Production and utilization facilities; domestic licensing: Nuclear power plants— Maintenance effectiveness monitoring,

[Federal Register: September 30, 1998 (Volume 63, Number 189)]

[Proposed Rules]

[Page 52201-52206]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr30se98-28]

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NUCLEAR REGULATORY COMMISSION

10 CFR Part 50

RIN 3150-AF95

Monitoring the Effectiveness of Maintenance at Nuclear Power Plants

AGENCY: Nuclear Regulatory Commission.

ACTION: Proposed rule.

SUMMARY: The Nuclear Regulatory Commission (NRC) is proposing to amend its power reactor safety regulations to require that licensees assess the cumulative effect of out-of-service equipment on the plant's capability to perform safety functions before beginning any maintenance activity on structures, systems, or components within the scope of the maintenance rule. The amendments would also clarify that the proposed rule applies under all conditions of operation including normal shutdown, that the safety assessments include both the plant conditions before and those expected during planned maintenance activities, and that the safety assessments are to be used to ensure that the plant is not placed in a condition of significant risk or a condition that would degrade the performance of safety functions to an unacceptable level.

DATES: Submit comments by December 14, 1998. Comments received after this date will be considered if it is practical to do so, but the Commission is able to ensure consideration only for comments received on or before this date.

ADDRESSES: Mail comments to: The Secretary of the Commission, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001. Attention: Rulemakings and Adjudications Staff.

Deliver comments to: 11555 Rockville Pike, Rockville, Maryland, between 7:30 a.m. and 4:15 p.m. on Federal workdays.

You may also provide comments via the NRC's interactive rulemaking web site through the NRC home page (http://www.nrc.gov). From the NRC home page, select ``Rulemaking'' from the tool bar. The interactive rulemaking website may then be accessed by selecting ``Rulemaking Forum.'' This site possesses the ability of uploading comments as files (any format) if your web browser supports that function. For information about the interactive rulemaking site, contact Ms. Carol Gallagher, 301-415-5905, e-mail CAG@nrc.gov.

Certain documents related to this rulemaking, including comments received, may be examined at the NRC Public Document Room, 2120 L Street NW. (Lower Level), Washington, DC. These same documents also may be viewed and downloaded electronically via the interactive rulemaking website established by NRC for this rulemaking.

FOR FURTHER INFORMATION CONTACT: Richard P. Correia, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555, 301-415-1009, e-mail rpc@nrc.gov.

SUPPLEMENTARY INFORMATION:

Background

The NRC's Maintenance Team Inspections of all nuclear power plant licensees in the late 1980s found the lack of consideration of plant risk in prioritizing, planning, and scheduling maintenance activities to be a common weakness. To address that weakness, paragraph (a)(3) of 10 CFR 50.65, the maintenance rule, currently includes the provision that ``(I)n performing monitoring and preventive maintenance activities, an assessment of the total plant equipment that is out of service should be taken into account to determine the overall effect on performance of safety functions.'' The maintenance rule was issued on July 10, 1991.

During plant visits in mid-1994, several NRC senior managers expressed concerns that licensees were increasing both the amount and frequency of maintenance performed during power operation without adequately evaluating safety when planning and scheduling these maintenance activities. The NRC Executive Director for Operations (EDO) addressed these concerns regarding the safety implications with performing maintenance while at power to the president of the Institute of Nuclear Power Operations (INPO) in a letter dated October 6, 1994. In this letter, the EDO noted that it appeared that some licensees were either not following INPO guidelines for the conduct of maintenance and management of outages or had adopted only portions of the guidance. The EDO also recommended that INPO support NEI and appropriate utility managers during meetings with NRC senior managers to discuss the concerns they raised during the site visits.

The growing amount of on-line maintenance (i.e., maintenance performed during power operations) being performed by licensees and the inadequate pre-maintenance safety evaluations have raised the Commission's concern.

Discussion

The nuclear power industry has changed since the 1991 issuance of the maintenance rule. Rate deregulation of the electric utility industry will likely cause all nuclear power plants to seek ways to operate more efficiently. One mechanism for increasing efficiency is shortening refueling and maintenance outages. Licensees have come to realize that performing more maintenance at power can lead to shorter refueling outages and the reduction or elimination of mid-cycle maintenance outages.

Licensees have relied upon their individual plant technical specifications to help assure safe operation of the plant when equipment is out of service. However, the removal of multiple pieces of equipment, especially safety-related equipment, from service can undermine the fundamental premise of the technical specifications for a plant, which is to provide adequate protection against random failures.

