[Federal Register Volume 64, Number 137 (Monday, July 19, 1999)]
[Rules and Regulations]
[Pages 38551-38557]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18325]


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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: Final rule.

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SUMMARY: The Nuclear Regulatory Commission (NRC) is amending its power 
reactor safety regulations to require that licensees assess the effect 
of equipment maintenance on the plant's capability to perform safety 
functions before beginning maintenance activities on structures, 
systems, and components (SSCs) within the scope of the maintenance 
rule. The amendments clarify that these requirements apply under all 
conditions of operation, including shutdown, and that the assessments 
are to be used so that the increase in risk that may result from the 
maintenance activity will be managed to ensure that the plant is not 
inadvertently placed in a condition of significant risk or a condition 
that would degrade the performance of safety functions to an 
unacceptable level. These amendments permit licensees to limit the 
scope of the assessments to SSCs that a risk-informed evaluation 
process has shown to be significant to public health and safety.

EFFECTIVE DATE: The final rule becomes effective 120 days after 
issuance of Revision 3 to Regulatory Guide 1.160, ``Monitoring the 
Effectiveness of Nuclear Power Plants.'' The NRC will publish a 
document in the Federal Register that announces the issuance of the 
revised guidance and that specifies the effective date.

FOR FURTHER INFORMATION CONTACT: Richard P. Correia, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001, 301-415-1009, e-mail [email protected].

SUPPLEMENTARY INFORMATION:

I. 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 (56 FR 31306).
    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 of 
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 the Nuclear Energy Institute 
(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 during 
power operations) being performed by licensees and the quality of pre-
maintenance assessments have merited the Commission's concern. To 
address this concern, to clarify the plant operating conditions under 
which the maintenance rule is applicable, and to make the requirements 
fully enforceable, the Commission published proposed revisions to 10 
CFR 50.65 in the Federal Register on September 30, 1998 (63 FR 52201-
52206). The 75-day comment period closed December 14, 1998.

II. Comments on the Proposed Rule

    Twenty-nine comments were submitted during the comment period, and 
five were submitted after the comment period closed. Copies of the 
letters are available for public inspection and copying for a fee at 
the Commission's Public Document Room, located at 2120 L Street, NW 
(Lower Level), Washington, DC. The last public comment was received on 
December 29, 1998. All comments were considered in formulating the 
final rule. The 34 comments were submitted by 26 utilities with 
operating power reactors, one utility with a decommissioning status 
facility, three nuclear industry service companies or consultants, one 
individual, one State agency, NEI, and one law firm representing 
several utilities. Twenty-nine commentors endorsed the NEI comments. 
NEI stated in its comment letter that the industry generally supports 
the Commission's intent in the proposed rule but has a number of 
significant concerns that should be addressed before rulemaking 
proceeds. Of the commentors who did not endorse the NEI comments, one 
(combined State agencies) supported the concept of the proposed rule 
and provided comments to enhance it, and two others (an individual and 
a utility) provided recommendations in specific areas to enhance the 
proposed rule. Two of the commentors (a consultant and a consulting 
firm) stated that the rule was unnecessary and presented supporting 
reasons.
    The comments have been grouped under the following general topics:

1. Rule issuance
2. New, vague, ambiguous, undefined terminology in the proposed rule
3. Scope issues
4. Suggestions for wording modifications
5. Regulatory controls overlapping technical specifications
6. Performing assessments
7. Assessing and managing risk
8. Emergent maintenance requirements
9. Documentation of the assessment
10. Definition of availability
11. Backfit and regulatory analyses
12. Regulatory analysis cost estimates
13. Application to decommissioning plants

    Summaries of the grouped comments and discussions of the NRC 
responses follow.

