[Federal Register Volume 61, Number 29 (Monday, February 12, 1996)]
[Proposed Rules]
[Pages 5318-5326]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-2698]



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NUCLEAR REGULATORY COMMISSION

10 CFR Part 50

RIN 3150-AF33


Reporting Reliability and Availability Information for Risk-
significant Systems and Equipment

AGENCY: Nuclear Regulatory Commission.

ACTION: Proposed rule.

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SUMMARY: The Nuclear Regulatory Commission (NRC) is proposing to amend 
its regulations to require that licensees for commercial nuclear power 
reactors report plant-specific summary reliability and availability 
data for risk-significant systems and equipment 1 to 

[[Page 5319]]
the NRC. The proposed rule would also require licensees to maintain on 
site, and to make available for NRC inspection, records and 
documentation that provide the basis for the summary data reported to 
the NRC. The systems and equipment for which data would be provided are 
a subset of the systems and equipment within the scope of the 
maintenance rule.

    \1\ In relation to this proposed rule, the term equipment is 
intended to apply to an ensemble of components treated as a single 
entity for certain probabilistic risk assessments (PRAs) where a 
system or train treatment would not be appropriate.
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    The Commission has determined that reporting of reliability and 
availability information is necessary to substantially improve the 
NRC's ability to make risk-effective regulatory decisions consistent 
with the Commission's policy statement on the use of probabilistic risk 
assessments (PRAs) (August 16, 1995; 60 FR 42622). This would assist 
the NRC in improving its oversight capabilities with respect to public 
health and safety and becoming more efficient by focusing its 
regulatory program on those issues of greatest risk significance and 
reducing unnecessary regulatory burdens on licensees. The Commission 
would use the data that would be required by the proposed rule in 
generic issue resolution, developing quantitative indicators that can 
assist in assessing plant safety performance, performing risk-based 
inspections, and pursuing modifications to specific plants and basic 
regulations and guidelines. Furthermore, this information would improve 
the NRC's oversight of licensees' implementation of the maintenance 
rule. It would also enhance licensees' capabilities to implement the 
evaluation and goal-setting activities required by the maintenance rule 
by providing licensees with access to current industry-wide reliability 
and availability information for some of the systems and equipment 
within the scope of the maintenance rule.

DATES: Comments regarding any aspect of the proposed rule are due to 
the Commission by June 11, 1996. Comments received after that date will 
be considered if it is practical to do so, but the Commission can give 
no assurance of consideration for late comments. The Commission intends 
that this expiration date will be at least 30 days after publication of 
an associated draft regulatory guide for public comment.
    In addition, comments regarding the collection of information, 
including the burden estimate and suggestions for reducing the burden, 
should be submitted to the Office of Management and Budget (OMB), and 
to the NRC, by March 13, 1996. For further information see the 
discussion below under the heading Paperwork Reduction Act Statement.

ADDRESSES: Mail written comments to: U.S. Nuclear Regulatory 
Commission, Washington, DC 20555-0001, ATTN.: Docketing and Service 
Branch. Deliver written comments to the NRC at One White Flint North, 
11555 Rockville Pike, Rockville, MD, between 7:30 am and 4:15 pm on 
Federal workdays.
    Send comments regarding the collection of information, including 
the burden estimate and suggestions for reducing the burden, to: (1) 
Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 
(3150-0011), Office of Management and Budget, Washington, DC 20503, and 
(2) Information and Records Management Branch (T-6F33), U.S. Nuclear 
Regulatory Commission, Washington, DC 20555-0001. For further 
information see the discussion below under the heading Paperwork 
Reduction Act Statement.
    Copies of the draft regulatory analysis, the supporting statement 
submitted to the OMB, and comments received may be examined, and/or 
copied for a fee, at: The NRC Public Document Room, 2120 L Street NW. 
(Lower Level), Washington, DC.

FOR FURTHER INFORMATION CONTACT: Dennis Allison, Office for Analysis 
and Evaluation of Operational Data, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555-0001, Telephone (301) 415-6835.

SUPPLEMENTARY INFORMATION:

Background

Current Requirements

    There are no existing requirements to systematically report 
reliability and availability information; nor is there an industry-wide 
database to provide such information.
    Current reporting requirements in 10 CFR 50.72, ``Immediate 
notification'' and 10 CFR 50.73, ``Licensee event report system,'' 
require the submittal of extensive descriptive information on selected 
plant and system level events. The Nuclear Plant Reliability Data 
System, a data base that industry supports and the Institute for 
Nuclear Power Operations (INPO) maintains, provides data on component 
engineering characteristics and failures. Neither of these sources 
includes all the data elements (i.e., number of demands on a system, 
number of hours of operation, and information on maintenance 
unavailability) that are needed to determine the reliability and 
availability of systems and equipment. Maintenance effectiveness 
monitoring requirements in 10 CFR 50.65, ``Requirements for Monitoring 
the Effectiveness of Maintenance at Nuclear Power Plants'', also do not 
contain reporting requirements.
    In recent years, plants have performed Individual Plant Evaluations 
(IPEs), as requested in Generic Letter 88-20 and its supplements, and 
submitted the results to the NRC. These submittals provide measures of 
risk such as core damage frequency, dominant accident sequences, and 
containment release category information. While system and component 
reliability data have been collected as part of some utility IPEs, this 
information is typically not included in the IPE submittals to the NRC.

