IR 05000269/1990025
| ML15224A718 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/17/1990 |
| From: | Binoy Desai, Poertner W, Shymlock M, Skinner P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML15224A717 | List: |
| References | |
| 50-269-90-25, 50-270-90-25, 50-287-90-25, 72-0004-90-25, NUDOCS 9009270012 | |
| Download: ML15224A718 (7) | |
Text
, REG UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION II
r o101 MARIETTA STREET, ATLANTA,GEORGIA 30323 Report Nos: 50-269/90-25, 50-270/90-25, 50-287/90-25 and 72-4/90-25 Licensee: Duke Power Company 422 South Church Street Charlotte, N.C. 28242 Docket Nos.:
50-269, 50-270, 50-287, 72-4 License Nos.: DPR-38, DPR-47, DPR-55, SNM-2503 Facility Name: Oconee Nuclear Station Inspection Conducted: July 15 - Sep mber 1, 1990 Inspectors:
9-10-57 P. H. Skinner, enfor I'
s Inspe tor Date Signed R nt Date Signed W. K. Poert r, Res nt nsp tor Date Signed Approved b :_
..
ymlock, Section Chief Date Signed Divisi In of Reactor Projects SUMMARY Scope:
This routine, announced inspection involved inspection on-site in the areas of operations, surveillance testing, maintenance activities, spent fuel transfer cask inspection, inspection of PWR moderator dilution requirements, and inspection of open item Results:
The inspectors continue to consider the ongoing Design Engineering (DE) effort associated with the Design Basis Documentation program to be a substantiated strength in the licensees program DE is dedicating significant resources and conducting thorough analysis during each portion of this program. The issue identified in this report (paragraph 2.c) is another example of how these efforts have directly resulted in increased plant safety. Also noteworthy is the licensees 10 CFR 50.59 evaluation program that resulted in the identification of the susceptibility of the emergency power source to single failure of air circuit breakers (ACBs) 1 or F'DR A5o d urin e
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a PDC
REPORT DETAILS 1. Persons Contacted Licensee Employees
- B. Barron, Station Manager
- M. Tuckman, General Manager Nuclear Support D. Couch, Keowee Hydrostation Manager
- T. Coutu, Operations Manager T. Curtis, Compliance Manager
- J. Davis, Technical Services Superintendent D. Deatherage, Operations Support Manager B. Dolan, Design Engineering Manager, Oconee Site Office
- W. Foster, Maintenance Superintendent D. Hubbard, Performance Engineer
- E. LeGette, Compliance Engineer H. Lowery, Chairman, Oconee Safety Review Group B. Millsap, Maintenance Engineer
- D. Powell, Station Services Superintendent
- G. Rothenberger, Integrated Scheduling Superintendent R. Sweigart, Operations Superintendent Other licensee employees contacted included technicians, operators, mechanics, security force members, and staff engineer NRC Resident Inspectors
- P. Skinner
- B. Desai
- K. Poertner
- Attended exit interview 2. Plant Operations (71707) (71710)
a. The inspectors reviewed plant operations throughout the reporting period to verify conformance with regulatory requirements, Technical Specifications (TS), and administrative controls. Control room logs, shift turnover records, temporary modification log and equipment removal and restoration records were reviewed routinely. Discussions were conducted with plant operations, maintenance, chemistry, health physics, instrument and electrical (I&E), and performance personne Activities within the control rooms were monitored on an almost daily basi Inspections were conducted on day and on night shifts, during weekdays and on weekends. Some inspections were made during shift change in order to evaluate shift turnover performance. Actions observed were conducted as required by the licensee's
determine the cause of the leak and the valve failure. The licensee determined that the outboard pump bearing had been previously replaced without a subsequent realignment of the pump and turbine shaft. Common practice at that time did not include a requirement for realignment associated with outboard pump bearing replacemen This alignment problem, along with subsequent use, apparently caused higher than normal vibrations which led to the failure of the low pressure turbine inboard bearing resulting in the oil leak. The turbine bearing was replaced and a performance test was conducted on the following day. During this test, high vibration readings were noted at the inboard bearing and the pump was stopped. Further evaluation by the licensee revealed that the replacement.turbine bearing that had been used is designed for a turbine that rotates in a counter-clockwise direction. The TDEFW pump turbine at Oconee rotates in a clockwise direction. Interchanging of these bearings could possibly damage the turbine. The Operations Manual for the turbine (OM-2008-006) and the replacement part order list apparently listed a part number for counter-clockwise turbine rotation. The licensee had previously ordered two of these bearings from this lis The additional bearing was still in stock and was later destroye The correct bearing was installed and the pump was run without further problems on July 20. The licensee stated that this problem was not applicable to Unit 1 and 2 because the dimensions of the shaft and the bearing part numbers of those units are different than Unit 3. The OM and the replacement part list have been changed to reflect the correct part number. The licensee is evaluating whether a realignment should be performed when a bearing is replace Valve 3MS-95 not fully closing was attributed to foreign material in the valve seat area. Two check valves upstream of 3MS-95 had been replaced during the last refueling outage. The piping associated with these valves had been cut. The cutting technique generated