[[Page 38552]]

1. Rule Issuance

    Comment. One commentor, a utility, stated that they consider the 
proposed rule unnecessary, and NEI and other utilities stated that the 
proposed rule, as written, should be withdrawn. However, they also 
stated that if the rule is approved, Regulatory Guide 1.160 should be 
revised and issued before finalizing the changes to the rule.
    Response. The NRC has determined that the rule is necessary and 
believes that the performance of this type of assessment is prudent 
because of changes in industry maintenance practices and findings 
during NRC inspections of maintenance rule programs. When the 
maintenance rule was first promulgated in 1991, the NRC had not 
foreseen the significant changes licensees would be making in 
maintenance practices. To enhance operational efficiency, made 
increasingly necessary 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, subsystems, and components taken off line, but also multiple 
systems, subsystems, and components are taken off line simultaneously. 
Taking systems and components off line for maintenance could result in 
an increase in risk because of the reduced capability to mitigate the 
consequences of an accident or a transient, compared to risk that 
occurs from expected random equipment failures. In addition, although 
the maintenance rule baseline inspections of all operating nuclear 
power plant sites found that all licensees have implemented programs to 
perform the assessments, about half of the sites had programs with 
discernable weaknesses in this area, including instances in which, in 
accordance with the licensees' own programs, assessments should have 
been made but were not.
    The NRC agrees that it is appropriate to revise Regulatory Guide 
1.160 to incorporate clarifying guidance before the final rule's 
effective date. Accordingly, Revision 3 to Regulatory Guide 1.160 will 
be prepared for public comment and will be published in final form 120 
days before the effective date of the rule.

2. New, Vague, Ambiguous, Undefined Terminology in the Proposed Rule

    Comment. Most commentors identified concerns related to the 
proposed rule's introduction of new, vague, ambiguous, or undefined 
terminology and recommended that the rule be withdrawn and reissued for 
public comment after substantial modification. NEI and utilities 
indicated that terms such as ``risk-significant condition'' and 
``unacceptable level'' should be explicitly defined.
    Response. Paragraph (a)(4) has been reworded. Guidance for the 
revised terminology appears below in Item 4 of Section III, ``The Final 
Rule.''

3. Scope Issues

    Comment. Many commentors stated that assessments required by the 
proposed rule should apply only to high safety-significance SSCs. NEI 
and utilities expressed concerns that the scope of SSCs subject to 
assessments was impractical. Such broad scope would dilute attention 
from high safety-significance SSCs by requiring too many detailed 
assessments.
    Response. Paragraph 50.65(b) defines the scope of SSCs that are 
covered by the rule (with the exception of SSCs for decommissioning 
plants). Chapter 11.0 of NUMARC 93-01, ``Industry Guidelines for 
Monitoring the Effectiveness of Maintenance at Nuclear Power Plants,'' 
Revision 2, dated April 1996 (which has been endorsed by Regulatory 
Guide 1.160, Revision 2, dated March 1997), is entitled ``Evaluation of 
Systems to be Removed from Service.'' Chapter 11.0 guidance makes the 
evaluation, or assessment, a three-step process: (1) Identify key plant 
safety functions to be maintained, (2) identify SSCs that support key 
plant safety functions, and (3) consider the overall effect of removing 
SSCs from service on key plant safety functions. Requiring, instead of 
recommending, those assessments does not change the expectation that 
the assessments need only involve SSCs associated with initiating and 
mitigating impacts on key plant safety functions. To codify this 
expectation, paragraph (a)(4) of the final rule contains a second 
sentence as follows: ``The scope of the assessment may be limited to 
structures, systems, and components that a risk-informed evaluation 
process has shown to be significant to public health and safety.''

4. Suggestions for Wording Modifications

    Comment. Five commentors provided suggestions clarifying regulatory 
text. Two of these commentors stated that the plant configuration 
should be defined as ``SSCs within the scope of the rule,'' and three 
commentors suggested limiting the scope of maintenance activities to 
those that result in removing equipment from service.
    Response. The NRC disagrees with these suggested language changes. 
The rule currently applies only to SSCs within the scope of the rule. A 
revision to specify that fact is not needed, although this rule is 
being revised to permit licensees to limit the scope of their 
assessments to SSCs that a risk-informed evaluation process has shown 
to be significant to public health and safety. Additionally, certain 
maintenance activities are performed that do not remove equipment from 
service but have the potential for challenging safety systems. One 
example is valve testing on certain balance-of-plant systems during 
which open valves are cycled shut and reopened. If such a valve were to 
inadvertently stick shut, a transient could ensue. Those scenarios must 
be assessed and managed to ensure that the risks associated with these 
activities are properly identified and controlled.