Prior Efforts

    In late 1991 and through 1992, the NRC staff participated on an 
INPO-established NRC/industry review group to make recommendations for 
changes to the Nuclear Plant Reliability Data System (NPRDS). The 
group's final recommendations to INPO to collect PRA-related 
reliability and availability data would have provided most of NRC's 
data needs. However, INPO took no action on these recommendations.
    During 1992 and 1993, the NRC staff continued through 
correspondence and meetings to outline the particular data needed and 
to seek INPO's assistance in obtaining the data. In a December 1993 
meeting with NUMARC (now the Nuclear Energy Institute (NEI)), INPO 
representatives suggested their Safety System Performance Indicator 
(SSPI) as a surrogate for reliability data. They proposed expanding the 
indicator to additional systems and indicated that data elements could 
be modified to compute actual reliability and availability data. 
Although general agreements were reached with INPO on which systems and 
components and what types of data elements are appropriate for risk-
related applications and maintenance effectiveness monitoring, no 
voluntary system of providing data resulted from these discussions. In 
the fall of 1994, the NRC staff began work on this rulemaking action. 
In June 1995, NEI proposed to discuss a voluntary approach of providing 
reliability and availability data to the NRC based on SSPI data. The 
NRC staff will continue to work with industry on voluntary submittal of 
reliability data, under a program that will meet the needs of all 
parties, while at the same time proceeding to obtain public comment on 
this proposed rule.
    Industry representatives have expressed concern that reliability 
data, if publicly available, would be subject to 

[[Page 5320]]
misuse. In certain circumstances it is permissible for the NRC to 
withhold information from public disclosure. For example, pursuant to 
10 CFR 2.790(b)(1), a licensee may propose that a document be withheld 
from public disclosure on the grounds that it contains trade secrets or 
privileged or confidential commercial or financial information. 
However, the data that would be reported under this proposed rule would 
not appear to qualify for withholding. Reliability data used as input 
to risk-based regulatory decisions should be scrutable and accessible 
to the public. The Commission's PRA policy statement indicates that 
appropriate supporting data for PRA analyses that support regulatory 
decisions should be publicly available. Similarly, the Commission's 
draft report on public responsiveness (March 31, 1995; 60 FR 16685) 
indicates that the policy of the NRC is to make information available 
to the public relating to its health and safety mission, consistent 
with its legal obligations to protect information and its deliberative 
and investigative processes. Commenters who believe that there is 
information subject to a proper 10 CFR 2.790(b)(1) withholding 
determination requested by the proposed rule should provide a specific 
justification for such belief.

Move to Risk-Based Regulation

    For several years the Commission has been working towards increased 
use of PRAs in power reactor regulation. In its policy statement on the 
use of PRAs, the Commission has indicated that the use of PRA 
technology should be increased in all regulatory matters to the extent 
supported by the state-of-the-art in terms of methods and data, and 
this implies that the collection of equipment and human reliability 
data should be enhanced. Implementation of these policies would improve 
the regulatory process through (1) improved risk-effective safety 
decision making, (2) more efficient use of agency resources, and (3) 
reduction in unnecessary burdens on licensees. These improvements would 
enhance both efficiency and safety.
    The data reported under this proposed rule would improve the NRC's 
oversight capability with respect to public health and safety by 
focusing the NRC's regulatory programs in a risk-effective manner. 
Generally, the NRC's ability to identify plants and systems at 
increased risk for significant events and, thus, to take appropriate 
action would be substantially improved. For example, a generic 
indication of low reliability or availability for a system might 
indicate a technical problem, with its attendant risk, that may warrant 
generic action. Similarly, a plant-specific indication of low 
reliability or availability for several systems might indicate a 
programmatic problem, with its attendant risk, and may warrant plant-
specific action.
    It has been noted that prior to some significant events (such as 
the scram failure at Salem and the accident at Three Mile Island) there 
was previously existing information (such as challenge data and 
reliability data for scram breakers and power operated relief valves) 
which, if collected, recognized, and acted upon might have led to 
preventive actions. Accordingly, it is expected that reliability and 
availability information for selected risk-significant systems would 
improve the NRC's oversight capability with respect to public health 
and safety--i.e., the ability to maintain or enhance safety by 
identifying and reviewing indications of increased risk and, if 
appropriate, taking generic or plant-specific action.
    Such problems could be subtle in nature. For instance, licensee(s) 
might schedule train outages for maintenance at certain times, such 
that risks are substantially increased over what would be expected 
based on random outages. This situation would not be indicated by 
current reporting requirements, or even by simply reporting train 
unavailability, but it could be indicated by the concurrent 
unavailability of two or more trains, as would be reported under the 
proposed rule. Additional examples discussed below describe further 
specific uses of the data that would help to enhance safety.
    In order to move towards risk-based regulation and the increased 
use of PRA information, the NRC needs scrutable, plant-specific and 
generic reliability and availability information. The framework for an 
overall move towards risk-based regulation involves the development of 
a regulatory process. This process includes operational procedures and 
decision criteria that require credible PRA methods, models, and data. 
This framework would provide for predictable, consistent, and objective 
risk-based regulatory decision making. The data that would be reported 
under this rule represent one of the needed elements. In addition, 
these data are needed to improve the efficiency and effectiveness of 
NRC regulatory applications that employ a risk-based perspective in 
advance of defining the entire framework.
    Generally, plant-specific information is needed because there can 
be wide plant-to-plant variations in the design, importance, 
reliability and availability of particular systems and equipment. It is 
necessary to identify similar equipment in various plants so that the 
data can be properly grouped and analyzed to estimate overall industry 
performance and plant-specific performance and to identify outliers 
(good or bad).\2\

