991 RHR System Counselling," from the electrical engineering supervisor to nuclear licensing. This memo discussed the purpose and scope of the counsellin The inspector considered these parts of the corrective actions acceptabl The inspector observed that there were no records which indicated that the three issues identified by the SSFI team in the short circuit current calculations were ever addressed befor In response to the inspector's questions during this inspection, the licensee was able to provide the following answers: For the short circuit current calculation for the energy source from the battery, 2 volts per cell was the correct voltag The licensee provided a letter from the battery manufacturer (C&D Battery) dated November 16, 1978, for the inspector's revie This letter explained the reasons of 2 volts per cell for the short circuit current
- .
calculation. The 2 volts per cell methodology was also confirmed by IEEE Standard 946-199 Because the battery consisted of 60 cells, the inspector agreed that 120 volts was the correct voltage for the short circuit current calculation. This issue was resolve The licensee stated that the battery cell temperature increase would not affect the short circuit current calculation. This statement was confirmed by a test report (AEI Test No. 0591-1, "Stationary Battery Short Circuit Test," dated may 16, 1991).
The inspector reviewed this test report and determined that this issue was resolve The licensee stated that although the battery charger was rated for 250 amperes output current, the battery charger had a current limiting device which limited the output current within 120% of 220 ampere This current was included in the original short circuit calculatio The inspector reviewed Calculation No. ES-4.003Q, page 44 and Station Procedure SC.MD-ST.125-000l{Q), section 5.6 and confirmed this informatio The inspector also reviewed the record of Calculation N ES-4.003(Q).
The record showed that the calculation number of S-C-EOOO-EDC-0129 had been changed to ES-4.003{Q) on November 6, 199 The inspector agreed that this issue was resolve Based on the above reviews, the inspector concluded that the corrective actions taken by the licensee were adequate. This item was close.3 (Closed) Violation 50-272/91-80-02 and 50-311/91-80-02 This violation pertained to failure to implement design control measures for emergency diesel generator {EDG) loading calculations. During the April 1991 SSFI, the team identified various deficiencies that were not addressed in the EDG loading calculations, such as: cable losses for all loads connected to EDGs were not considered; battery charger limiting conditions w~re not accounted for; hydrogen recombiner full load kW loading was not considered, etc. This EDG loading calculation, S-C-4kV-EDC-0650, Revision 0, was performed by a contractor, ASTA Engineering, Inc. and had not been reviewed by licensee engineering. The team determined that these deficiencies were caused by inadequacies in the licensee's design control process in that a detailed design verification was not conducted to identify and correct the deficiencies before the loading calculations were issued for us The licensee did not contest this violatio In their July 12, 1991, response letter to the Notice of Violation, the licensee attributed the root cause for this failure to implement design control measures to personnel error in failure to follow an established procedur The corrective actions taken by the licensee to resolve this issue included:
1) the-supervisor and the engineer involved in this incident received counselling on the importance of attention to detail; 2) the entire functional engineering staff received counselling, emphasizing the requirements for design verification; 3) the engineering department performed a line-by-line peer review and a complete, independent design verification of the EDG loading calculations; and 4) the
electrical engineering department verified that all other electrical calculations had received design verification in accordance with Station Procedure OE-AP.ZZ-OOlO{Q), and determined that the incident was an isolated cas The inspector reviewed the records for counselling the functional engineering groups, including the supervisor and the engineer involved in this incident, and a memo (ELE-91-0635) from the electrical engineering supervisor to nuclear licensing. This memo discussed the objective and scope of the counsellin The inspector also reviewed the records of independent design review of the EOG load calculations. The calculation number was changed from S-C-4KV-EOC-0650 to ES-9.002 on December 31, 199 The design review record documented various comments and resolution. These comments and resolution indicated a thorough and in-depth revie For Corrective Action (4), the licensee stated that, because this corrective action was completed before the July 12, 1991, that corrective action was not in the tracking system, therefore, there were no records for the inspector's review and verificatio However, the inspector reviewed a licensee internal memorandum dated June 28, 1991, from electrical engineering to nuclear licensing. This memorandum indicated that as of June 28, 1991, all electrical calculations were