5. Regulatory Controls Overlapping Technical Specifications

    Comment. Several commentors stated that there is a need to 
reconcile the overlapping regulatory regimes of the maintenance rule, 
technical specifications (TS), and the configuration risk management 
program (CRMP) (described in Regulatory Guide 1.177, ``An Approach for 
Plant-Specific, Risk-Informed Decisionmaking: Technical 
Specifications''). NEI and the utilities were mainly concerned with the 
overlap of regulatory controls in the revised rule and TS.
    Response. The NRC agrees that some overlap exists among these 
regulatory controls. Under certain conditions, a plant's TS may allow 
an SSC to be out of service, while a pre-maintenance assessment 
proposing the removal of that same SSC from service may indicate a need 
to take other actions to preclude that configuration. It is possible 
that allowed outage times of TS may not be in complete agreement with 
reasonable out-of-service times resulting from the required 
assessments. However, TS limiting conditions for operation were, in 
part, developed to address random single failures of plant SSCs; they 
were not intended to be used by licensees as rationale for removing 
multiple SSCs from service to perform on-line maintenance. In general, 
TS may serve as a pre-analyzed assessment, when used with sound 
judgement, when a licensee proposes to remove a single SSC from service 
for maintenance. Paragraph (a)(4) is intended to cause the licensee to 
determine its options and follow a prudent course of action. 
Nevertheless, while performing on-line or shutdown

[[Page 38553]]

maintenance, the licensee will remain in conformance with its TS.
    In NRC staff requirements memorandum dated June 29, 1998, for SECY-
98-067, the Commission directed the NRC staff to take actions to ensure 
that CRMP regulatory guidance conforms to the provisions of the final 
maintenance rule. After revisions to the maintenance rule are 
completed, the NRC will expeditiously support licensee requests to 
remove the CRMP requirements from plant TS.

6. Performing Assessments

    Comment. NEI and the utilities expressed the need for clarification 
of when an assessment would be required, the level of complexity 
necessary in the assessment, and the criteria to be used to evaluate 
the adequacy of the assessment process.
    Response. Please refer to the discussion in Item 4 of Section III, 
``The Final Rule,'' below.

7. Assessing and Managing Risk

    Comment. Three commentors expressed similar views related to high-
risk activities. One noted that, under suitable controls, a shorter 
time in a more risk-significant configuration may be safer than a 
longer time in a less risk-significant configuration. Another noted 
that high risk-significant activities should be recognized and avoided, 
where practical, and limited in duration when they are necessary. The 
third noted that the proposed rule does not address situations in which 
failure to perform a maintenance activity may have a greater impact on 
risk than performing the high safety-significant activity.
    Response. The NRC agrees that the proposed rule precluded entering 
risk-significant configurations, no matter the duration, when, in fact, 
situations may exist that would yield a net safety benefit by 
performing maintenance in a risk-significant configuration for a short 
time. The rule has been revised to require licensees to understand 
their options with respect to risk and to manage their maintenance 
activities according to their best judgment, considering insights from 
operating experience and deterministic and probabilistic analyses.

8. Emergent Maintenance Requirements

    Comment. Two commentors stated that the proposed rule does not 
address expectations for revising assessments upon the discovery of a 
previously unknown condition requiring maintenance (emergent 
maintenance). They also expressed concerns that if certain emergent 
maintenance activities are not completed immediately, the plant could 
be at greater risk.
    Response. Under the revised rule, an assessment is required to be 
initiated following the discovery of emergent failures or changes in 
plant conditions to determine the safety impact of the failure or the 
change in plant conditions. For additional information on this subject, 
please see the discussion in Item 4 of Section III, ``The Final Rule,'' 
below.