    \2\ For many of the systems involved, plant specific demand and 
failure data will be sparse, at least initially. Until data have 
been collected for some time, it will be necessary to use data from 
similar equipment, applications, and environments at several plants 
in order to obtain practical estimates of reliability and 
uncertainty. Even when sufficient plant-specific data exist to 
estimate plant performance, comparison to industry or group averages 
is often desirable.
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    Some examples of how reliability and availability information would 
be used to improve current NRC regulatory applications that consider 
risk in the decision process are discussed below. One of the examples 
involves the need for information to support generic regulatory 
actions--i.e., generic issue resolution and its associated rulemaking 
or regulatory guide revision. Another example involves the need for 
information to determine whether further NRC action is needed at 
specific plants--i.e., indicators of plant performance. Some involve a 
mixture of plant specific and generic elements. For example, analyzing 
an event at a given plant could lead to a plant-specific action such as 
a special inspection and/or to a generic action such as a bulletin or 
generic letter.
Generic Issue Resolution
    The NRC currently uses risk estimates in: (1) prioritizing safety 
issues, (2) deciding whether new requirements or staff positions to 
address these issues are warranted, and (3) deciding whether proposed 
new requirements or staff positions should be implemented. Knowing the 
current, updated reliability and availability of key systems would, in 
some cases, lead to a better understanding of the risk in these areas 
and, thus, to more risk-effective decisions. This should both enhance 
public protection and reduce unnecessary regulatory burdens. Generic 
data would usually suffice for this purpose; however, in some cases the 
data would need to be divided to account for specific classes or groups 
of plants.
Indicators of Plant Performance
    PRA models with plant-specific reliability and availability data 
would be used to develop indicators of plant performance and trends in 
plant performance which are more closely related to risk than those 
currently in use. These new indicators would replace some of those 
currently in use 

[[Page 5321]]
and thereby enhance NRC's ability to make risk-effective decisions with 
regard to identifying plants for increased or decreased regulatory 
attention. For example, it is important to detect situations where an 
individual plant may be having reliability or availability problems 
with multiple systems.
Accident Sequence Precursor (ASP) and Event Analysis
    Plant-specific, train-level reliability and unavailability data 
would be used to improve the plant-specific ASP models which the NRC 
uses to compute conditional core damage probability for determining the 
risk-significance of operational events. In addition, dates and causes 
of equipment failures would be used to identify common cause failures 
and to compute common cause failure rates for input to these models. 
Improving these methods would enhance the staff's ability to make risk-
effective decisions about which events warrant further inspections or 
investigations and/or generic actions such as bulletins and generic 
letters. Plant-specific data are needed to better understand an event 
and calculate the associated conditional core damage probability. It is 
also useful to identify systems that have the most influence on the 
results. Then the risk associated with the potential for similar events 
at other plants, which may be known to have low reliability for the key 
systems, can be considered in determining whether further actions are 
warranted.
Risk-Based Inspections
    Current and updated system reliability, availability and failure 
data in a generic and plant-specific risk-based context would be used 
to enhance the staff's ability to plan inspections focused on the most 
risk-significant plant systems, components, and operations. While 
generic data would be used in developing risk-based inspection guides 
and a framework for inspections, plant-specific data would be used to 
focus and optimize inspection activities at specific plants. For 
example, an individual plant may have an atypical reliability problem 
with a specific risk-significant system and thereby warrant additional 
attention. In addition, special studies can be conducted to determine 
the root cause of reliability problems by comparing the characteristics 
of plants that have these problems with those that do not.
Aging
    Equipment reliability data would help identify equipment that is 
being degraded by aging and define the extent and the risk-significance 
of aging problems.
    Another class of examples involves the need for information to 
evaluate anticipated cost beneficial licensing actions, where the 
rationale is that risk permits reductions in previous margins of safety 
or less prescriptive requirements without adverse impact on overall 
safety. The NRC is actively pursuing a variety of modifications to the 
basic regulations and guidelines that govern the operation of 
commercial nuclear power reactors. These modifications are 
characterized by allowing individual licensees to utilize insights from 
plant-specific risk evaluations to reduce or remove current 
requirements that are found to have low risk-significance. Current 
regulatory requirements under consideration for risk-based modification 
include those prescribing quality assurance, in-service inspection, in-
service testing, and surveillance testing. It is anticipated that a 
significant number of additional requests will be received that rely 
upon risk-based arguments. These changes could adversely affect the 
level of safety achieved by the plants if the risk evaluations are 
flawed or the changes are improperly executed or the changes involve 
synergistic effects that are not covered by the risk models or captured 
by historical data. Current, plant-specific reliability and 
availability data would help the NRC monitor the licensees' programs to 
maintain safety while reducing regulatory burdens. Relaxation of undue 
regulatory burdens then can proceed with confidence that there will be 
appropriate feedback to assure that the level of safety is not being 
degraded. Some examples are discussed below.
Risk-Based Technical Specification
    Technical Specification requirements specify surveillance intervals 
and allowed outage times for safety equipment for the various modes of 
plant operation. It is anticipated that licensees will request a number 
of relaxations in surveillance intervals and allowed outage times. 
Current, plant-specific reliability and availability data would help 
the NRC monitor performance for the systems and equipment subject to 
the proposed rule. Thus, proposed relaxations of surveillance intervals 
and allowed outage times for such systems could be evaluated more 
effectively based on past performance and on confidence that there 
would be appropriate feedback to ensure that performance is not being 
degraded. In addition, failure rates from actual demands will be used 
to verify that failure rates estimated from testing are approximately 
the same.
Inservice Testing
    Inservice testing requirements, which are based on the provisions 
of the American Society of Mechanical Engineers Boiler and Pressure 
Vessel Code (ASME Code), measure the functional characteristics of 
equipment performance, such as pump flow, in order to detect 
degradation. The ASME and licensee owners' groups are working toward 
establishing risk-based frequencies for inservice testing, based on 
plant-specific risk ranking methodologies. Changes in testing frequency 
can affect reliability in many ways. For example, less frequent valve 
testing might lead to an increase in the demand failure rate because 
the valve actuating mechanism tends to bind or freeze after extended 
periods of idleness. However, using plant-specific demand failure and 
unavailability data, proposed changes can be more effectively evaluated 
based on the risk-significance and performance of plant systems and 
based on confidence that there will be appropriate feedback to assure 
that the level of safety is not being degraded.

