IR 05000269/1981027
| ML15224A455 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/29/1981 |
| From: | William Orders NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML15224A453 | List: |
| References | |
| 50-269-81-27, 50-270-81-27, 50-287-81-27, NUDOCS 8111130618 | |
| Download: ML15224A455 (6) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 Report Nos. 50-269/81-27, 50-270/81-27 and 50-287/81-27 Licensee:
Duke Power Company 422 South Church Street Charlotte, NC 28242 Facility Name:
Oconee Nuclear Station Docket Nos. 50-269, 50-270, and 50-287 License Nos. DPR-38, DPR-47, and DPR-55 Inspection at Oconee site near Charlotte, North Carolina Inspectors:
7v W. OrdersJ r/Dte Signed D. Myers V
Date igned Approved by:
/P/p/ ryrnt, e hief, Division of Date Signed ident and Reactor Project Inspection SUMMARY Inspection on September 10 - October 10, 1981 Areas Inspected This routine announced inspection involved 163 resident inspector-hours on site in the areas of plant operations, surveillance testing, maintenance observation, and steam generator tube lea Results Of the four areas inspected, no items of noncompliance or deviations were identifie j0 81104
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DR ADOCK 05000269 PDR
DETAILS 1. Persons Contacted Licensee Employees
- J. E. Smith, Station Manager J. M. Davis, Superintendent of Maintenance J. N. Pope. Superintendent of Operations
- T. B. Owen, Superintendent of Technical Services R. T. Bond, Licensing and Projects Engineer
- T. Cribbs, Licensing Engineer Other licensee employees contacted included operations personnel, technicians, operators, mechanics, security force members, and office personne *Attended exit interview Exit Interview The inspection scope and findings were summarized on October 16, 1981, with those persons indicated in Paragraph 1 above. The licensee acknowledged the finding. Licensee Action on Previous Inspection Findings Not inspecte. Unresolved Items Unresolved items are matters about which more information is required to determine whether they are acceptable or may involve noncompliance or deviations. New unresolved items identified during this inspection are discussed in paragraph.
Plant Operations Safety Verification Unit 1 remained defueled throughout the inspection period (9/10 to 10/10/81). The majority of the in-service inspection (ISI) work continued without significant event. The work on modification of the broken thermal shield bolts continued with all but one of the 96 retaining bolts removed from the core support assembly. The remaining bolt will require additional work, such as drilling and/or end milling to facilitate remova The licensee and vendor are continuing investigations as to the cause of the bolt failur Unit 2 began the report period in a cooldown required by low oil levels on the 2A2 and 2B2 RC pump motors. Refilling of the motor oil pots is not possible from outside of the reactor building (RB).
Efforts to fill the resevoirs were inhibited by high radiation levels in the RB and the
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inconvenient location of the pot The licensee attributed low levels of oil to normal mechanical joint leakage on the pumps and oil resevoir syste After other maintenance activities were completed, including repair of a degraded electrical penetration and addition of 2 gallons of oil to all Unit 2 RCP motors, the heat-up and return to power commenced. On 9/17 the generator was on line and power escalation to 100% in progress. On 9/18 at 11:45 a.m. the licensee noted that air ejector off-gas radiation levels were increasing slightly; this is an early indication of a possible steam generator tube leak. At 3:30 p.m. the "B" OTSG developed a significant tube leak and the unit was shutdown. A more detailed discussion of this event and ensuing complications is found in paragraph 8 of this report. The unit remained shutdown at the close of this report perio Unit 3 has operated at virtually full power with no major problems throughout the perio Througout this inspection period facility tours were conducted to observe operations and maintenance activities in progres The tours encompassed the following areas:
perimeter fence; turbine building; control rooms; auxiliary building; battery rooms; equipment rooms; and penetration room During these tours the following observations were made:
(a) Monitoring Instrumentation - control room panels and plant computer information were perused to verify that indicated parameters were in compliance with Technical Specifications (TS) for the current operational mod (b) Shift Staffing - the inspector verified by spot checks that the operating shift staffing was in accordance with Technical Specif ications and that operators were attentive and cognizant of plant work and alarm condition (c) Plant Housekeeping and Fire Protection - Storage of material and components and cleanliness conditions of various areas througout the facility were observed to determine whether safety or fire hazards existed and that fire extinguishers and other fire fighting equipment were unobstructed and operabl (d) Radiation Areas - Radiation control zones were observed to verify proper identification and implementation. These observations included review of step-off pad conditions, disposal of contaminated clothing, area posting, and de-contamination procedures. The following observations were made:
A considerable effort has been made by the licensee to contain and process possibly contaminated water resulting from the Unit 2 OTSG tube leak. The effort reflected proper engineering and safet *I
(e)
Equipment Condition - During routine tours the inspector identified to the licensee two examples of apparent improper thread engagement of nuts on safety-related equipment. The nuts attached to packing gland retaining studs should have at least one full stud thread showing outside of the retaining nu The examples are detailed below:
2-BS-1 - Containment Spray System isolation valve in the east penetration room had its retaining nut attached by 2 of 6 threads in the nut. The inspector reviewed the valve technical manual VEL-NO-1 to determine if thread engagement was addressed. It was not. The licensee subsequently adjusted the valve packing to obtain proper engagement and cycled the valve to verify operability. (WR # 51045 B)
Turbine driven emergency feedwater pumps - located in the turbine building basement have shaft packing glands on each end of the pump. It appeared that only one retaining nut of the 12 on the stations 3 pumps was properly engaged. The licensee confirmed the condition and will initiate work requests to adjust the packing and achieve proper engagemen Inspector review of MP/0/A/1300/29 revealed that no mention of thread engagement was mad The inspector reviewed the related equipment technical manuals and determined that full thread engagement of retaining nuts was implied but was not expressively stated. The licensee has committed to change maintenance procedures to by adding a statement regarding proper make-up of packing gland retaining nut The inspectors will carry this issue as an unresolved item until maintenance procedures are reviewed or changed to address thread engagement. (Unresolved Item 50-269, 270, 287/81-27-01).