9. Documentation of the Assessment

    Comment. Three utility commentors stated that the proposed rule is 
not explicit enough regarding assessment documentation expectations.
    Response. The rule has no explicit documentation requirements. 
Instead, the rule emphasizes performance. A licensee's assessment 
process is expected to identify the impact on safety that is caused by 
the performance of maintenance. Licensees should use documentation to 
the extent necessary to assure themselves that the requirement for an 
assessment has been acknowledged and performed adequately. NRC 
expectations are that a licensee will have a requirement for the 
assessments and an explanation of the process to be followed in its 
maintenance rule program, along with a description of assessment 
tool(s) to be used and their limitations, implementing procedures, and 
explicit direction covering instances when the plant configuration is 
or is proposed to be outside the span of the assessment tool. Further, 
the assessment process is expected to be incorporated into the 
maintenance planning and scheduling process and into work package 
requirements. Moreover, control room operators, who are expected to 
understand, use, and know the limitations of the assessment tools, 
generally use and maintain a variety of documents, such as logs and 
checklists, that contain information relating to out-of-service SSCs.

10. Definition of Availability

    Comment. Three commentors stated that the definition of 
availability will be key to this rulemaking. They also stated that the 
availability definition should take into account the time required to 
restore the functionality of an SSC and should also be risk informed.
    Response. A definition of availability for licensee maintenance 
rule programs is set forth in NUMARC 93-01, Revision 2, which was 
endorsed by the NRC in Regulatory Guide 1.160, Revision 2, of March 
1997. According to that document, availability is ``(t)he time that 
a(n) SSC is capable of performing its intended function (expressed) as 
a fraction (usually as percent) of the total time that the function may 
be demanded.'' Also according to that document, under the definition of 
``unavailability,'' is the following statement: ``An SSC that is 
required to be available for automatic operation must be available and 
respond without human action.'' Additionally, in the instance where an 
SSC is taken out of service for testing but could be manually 
activated, the NRC has accepted that, as long as the dedicated 
operator's written procedure specifies a single action that would 
permit an automatic initiation of the out-of-service SSC in the event 
of an accident or transient during the test, the SSC could be 
considered available. (Meeting Summary--November 19, 1991, NRC/NUMARC 
Public Meeting on the Development of Guidance Documents for the 
Implementation of the Maintenance Rule (10 CFR 50.65), R.P. Correia, 
Office of Nuclear Reactor Regulation, memorandum to E.W. Brach, Office 
of Nuclear Reactor Regulation, dated November 23, 1991.) The NRC's 
expectation is that, by procedure, the dedicated operator is stationed 
at the equipment and is ready and qualified to perform that single 
action in a moment. An acceptable single action could be the rapid 
repositioning of a switch or a lever; an unacceptable action would be 
racking in a breaker or, in some instances, opening a manual gate 
valve.
    With respect to risk-informing the maintenance rule definition of 
availability, the reliance of initial availability performance measures 
on probabilistic risk assessment (PRA) data provided such a basis. 
However, in quality maintenance programs, availability is monitored to 
identify and trend the performance of equipment, thereby permitting 
certain conclusions to be drawn about the effectiveness of the 
equipment's maintenance program. Paragraph (a)(3) of the rule requires 
that the prevention of SSC failures (reliability) through maintenance 
is appropriately balanced against the objective of minimizing 
unavailability. Omitting unavailability time from the maintenance 
effectiveness determination analysis is flawed logic. Omitting 
unavailability time because, in an accident scenario, the equipment may 
not be needed for the time it may take to restore its safety function 
recognizes the role of the equipment but masks the actual requirement 
for maintenance. The maintenance rule requires licensees to monitor the 
effectiveness of their maintenance

[[Page 38554]]

programs. Omitting significant details, such as how much maintenance 
time an SSC requires in order to attain the objective of preventing 
failures, is contrary to the purpose of the rule.
    Note also that maintenance rule ``availability'' is not technical 
specification ``operability.''