NRC Maintenance Rule

    The maintenance rule, 10 CFR 50.65, was issued on July 10, 1991 (56 
FR 31306). The reliability and availability information that would be 
required by the proposed reporting rule would improve the NRC's 
oversight of licensees' implementation of the maintenance rule. It 
would also enhance licensee's capabilities to implement the evaluation 
and goal-setting activities required by the maintenance rule by 
providing licensees with access to current industry-wide reliability 
and availability information for some of the systems and equipment 
within the scope of the maintenance rule.
NRC Monitoring
    As discussed above, current plant-specific data can provide 
feedback on the effectiveness of licensee programs, including 
maintenance programs. Accordingly, these data would improve the NRC's 
monitoring ability by providing risk-based measures of the 
effectiveness of individual licensee maintenance programs and the 
overall effectiveness of the maintenance rule.
    In addition, the NRC has expressed concern about the extent to 
which some reactor licensees are taking systems and equipment out of 
service for maintenance during plant operation. Although this practice 
may offer economic benefits by reducing plant 

[[Page 5322]]
downtime, it must be properly managed to assure that safety is not 
compromised. It should be noted that licensees are required by 10 CFR 
50.65(a)(3) to periodically conduct assessments and make adjustments to 
ensure that the objective of preventing failures through maintenance is 
appropriately balanced against the objective of minimizing 
unavailability due to monitoring and preventive maintenance. The NRC 
would use the hours when any two or more trains from the same or 
different systems are concurrently unavailable to monitor how well 
licensees are managing the risk associated with such maintenance. As 
discussed below, under ``Licensee Implementation,'' the data would also 
enhance licensees' capabilities to make prudent on-line maintenance 
decisions.
    The maintenance rule is also important to license renewal (10 CFR 
Part 54). Hence, improving the NRC's oversight of the maintenance rule 
could strengthen one of the bases for the scope of the license renewal 
rule.
Licensee Implementation
    In connection with the NRC's PRA policy, the NRC staff has defined 
the data elements that would improve the evaluation of maintenance and 
has established that they are the same as those needed to support a 
transition toward a risk- and performance-based regulatory process. The 
NRC believes that the reliability and availability data that would be 
required by this rule would enhance licensee's capabilities to 
implement the evaluation and goal-setting activities required by the 
maintenance rule by providing licensees with access to current 
industry-wide reliability and availability information for some of the 
systems and equipment within the scope of the maintenance rule.3

    \3\ The systems and equipment covered by this proposed rule are 
a subset of the systems and equipment within the scope of the 
maintenance rule. The data elements are more extensive than what 
would be required for compliance with the maintenance rule; however, 
for the systems covered, these data elements would serve to improve 
implementation of the maintenance rule. To cite one example, under 
10 CFR 50.65(a)(2), risk-significant systems may be considered to be 
subject to an effective preventive maintenance program and, thus, 
not subject to condition or performance monitoring unless 
``maintenance preventable'' failures occur. However, gathering the 
reliability and availability information specified in this proposed 
rule, including data elements such as concurrent outages and the 
causes of failures, would provide a better picture of a system's 
performance and the effectiveness of the preventive maintenance 
program than simply awaiting the occurrence of ``maintenance 
preventable'' failures.
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    In some circumstances, the maintenance rule requires licensees to 
establish performance or condition goals, taking into account industry-
wide operating experience where practical. It also requires periodic 
program evaluations, including consideration of unavailability due to 
monitoring or preventive maintenance, taking industry-wide operating 
experience into account, where practical. Licensees will need to 
monitor reliability and availability of risk-significant systems, 
particularly for the periodic program evaluations.4

    \4\ NUMARC 93-01, which the NRC has endorsed as describing one 
acceptable way of meeting the requirements of the NRC's maintenance 
rule, indicates in Section 12.2.4 that the adjustment for balancing 
of objectives needs to be done for risk-significant structures, 
systems, and components (SSCs). However, for other SSCs it is 
acceptable to measure operating SSC performance against overall 
plant performance criteria and standby system performance against 
specific performance criteria. This is reasonable in that, for 
systems that are less risk-significant, the expense of a rigorous 
balancing is not warranted.
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    For many of the systems involved, plant-specific demand and failure 
data will be sparse, at least initially. However statistical analysis 
techniques exist that allow a licensee to analyze and evaluate data 
from similar equipment, applications and environments from other 
plants, besides the data from their plant. These analyses yield 
meaningful reliability estimates for the subject plant that can be 
compared with performance goals. Industry-wide data would also provide 
a practical source for comparing plant-specific performance with 
industry operating experience. Although plant-specific information is 
generally available on site, and utilities review licensee event 
reports and other generic event information, NRC site visits, 
associated with early efforts to prepare for maintenance rule 
implementation in 1996, indicate that utilities do not use industry 
operating experience in a systematic and consistent way for goal 
setting purposes under the maintenance rule. Based on these 
considerations, the availability of current, industry-wide reliability 
and availability data would enhance licensee's capabilities to 
implement the evaluation and goal-setting activities required by the 
maintenance rule.
    As discussed previously, the NRC has recently found cause for 
concern about how some reactor licensees handle on-line maintenance. 
Prudent on-line maintenance decisions depend on a full appreciation of 
the risk-significance of taking equipment out of service (individually 
or collectively) and use of plant-specific and generic reliability and 
availability data would play a significant role in improving such 
decision making.