verified to have received design verification in accordance with.the station procedur Therefore, this violation was an isolated cas The inspector considers the licensee corrective actions adequat This item is close.4 (Closed) Unresolved Item 50-272; 311/93-82-10 This pertained to high ambient temperatures in the switchgear and penetration area During the August 1993 electrical distribution system functional inspection (EOSFI), the team reviewed the draft calculations (S-l-CAV-MDC-0678 and S-2-CAV-MOC-0696), which were the only calculations available at that time for the ambient temperature of these areas. These calculations'*indicated that the maximum ambient temperature could be as high as ll8°F during a postulated accident. This temperature was substantially higher than the equipment design temperature of 105° The licensee maintained that these calculations (performed by a contractor) were unrealistically conservative, and that the actual temperatures would be significantly lower and would be within the design commitment Following the EDSFI, the licensee conducted a series of heat load calculations and revised Calculation No. S-l-CAV-MOC-0678, "Unit 1 SPAVS Cooling Load Calculation, Revision 1, dated April 28, 1994." The revised calculation indicated that the highest ambient temperature, during a postulated accident, was 110.4°F in the switchgear room at elevation 84 ft. These calculations were reviewed by an NRC inspector during an EOSFI followup inspection conducted in December 199 During that inspection, the *inspector identified that the calculations for the electrical heat loads (ES-50.005 and 50.006, Revision 0) used a questionable assumption that nonsafety-related equipment did not operate during the emergency mode, and, therefore, did not contribute
- to the heat load. There was no justification for this assumption, nor a controlled procedure to instruct the operators to shed nonsafety-related electrical loads during an accident. Therefore, this item remained ope Following the December 1994 followup inspection, the licensee revised electrical heat load calculations, ES-50.005 (Revision 1) and ES-50.006, Revision 1, to include the nonsafety-related electrical heat loads and refined their total heat load calculations. The revised calculations showed that the ambient temperature for the Unit 1 switchgear room at elevation 84 ft was 110.3°F (slightly lower than the temperature of the old calculation) and that the ambient temperature for Unit 2 switchgear room at elevation 84 ft was 109.3° The inspector reviewed the above calculations and found them to be acceptabl Engineering Evaluation S-l-EOOO-EEE-0890 was issued by the licensee to review the effect of the ll5°F ambient temperature on the electrical equipment in the switchgear roo This engineering evaluation was reviewed by the NRC during the December 1994 inspection, and was determined to be technically acceptable except that the reference to Calculation ES-50.005 used Revision 1, which was preliminary. Since Revision 1 was issued for both Units 1 and 2, the inspector considered this issue resolve Based on the above review, the inspector determined that this item was close.0 MANAGEMENT OVERSIGHT The inspector discussed the electrical open items with the manager of Salem electrical engineering and found the individual to be very familtar with the issues of the open items, and the corrective action for each issu Based on the reviews of corrective actions taken by the licensee to resolve the electrical open items, the inspector found that the quality.~f these corrective actions was generally goo For example, the independent design reviews of the emergency diesel generator calculations were found to be very thorough and in-dept However, the three issues identified by the safety system functional inspection (SSFI) team for the de system short circuit current calculations were never addressed and were not.mentioned in the open item package for Violation 91-80-0 It appeared that the licensee did not read the inspection report before preparing the package for closing out the electrical ite However, the responsible engineers were found to be very knowledgeable and were able to answer the inspector's technical questions promptly and correctl The inspector concluded that the management oversight in providing support to resolve the technical issues of electrical open items was generally good, and the engineering personnel were very knowledgeable.
6 EXIT MEETING The inspector met with the licensee personnel, denoted in the Attachment, at the conclusion of the inspection conducted on May 12, 1995, and summarized the scope of the inspection and the inspection result No proprietary materials were reviewed during this inspectio The licensee did not dispute the inspection findings at the exit meetin ATTACHMENT Persons Contacted Public Service and Gas Company
- R. Beckwith A. Bell
- M. Bursetein P. Duke
- L. Hajos
- C. Lambert S. Makam M. Quadir Station Licensing Engineer Electrical Designer Nuclear Electrical Engineering Manager Licensing Engineer Electrical Engineering Supervisor Manager, Nuclear Engineering Design Specialist Engineering, Nuclear Mechanical Electrical Engineer
- Denotes those present at the exit meeting on May 12, 1995.