ML16152A415
| ML16152A415 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/20/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16152A416 | List: |
| References | |
| NUDOCS 8504040175 | |
| Download: ML16152A415 (10) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION ON ENVIRONMENTAL QUALIFICATION OF ELECTRIC EQUIPMENT IMPORTANT TO SAFETY BY THE OFFICE OF NUCLEAR REACTOR REGULATION DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS 1, 2 AND 3 DOCKET NOS. 50-269, 50-270 AND 50-287 INTRODUCTION Equipment which is used to perform a necessary safety function must be demonstrated to be capable of maintaining functional operability under all service conditions postulated to occur during its installed life for the time it is required to operate. This requirement, which is embodied in General Design Criteria 1 and 4 of Appendix A and Sections III, XI, and XVII of Appendix B to 10 CFR 50, is applicable to equipment located inside as well as outside containment. More detailed requirements and guidance relating to the methods and procedures for demonstrating this capability for electrical equipment have been set forth in 10 CFR 50.49, "Environmental Qualification of Electric Equi'pment Important to Safety for Nuclear Power Plants," NUREG-0588, "Interim Staff Position on Environmental Qualification of Safety-Related Electrical Equipment" (which supplements IEEE Standard 323 and various NRC Regulatory Guides and industry standards), and "Guidelines for Evaluatino Environmental Qualification of Class 1E Electrical Equipment in Operating Reactors" (DOR Guidelines).
BACKGROUND On February 8, 1979, the NRC Office of Inspection and Enforcement (IE) issued to all licensees of operating plants (except those included in the systematic evaluation program (SEP)) IE Bulletin (IEB) 79-01, "Environmental Qualification of Class 1E Equipment."
This Bulletin, together with IE Circular 78-08 (issued on May 31, 1978), required the licensees to perform reviews to assess the adequacy of their environmental qualification programs.
6504040175 850320 PDR ADOCK 05000269 P
2 On January 14, 1980, NRC issued IEB 79-018 which included the DOR Guidelines and NUREG-0588 as attachments 4 and 5, respectively. Subsequently, on May 23, 1980, Commission Memorandum and Order CLI-80-21 was issued and stated that the DOR Guidelines and portions of NUREG-0588 form the requirements that licensees must meet reoarding environmental oualification of safety-related electrical equipment in order to satisfy those aspects of 10 CFR 50, Appendix A, General Design Criterion (GDC) 4. Supplements to IEB 79-018 were issued for further clarification and definition of the staff's needs.
These supplements were issued on February 29, September 30, and October 24, 1980.
In addition, the staff issued Orders dated August 29, 1980 (amended in September 1980) and October 24, 1980 to all licensees. The August Order required that the licensees provide a report, by November 1, 1980, documenting the qualification of safety-related electrical equipment. The October order required the establishment of a central file location for the maintenance of all equipment qualification records. The central file was mandated to be established by December 1, 1980. The staff subsequently issued a Safety Evaluation Report (SER) on environmental oualification of safety-related electrical equipment to the licensee in mid-1981. This SER directed the licensee to "either provide documentation of the missing qualification information which demonstrates that safety-related equipment meets the DOR Guidelines or-NUREG-0588 requirements or commit to a corrective action (requalification, replacement (etc.))." The licensee was required to respond to NRC within 90 days of receipt of the SER.
In response to the staff SER issued in 1981, the licensee submitted additional information regarding the qualification of safety-related electrical equipment. This information was evaluated for the staff by the Franklin Research Center (FRC) in order to:
- 1) identify all cases where the licensee's response did not resolve the significant qualification issues, 2) evaluate the licensee's qualification documentation in accordance with established criteria to determine which equipment had adequate documentation and which did not, and 3) evaluate the licensee's qualification documentation for safety-related electrical equipment located in harsh environments required for TMI Lessons Learned Implementation.
A Technical Evaluation Report (TER) was issued by FRC. A Safety Evaluation Report was subsequently issued to Duke Power Company on April 11, 1983, with the FRC TER as an attachment.
3 A final rule on environmental qualification of electric equipment important to safety for nuclear power plants became effective on February 22, 1983.
This rule, Section 50.49 of 10 CFR 50, specifies the requirements to be met for demonstratina the environmental qualification of electrical equipment*
important to safety located in a harsh environment. In accordance with this rule, equipment for Oconee Nuclear Station, Units 1, 2 and 3 may be qualified to the criteria specified in either the DOP Guidelines or NUREG-0588, except for replacement equipment.
Replacement equipment installed subsequent to February 22, 1983 must be qualified in accordance with the provisiors of 10 CFR 50.49, using the guidance of Regulatory Guide 1.89, unless there are sound reasons to the contrary.
A meeting was held with each licensee of plants for which a TER had been prepared for the staff by FRC in order to discuss all remaining open issues regarding environmental qualification, including acceptability of the environmental conditions for equipment qualification purposes, if this issue had not yet been resolved. On January 31, 1984 a meeting was held to discuss Duke Power Company's proposed method to resolve the environmental qualification deficiencies identified in the April 11, 1983 SER and the TER. Discussions also included Duke Power Company's general methodology for compliance with 10 CFR 50.49, and justification for continued operation for those equipment items for which environmental qualification is not yet completed. The minutes of the meeting and proposed method of resolution for each of the environmental qualification deficiencies are documented in an October 26, 1984 submittal from the licensee.