Description of Proposed Rule

    The proposed rule would require holders of operating licenses for 
nuclear power reactors to report reliability and availability data for 
certain risk-significant systems and equipment. The proposed reporting 
requirements would apply to the event-mitigating systems and equipment 
which have or could have a significant effect on risk in terms of 
avoiding core damage accidents or preserving containment integrity. 
Summary information reported to the NRC would be:
    1. The number of demands, the number of failures to start 
associated with such demands, and the dates of any such failures, 
characterized according to the identification of the train affected, 
the type of demand (test, inadvertent/spurious, or actual need), and 
the plant mode at the time of the demand (operating or shutdown);
    2. The number of hours of operation following each successful 
start, characterized according to the identification of the train 
affected and whether or not the operation was terminated because of 
equipment failure, with the dates of any such failures;
    3. The number of hours equipment is unavailable, characterized 
according to the identification of the train affected, the plant mode 
at the time equipment is unavailable (operating or shutdown), 
characterization of the unavailable period (planned, unplanned, or 
support system unavailable), and, if due to a support system being 
unavailable, identification of the support system;
    4. For each period equipment is unavailable due to component 
failure(s), a failure record identifying the component(s) and providing 
the failure date, duration, mode, cause, and effect; and
    5. The number of hours when two or more trains from the same or 
different systems were concurrently unavailable, characterized 
according to the identification of the trains that were unavailable.
    The first annual report would identify the systems, trains, and 
ensembles of components covered by the reporting requirements of the 
rule; subsequent annual reports would either state that no changes were 
made subsequent to the previous annual report or describe the changes 
made.
    The summary information would be reported annually and compiled on 
the basis of calendar quarters, or on a more frequent basis at the 
option of each individual licensee. Records and documentation of each 
occurrence of a demand, failure, or unavailable period 

[[Page 5323]]
that provide the basis for the summary data reported to the NRC would 
be required to be maintained on site and made available for NRC 
inspection.
    In developing these data elements the NRC has, over the past three 
years, reached a consensus on the minimum data needed to support risk-
based applications and enhance implementation of the maintenance rule. 
During this period NRC staff has also interacted extensively with INPO 
and NEI in an effort to define the minimum reliability and availability 
data needed to satisfy the needs of both NRC risk-based regulatory 
applications and industry (licensee) uses of PRA.
    The number of demands and the number of successful starts are 
needed to estimate demand reliability, i.e., the fraction of demands 
that result in successful starts. (The complement of this fraction 
provides an estimate of the probability of failure on demand). The 
actual number of demands and successes, as opposed to the ratio, is 
needed for purposes such as: (1) providing a measure of confidence in 
the results and (2) permitting proper combination of data from 
different plants.
    The type of demand is needed to determine whether or not the demand 
reliability estimated by testing is approximately the same as the 
demand reliability for actual demands. Sometimes it is not, indicating 
a need for additional data analysis in making reliability estimates.
    The plant mode at the time of a demand is needed to estimate the 
demand frequency, demand reliability, and unavailability according to 
plant mode. These factors, as well as the risk associated with 
unreliability and unavailability, can be quite different depending on 
whether the plant is in operation or shut down.
    The hours of operation following successful starts are needed to 
estimate the probability the equipment will function for a specified 
period of time. This information is needed for systems that must 
operate for an extended period following an accident to fulfill a risk-
significant safety function.
    The number of hours that equipment is not available (unavailable 
hours) is needed to estimate the fraction of time that a train is not 
available to perform its risk-significant safety function. For some 
systems this can be an important or dominant contributor to the overall 
probability of failure to perform the system's safety function. It can 
be significantly affected by elective maintenance.
    The type of unavailable hours (planned or unplanned) is needed to 
effectively utilize these estimates. For example, a high unplanned 
unavailability may indicate a need for more preventive maintenance; a 
high planned unavailability may indicate the opposite.
    The unavailable hours due to support systems failure or 
unavailability are needed to properly capture concurrent outages and to 
eliminate double counting. For example, an Emergency Service Water 
(ESW) train being unavailable may result in other trains being 
unavailable as well; however, for purposes of estimating risk in a PRA 
study, that unavailability should not be counted more than once.
    The date of each failure is needed to allow screening for potential 
common cause failures. Failures that occur closely together in time 
warrant review to see whether a common cause failure may be involved. 
Common cause failures may indicate a need for revised maintenance 
procedures or staggered testing. Common cause failure rates are also 
needed for PRA models because of their importance in system reliability 
and availability estimates.
    Failure cause and failure mode information are needed to support 
common cause failure analysis as discussed above and to associate the 
failure with the correct failure mode for input into PRA models.
    Quarterly data are needed to conduct first order trending studies 
to identify areas of emerging concern with regard to overall plant and 
system performance. More frequent compilation is acceptable at the 
discretion of each licensee.
    An identification of the systems, trains, and ensembles of 
components subject to the rule is needed because identification of the 
components within the systems, trains, and ensembles is necessary for 
proper use and evaluation of the data by the staff and for industry 
wide generic applications to account for physical differences between 
plants. For example, simplified system diagrams could be marked to show 
the systems, trains, and ensembles against which the data would be 
reported.
    Retention of records and documentation that provide the bases for 
the summary data report to the NRC for a period of several years is 
consistent with maintenance rule applications. For example, monitoring 
reliability for a few years may be used to determine trends in order to 
achieve the balance described in 10 CFR 50.65(a)(3)--i.e., the balance 
between preventing failures through maintenance and minimizing 
unavailability due to monitoring and preventive maintenance. In 
addition, on-site data are needed to provide a scrutable basis for 
regulatory decisions. For example, it is expected to be necessary to 
review the actual unavailable hours in order to estimate the mean 
repair times for key components for the purpose of updating the staff's 
PRA models.