During plant visits in mid-1994, several NRC senior managers had concerns with the fact that licensees were increasing both the amount and frequency of maintenance performed during power operations. Some licensees were limiting the planned maintenance to a single train of a system while others would allow multiple equipment in other systems within a single train to be out of service as long as it did not violate the plant's technical specifications. However, allowable outage times specified in technical specifications are based upon a random single failure in a system and a judgement of a reasonable time to effect repairs before plant shutdown is required. Technical specifications were not intended to address allowable outage times for multiple equipment being out of service at the same time. Further, it can not be implied that it is acceptable to voluntarily remove equipment from service to perform on-line maintenance on the assumption that such actions are bounded by a worst case single failure which is a plant specific design requirement that is contained in a number of the general design criteria (GDC) in 10 CFR 50, Appendix A. The NRC senior managers also had concerns with the fact that on-shift personnel, planning and scheduling personnel, and licensee management lacked an understanding of the relative safety importance of safety systems or combinations of equipment that would have risk significance if taken out of service. It appeared that risk insights from plant specific Individual Plant Examination (IPE)

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results, whose purpose was to improve licensee understanding of the plant's safety and to address potential vulnerabilities, were not fully utilized in the plant's operational and maintenance decision process. These concerns were addressed in a letter dated October 6, 1994, from the Director of the Office of Nuclear Reactor Regulation to the Executive Vice-President of the Nuclear Energy Institute. The growing amount of maintenance performed during power operations and the underutilization of risk insights in plant operations and maintenance activities have raised the Commission's concern.

In determining the need for the maintenance rule a decade ago, one factor the Commission considered was its belief that there existed ``a need to broaden its capability to take timely enforcement action where maintenance activities fail to provide reasonable assurance that safety-significant SSCs [structures, systems, and components] are capable of performing their intended function.'' Now, the Commission desires to act to help ensure that there is reasonable assurance such that maintenance activities will not place a plant in (1) a configuration that would degrade unacceptably a SSC's capability to perform its intended safety functions or (2) a risk-significant configuration, i.e., a configuration for which the incremental contribution to the annual risk associated with accidents that result in damage to the reactor fuel or the release of fission products to the environment is not insignificant.

The first 50 NRC maintenance rule baseline inspections (MRBIs) for which inspection reports had been issued as of April 20, 1998, found that all licensees had developed programs to implement the safety assessment provision of paragraph (a)(3). However, at 5 sites, instances were found in which the licensee did not assess the impact on safety of total plant equipment out of service before it entered one or more specific plant configurations for maintenance purposes. At 19 other sites, weaknesses--the term reserved for situations in which the overall assessment of a licensee program has found the program, or significant aspects of that program, to be particularly ineffective or for individual findings that have either high safety significance or programmatic implications--were found, among which were paragraph (a)(3) safety assessment tools that did not include all high-safety- significant SSCs.

Although the safety significance of the unassessed plant configurations at the 5 sites was not quantitatively determined during the inspection in all cases, it appears that some of the unassessed configurations had resulted in plants that were in a state of substantially greater risk than was realized by the licensees. Given the concerns raised by NRC senior managers during site visits in 1994, the increased amount of on-line maintenance, the number of missed assessments and their apparent risk significance, in addition to the weaknesses found with the paragraph (a)(3) safety assessment programs, the Commission considers this to be a safety concern. The Commission, therefore, believes it is necessary to explicitly require licensees to perform safety assessments prior to removing equipment from service for maintenance during all conditions of plant operations including normal shutdown.

With regard to the operating conditions under which the proposed rule would apply, extensive interaction among the NRC, the industry, and the public has taken place over the need for regulations governing activities during shutdown conditions (i.e., shutdown as may be defined in each plant's individual technical specifications, but generally considered as a time when all control rods are inserted and the average reactor coolant temperature is below 200 deg.F). The question of whether 10 CFR 50.65 applies during shutdown conditions became an issue. The Commission desires to clarify that the rule does apply during shutdown conditions.

