IR 05000280/1994019
| ML18153B018 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 07/15/1994 |
| From: | Moore R, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18153B017 | List: |
| References | |
| 50-280-94-19, 50-281-94-19, 50-338-94-17, 50-339-94-17, NUDOCS 9407290098 | |
| Download: ML18153B018 (8) | |
Text
Report Nos. :
Licensee:
UNITED STATES NUCLEAR REGULATORY COMMISSION
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REGION II
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101 MARIETTA STREET, N;W., SUITE 2900 ATLANTA, GEORGIA 30323-0199 50-280/94-19 and 50-281/94-19 50-338/94-17 and 50-339/94-17 *
Virginia Electric and Power Company Glen Allen,. VA 23060 Docket Nos.:
50-280 and 50-281 50-338 and 50-339 License Nos.:
License Nos.:
DPR-32 *and DPR-37 NPF-4 and NPF~7 Facility Names:
Scope:
Surry 1 and 2 North Anna 1 and 2 SUMMARY Date Signed This routine, announced inspection ~as conducted in the area of Electrical Maintenanc The inspectirin reviewed the licensee's status of Station Blackout (SBO) commitments at Surry and North Anna nuclear plant Results:
The design of the Alternate AC power source at Surry and North Anna
_ appropriately incorporated the required elements of Regulatory Guide Station Blackout, dated August, 198 The progress of modifications sites indicated that scheduled completion dates would be achieved.
1.155, at both
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- 1. 0 persons Contacted *
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. Licensee Employees REPORT DETAILS
- W. Benthall, Licensing supervisor, Surry R. Berquist, Station Procedure Supervisor, North Anna
- B. Bryant, Licensing Vice President, Surry
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- B. Dunlap, Station Blackout Project Manager,.North Anna
- J. Jacoby, Station Blackout Project Manager, Surry R. Jones, Quality Assurance Supervisor, North Anna
- M. Kansler, Station Manager, Surry S. Knox, Design Engineering and Support Senior Electrical Engineer, Corporate
- W. Mathews, Assist~nt Station*Manager, North Ann *A. Price, Assistant Station Manager, Surry
- D. Roberts, Supervisor Station Nuclear Safety, North Anna*
- R. Saunders, Vice President, Nuclear Operations, Surry
- R. *shears, Superintendent-Maintenance, North Anna
- T. Sowers, Engineering Manager,' Surry
- E. Smith, Quality Assurance Manager, Surry
- J. Smith, Quality Assurance Supervisor, North Anna
- M. Whalen, Licensing Technical Analyst, North Anna Other licensee employees contacted during this inspec~ion included engineers and administrative personne NRC Resident Inspectors
- M. Branch, Senior resident Inspector, Surry
- R: McWhorter, Senior Resident Inspector, North Anna
- Attended exit meeting Acronyms and abbreviations are listed in paragraph.0 Electrical Maintenance {62705) SBO Status The inspector reviewed the status*of the licensee's Station Blackout
{SBO) modifica:tions at Surry and North Ann The modifications were similar in that an identical non-safety diesel generator was being installed at each plant as an alternate AC (AAC) power source for SB Similar buildings were being constructed at each plant to house the AAC DG and its auxiliaries. Due to the differing electrical distributio systems, the electrical tie-in between the MC DG and the station buses was different. The scheduled completion dates differed in that Surry was* approximately one year behind North Ann *
The inspector reviewed the design change packages {DCPs) for the SBO modifications to determine if specific elements of Regulatory Guide (RG) 1.155, Station Blackout, dated August 1988, were incorporated in the AAC DG. design and installation. * These elements included an AAC DG design which minimized the potential for common cause failure with the emergency AC power source, quality assurance (QA) coverage of the SBO modifications, and implementation of the EDG reliability progra Surry SBO Surry*will install one non-safety DG as an AAC power source with plant electrical tie-ins to the D and E transfer buse The Surry SBO commitment stated that the AAC DG source would be avail able to energize
- loads within 10 minutes of the identification of an SBO conditio An emergency diesel generator EDG target reliability of 0.975 was establishe The commitments were documented in the licensee's letter to the NRC, * (1 icensee serial No. 91-738A) dated February 10, 1992, an~
