ML20045G386
| ML20045G386 | |
| Person / Time | |
|---|---|
| Issue date: | 06/16/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20045G374 | List: |
| References | |
| PROC-930616-02, NUDOCS 9307130288 | |
| Download: ML20045G386 (11) | |
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ENVIRONMENTAL QUALIFICATION (EO) i 10 CFR 50.49 TASK ACTION PLAN June 16,1993 NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION l
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ENVIRONMENTAL QUALIFICATION (EQ) 10 CFR 50.49 TASK ACTION PLAN Purpose The purpose of this task action plan (TAP) is to evaluate and resolve existing environmental qualification (EQ) concerns and to identify and resolve any other EQ issues that may exist.
Backcround As a result of the staff's activities related to license renewal, EQ was identified as an area that required further review. As discussed in SECY-93-049, a major concern related to EQ was whether the EQ requirements for older plants were adequate to support license renewal. Consequently, the staff concluded that differences in EQ requirements between older and newer plants constituted a potential generic issue which should be evaluated for backfit independent of license renewal activities.
In support of the license renewal initiative, EQ testing of electric cables was performed by Sandia National Laboratories (SNL) under contract with the NRC. Some tests were performed to determine the effects of aging on typical electric cable products used in nuclear power plants.
In addition, other SNL tests (unrelated to license renewal) were performed to assess the functionality of damaged electric cables during loss-of-coolant accident conditions. After accelerated aging, some of the environmentally qualified cables either failed or exhibited marginal insulation resistance during accident simulation, indicating that qualification of some electric cables may be non-conservative. Depending on the specific application, failure of electric cables during or following design-basis events could compromise the ability of safety-related equipment to function.
While some of the SNL tests may have been more severe than required by NRC regulations, the test results raise questions with respect to the environmental qualification and accident performance capability of certain artificially aged equipment. The SNL test results are discussed in NUREG/CR-5772, " Aging, Condition Monitoring, and Loss-of-Coolant Accident (LOCA) Tests of Class IE Electrical Cables," Volumes 1, 2 and 3; NRC Information Notice (IN) 92-81, " Potential Deficiency of Electrical Cables with Bonded Hypalon Jackets," dated December 11, 1992; and NRC Information Notice 93-33, " Potential Deficiency of Certain Class IE Instrumentation and Control Cables," dated April 28, 1993. The SNL test results associated with LOCA testing of damaged electric cables (referred to in IN 92-81) are scheduled to be published as a NUREG/CR in July 1993.
Independent of the SNL tests, the NRC staff recently performed a preliminary risk scoping analysis to assess the potential impact of inadequate equipment qualification on core damage frequency. The scope of the analysis was limited to core damage prevention, considering internal events only with postulated failures of in-containment electrical equipment, with emphasis on electric cables. The major conclusions of the preliminary risk scoping analysis are i
that (1) EQ failures could have significant risk impact if electrical
component reliabilities are reduced in the presence of a harsh environment, (2) the magnitude of the impact on core damage frequency is plant specific, and (3) the lack of reliability data and limitations in current probabilistic risk assessment models result in significant uncertainty.
Based on'the results of the preliminary risk scoping study, the staff concluded that a more detailed EQ risk assessment should be completed.
Separate from the license renewal and risk assessment activities associated with EQ, the staff recently completed an assessment of the NRC fire protection program in response to issues that were raised by the Office of the Inspector General (OIG) in a report dated August 12, 1992.
The staff's assessment of the fire protection program dated February 27, 1993, identified a number of weaknesses and made specific recommendations for programmatic improvements.
In view of the weaknesses that were identified relative to the NRC fire protection program, the staff concluded that other programs such as EQ should also be reviewed to identify and correct any programmatic weaknesses that may exist.
Although the original issue involved whether the EQ requirements for older plants were adequate for license renewal, the issue has evolved into whether existing EQ standards and regulations are adequate for all operating reactors.
With the preliminary risk scoping assessment indicating that inadequate EQ could be a significant contributor to core damage frequency, the staff has determined that focused staff and management attention are necessary to fully address EQ concerns. This TAP will focus NRC staff attention to:
(1) evaluate differences that currently exist in EQ requirements between older and newer plants; (2) assess the adequacy of accelerated aging practices that are currently used for demonstrating equipment qualification; and (3) perform a programmatic review of EQ requirements to identify and resolve any other EQ issues that may exist.