Regulatory Guide

    A new regulatory guide will be prepared and issued to provide 
supplementary guidance. The guide will present an acceptable way to 
define the systems and equipment subject to the rule and it will 
provide risk-based definitions of failure as well as train and system 
boundaries consistent with PRA applications. The format in which data 
would be provided to the NRC and a suggested format for maintaining on-
site documentation and record keeping would be included. In order to 
reduce costs, use of electronic data submittal will be considered a 
priority objective in developing and implementing the guide. A draft 
guide will be published for comment before it is finalized. A public 
workshop is planned after publication of the draft guide. The comment 
period for this proposed rule will not expire until at least 30 days 
after publication of the draft regulatory guide.
Definitions
    The basic definitions used in reporting under Sec. 50.76 are 
discussed below; further details will be addressed in the regulatory 
guide. For example, the basic definition of failure is provided here; 
further details, such as how to handle a case where the operators 
prematurely terminate system operation following a real demand, will be 
discussed in the regulatory guide. In particular, the regulatory guide 
will define risk-significant safety function(s) and failures for 
systems and equipment covered by this proposed rule.
    Demand is an occurrence where a system or train is called upon to 
perform its risk-significant safety function. A demand may be manual or 
automatic. It may occur in response to a real need, a test, an error, 
an equipment malfunction or other spurious causes. For the purposes of 
reporting under this rule, the demands of interest are those which are 
actual demands or closely simulate actual demands for the train or 
specific equipment involved.
    Failure, for the purpose of reporting under this rule, is an 
occurrence where a system or train fails to perform its risk-
significant safety function. A failure may occur as a result of a 
hardware malfunction, a software malfunction, or a human error. 
Failures to start in response to a demand are reported under paragraph 
50.76(b)(1)(i). Failures 

[[Page 5324]]
to run after a successful start are reported under paragraph 
50.76(b)(1)(ii).
    Unavailability is the probability that a required system or train 
is not in a condition to perform or is not capable of performing its 
risk-significant safety function. This may result from failure to 
start, from failure to run, or from intentional or unintentional 
removal of equipment from service (e.g., for maintenance or testing).
    Risk-significant safety function is a safety function that has or 
could have a significant effect on risk (in terms of avoiding core 
damage accidents or preserving containment integrity for the purposes 
of reporting under this proposed rule).
    Reportable systems and equipment are the event-mitigating systems 
and equipment which have or could have a significant effect on risk in 
terms of avoiding core damage accidents or preserving containment 
integrity. The reportable systems and equipment will be determined by 
each licensee. The regulatory guide will describe acceptable methods 
for making that determination.
    It is expected that the rule will produce a set of basic systems 
for which reliability data will be reported for all plants that have 
them. However, these basic systems are not sufficient by themselves. 
Additional systems and equipment to be addressed will depend on plant-
specific features. Listed below is the set of basic systems that the 
Commission is currently considering for identification in the draft 
regulatory guide.

------------------------------------------------------------------------
             Basic PWR systems                    Basic BWR systems     
------------------------------------------------------------------------
Auxiliary feedwater.......................  Reactor core isolation      
                                             cooling or isolation       
                                             condenser.                 
High pressure safety injection............  Feedwater coolant injection,
                                             high pressure coolant      
                                             injection or high pressure 
                                             core spray, as appropriate.
Reactor protection........................  Reactor protection.         
Low pressure safety injection.............  Low pressure coolant        
                                             injection and low pressure 
                                             core spray.                
Emergency ac power........................  Emergency ac power.         
------------------------------------------------------------------------