11. Backfit and Regulatory Analyses

    Comment. One commentor stated that the regulatory analysis does not 
justify the expansion of the maintenance rule to ``normal shutdown 
operations'' and that a revision of the analysis to better consider 
such expansion would show through backfit considerations that the 
expansion is not justified. Another commentor also presented a concern 
that the overall implications of the rule were not supported by the 
backfit analysis.
    Response. The new preamble to the rule is an introductory sentence 
clarifying that the rule applies under all operating conditions, 
including normal shutdown. The Commission intended the rule to apply to 
all operating conditions, and it has been implemented by the NRC staff 
consistent with such an interpretation. Moreover, Section 11.2.3 of 
NUMARC 93-01 specifically states that ``assessment applies during all 
modes of plant operation.'' The overall implications of the rule were 
assessed in the backfit analysis for the original maintenance rule, 
which was issued July 10, 1991.

12. Regulatory Analysis Cost Estimates

    Comment. One commentor raised the concern that if facilities are 
required to develop numerical models for every combination of low 
safety-significance SSCs, the cost of implementing the program would be 
significantly higher than estimated in the regulatory analysis.
    Response. The NRC does not expect licensees to develop numerical 
models for assessing all possible combinations of low risk-significant 
SSCs. The regulatory analysis states that the complexity of assessments 
to be performed can vary, depending upon the configuration of SSCs to 
be maintained on line or out of service. It was presumed that 
assessments involving SSCs having little bearing on safety could be 
performed in an uncomplicated, deterministic manner and that the cost 
of the overall program would be dominated by the need for assessment of 
combinations of SSCs, which, when taken out of service simultaneously, 
could have an adverse effect on the safe operation of the facility. 
Additionally, the licensee controls the degree of complexity of the 
proposed configuration and thereby controls the level of sophistication 
required for the assessment. Consequently, the licensee should not 
propose to enter a plant configuration the complexity of which exceeds 
the licensee's ability to assess.

13. Application to Decommissioning Plants

    Comment. One commentor presented concerns regarding the application 
of the rule to plants in a decommissioning status. The commentor 
requested that, as part of this rulemaking, the NRC remove the 
applicability of the rule to decommissioning status plants following 
some modest level of fission product decay.
    Response. This rulemaking is focused on requiring pre-maintenance 
assessments of plant risk. However, the NRC is considering the issue in 
a separate rulemaking activity.

III. The Final Rule

    The final rule amends 10 CFR 50.65 as follows:
    1. An introductory paragraph has been added to 10 CFR 50.65 
clarifying that the rule applies under all conditions of operation, 
including shutdown. This introductory language reads as follows: ``The 
requirements of this section are applicable during all conditions of 
plant operation, including normal shutdown operations.'' The intent of 
this paragraph is to ensure that assessments are performed before 
maintenance activities when the plants are shut down as well as when 
the plants are at power. (Note that the word ``section,'' as used in 
this rulemaking, means all of Sec. 50.65.)
    2. The second sentence in paragraph (a)(3) has been revised as 
follows: ``The evaluations shall take into account, where practical, 
industry-wide operating experience.'' The change was made only to 
simplify the language and is purely editorial.
    3. The last sentence of paragraph (a)(3), containing the current, 
non-mandatory provision for performing safety assessments, is deleted. 
The revised paragraph (a)(3) now contains only the requirement for 
periodic, programmatic, long-term review.
    4. A new paragraph, (a)(4), has been added requiring the 
performance of assessments. The first sentence of the new (a)(4) 
paragraph states: ``Before performing maintenance activities (including 
but not limited to surveillance, post-maintenance testing, and 
corrective and preventive maintenance), the licensee shall assess and 
manage the increase in risk that may result from the proposed 
maintenance activities.'' Separating the assessment requirement from 
the long-term review requirement in paragraph (a)(3) will more clearly 
distinguish between the two types of activity.
    The intent of this requirement is to have licensees appropriately 
assess the risks related to proposed maintenance activities that will 
directly, or may inadvertently, result in equipment being taken out of 
service and then, using insights from the assessment, suitably minimize 
the time needed for the proposed maintenance activities while also 
controlling the configuration of the total plant to maintain and 
support the key plant safety functions.
    Risk is the result of the likelihood of an event with due 
consideration of the consequences of that same event. The term ``risk'' 
is used to address what can go wrong, its likelihood, and its 
consequences. The risk perspective can be assessed deterministically or 
probabilistically.
    In general, a risk assessment is necessary before all planned 
maintenance activities. Assessments should also be performed when an 
unexpected SSC failure initiates required maintenance activities or 
when changes to plant conditions affect a previously performed 
assessment. However, the reevaluation of a previous assessment should 
not interfere with, or delay, the plant staff's taking timely actions 
to restore the appropriate SSC to service or taking compensatory 
actions necessary to ensure that plant safety is maintained. If the SSC 
is restored to service before performing the assessment, the assessment 
need not be conducted.
    Assessments may vary from simple and straightforward to highly 
complex. However, the degree of sophistication required for the 
assessment notwithstanding, the NRC intends that the assessment process 
will examine the plant condition existing before the commencement of 
the maintenance activity, examine the changes expected by the proposed 
maintenance activity, and identify the increase in risk that may result 
from the maintenance activity. The assessments are expected to provide 
insights for identifying and limiting risk-significant maintenance 
activities and their durations.
    The level of complexity necessary in the assessment would be 
expected to differ from configuration to configuration. When a licensee 
proposes to perform maintenance on a single SSC from service for 
maintenance while no other SSC is out of service, a simple 
deterministic assessment may suffice. If the SSC is covered by TS, a 
qualitative