Although this TAP describes planned actions, it should be recognized that this is an evolving issue and the actions, as described, may be modified as additional information is obtained through further research and review of industry operating experience.
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ENVIRONMENTAL QUALIFICATION (EQ) 10 CFR 50.49 TASK ACTION PLAN Rtion items 1.
Inform the Comission, senior NRC management, and the industry of the emerging EQ issue.
Scope - Activities for the Office of Nuclear Reactor Regulation (NRR) include preparation of NRC Information Notices, a letter to the Commission, and making a presentation at the NRR Regulatory Information Conference to inform the necessary people of the emerging EQ issue.
Completion Date - 5/2B/93 Status - NRR has issued two Information Notices and sent a letter to the NRC Commission on EQ. NPR staff presented a paper on EQ at the NRC Regulatory Information Conference. NRR made a presentation on EQ to staff members of the House Subcomittee on Mining and Energy.
2.
Encourage industry participation in identifying and resolving specific EQ concerns.
Scope - NRR activities will include initiation of open exchanges of information with industry groups. NRR and the Office of Nuclear Reactor Research (RES) will hold meetings with NUMARC, NUGEQ, and EPRI to apprise them of EQ review activities and exchange information. SPLB will be responsible for coordinating activities with these industry groups.
Comoletion Date - Ongoing Sljttn - NRC staff is scheduled to meet with NUMARC in June 1993.
3.
Programatic Review a.
Review license renewal background information.
Scoce - The Plants Systems Branch (SPLB) of HRR will collect and evaluate information that has been developed during the last few years on EQ from the NRR License Renewal Project Directorate. SPLB will evaluate the differences in the EQ requirements and the basis for the differences.
Completion Date - 7/93 Status - SPLB has collected and reviewed the license renewal information pertaining to EQ.
Currently, SPLB is in the process of documenting the results.
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EQ Action Plan page 2 b.
Review Fire Protection Reassessment Report Scope - SPLB will review recommenifations from the NRC staff's reassessment of the fire protection program, and identify specific issues that could relate to EQ.
Comoletion Date - 7/93 Status - SPLB is reviewing the fire protection reassessment report.
c.
Elicit opinions from others (Regions, EQ experts).
Scope - SPLB will survey NRC regional offices, NRC headquarters, and industry experts for potential problems with environmental qualification and evaluate the results of the survey.
Comoletion Date - 12/93 Status - SPLB is developing the survey questions.
d.
Review existing EQ program requirements.
Scope - SPLB will review EQ program requirements to determine whether EQ issues, in addition to those already identified, exist and need to be addressed. This review will determine if potential programmatic problems exist.
Comoletion Date - 8/93 Status - SPLB is reviewing the EQ program requirements in order to determine if potential programatic problems exist.
e.
Review NRC audit / inspection practices.
Scope - SPLB will review EQ inspection guidance and a sample of reports from licensee EQ inspections and vendor EQ inspections to identify potential pregramatic problems.
Comoletion Date - 10/93 1
Status - SPLB is scheduled to begin the review in August 1993.
f.
Review licensee implementation practices.
Scope - SPLB will review and evaluate selected licensees' implementation of their EQ programs through site visits to determine whether problems exist.
Completion Date - 4/94 Status - SPLB will be coordinating the site visits with an SPLB
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EQ Action Plan page 3 contractor. The site visits will be performed in conjunction with the contracted efforts stated in task 4.b.
g.
Finalize Review Results Scope - SPLB will document and finalize the results of the programmatic review in a final report.
Completion Date - 6/94 Status - SPLB will prepare the final report after completion of the activities identified in 3.a-f.
4.
Data Collection and Analysis a.
Review published documents and industry reports pertaining to EQ.
Scope - SPLB and RES will review and evaluate information about aging to assess the validity of qualification methods.
SPLB and RES will review and evaluate vendor and licensee qualification test reports to determine the test conditions and results.
Comoletion Date - 4/94 Status - SPLB and RES are discussing the activities required and the individual responsibilities of each office.
b.
Equipment Replacement Experience J
Scope - SPLB will make site visits to a sample of plants to review qualification tests, EQ binders, and maintenance and replacement records of EQ components.
SPLB will review and evaluate equipment replacement schedules to provide insight as to where NRC should focus its resources in the performance of EQ aging reviews.
Comoletion Date - 4/94 Status - SPLB and an SPLB contractor will be performing this task. SPLB has identified the contractor and placement of the contractor is in progress.
j c.