    As discussed above, the systems and equipment to be included in the 
scope of the rule would be those event-mitigating systems and equipment 
that have or could have a significant effect on risk in terms of 
avoiding core damage accidents or preserving containment integrity. To 
ensure that this approach is consistent with operating experience, the 
NRC has considered the systems and equipment that have been 
substantially involved in significant events in U. S. reactors. These 
systems were found to fall into the following categories:
    1. Basic systems. As indicated above, the NRC expects that these 
systems would be included in the scope of the rule for all plants. The 
basic systems on the proposed list have been confirmed to have been 
substantially involved in significant events.
    2. Plant-specific systems. Systems such as service water and 
component cooling water are risk-significant, but the significance 
varies widely, depending upon plant-specific designs. It is expected 
that these systems will be included, as appropriate, based on plant-
specific PRA studies. Other systems, such as containment purge, appear 
infrequently in connection with significant events and are not expected 
to be risk-significant for any plants.
    3. Initiating systems. Systems such as main feedwater and offsite 
power are primarily considered to be initiators of significant events, 
rather than mitigation systems. Existing reporting requirements in 10 
CFR 50.72 and 10 CFR 50.73 provide enough information to characterize 
the important initiating systems for the purpose of PRA studies.
    4. Non-measurable items. Items such as reactor coolant system 
corrosion are not amenable to meaningful measurement by the methods of 
this proposed rule.
    Based on this review, the systems and equipment to be included in 
the scope of the rule are considered reasonably consistent with 
operating experience in terms of involvement in significant events. 
Accordingly, it is expected that reliability and availability 
information for those systems and equipment will be well suited for 
identifying plants and systems at increased risk for significant 
events.
    Minimizing Costs. The NRC intends that the data required to be 
collected and reported under this proposed rule be essentially the same 
as would be required for monitoring reliability and/or availability for 
other purposes, such as monitoring system reliability where that is the 
option chosen for compliance with the maintenance rule. Thus, it should 
be practical to gather and report the data without significant 
additional cost. This will be a priority goal in developing the 
guidance to be included in the new regulatory guide.
    Sunset Provision. As experience is gained with implementing the 
proposed rule and utilizing the information required to be collected 
and reported, a reassessment may be necessary or desirable. One way of 
assuring such a reassessment would be to include a ``sunset provision'' 
in the rule, whereby the rule would automatically expire after a 
specified period of time unless: (i) a condition specified in the rule 
is fulfilled, or (ii) the Commission engages in a rulemaking which 
extends the effectiveness of the rule. The Commission requests public 
comments on whether the proposed rule should contain such a sunset 
provision, and if so, the period of time after which the rule should 
automatically expire.
    Grandfather Provision. There may be some plants for which, at the 
time that the proposed rule may be adopted by the Commission as a final 
rule, licensees have already announced plans to discontinue operation 
in the near future. Furthermore, licensees may determine in the future 
to discontinue operation at some plants. In either case, there may be 
less reason to require collection and reporting of the information 
contemplated by the proposed rule at such plants and it may be 
advisable to exempt such plants from the information collection and 
reporting requirements of the proposed rule (i.e., ``grandfathering''). 
The Commission requests public comments on whether the proposed rule 
should exempt plants that have announced (or will announce) plans to 
discontinue operation within a short time (e.g., two years).

Conclusion

    As discussed under the subject ``Move to Risk-Based Regulation,'' 
the information to be collected under the proposed rule is necessary 
for the development and implementation of risk-based regulatory 
processes. Risk-based regulatory approaches provide a means for the 
Commission to maintain, and in some cases improve, safety while 
reducing impacts on licensees as well as NRC resource expenditures, by 
focusing regulatory requirements and activities on the most risk-
significant areas. In addition, this information would improve the 
NRC's oversight of licensees' implementation of the maintenance rule. 
It would also enhance licensee's capabilities to implement the 
evaluation and goal-setting activities required by the maintenance rule 
by providing licensees with access to current industry-wide reliability 
and availability information for some of the risk-significant systems 
and equipment within the scope of the maintenance rule. The Commission 
has also prepared a regulatory analysis (see ``Regulatory Analysis'') 
which identified alternatives for collecting the information for use by 
both licensees and the NRC, and evaluated the costs of each viable 
alternative. Based upon these factors, the Commission believes that the 
costs 

[[Page 5325]]
of the proposed rule's information collection and reporting 
requirements are justified in view of the potential safety significance 
and projected benefits of the information in NRC regulatory activities.

Submission of Comments in Electronic Format

    Commenters are encouraged to submit, in addition to the original 
paper copy, a copy of their comments in an electronic format on IBM PC 
DOS- compatible 3.5- or 5.25-inch, double-sided, diskettes. Data files 
should be provided in WordPerfect 5.0 or 5.1. ASCII code is also 
acceptable, or if formatted text is required, data files should be 
submitted in IBM Revisable Format Text Document Content Architecture 
(RFT/DCA) format.

Environmental Impact: Categorical Exclusion

    The proposed rule sets forth requirements for the collection, 
maintenance, and reporting of reliability and availability data for 
certain risk-significant systems and equipment. The NRC has determined 
that this proposed rule is the type of action described in categorical 
exclusion, 10 CFR 51.22(c)(3)(ii). Therefore, neither an environmental 
impact statement nor an environmental assessment has been prepared for 
this proposed regulation.

Paperwork Reduction Act Statement

    This proposed rule amends information collection requirements that 
are subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et 
seq.). This rule has been submitted to OMB for review and approval of 
the Paperwork Reduction Act requirements.
    The public reporting burden for this collection of information is 
estimated to average 1375 hours per response (i.e., per commercial 
nuclear power reactor per year), including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information. The Commission is seeking public comment on 
the potential impact of the collection of information contained in the 
proposed rule and on the following issues:
    1. Is the proposed collection of information necessary for the 
proper performance of the functions of the NRC, and does the 
information have practical utility?
    2. Is the estimate of burden accurate?
    3. Is there a way to enhance the quality, utility, and clarity of 
the information to be collected?
    4. How can the burden of the collection of information be minimized 
including by using automated collection techniques?
    Send comments on any aspect of this proposed collection of 
information, including suggestions for reducing the burden, to the 
Information and Records Management Branch (T-6-F33), U.S. Nuclear 
Regulatory Commission, Washington, DC 20555-0001, and to the Desk 
Officer, Office of Information and Regulatory Affairs, NEOB-10202, 
(3150-0011), Office of Management and Budget, Washington, DC 20503.
    Comments to OMB on the collections of information or on the above 
issues should be submitted by March 13, 1996. Comments received after 
this date will be considered if it is practical to do so, but assurance 
of consideration cannot be given to comments received after this date.

Public Protection Notification

    The NRC may not conduct or sponsor, and a person is not required to 
respond to, a collection of information unless it displays a currently 
valid OMB control number.