[[Page 38555]]

assessment based on TS allowed outage time pertinent to the SSC and the 
informed judgement of a trained, licensed operator is sufficient. When 
one SSC is out of service and the licensee proposes to remove a second 
SSC from service for maintenance, the assessment could be simplified 
through the use of a table of results for pre-analyzed combinations, 
typically high safety-significance SSCs paired against each other. 
However, more detailed assessments are required if a licensee proposes 
to remove multiple SSCs from service during power operations or to 
remove from service systems necessary to maintain safe shutdown during 
shutdown or startup operations. These more detailed assessments are 
expected to involve probabilistic analyses where possible, and to also 
include considerations of key plant safety functions to be maintained 
and defense in depth.
    The NRC believes that an appropriate assessment and management 
process should include the following considerations:

a. The likelihood that the maintenance activity will increase the 
frequency of an initiating event;
b. The probability that the activity will affect the ability to 
mitigate the initiating event;
c. The probability that the activity will affect the ability to 
maintain containment integrity;
d. Whether multiple trains are affected;
e. How probabilistic insights are used;
f. How non-probabilistic insights are used;
g. Component and system dependencies;
h. Measures to prevent concurrent unavailabilities of equipment 
necessary for accident mitigation;
i. Methods to determine the duration of the activity and account for 
the projected duration;
j. The analytical basis for allowed configurations (quantitative or 
qualitative consideration);
k. Provisions for accommodating configurations not encompassed by 
preanalyzed, acceptable configurations; and
l. Scope and quality of analysis for quantified assessments.

    In general, it is the NRC's expectation that the processes for 
managing the risk are scrutable and control the risk increase of the 
proposed maintenance activities. This process should include an 
understanding of the nature (i.e., affecting the core damage, or large 
early release frequency) and significance of the risk implications of a 
maintenance configuration on the overall plant baseline risk level. For 
example, risk-significant plant configurations should generally be 
avoided, as should conditions where a key plant safety function would 
be significantly degraded while conducting maintenance activities. The 
effective control of potentially significant risk increase due to an 
unexpected failure of another risk-important SSC can be reasonably 
assured by planning for contingencies, or coordinating, scheduling, 
monitoring, and modifying the duration of planned maintenance 
activities.
    5. The second sentence in the new (a)(4) paragraph states: ``The 
scope of the assessments may be limited to structures, systems, and 
components that a risk-informed evaluation process has shown to be 
significant to public health and safety.'' In response to public 
comments on the proposed rule, this second sentence has been added so 
that licensees may reduce the scope of SSCs subject to the pre-
maintenance assessment to those SSCs which, singularly or in 
combination, can be shown to have a significant effect on the 
performance of key plant safety functions. The focus of the assessments 
should be on the SSCs modeled in the licensee's PRA, in addition to all 
SSCs evaluated as risk significant (high safety-significance) by the 
licensee's maintenance rule expert panel. Typically, these SSCs have 
been analyzed as causing potential initiating events, if failed, and as 
accident mitigators, or as high safety-significance SSCs with their 
support systems. Such SSCs may be identified by operating experience or 
by deterministic or probabilistic analyses.