the Supplemental Safety Evaluation (SSE) report dated June 25, 199 The inspector reviewed DCP 92-052-3, AAC DG Installation, Surry Units 1 and 2, revision 0, to verify incorporation of RG 1.155 requirement.1.1 Surry Status The AAC DG building at Surry was near completion with only ventilation louver installations and final inspections remainin The building was constructed under contract with a commercial vende The design was essentially the same as the North Anna AAC DG building and. used the Virginia Building Officials and Administrators Code (BOCA) and the Uniform Building Code (UBC) for wind and environmental loads.* The AAC DG and the plant electrical tie-ins were included in DCP 92-052-3.. The AAC DG had been procured and was undergoing testing at the off site vender facility. The following calculations which support the SBO modification were not completed and were listed in section 2.3.14 of DCP.92-052-3:
. N~w Calculations EE-0531, AAC Generator Protective Relay Setting EE-0532, OM and OL Bus Relay Settings EE-0673, Surry AAC System 480 VAC Low Voltage Breaker Settings EE-0670, Surry AAC Electrical System Design Revised Calculations EE-0034, Surry Voltage Profiles
- EE-0334, Surry Emergency Bus Fault Current Analysis EE-0046, 125 VDC System Load Analysis EE~0501, Motor Terminal Voltage for GL 89-10 MOV **
- Responsibilities had been designated for the identification and development of SBO related procedures and training. The following SBO project milestones were applicable for Surry:
- End of 1.995 Unit 1 Refueling *outage - AAC DG installation.and
- plant electrical tie-in to Unit 1 complet * End of 1996 Unit 2 Refueling Outage - Plant electrical tie-in to Unit 2 complet.1.2 Surry AAC DG Design Yhe AAC-DG was a skid mounted Caterpil~ar Model 3612 diesel coupled to a KATO Engineering generator. This was a 4160 V unit with a 2000 hour0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> rating of 3460 kW and continuous rating of 3300 kW at a 0.8 power facto The design minimized the potential for common cause failure with the emergency AC power source by physical separation of the AAC DG in a separate building and the self contained design of the DG and its support syst.em The plant electrical tie-ins through the transfer
- buses provided the capability to power emergency bus loads without a direct ~onnection to the emerge~cy bu The DG capacity exceed~d the estimated SBO load of 3062 k The post modification testing in the DCP inc 1 uded verifying the Surry ten minute AAC DG availability commitmen The inspector concluded that the DCP appropriately incorporated the AAC DG design requirements of RG 1.15 *
2.1. 3 Surry QA.Coverage Appendix 4.10 of DCP 92-052-3 addressed the ten QA program elements specified in RG 1.155, Appendix A, for establishment of appropriate QA monitoring of SBO modi fi cations. The purchase spe.cifi cation for the Surry AAC DG, Purchase Specification No. SUP-0053, dated February 11, 1992, section 5.0, stated the QA program requirements for the vender were to be in accordance with RG 1.15 The purchase specification Vender Final Inspection Report included a check list for the licensee's Nuclear Quality Assurance acceptance of the AAC D A Surry QA inspector was assigned to SBO modification project. During*
this inspection the licensee's QA inspector was observing the North Anna modification implementation to enhance the Surry project QA coverag The inspector concluded that the QA program for the Surry SBO modifications appropriately implemented the* elements of RG 1.15.1. 4 Surry EDG Re 1 i ability Program*
The inspector reviewed the 1 i censee' s EOG Re 1 i ability Program to determine if the related RG.1.155 elements were incorporated in the progra The licensee's program was implemented by Virginia Power Administrative Procedure (VPAP} 0808, EDG Reliability Program, revision 3. The program EDG targ*et reliability of 0.975 with trigger values of 3, 4, and 5 failures was consistent with the plant SBO plant category. A surveil 1 ance testing and monitoring program was implemented
- by Surry Station Engineering Services (SSES) procedure 3.07, Controlling Procedure fat Tracking, Trending; and Evaluation of EDG Surveillance and Operational Data,.revision Failure analysis and root cause analysis was included in VPAP 080 Responsibilities for major program elements and establishment of a management oversight was designated in VPAP080 The inspector concluded that the Surry EDG Reliability program
implemented *the applicable requirements of RG 1.15 North Anna SBO North Anna will install one non-safety DG as the alternate AC power source~
Plant electrical tie-ins will be to the D, E, and F transfer buse The North Anna AAC DG availability requirement was.one hour from the identification of an SBO conditio The commitment and
.implementation schedule were specified in the February 10, 1992 letter (licensee serial NO. 91-738A) from Virginia Power to the NR The implementation schedule for North Anna was approximately one year ahead of the Surry schedul The inspector reviewed the following DCPs which implemented the SBO modifications at North Anna:
DCP 92-11-3, AAC DG Installation, North Anna (NAPS} Units 1 and 2, dated January 20, 199 DCP 92-12-3, SBO Diesel Tie-in to Station NAPS 1 and 2, dated March 21, 199 DCP 92010-3 SBO DG Building,*dated November 19, 199.2.1 North Anna Status
- The AAC DG building a*nd installation of the heating, ventilation and air conditioning (HVAC} systems were complete The AAC DG and the majority of mechanical support sjstem equipment was installed in the buildin The plant electrical tie-ins were not completed although the 4160 V cable between the AAC DG and turbine building had been pulled. All DCPs to accomplish the SBO modifications were completed and approve One calculation to support the modifications was not yet complete~
Calculation EE-0550, AAC System 480 VAC Low Voltage Breaker Setting Required procedures for SBO were identified and being develope Ma-intenance training was initiated and operator training was being develope The following were the schedule milestones for the SBO modifications:
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- End of 1994 Unit 1 Refueling Outage - Installation of AAC DG and support systems arid plant electrical tie-in to Unit 1 transfer bus D complete *
- En9 of 1995 Unit 2 Refueling Outage Plant electrical tie-ins to E and F transfer buses complet..
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2.2.2 North Anna AAC DG Design The North Anna AAC DG was identical to the Surry AAC DG, i.e. a skid mounted Caterpillar model 3612 diesel coupled to a KATO 4160 V generator with a rated capacity of 3460 kW for 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br /> and 3300 kW continuou Common cause failure potential was minimized by designing the DG as a self sufficient power source without support from plant system With the exception of the additional tie-in to the F transfer bus, the Surry and North Anna AAC DG designs were essentially the sam The AAC DG continuous rating of 3300 kW exceeded the 2731 kW SBO load calculated in calculation EE-0509, NAPS AAC Electrical System Design, dated December 31, 199 The inspector concluded that the DCPS for the SBO modification appropriately incorporated RG 1.155 elements for an AAC sourc.2.3 QA Coverage Appendix 4-16 of DCP 92-11-3 addressed the ten elements specified in RG 1.155 for a QA program applied to SBO Modification The* apperidix further identified specific activities to be monitored by Q For example, the licensee's corporate QA vender surveillance group would inspect large components and cable. Daily QA monitoring of the DG *
installation was performed and the results documented on Quality Control*
Inspection Report The inspector reviewed a design change audit dated April 28, 1994, which included a review of DCP 92-11-The inspector concluded that the licensee's QA coverage for the SBO modifications was consistent with the requirements of RG 1.15.. 2.4 EOG Reliability Program The licensee's EDG reliability program at North Anna was a corporate *
level program which is ess~ntially identical at North Anna and Surr Corporate Procedure VPAP 0808, which was previously discussed in paragraph 2.14 of this report, describes the reliability progra This procedute specified the 0.95 EDG target reliability and associated failure trigger valules consistent with North Anna's SBO categor The inspector cone l uded that the Ti censee' s EDG reliability program appropriately incorporated the required elements of RG 1.155, section.0. Follow-up* on Previously Identified Inspection Findings (92701)
The inspector reviewed two previously identified items at North Ann These items are discussed in the following paragraph.1 (Closed) Inspector Follow-up Item (!FI) 50-339/90-05-11, Electrical Coordination* of Safety Related Emergency Bus Breakers This item identified a lack of coordination where a fault on ~he feeder breaker to the safety-related 480 V bus could cause the associated 4160 V feeder breaker to tri For example, at North Anna, one EDG
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feeds an 4160 V emergency bus which feeds its a*ssociated 480 V transformers through feeder breaker 15H8. The two 480 V buses for one safety related equipment train were fed through main breakers 14H-l and *
14Hl-l downstream of the two 4160/480 V transformer A fault on.
breaker IH or IHI could result in tripping of the 4160 V feeder breaker 15H8 and subsequent loss of both 480 V buses rather than just the
faulted 480 V bus. This would result in the loss of one train of safety related equipmen The other train, fed from the.other EDG, would not be impacted by this fault, therefore there was not a condition where a single failu.re could impact both trains of safety related equipmen The issue was initially identified as unresolved item 50-339/89-200-11 in a 1989 Safety System Outage and Modifications Inspection {SSOMI).