Regulatory Analysis

    The Commission has prepared a draft regulatory analysis on this 
proposed regulation. The analysis examines the costs and benefits of 
the alternatives considered by the Commission. The draft analysis is 
available for inspection in the NRC Public Document Room, 2120 L Street 
NW. (Lower Level), Washington, DC. Single copies of the draft analysis 
may be obtained from: Dennis Allison, Office for Analysis and 
Evaluation of Operational Data, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555-0001, Telephone (301) 415-6835.

Regulatory Flexibility Certification

    In accordance with the Regulatory Flexibility Act of 1980 (5 U.S.C. 
605 (B)), the Commission certifies that this rule will not, if 
promulgated, have a significant economic impact on a substantial number 
of small entities. The proposed rule affects only the licensing and 
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 on April 11, 1995 (60 FR 18344--10 CFR 2.810.

Backfit Analysis

    The proposed rule sets forth requirements for reporting and record 
keeping. The NRC has determined that the backfit rule, 10 CFR 50.109, 
does not apply to this proposed rule, and therefore, a backfit analysis 
is not required for this proposed rule because these amendments do not 
involve any provisions which would impose backfits as defined in 10 CFR 
50.109(a)(1).
    However, as discussed above in ``Regulatory Analysis,'' the 
Commission has prepared a regulatory analysis which summarizes the 
purpose and intended use of the information proposed to be collected, 
identifies alternatives for collection and reporting of the proposed 
information, and identifies the impacts and benefits of the 
alternatives.
    This regulatory analysis constitutes a disciplined process for 
evaluating the potential benefits and projected impacts (burdens) of 
information collection and reporting requirements such as the proposed 
rule. The Commission therefore concludes that the objective underlying 
the Commission's adoption of the Backfit Rule--that regulatory impacts 
are assessed under established criteria in a disciplined process--is 
being met for this proposed rule.

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 
record keeping 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: Sections 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. 1244, 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 as amended by Pub. L. 102-486, sec. 2902, 106 Stat 3123, (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, and 
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, 

[[Page 5326]]
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. Section 50.8(b) is revised to read as follows:


Sec. 50.8  Information collection requirements: OMB approval.

* * * * *
    (b) The approved information collection requirements contained in 
this part appear in Secs. 50.30, 50.33, 50.33a, 50.34, 50.34a, 50.35, 
50.36, 50.36a, 50.48, 50.49, 50.54, 50.55, 50.55a, 50.59, 50.60, 50.61, 
50.63, 50.64, 50.65, 50.71, 50.72, 50.75, 50.76, 50.80, 50.82, 50.90, 
50.91, 50.120, and Appendices A, B, E, G, H, I, J, K, M, N, O, Q, and 
R.
* * * * *
    3. Section 50.76 is added to read as follows:


Sec. 50.76  Reporting reliability and availability information for 
risk-significant systems and equipment.

    (a) Applicability. This section applies to all holders of operating 
licenses for commercial nuclear power plants under 10 CFR 50.21b or 
50.22 and all holders of combined operating licenses for commercial 
nuclear power plants under 10 CFR 52.97.
    (b) Requirements. (1) Each licensee shall submit an annual report 
to the NRC that contains the following information, compiled on the 
basis of calendar quarters, or on a more frequent basis at the option 
of each licensee, for systems, trains, and ensembles of components in 
paragraph (b)(3) of this section:
    (i) The number of demands, the number of failures to start 
associated with such demands, and the dates of such failures, 
characterized according to the identification of the train affected, 
the type of demand (test, inadvertent/spurious, or actual need), and 
the plant mode at the time of the demand (operating or shutdown);
    (ii) The number of hours of operation following each successful 
start, characterized according to the identification of the train 
affected and whether or not the operation was terminated because of 
equipment failure, with the dates of any such failures;
    (iii) The number of hours equipment is unavailable, characterized 
according to the identification of the train affected, the plant mode 
at the time equipment is unavailable (operating or shutdown), 
characterization of the unavailable period (planned, unplanned, or 
support system unavailable), and, if due to a support system being 
unavailable, identification of the support system;
    (iv) For each period equipment is unavailable due to component 
failure(s), a failure record identifying the component(s) and providing 
the failure date, duration, mode, cause, and effect; and
    (v) The number of hours when two or more trains from the same or 
different systems were concurrently unavailable, characterized 
according to the identification of the trains that were unavailable.
    (2) The initial annual report described in (b)(1) above shall 
identify the systems, trains, and ensembles of components covered by 
paragraph (b)(3) below; subsequent annual reports shall either state 
that no changes were made subsequent to the previous annual report or 
describe any changes made.
    (3) The requirements of paragraphs (b)(1) and (b)(2) of this 
section apply to those event-mitigation systems, and ensembles of 
components treated as single entities in certain probabilistic risk 
assessments where a system or train treatment would not be appropriate, 
which have or could have a significant effect on risk in terms of 
avoiding core damage accidents or preserving containment integrity.
    (4) Each licensee shall maintain records and documentation of each 
occurrence of a demand, failure, or unavailable period that provide the 
basis for the data reported in paragraph (b)(1) of this section on site 
and available for NRC inspection for a period of 5 years after the date 
of the report specified in paragraph (b)(1) of this section.
    (c) Implementation. Licensees shall begin collecting the 
information required by paragraph (b) of this section on January 1, 
1997, and shall submit the first report required by paragraph (b)(1) of 
this section by January 31, 1998. Thereafter, each annual report 
required by paragraph (b)(1) of this section shall be submitted by 
January 31 of the following year.

    Dated at Rockville, MD, this 2nd day of February, 1996.

    For the Nuclear Regulatory Commission.
John C. Hoyle,
Secretary of the Commission.
[FR Doc. 96-2698 Filed 2-9-96; 8:45 am]
BILLING CODE 7590-01-P