Regarding which activities would be preceded by a safety assessment, the Commission has recognized that, although definitions regarding maintenance activities are fairly consistent from organization to organization, there is some variation in the definition of corrective maintenance. For example, some definitions bring a time dependency while some others consider the urgency of the repair. To eliminate inconsistency, and to cause more prudent use of the safety assessments, the Commission desires the regulation to cover all planned maintenance activities, rather than only the recommended monitoring and preventive maintenance in the current rule. Each planned non-emergency maintenance activity would now include a safety assessment prior to its being authorized to begin. In fact, many licensees have followed the guidance contained in Regulatory Guide 1.160 and NUMARC 93-01 and have already voluntarily included all planned maintenance activities in the scope of their safety assessment programs.

With regard to the safety assessments themselves, licensee implementation has been inconsistent. The Commission desires to specify that an appropriate safety assessment would include a review the current condition of the plant and the plant condition expected during the planned maintenance activity. Assessing the current plant configuration as well as expected changes to plant configuration that will result from the proposed maintenance activities, as would be called for under paragraph (a)(4) of the proposed rule, is intended to ensure that the plant is not placed in risk-significant configurations, i.e., a configuration for which the incremental contribution to the annual risk is not insignificant, or a configuration that would degrade safety functions to an unacceptable level. These assessments do not necessarily require that a quantitative assessment of probabilistic risk be performed. The licensee would have the flexibility to perform a probabilistic and/or deterministic assessment, as appropriate. The level of sophistication with which such assessments are performed is expected to vary, based on the circumstances involved. It should be understood, however, that the contribution to risk of a specific plant configuration depends on both the degree of degradation of the safety functions and the duration for which the plant is in that configuration. Further, assessing the degree of safety function degradation requires that there be an understanding of the impact of removal of the equipment on the capability of the plant to prevent or mitigate accidents and transients. The assessments may range from deterministic judgements to the use of an on-line, living probabilistic risk assessment (PRA).

Additional guidance will be developed and promulgated in Regulatory Guide 1.160, Revision 3 (proposed), to assist licensees in implementing this provision of the proposed rule. The guidance will contain information regarding risk-significant configurations and unacceptable levels of safety function degradation.

Proposed Rule

This proposed rule would make five changes to 10 CFR 50.65:

1. Add an introductory paragraph to 10 CFR 50.65 clarifying that the proposed rule applies under all conditions of operation, including normal shutdown.

   Prior to paragraph (a)(1), add the following wording: ``The requirements of this section are applicable during all

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   conditions of plant operation, including normal shutdown operations.'' The intent of this paragraph is to ensure that safety assessments are performed before maintenance activities when the plants are shut down as well as when the plants are at power. The shutdown condition may be defined in a plant's technical specifications, but the intent of this paragraph is that shutdown is generally considered as a time when all control rods are inserted and the average reactor coolant temperature is below 200 deg. F.

2. Delete the last sentence of paragraph (a)(3) and create a new paragraph, (a)(4), that requires the performance of safety assessments.

   The proposed rule would remove the last sentence of paragraph (a)(3) and would add a new paragraph, (a)(4), as follows in its entirety: ``Before performing maintenance activities on structures, systems, or components within the scope of this section (including, but not limited to, surveillance testing, post-maintenance testing, corrective maintenance, performance/condition monitoring, and preventive maintenance), an assessment of the current plant configuration as well as expected changes to plant configuration that will result from the proposed maintenance activities shall be conducted to determine the overall effect on performance of safety functions. The results of this assessment shall be used to ensure that the plant is not placed in risk-significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level.'' Deleting the current last sentence in paragraph (a)(3) will remove the recommendation for performing safety assessments from the paragraph that contains the periodic, programmatic, long-term review considerations of the rule. Creating a new paragraph, (a)(4), specifically for the safety assessment requirements would cause the assessment concept to stand as a separate entity within the maintenance rule.

3. Define in paragraph (a)(4) the scope of the requirement for performing those assessments to be all conditions of operation including normal shutdown.

   The proposed rule would add the following in paragraph (a)(4) to define the scope of pre-maintenance safety assessments: ``Before performing maintenance activities on structures, systems, or components within the scope of this section (including, but not limited to, surveillance testing, post-maintenance testing, corrective maintenance, performance/condition monitoring, and preventive maintenance), an assessment * * * shall be conducted * * * .'' The NRC's intent is that licensees perform safety assessments before all planned maintenance activities that require removing from service equipment that is within the scope of the maintenance rule, as defined in 10 CFR 50.65(b) and (a)(1). The safety assessments required in this paragraph need not be sophisticated probabilistic risk assessment analyses in all cases. Licensees would have the flexibility to use probabilistic and/or deterministic methods, as appropriate, when performing the safety assessments required by paragraph (a)(4).