EVALUATION The evaluation of the acceptability of the licensee's electrical equipment environmental qualification program is based on the results of an audit review performed by the staff of:
(1) the licensee's proposed resolutions of the environmental qualification deficiencies identified in the April 11, 1983 SER and the TFR; (2) compliance with the requirements of 10 CFR 50.49; and (3) justification for continued operation (JCO) for those equipment items for which the environmental qualification is not yet completed.
4 Proposed Resolutions of Identified Deficiencies The proposed resolutions for the equipment environmental qualification deficiencies, identified in the April 11, 1983 SER, and the TER enclosed with it, are described in the licensee's October 26, 1984 submittal.
Durina the January 31, 1984 meetinq with the licensee, the staff discussed the proposed resolution of each deficiency for each equipment ifpre ident I in the TER and found the licensee's approach for resolving the identified environmental qualification deficiencies acceptable. The majority of deficiencies identified were documentation, similarity, aging, qualified life and replacement schedule. All open items identified in the April 11, 1983 SER were also discussed and the resolution of these items has been found acceptable by the staff.
The approach described by the licensee for addressing and resolving the identified deficiencies includes replacing equipment, performing additional analyses, utilizing additional qualification documentation beyond that reviewed by FRC, obtaining additional qualification documentation, and determining that some equipment is outside the scope of 10 CFR 50.49, and therefore not recuired to be environmentally qualified, e.q., located in a mild environment. We discussed the proposed resolutions in detail on an item by item basis with ft-M 'icensee during the January 31, 1984 meeting. Replacing or exempting equipment, for an acceptable reason, are clearly acceptable methods for resolving environmental qualification deficiencies. The more lengthy discussions with the licensee concerned the use of additional analyses or documentation. Although we did not review the additional analyses or documentation, we discussed how analysis was being used to resolve deficiencies identified in the TER, and the content of the additional documentation in order to determine the acceptability of these methods.
The licensee's equipment environmental qualification files will be audited by the staff during follow-up inspections to be performed by Region II, with assistance from IE Headquarters and NRP staff as necessary. Since a significant amount of documentation has already been reviewed by the staff and Franklin Research Center, the primary objective of the file audit will be to
verify that they contain the appropriate analyses and other necessary documentation to support the licensee's conclusion that the equipment is qualified. The inspections will verifY that the licensee's program for surveillance and maintenance of environmentally qualified equipment is adeouate to assure that this equipment is maintained in thp as analyzed or tested condition. The method used for tracking periodic replacement parts, and implementation of the licensee's commitments and actions, e.g., regarding replacement of equipment, will also be verified.
Based on our discussions with the licensee and our review of its submittal, we find the licensee's approach for resolvina the identified environmental qualification deficiencies acceptable.
Compliance With 10 CFR 50.49 In its October 26, 1984 submittal, the licensee has described the approach used to identify equipment within the scope of paragraph (b)(1) of 10 CFR 50.49, equipment relied upon to remain functional during and following design basis events. The licensee states that the flooding and environmental effects resulting from all postulated design-basis accidents documented in the Oconee Nuclear Station, Units 1, 2 and 3 Final Safety Analysis Report (FSAR), includinq the Loss-of-Coolant Accident (LOCA) and the Steam Line Break (SLBA) Accidents, were considered in the identification of safety-related electrical equipment which was to be environmentally qualified. The flooding and environmental effects resulting from High-Energy Line Breaks (HELBs) outside containment were also considered in the identification of this equipment. Therefore, all design-basis events including accidents at Oconee Nuclear Station, Units 1, 2 and 3 were considered in the identification of electrical eouipment within the scope of paragraph (b)(1) of 10 CFR 50.49 (i.e., "Safety-related electric eouipment..
.").
The licensee's approach for identifying equipment within the scope of paragraph (b)(1) is in accordance with the requirements of that paragraph, and therefore acceptable.
The method used by the licensee for identification of electrical equipment within the scope of paragraph (b)(2) of 10 CFR 50.49, nonsafety-related electric equipment whose failure under postulated environmental conditions could prevent satisfactory accomplishment of safety functions, is summarized below:
- 1. A list was generated of safety-related electric equipment as defined in paragraph (b)(1 of 10 CFR 50.49 required to remain functional during or following design-basis Loss of Coolant Accident (LOCA) or Hiah Energy Line Break (HELB) Accidents. The LOCA/HELB accidents are the only design-basis accidents which result in significantly adverse environments to electrical-equipment which is required for safe shutdown or accident mitigation. The list was based on reviews of the Oconee Nuclear Station, Units 1, 2 and 3 Final Safety Analysis Report (FSAR' and design documents of the elementary diagrams, connection diagrams, P&ID's and cable lists.