Review operating experience data.
i Scope - SPLB with contractor assistance will review Licensee Event Report (LER) and Nuclear Plant Reliability Data System (NPRDS) data.
The contractor will identify and evaluate whether environmentally qualified equipment is experiencing age-related degradation.
Completion Date - 12/93 Status - SPLB reviewed the LER data base that contains 72 reports of
EQ Action Plan page 4 t
cables that failed under normal operating conditions for various reasons. The SPLB contractor will be conducting a more detailed review.
SPLB has identified the contractor and placement of the contractor is in progress.
d.
Review TMI information via DOE.
Scope - RES, with SPLB assistance, will obtain and evaluate information on equipment failures during the THI accident.
Completion Date - 4/94 Status - RES is contacting the Department of Energy to obtain information.
e.
EQ Data Base Scope - SPLB with RES input will develop an integrated data base using qualification test reports, research tests, and other test activities related to qualified equipment to provide a source of information for future EQ activities.
Comoletion Date - 8/94 Status - SPLB will be developing the integrated data base in fiscal year 1994.
5.
Risk Assessment a.
Preliminary Risk Scoping Study Scope - The Probabilistic Safety Assessment Branch (SPSB) of NRR will perform a preliminary risk scoping analysis to quantify the risk impact of environmentally qualified electrical equipment.
Coroletion Date - 3/30/93 Status - SPSB completed a preliminary risk scoping analysis in March 1993.
b.
Final Risk Analysis Scope - SPSB with contractor assistance will perform a more detailed assessment of the risk associated with EQ issues. SPSB will incorporate results of other tasks into the final risk analysis.
Completion Date - 10/94 Status - The SPSB has a contractor working on the detailed assessment.
b
EQ Action Plan page 5 c.
PRA Insights Scope - SPLB will coordinate with SPSB and RES to incorporate insights from PRA into the other tasks in the action plan. Based on the results of the final risk analysis, NRC will make a determination of the risk significance of the differences in EQ requirements.
Comoletion Date - 10/94 Status - Preliminary risk scoping study has been considered in establishing tasks of the action plan.
6.
Technical Issues a.
Uncertainties associated with accelerated aging methodology.
Scoce - SPLB will coordinate with RES to develop and implement a test program that evaluates the use of accelerated aging in the qualification of safety-related equipment within the scope of 10 CFR 50.49.
Completion Date - 10/94 Status - SPLB and RES are discussing the activities required and-the individual responsibilities of each office.
b.
Condition Monitoring Methods Scope - SPLB will coordinate with RES to develop and implement a test program to investigate and develop methods that can be used for condition monitoring of qualified equipment to determine the actual condition of installed plant equipment.
Completion Date - 10/94 Status - SPLB and RES are discussing the activities required and the individual responsibilities of each office.
c.
Impact of new source term on EQ.
Scope - Since the usage of a new source term is an ongoing activity, SPLB and RES will follow its development and analyze its impact on EQ issues.
Completion Date - 7/94 Status - SPLB and RES will start this effort in 1994.
7.
Options for Resolution Scope - NRR and RES will develop options for the resolution of EQ concerns, including Generic Letter, rule change, or documentation of
EQ Action Plan page 6 acceptability of the current EQ rule and standards.
Comoletion Date - 10/94 Status - N/A 8.
Implementation a.
NRC Regulatory Initiative Scope - NRR and RES will decide on appropriate regulatory action; plan and implement the action; and document the basis for the action.
Possible actions to be considered by NRR and RES may include a Generic Letter or Rulemaking.
Comoletion Date - TBD Status - N/A b.
Industry Action /NRC Review and Verification Scooe - NRR will monitor licensee actions in response to the NRC staff's initiative on EQ.
NRR and NRC Regional Offices will verify that' licensees have taken appropriate action to correct any EQ problems.
Comoletion Date - TBD Status - N/A i
EQ Action Plan page 7 ENVIRONMENTAL QUALIFICATION (EQ) 10 CFR 50.49 TASK ACTION PLAN STAFF RESOURCE ESTIMATES NUCLEAR REACTOR REGULATION Plant Systems Branch (SPLB):
2.5-3.0 Professional Staff June 1993 through October 1994 Probabilistic Safety Assessment Branch (SPSB):
0.5 Professional Staff June 1993 through October 1994 NUCLEAR REACTOR RESEARCH Electrical and Mechanical Engineering Branch (EMEB):
2.0 Professional Staff June 1993 through October 1994 4
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