4. Specify in paragraph (a)(4) that the safety assessments are to examine the extant plant condition and the condition expected during the planned maintenance activity.

   The proposed rule would include the following wording in paragraph (a)(4): ``* * * an assessment of the current plant configuration as well as expected changes to the plant configuration that will result from the proposed maintenance activities * * * .'' The NRC's intent is that a reasonable safety assessment be performed. The assessment may range from simple and straightforward to complex. However, notwithstanding the degree of sophistication required for the assessment, the NRC intends that the assessment will examine the plant condition existing prior to the commencement of the maintenance activity and examine the changes expected by the proposed maintenance activity.

5. Specify in paragraph (a)(4) that the objective of performing the safety assessments is to ensure that the plant is not placed in risk- significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level.

   The proposed rule would add in paragraph (a)(4) the wording to specify the NRC's expectations regarding the use of each safety assessment, as follows: ``The results of this assessment shall be used to ensure that the plant is not placed in risk-significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level.'' The NRC's intent is to require that each licensee perform a safety assessment before undertaking each planned maintenance activity and be aware of the risk issues associated with that maintenance activity. The guidance to be developed for licensees and promulgated in Regulatory Guide 1.160, Revision 3 (proposed), is expected to assist the industry in implementing this provision of the proposed rule, providing guidance regarding risk-significant configurations and unacceptable levels of safety function degradation.

   The Commission requests public comment on these proposed rule provisions. The Commission also requests public comment on the explanatory language in item 3 pertaining to licensee flexibility to use probabilistic and/or deterministic methods to perform the safety assessments. Specifically, should there be further clarification of this point in the final rule?

   Finding of No Significant Environmental Impact: Environmental Assessment

   The Commission has determined under the National Environmental Policy Act of 1969, as amended, and the Commission's regulations in Subpart A of 10 CFR Part 51 that this rule, if adopted, would not be a major Federal action significantly affecting the quality of the human environment and, therefore, an environmental impact statement is not required. The draft environmental assessment that forms the basis for this determination reads as follows.

   Identification of the Proposed Action

   The Commission is proposing to amend its regulations to require commercial nuclear power plant licensees to perform assessments of the plant's status before performing maintenance activities on structures, systems, and components (SSCs) within the scope of 10 CFR 50.65, the maintenance rule. The rule would be modified by adding an introductory sentence to clarify that the proposed rule would apply under all conditions of operation, including normal shutdown; deleting the last sentence of paragraph (a)(3); and creating a new paragraph, (a)(4). The new paragraph (a)(4) would change ``should'' to ``shall'' regarding the performance of safety assessments; define the scope of the requirement for performing those assessments to include all planned maintenance activities; specify that the safety assessments are to examine the extant plant condition and the condition expected during the maintenance activity; and specify that the safety assessments are to be used to ensure that, by the conduct of maintenance, the plant is not placed in risk-significant conditions or safety system performance is not degraded to an unacceptable level.

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   The Need for the Proposed Action

   Paragraph (a)(3) of the maintenance rule, in part, currently recommends that, ``(I)n performing monitoring and preventive maintenance activities, an assessment of the total plant equipment that is out of service should be taken into account to determine the overall effect on performance of safety functions.'' The Commission believes the performance of this type of assessment is prudent. The maintenance rule baseline inspections, being performed at each commercial nuclear power plant site, have found that all inspected licensees have implemented programs to perform the assessments, but about half of the sites inspected had programs with discernable weaknesses in this area, including instances in which, in accordance with the licensee's own programs, safety assessments should have been made but were not. Because of the hortatory nature of the safety assessment provision in Sec. 50.65(a)(3), the Commission cannot ensure that licensees perform the assessments. Moreover, licensees are free to remove the performance of the assessments from their programs as they so desire. This proposed change to the Commission's regulations will permit the Commission to ensure that licensees perform the assessments, as appropriate.

   The other changes are clarifications regarding applicability of the rule. During preliminary discussions prior to potential development of a rule on shutdown plant operations, a major question arose regarding whether 10 CFR 50.65 requirements apply during the time a plant is shut down. The Commission concluded that inclusion of a statement to the affirmative would eliminate the doubt.