Of the areas inspected no violations were identifie. Surveillance Testing The surveillance tests detailed below were analyzed and/or witnessed by the inspector to ascertain procedural and performance adequac The completed test procedures examined were analyzed for embodiment of the necessary test prerequistes, preparations, instructions, acceptance criteria and sufficiency of technical conten The selected tests witnessed were examined to ascertain that current written approved procedures were available and in use, that test equipment in use was calibrated, that test prerequisites were met, system restoration was completed and test results were adequat The selected procedures perused attested conformance with applicable Technical Specifications; they appeared to have received the required administrative review, and they apparently were performed within the surveillance frequency prescribe Procedure Title Date PT/3/A/600/12 EFDWP Performance Test 10/6/81 PT/O/A/0150/08B RB Emergency Airlock Leak 10/6/81 Rate Test PT/O/A/150/20 Electric Penetration Leak 10/16/81 Rate Test The inspector employed one or more of the following acceptance criteria for evaluating the above items:
10 CFR ANSI N1 Oconee Station Directives Duke Administrative Policy Manual Of the areas inspected no violations or deviations were identifie. Monthly Maintenance Observation Maintenance activities on thermal shield bolts, hydrogen purge unit, and safety-related valve packing were observed and/or reviewed during the inspection period to ascertain that the activities were accomplished employing approved procedures or that the activities were within the skill of the trade and that the activities were performed by qualified personne Limiting conditions for operation were examined, where applicable, to ensure technical specification compliance. Acceptance criteria employed for this observation/review were as follows:
-Station Directives 3....3.11 3.3.15-Administrative Policy Manual Sections 3.3 and Technical Specifications Within the areas inspected no violations or deficiencies were identifie. Unit 2 Steam Generator Tube Leak At approximately 11:30 a.m. on September 18, 1981, Oconee Unit 2 ceased power escalation at 93% of full power due to indications of a once-through steam generator (OTSG) tube leak of about.035 gpm. At 3:30 p.m. the leak
increased rapidly to a rate of 25-30 gpm. A controlled unit shutdown was commenced and an "Unusual Event" was declared. The NRC was notified immediately and the Region II incident response center was manned. The reactor was shutdown and the affected OTSG was isolated by 4:50 p.m. in accordance with EP/0/A/1800/17. During the subsequent cooldown/depres surization, 2-LP2, the loop isolation valve for the decay heat removal system, could not be opened. This delayed achievement of cold shutdown conditions and prolonged the primary-to-secondary leakage. Drain lines from the affected OTSG were opened to compensate for increasing OTSG leve As a result a large volume of contaminated secondary water accumulated in the turbine building basement. No off-site liquid releases occurred and airborne release of radioactivity from the condenser air ejector was less than 1% of the Technical Specification (TS) limit. The resident inspector was in the control room throughout the even Efforts to open LP-2, a 12" Walworth split-disk gate valve continued until 06:47 a.m. on 9/20/81 when, after the valve motor had been removed, the valve disk stem was manually jacked to open the valv Decay heat removal via the LPI system commence After depressurization and draining of the primary systems the "B" OTSG was opened and a survey of OTSG tubes was performed as required by TS 4.17. Of the 300 tubes that were Eddy-Current tested, one tube was found defective and one tube degraded to a 30% wall imperfection. The defective tube (77-2), a "lane tube", was subsequently plugged and the OTSG reclosed. The required integrity test was performed satisfactoril Inspectors toured the turbine building for periods during the event and recovery to verify that control of secondary system contamination was in accordance with applicable procedures and that adequate radiation surveys and postings were being accomplished. It was noted that numerous electric-motors located in various sumps were submerged for a period of tim Inspectors verified that TS required equipment was operabl The radiation surveys appeared adequate as do the decontamination efforts in progres Following the decontamination and clean-up of the unit's secondary system, the licensee expects to return the unit to servic Inspectors will continue to monitor the licensee efforts in the restart of Unit 2.