- 2. The elementary wiring diagrams of the safety-related electrical equipment identified in Step 1 were reviewed to identify any auxiliary devices electrically connected directly into the control or power circuitry of the safety-related equipment (e.g., automatic trips) whose failure due to postulated environmental conditions could prevent the required operation of the safety-related equipment; and
- 3. In reviewing the environmental qualification documentation for Class 1E equipment, the function of the equipment was reviewed via P&TD's, com ponent technical manuals, and/or systems in the FSAR. Any directly connected mechanical auxiliary systems to electrical equipment which are necessary for the safety related electrical equipment to perform its safety function were considered in the oualification of the Class 1E Equipment.
- 4. Nonsafety-related electrical circuits indirectly associated with the electrical equipment identified in Step 1 by common power supply or physical proximity were considered by a review of the original Oconee electrical design including the use of applicable industry standards (e.g., IEEE) and the use of properly coordinated relays, contacts, isolation amplifiers, individual output relays, circuit breakers, and fuses for electrical fault protection.
7 The licensee states that the results of the above review indicated that additional electrical equipment was identified which was not previously included on that "Master List."
Therefore, the list of electrical equipment provided in its October ?6, 1984 submittal is judged by the licensee to address all electrical equipment within the scope of paragraph (b)(?) of 10 CFR 50.49.
We find the methodology used by the licensee is acceptable since it provides reasonable assurance that equipment within the scope of paraoraph (h)(?) of 10 CFR 50.49 has been-identified.
With regard to paragraph (b)(3) of 10 CFR 50.49, the licensee evaluated existing system arrangements and identified equipment for the variables defined in R.G. 1.97, Rev. 3. A report outlining the results of the review, schedules for modifications where necessary, and justification of deviations not requiring modifications has been submitted to the NRC for review. Since the report is still under review by the staff, some of the equipment identified in the report has not been added to the 10 CFR 50.49 scope.
However, some of the equipment items jointly within the scope of NUREG-0737 and R.G. 1.97 have been included in the 10 CFR 50.49 scope. When the R.G.
1.97 report and equipment lists contained therein have been finalized and accepted by the staff, appropriate equipment not already in the 10 CFR 50.49 scope will be added in accordance with the R.G. 1.97 implementation schedule.
We find the licensee's approach to identifying equipment within the scope of paragraph (b)(3) of 10 CFR 50.49 acceptable since it is in accordance with the requirements of that paragraph.
Justification for Continued Operation The licensee has provided, in its October 26, 1984 submittal, justification for continued operation addressing each item of equipment for which the environmental qualification is not yet completed (see enclosure for the JCO equipment list).
8 We have reviewed each JCO provided by the licensee in its October 26, 1984 submittal and find them acceptable since they are based on essentially the same criteria that were used by the staff and its contractor to review JCO's previously submitted by licensees. These criteria, listed below, are also essentially the same as those contained in 10 CFR 50.49(i).
- a. The safety function can be accomplished by some other designated equipment that is qualified, and failure of the principal equipment as a result of the harsh environment will not degrade other safety functions or mislead the operator.
- b. Partial test data that does not demonstrate full qualification, but provides a basis for concluding the equipment will perform its function.
If it can not be concluded from the available data that the equipment will not fail after completion of its safety function, then that failure must not result in significant degradation of any safety function or provide misleading information to the operator.
- c. Limited use of administrative controls over equipment that has not been demonstrated to be fully qualified. For any eauipment assumed to fail as a result of the accident environment, that failure must not result in significant degradation of any safety function or provide misleading information to the operator.
CONCLUSIONS Based on the above evaluation, we conclude the following with regard to the qualification of electric equipment important to safety within the scope of 10 CFR 50.49.
0 Duke Power Company's electrical equipment environmental qualification program for Oconee Nuclear Station, Units 1, 2 and 3 complies with the reouirements of 10 CFR 50.49.
9 o
The proposed resolutions for each of the environmental qualification deficiencies identified in the April 11, 1983 SER and TER are acceptable.
o Continued operation until completion of the licensee's environmental qualification program will not present undue risk to the public health and safety.
Principal Contributor: P. Shemanski Dated:
March 20, 1985
10 Justification for Continued Operation Equipment List Oconee 1 Tag No.
NRC TER No.
Description LP-17/18 8
Limitorque VMTRs RC-162/163 15 Target Rock Solenoids PS-65 thru 68 26 Mercoid Pressure Switches LT-80 thru 83 62 Rosemount Level Transmitters PS-18 thru 23 63 Mercoid Pressure Switches Oconee 2 Tag No.
NRC TER No.
Description RC-162/163 20 Target Rock Solenoids PS-65 thru 68 30 Mercoid Pressure Switches LT-80 thru 83 61 Rosemount Level Transmitters PS-18 thru 23 62 Mercoid Pressure Switches Oconee 3 Tag No.
NRC TER No.
Description PS-65 thru 68 27 Mercoid Pressure Switches LT-80 thru 83 56 Rosemount Level Transmitters PS-18 thru 23 60 Mercoid Pressure Switches