   Removing the provision regarding safety assessments from paragraph (a)(3) and creating for it a new, separate paragraph, (a)(4), would disassociate that new requirement from the more time-dependent requirement for evaluating of the program and the program's effectiveness at maintaining an appropriate balance between reliability and availability for each SSC. In the new paragraph, the requirement for safety assessment performance is stipulated to ensure licensees will perform those assessments. Because there were questions regarding when the assessments were to be performed, what plant conditions are to be evaluated and how they were to be used, the proposed new paragraph (a)(4) describes that the assessments are to be performed before all planned maintenance activities, are to examine pre-maintenance plant conditions and expected changes due to the proposed maintenance activity, and are to be used to ensure that the plant is not placed in risk-significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level.

   Environmental Impacts of the Proposed Action

   The proposed rule would require that commercial nuclear power plant licensees perform certain assessments of plant equipment status prior to performing all planned maintenance activities. The purpose of the proposed rule is to increase the effectiveness of the maintenance rule by requiring licensees to perform an assessment of plant conditions prior to planned maintenance and changes expected to result from the planned maintenance activity, to ensure that licensees understand the assessments are to be performed when the plant is shut down as well as at power, and to improve licensees' understanding of what conditions to assess and to what use to put the completed assessment. Accordingly, implementation of this proposed rule would not have any significant adverse impact on the quality of the human environment. The Commission believes that proper implementation of the proposed rule will reduce the likelihood of an accidental release of radioactive material caused by imprudently prioritized, planned, or scheduled maintenance.

   The determination of this environmental assessment is that there will be no significant offsite impact to the public from this action. The NRC has also committed to complying with Executive Order (EO) 12898, ``Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations,'' dated February 11, 1994, in all its actions. The NRC has determined that there are no disproportionate, high, or adverse impacts on minority or low-income populations. In the letter and spirit of EO 12898, the NRC is requesting public comment on any environmental justice considerations or questions that the public thinks may be related to this proposed rule but somehow were not addressed. Comments on any aspect of the Environmental Assessment, including environmental justice, may be submitted to the NRC as indicated under the ADDRESSES heading.

   States Consulted and Sources Used

   The NRC has sent a copy of this proposed rule to every State Liaison Officer and requested his or her comments on the Environmental Assessment.

   Paperwork Reduction Act Statement

   This proposed rule does not contain a new or an amended information collection requirement subject to the requirements of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.). Existing requirements were approved by the Office of Management and Budget, approval number 3150-0011.

   Public Protection Notification

   If an information collection requirement does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

   Regulatory Analysis

   The Commission has prepared a draft regulatory analysis on this proposed regulation. The analysis examined the costs and benefits of the alternatives considered by the Commission for revising 10 CFR 50.65, the maintenance rule. Those alternatives were to (1) make no change to the rule, (2) require the safety assessments currently recommended in paragraph (a)(3) of the rule, and (3) make comprehensive revisions to paragraph (a)(3) of the rule. The analysis selected Alternative 2 as the preferred course of action. Details of the alternative selection are contained in the draft analysis, which is available for inspection in the NRC Public Document Room, 2120 L Street NW (Lower Level), Washington, D.C. Single copies of the analysis may be obtained from Richard P. Correia, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555, 301-415-1009, e-mail rpc@nrc.gov.

   The Commission requests public comments on the draft regulatory analysis. Comments on the draft analysis may be submitted to the NRC as indicated under the ADDRESSES heading.

   Regulatory Flexibility Certification

   In accordance with the Regulatory Flexibility Act of 1980 (5 U.S.C. 605(b)), the Commission certifies that this proposed rule will not, if adopted, have a significant economic impact on a substantial number of small entities. This proposed rule affects only the operation of nuclear power plants. The companies that own these plants do not fall within the scope of the definition of small entities set forth in the Regulatory Flexibility Act or the size standards adopted by the NRC (10 CFR 2.810).

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   Backfit Analysis

   As required by 10 CFR 50.109, the Commission has completed a backfit analysis for this proposed rule. The Commission has determined, on the basis of this analysis, that backfitting to comply with the requirements of this proposed rule provides a substantial increase in protection to the public health and safety or the common defense and security at a cost that is justified by the increased protection.

   When the maintenance rule was first promulgated in 1991, the NRC staff did not foresee the significant changes licensees would be making in maintenance practices. To enhance operational efficiency brought about by the rate deregulation of the electric utility industry, licensees are shortening their refueling outages by performing more maintenance while the plant is at power. At-power maintenance practices have evolved to the point that not only are major systems and components taken off line, but also multiple systems and components are taken off line simultaneously. Taking systems and components off line for maintenance could result in an increased likelihood of an accident or transient, compared to risk that occurs from expected random equipment failures.