some slag that had apparently not been removed from the piping during post-cut cleaning. Prior to July 18, 1990, on two other occasions some of this slag had gotten by the MS-95 valve strainer and had caused the valve to stick. At that time the licensee rectified this problem by disassembling the valve and removing the sla In addition to disassembly and cleaning of this valve again, a station problem report has been generated requesting design engineering to look into the possibility of installing another full flow basket type strainer or a conical line strainer of sufficient effectiveness to prevent slag intrusion and subsequent valve sticking. Also, the licensee has decided to use pipe cutting methods involving the TDEFW system that will not create slag material. The inspectors will continue to monitor the licensee's actions associated with this proble C. Overloading of Keowee Units Under Certain Postulated Accident Conditions On July 31, 1990, Design Engineering (DE) identified a potential problem concerning availability of Oconee's emergency power supply during a postulated Loss of Coolant Accident (LOCA)/Loss of Offsite Power (LOOP) Design Basis Event while both or one of the Keowee units is generating to the grid. This issue was identified during the licensee's Design Basis Documentation effort on the Keowee Emergency Power syste Per the as-built Keowee emergency power configuration, either or both of the two Keowee generators may supply power to the 230KV switchyard. If a Keowee emergency start signal is initiated, the Keowee generator air circuit breakers (ACB 1 for generator No. 1 and ACB 2 for generator no. 2) would automatically trip to ensure separation of the Keowee unit(s) from the switchyard. Positive indication of switchyard isolation provides a close permissive to the tripped ACBs, and after a 0.5 second time delay, one ACB would close to align power to the overhead path through power circuit breaker (PCB) 9. The other Keowee unit would be aligned to transformer CT4 via the underground path. With the Keowee unit aligned to the overhead path supplying power to the startup transformers through the 230 KV switchyard following closure of ACB 1 or 2, the reactor coolant pumps (RCP) circuit breakers would not have opened (on bus undervoltage), as the total reactor coolant pump undervoltage relay/breaker logic time delay is longer in duration than the ACB time delay prior to breaker reclosure (3.5 seconds versus seconds).
With the Keowee units in the configuration discussed above and a LOCA/LOOP, the LOCA loads on one unit plus the hot shutdown loads on the other two units would be 20.628 MVA. The twelve RCPs for all three units would be equal to about 90 MVA resulting in a total load for all three units of 110.628 MVA. This would exceed the 87.5 MVA capacity of a single Keowee unit causing it to overload and possibly result in the loss of essential equipmen The licensee was originally considering proposal for operability on the condition that only the Keowee unit aligned to the underground path (via ACB 3 or ACB 4) be utilized when necessary to generate power to the 230 KV switchyard. With this alignment, following switchyard isolation, both overhead path circuit breakers ACB 1 and ACB 2 would trip and only the ACB (3 or 4) for the Keowee unit not aligned to the underground path would close. This standby Keowee unit would then take approximately 12 seconds to provide power to the 6.9KV bus, thus allowing sufficient time for the RCPs to trip on undervoltage. However, while preparing the 10 CFR 50.59 evaluation for this condition, a single failure of ACB 1 or 2 to open on an ES 0I
signal was postulated. With this failure, the running Keowee unit would fail to separate from the 230 KV switchyard causing the RCPs to continue to operate and overload the operating Keowee uni The licensees immediate corrective action was to declare that the Keowee units would be used solely as a dedicated, onsite, safety related power source, and not used to generate power for grid peaking. As a permanent resolution, the licensee implemented a Nuclear Station Modification (NSM) to modify switchyard isolation logic and PCB 9 trip and closure circuit This NSM installed equipment that produces a trip signal with a four second later reclose signal for PCB 9. Also, time delays for the permissive circuits to close ACB 1 and ACB 2 were increased to four seconds. This allows enough time for the reactor coolant pumps to trip, preventing overloading a Keowee uni A four hour non-emergency notification pursuant to 10 CFR 50.72b.2.iii.D was made on August 2, 199 The inspector closely followed the licensee's resolution of the problem including functional verification following completion of the modifications. TS requirements regarding LCOs were met, integrity of the plant was maintained by ensuring proper isolation of wiring and mounting of equipment, and independent verification was used when require CFR 50, Appendix B, Criterion III, Design Control requires measures be established to assure that applicable design requirements are correctly translated into specifications, drawings, procedures and instructions. The failure to meet this requirement for this design deficiency is being identified as a non-cited violation since all criteria specified in 10 CFR 2, Appendix C, Section V.G has been addressed by the licensee. For tracking purposes this is identified as non-cited violation (NCV) 50-269, 270, 287/90-25-01:
Potential overloading of Keowee generators under certain postulated accident condition No additional violations or deviations were identifie. Surveillance Testing (61726)