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 final rule is not a major Federal 
action significantly affecting the quality of the human environment 
and, therefore, an environmental impact statement is not required. The 
environmental assessment that forms the basis for this determination 
reads as follows:

Identification of the Proposed Action

    The Commission is amending its regulations to require commercial 
nuclear power plant licensees to perform assessments of changes to the 
plant's status that would result from maintenance activities before 
performing the maintenance activities on structures, systems, and 
components (SSCs) within the scope of 10 CFR 50.65, the maintenance 
rule. Thus, the maintenance rule has been modified by adding an 
introductory sentence to clarify that the rule applies under all 
conditions of operation, including normal shutdown; by making editorial 
revision to the second sentence of paragraph (a)(3); by deleting the 
last sentence of paragraph (a)(3); and by creating a new paragraph, 
(a)(4), that requires licensees to assess and manage the risk that may 
result from proposed maintenance activities and gives licensees an 
option to limit the scope of SSCs subject to the assessments.

The Need for the Proposed Action

    Formerly, paragraph (a)(3) of the maintenance rule was in the form 
of a recommendation because it read as follows: ``(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 that the performance of this type 
of assessment is prudent. The maintenance rule baseline inspections, 
performed at each operating nuclear power plant site, found that all 
licensees have implemented programs to perform the assessments. 
However, about half of the sites had programs with discernable 
weaknesses in this area, including instances in which, in accordance 
with the licensee's own programs, assessments should have been made but 
were not. Because of the hortatory nature of the 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 final rule permits the Commission to ensure that licensees perform 
the assessments, as appropriate.
    Removing the provision regarding safety assessments from paragraph 
(a)(3) and creating for it a new, separate paragraph, (a)(4), 
disassociates the new requirement from the more time-dependent 
requirement for evaluating 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 
assessment performance is stipulated to ensure that licensees will 
perform those assessments. There were questions regarding when the 
assessments are to be performed, which plant conditions are to be 
evaluated, how the assessments are to be used, and which SSCs are 
subject to the assessments. The new paragraph (a)(4) was revised to 
describe that the assessments are to be performed before proposed 
maintenance activities and are to examine pre-maintenance plant 
conditions and

[[Page 38556]]

expected changes as a result of the proposed maintenance activities. 
The assessments may be limited to SSCs that a risk-informed evaluation 
process has shown to be significant to public health and safety. The 
assessments are to be used to manage the increase in risk that may 
result from the maintenance activity.
Environmental Impacts of the Proposed Action
    This final rule requires that commercial nuclear power plant 
licensees perform certain assessments of the status of plant equipment 
before performing proposed maintenance activities. The purpose of this 
change is to increase the effectiveness of the maintenance rule by 
requiring licensees to--
    (1) Perform an assessment of the plant conditions before the 
proposed maintenance and the changes expected to result from the 
proposed maintenance activity;
    (2) Ensure that the assessments are performed when the plant is 
shut down as well as at power; and
    (3) Manage the increase in risk that may result from the proposed 
maintenance activity.
    The Commission believes that proper implementation of the rule will 
reduce the likelihood and consequences 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 requested 
public comment on any environmental justice considerations or questions 
that the public thinks may be related to this rule but somehow were not 
addressed. No public comments on this issue were received.

States Consulted and Sources Used

    The NRC sent a copy of the proposed rule to every State Liaison 
Officer and requested his or her comments on the environmental 
assessment. No comments were received on this issue.

Paperwork Reduction Act Statement

    This final 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 (OMB), approval 
number 3150-0011.