   The objective of this proposed rule is to make mandatory that licensees assess the cumulative impact of out-of-service equipment on the capability of the plant to perform safety functions and that licensees consider the results of the assessment before undertaking maintenance activities at operating nuclear power plants in order to ensure that the plants are not placed in risk-significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level. Thus, the proposed rule would state that licensees must perform safety assessments before removing SSCs from service for planned maintenance.

   In addition, this proposed rule would (1) add an introductory sentence to 10 CFR 50.65 clarifying that the rule applies under all conditions of operation, including normal shutdown; (2) delete the last sentence of paragraph (a)(3) of the rule and create a new paragraph, (a)(4), that requires the performance of safety assessments; (3) specify that the scope of the requirement for performing those assessments covers all planned maintenance activities; (4) specify that the safety assessments are to examine the extant plant condition and the condition expected during the maintenance activity; and (5) specify that the results of the safety assessments are to be used to help the licensee ensure that the plant is not placed in risk-significant configurations or configurations that would degrade safety functions to an unacceptable level.

   The pre-maintenance assessments, along with the clarifications regarding their scope and their use, which the Commission proposes to require are intended to cause licensees to manage this risk and ensure their plants are not placed in risk-significant conditions or conditions in which the performance of safety functions is not degraded to unacceptable levels.

   The details of this backfit analysis have been incorporated in the regulatory analysis.

   For the reasons elaborated in the regulatory analysis, which also contains cost information, the Commission concludes that the proposed modification to the maintenance rule will result in a level of safety beyond that currently provided by the Commission's regulations, a substantial increase in the overall protection of public health and safety, and that the net costs of the rule are justified in view of this increased level of safety.

   List of Subjects in 10 CFR Part 50

   Antitrust, Classified information, Criminal penalties, Fire protection, Intergovernmental relations, Nuclear power plant and reactors, Radiation protection, Reactor siting criteria, Reporting and recordkeeping requirements.

   For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended; the Energy Reorganization Act of 1974, as amended; and 5 U.S.C. 553, the NRC is proposing to adopt the following amendments to 10 CFR Part 50:

   PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES

1. The authority citation for part 50 continues to read as follows:

   Authority: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 444, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88 Stat. 1242, as amended, 1244, 1246, (42 U.S.C. 5841, 5842, 5846).

   Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat. 2951 (42 U.S.C. 5851). Section 50.10 also issued under secs. 101, 185, 68 Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd), and 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42 U.S.C. 2138). Sections 50.23, 50.35, 50.55, and 50.56 also issued under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a, 50.55a, and Appendix Q also issued under sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58, 50.91, and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42 U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939 (42 U.S.C. 2152). Sections 50.80-50.81 also issued under sec. 184, 68 Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued under sec. 187, 66 Stat. 955 (42 U.S.C. 2237).

2. In Sec. 50.65, an introductory paragraph is added, paragraph (a)(3) is revised, and a new paragraph (a)(4) is added, to read as follows:

   Sec. 50.65 Requirements for monitoring the effectiveness of maintenance at nuclear power plants.

   The requirements of this section are applicable during all conditions of plant operation, including normal shutdown operations.

   (a) * * *

   (3) Performance and condition monitoring activities and associated goals and preventive maintenance activities shall be evaluated at least every refueling cycle provided the interval between evaluations does not exceed 24 months. The evaluations shall be conducted taking into account, where practical, industry-wide operating experience. Adjustments shall be made where necessary to ensure that the objective of preventing failures of structures, systems, and components through maintenance is appropriately balanced against the objective of minimizing unavailability of structures, systems, and components due to monitoring or preventive maintenance.

   (4) Before performing maintenance activities on structures, systems, or components within the scope of this section (including, but not limited to, surveillance testing, post-maintenance testing, corrective maintenance, performance/condition monitoring, and preventive maintenance), an assessment of the current plant configuration as well as expected changes to plant configuration that will result from the proposed maintenance activities shall be conducted to determine the overall effect on performance of safety functions. The results of this assessment shall be used to ensure that the plant is not placed in risk-significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level. * * * * *

   Dated at Rockville, Maryland, this 24th day of September, 1998.

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   For the Nuclear Regulatory Commission. John C. Hoyle, Secretary of the Commission.

   [FR Doc. 98-26204Filed9-29-98; 8:45 am]

   BILLING CODE 7590-01-P