Surveillance tests were reviewed by the inspectors to verify procedural and performance adequacy. The completed tests reviewed were examined for necessary test prerequisites, instructions, acceptance criteria, technical content, authorization to begin work, data collection, independent verification where required, handling of deficiencies noted, and review of completed work. The tests witnessed, in whole or in part, were inspected to determine that approved procedures were available, test equipment was calibrated, prerequisites were met, tests were conducted according to
These reviews indicated that the licensee had established adequate controls and procedures to implement the TS requirements associated with the ISFS Changes to procedure OP/1&2/A/1510/14 dated June 27, 1990, Independent Spent Fuel Storage Installation, were made as a result of lessons learned during the preoperational testing. The inspectors witnessed various portions of the first two dry storage cask (DSC) loading and transfer operations. Activities witnessed included:
- preparation of the DSC and transfer cask
- radiation safety requirements associated with loading and movement
- welding of DSC
- drying and helium leak testing
- movement of DSC to horizontal storage modules (HSM)
- installation of DSC into HSM, and welding of seal door to HSM
- review of radiation levels after loading of DSC into HS The inspectors also reviewed the procedure to assure that only approved spent fuel assemblies were loaded into the DSC. The first DSC was transferred to the HSM on July 24 and the second DSC was transferred on August 11, 1990. All activities reviewed met the requirements identified in the TS associated with materials license SNM-2503 and the operational T No violations or deviations were identifie. Inspection of PWR Moderator Dilution Requirements (TI 2515/94) (71707)
The inspector reviewed the licensee's action with regard to the PWR moderator dilution issue as addressed by multi-plant action item B-0 DOR Information Memorandum No. 7, PWR Moderator, discussing an unreviewed method of moderator dilution which had been identified by an incident at an operating PWR facility. The licensee responded to this DOR in correspondence dated December 2, 1977. This response stated in summary that the only system with a potential for unplanned dilution not considered in the FSAR is the caustic mix tank. Since this mix tank is normally empty, contains multiple closed vales for isolation purposes, and is only used in an emergency, the probability of inadvertent injection was very lo However, an analysis was performed which showed that even if this inadvertent injection were to occur, the resulting reactivity addition would be such that it would not result in an inadvertent criticality. The NRC in correspondence dated February 23, 1989, stated that the licensee' response had been reviewed by the staff and no additional actions were necessar Based on this review this item is close. Inspection of Open Items (92700) (90712) (92701)
The following items were reviewed using licensee reports, inspection, record review, and discussions with licensee personnel, as appropriat a. (Closed) IFI 72-004/90-19-01: Incorporate Into Two Abnormal Procedures (APs) Requirements to Include the ISFSI in Damage Surveys Following an Earthquake and Other Natural Disaster The licensee has revised AP/1/A 1700/05, Earthquake, and AP/1/A/1700/06, Natural Disasters, to include requirements to inspect the independent spent fuel storage facility for any indications of damage for either of these events. Based on this action, this item is close b. (Open) IFI 50-269,270,287/89-03-03:
Discrepancies Between One-line Drawings and Elementary Wiring Diagrams. This item addressed concerns identified by the Augmented Inspection Team following the fire in the 1TA switchboard in January 1989. The inspector identified several discrepancies between the one-line drawings and the elementary diagrams (OEE). As a result, the licensee reviewed all switchgear, load centers and safety-related 600V and 208V motor control centers. A total of 18 drawings containing errors were identified. The drawings, with errors noted, have been sent to various organizations for review. One-line drawings ('0' drawings)
have been determined to be correct and an electrical panel program has labeled all loads in each panel which assures personnel working on the panels to be on the correct component. The licensee states that if the review of the OEEs by the various groups indicates no changes to equipment or procedures are required, then the OEEs will be corrected within 60 days. This item remains open pending additional review following revisions to subject drawing c. (Closed) LER 287/89-05:
Inappropriate Actions Cause Engineering Safeguards Actuation Which Led to Fire Protection Technical Specification Violation. This LER was submitted by the licensee in correspondence dated December 6, 1989. All corrective actions identified have been completed. The inspector reviewed documentation changes and periodically reviews the placement of fire extinguishers during routine plant tours. Based on these actions this item is close d. (Closed) Violation 50-269,270,287/89-36-01:
Failure to provide adequate Procedures - 2 Examples. This violation was responded to in correspondence dated February 7, 1990. The first example identified in this violation was associated with the operation of a valve in the building spray system that was improperly operated and resulted in a spill of approximately 2000 gallons of water in the unit 3 containment building. The licensee acknowledged the violation but described the deficiency as a management deficiency rather than a procedural inadequacy. The actions identified by the licensee for this example have been completed and reviewed by the inspector. In the second example, the licensee did not agree that the example was