The SSOMI finding stated that the coordination was not a safety concern but that this was a poor coordination desig The licensee's response to the SSOMI finding was that the condition was safe though undesirable and a further study of the issue would be initiated. The coordination issue was addressed in the following NRC Inspection Reports:
50-33.8,339/90-05, 50-338,339/90-12, 50-338,339/91-17, and 50-338,339/92-2 The SSOMI follow-up inspection (report 90-05) converted URI 50-339/89-200-ll into IFI 50-339/90-05-1 The Electrical Distribution System Functional Inspection (EDSFI - report 91-17)
identified an additional lack of coordination between the 4160 V feeder breaker and the 480 V branch breakers which supply equipment loads from the 480 V bus. Therefore the original coordination issue ekpanded to include two items; the SSOMI item and the EDSFI ite The coordination issue was identified as Finding 91-17-03, item 12.7, in the EDSFI report.. The EDSFI follow-up inspection (report 92-21) reviewed the coordination issue and related licensee engineering evaluations. The
- conclusion was that Finding 91-17-03, item 12.7 was r*esolved and the licensee's development of action plans to implement plant changes was reference The following paragraphs address the resolution of the SSOMI item and the EDSFI item related to the coordination issu The SSOMI Item was evaluated in licensee Technical report EE-0021 and Type 2 Report NP2122 Potential resolutions included modifications to power the 480 V buses through separate 4160 V breakers (add a 4160 V breaker from the emergency bus) or replace the 4160 V type lJCV voltage restraint overcurrent relays. These solutions were determined to be not feas*ibl Physical restraints on the emergency bus impacted
installation of an.additional* 4160 V breaker and replacement of the overcurrent relays introduced additional coordination problems with the EDG breake The licensee completed the coordination*studies specified in their response to the SSOMI item and concluded that no action was warrante The EDSFI item was resolved via modifications. The following de~ign changes were implemented on Uriit 2 and were scheduled for the ~ext Unit 1 outage to resolve the coordination issues identified by the EDSFI:
. EWR 92-379, Revise Setpoint for 50/51 V Relays on Breakers 15H8 and 15J8 r
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DCP 92-301, replace Trip Devices for Various 480 V and 4 kV Equipment
.DCP 92-302, Replace Trip Devices for Various 480 V Equipmen Bas~d on completed and scheduled corrective actions, this issue is close.2 (Closed) IFI 50-338,339/92~21-0l, Electrical Isolation of Plant Process Computer This item addressed a concern initially identified during the SSOMI associated with.the electrical isolation of the plant process computer from RG 1.97 instruments. The item was initially identified as unresolved item 89-11-01 pending -a licensee study to select a method of isolation. The issue was reviewed in NRC inspection report
. 50-338,339/92-21 and converted to IFI 92-21-01 because the study had been completed but not reviewed by the NR A letter from NRR Project Directorate II-2, dated May 19, 1993, to the licensee regarding North Anna's conformance to RG 1.97, accepted the existing plant computer electrical configuration. Thii decision was documented in a NRR Supplemental Safety Evaluation included with the letter. This item is close *
Exit Meeting The inspection scope and findings were summarized on June 19, *1994, at Surry and on July 1, 1994, at North Anna, with those persons indicated
- in paragraph The inspector described the areas inspected and discussed in detail the inspection findings listed belo No dissentin comments were received froni the licensee. The licensee did not identify as proprietary any of the material provided to the inspector * (Closed) IFI 50-339/90-05-11, Electrical Coordination of Safety Related Emergency Bus Breakers*
(Closed) IFI 50-338,339/92-21-0l, Electrical Isolation of Plant Process
.Computer