Public Protection Notification

    If a means used to impose an information collection 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 final regulatory analysis for this 
rule. 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 supported the selection of Alternative 
2 as the preferred course of action. Details of the alternative 
selection are contained in the regulatory analysis, which is available 
for inspection in the NRC Public Document Room, 2120 L Street NW (Lower 
Level), Washington, DC. Single copies of the analysis may be obtained 
from Richard P. Correia, Office of Nuclear Reactor Regulation, U.S. 
Nuclear Regulatory Commission, Washington, DC 20555-0001, 301-415-1009, 
e-mail [email protected].

Regulatory Flexibility Certification

    In accordance with the Regulatory Flexibility Act of 1980 (5 U.S.C. 
605(b)), the Commission certifies that this final rule will not have a 
significant economic impact on a substantial number of small entities. 
This 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).

Backfit Analysis

    As required by 10 CFR 50.109, the Commission has completed a 
backfit analysis for this final rule. The Commission has determined, on 
the basis of this analysis, that backfitting to comply with the 
requirements of this 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 issued, the NRC had not foreseen the 
rate deregulation of the electric utility industry and the changes to 
maintenance practices that licensees would make to enhance operational 
efficiency. Specifically of concern is the significant increase in 
maintenance while the plant is at power, permitting shortened refueling 
outages. At-power maintenance practices have evolved to the point that 
multiple systems, trains, and components are simultaneously out of 
service. Compared to the risk that occurs from expected random 
equipment failures, the risk of an accident or transient caused by 
taking systems, trains, and components off line for maintenance or from 
performing maintenance on systems, trains, or components while they 
remain on line could be increased.
    The objective of this rule is to require that--
    (1) Licensees assess the impact of equipment maintenance on the 
capability of the plant to perform key plant safety functions; and
    (2) Licensees use the results of the assessment before undertaking 
maintenance activities at operating nuclear power plants to manage the 
increase in risk caused by those activities.
    Thus, the rule adds a new paragraph, (a)(4), that requires the 
performance of assessments, specifies that the scope of the requirement 
for performing those assessments covers proposed maintenance 
activities, specifies that the scope of SSCs to be assessed may be 
limited to those that a risk-informed evaluation process has shown to 
be significant to public health and safety, and specifies that the 
increase in risk that may occur from the maintenance activity must be 
managed.
    This final rule also adds an introductory sentence to 10 CFR 50.65 
clarifying that the rule applies under all conditions of operation, 
including normal shutdown; revises the second sentence of paragraph 
(a)(3) to simplify the language; and deletes the last sentence of 
paragraph (a)(3) of the rule.
    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 this modification to the maintenance rule will result in 
a substantial increase in the overall protection to the public health 
and safety, and that the net costs

[[Page 38557]]

of the rule are justified in view of this increased level of safety.

Small Business Regulatory Enforcement Fairness Act

    In accordance with the Small Business Regulatory Enforcement 
Fairness Act of 1996, the NRC has determined that this action is not a 
major rule and has verified this determination with the Office of 
Information and Regulatory Affairs of OMB.

National Technology Transfer and Advancement Act

    The National Technology Transfer and Advancement Act of 1995, Pub. 
L. 104-113, requires that Federal agencies use technical standards 
developed or adopted by voluntary consensus standards bodies unless the 
use of such a standard is inconsistent with applicable law or is 
otherwise impractical. There are no industry consensus standards that 
apply to the area of maintenance. Thus, the provisions of the Act do 
not apply to this rulemaking.

List of Subjects in 10 CFR Part 50

    Antitrust, Classified information, Criminal penalties, Fire 
protection, Intergovernmental relations, Nuclear power plants 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. 552 and 553, the NRC is adopting 
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. 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, 68 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 take 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 (including but not 
limited to surveillance, post-maintenance testing, and corrective and 
preventive maintenance), the licensee shall assess and manage the 
increase in risk that may result from the proposed maintenance 
activities. The scope of the assessment may be limited to structures, 
systems, and components that a risk-informed evaluation process has 
shown to be significant to public health and safety.
* * * * *
    Dated at Rockville, Maryland, this 13th day of July, 1999.

    For the Nuclear Regulatory Commission.
Annette Vietti-Cook,
Secretary of the Commission.
[FR Doc. 99-18325 Filed 7-16-99; 8:45 am]
BILLING CODE 7590-01-P