81 FR 11681 - Environmental Qualification of Electrical Equipment

NUCLEAR REGULATORY COMMISSION

Federal Register Volume 81, Issue 44 (March 7, 2016)

The U.S. Nuclear Regulatory Commission (NRC) is denying a petition for rulemaking (PRM) submitted by the Natural Resources Defense Council, Inc. (NRDC), and Mr. Paul M. Blanch (collectively, the petitioners) on June 18, 2012. The petitioners requested that the NRC amend its regulations to clearly and unequivocally require the environmental qualification of all safety-related cables, wires, splices, connections and other ancillary electrical equipment that may be subjected to submergence and/or moisture intrusion during normal operating conditions, severe weather, seasonal flooding, and seismic events, and post-accident conditions, both inside and outside of a reactor's containment building. The NRC is denying this petition because the current regulations already address environmental qualification in both mild and design basis event conditions of electrical equipment located both inside and outside of the containment building that is important to safety, and the petition does not provide significant new or previously unconsidered information sufficient to justify rulemaking.

[Federal Register Volume 81, Number 44 (Monday, March 7, 2016)]
[Proposed Rules]
[Pages 11681-11686]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2016-05028]


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NUCLEAR REGULATORY COMMISSION

10 CFR Parts 50, 52, 54, and 100

[Docket Nos. PRM-50-106; NRC-2012-0177]


Environmental Qualification of Electrical Equipment

AGENCY: Nuclear Regulatory Commission.

ACTION: Petition for rulemaking; denial.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is denying a 
petition for rulemaking (PRM) submitted by the Natural Resources 
Defense Council, Inc. (NRDC), and Mr. Paul M. Blanch (collectively, the 
petitioners) on June 18, 2012. The petitioners requested that the NRC 
amend its regulations to clearly and unequivocally require the 
environmental qualification of all safety-related cables, wires, 
splices, connections and other ancillary electrical equipment that may 
be subjected to submergence and/or moisture intrusion during normal 
operating conditions, severe weather, seasonal flooding, and seismic 
events, and post-accident conditions, both inside and outside of a 
reactor's containment building. The NRC is denying this petition 
because the current regulations already address environmental 
qualification in both mild and design basis event conditions of 
electrical equipment located both inside and outside of the containment 
building that is important to safety, and the petition does not provide 
significant new or previously unconsidered information sufficient to 
justify rulemaking.

DATES: The docket for the petition for rulemaking, PRM-50-106, is 
closed on March 7, 2016.

[[Page 11682]]


ADDRESSES: Please refer to Docket ID NRC-2012-0177 when contacting the 
NRC about the availability of information regarding this petition. You 
may obtain publicly-available information related to the petition by 
using any of the following methods:
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2012-0177. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: [email protected]. For technical questions, contact 
the individual listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and 
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS, 
please contact the NRC's Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to [email protected]. The 
ADAMS accession number for each document referenced (if it is available 
in ADAMS) is provided the first time that it is mentioned in the 
SUPPLEMENTARY INFORMATION section.
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

FOR FURTHER INFORMATION CONTACT: Margaret Ellenson, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001, telephone: 301-415-0894; email: [email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. The Petition
II. NRC Analysis
III. Determination of Petition

I. The Petition

    On June 18, 2012, the NRC received a petition for rulemaking filed 
jointly by the NRDC and Mr. Paul Blanch (ADAMS Accession No. 
ML12177A377). The petitioners requested that the NRC amend its 
regulations in parts 50, 52, 54, and 100 of title 10 of the Code of 
Federal Regulations (10 CFR) to clearly and unequivocally require the 
environmental qualification of all safety-related cables, wires, 
splices, connections and other ancillary electrical equipment that may 
be subjected to submergence and/or moisture intrusion during normal 
operating conditions, severe weather, seasonal flooding, and seismic 
events, and post-accident conditions, both inside and outside of a 
reactor's containment building.
    The petition was docketed by the NRC on June 22, 2012, and was 
assigned Docket No. PRM-50-106. On September 27, 2012 (77 FR 59345), 
the NRC published a notice of receipt in the Federal Register. The NRC 
did not request public comment on PRM-50-106.

II. NRC Analysis

    The petitioners raised three issues in support of their request 
that the NRC amend the regulations related to environmental 
qualification of electrical equipment at nuclear power plants. The 
three issues and the NRC's responses to each issue are presented in 
this section.
    Issue 1: Through the issuance of Generic Letter (GL) 82-09, 
``Environmental Qualification of Safety-Related Electrical Equipment,'' 
dated April 20, 1982 (ADAMS Accession No. ML031080281), the NRC staff 
limited the scope of Sec.  50.49 based on the location of the 
electrical equipment.
    The petitioners stated that as a result of the accident at Three 
Mile Island, the NRC strengthened the regulatory requirements for 
electrical equipment by, among other things, revising Sec.  50.49(e) to 
add paragraph (6) to address the possibility of electrical equipment 
submergence. The petitioners asserted that Sec.  50.49(e)(6), as 
written, did not limit or restrict its applicability based upon the 
location of the equipment, but that the NRC staff limited this 
applicability through a question and answer (Q&A) set in GL 82-09:
    Q. For equipment qualification purposes, what are the staff 
requirements concerning submergence of equipment outside containment?
    A. The staff requires that the licensee submit documentation on the 
qualification of safety-related equipment that could be submerged due 
to a high energy line break outside containment.
    The petitioners asserted that the problem with this excerpt from GL 
82-09 is that safety-related cables and wires outside containment are 
routinely submerged in water not only during high energy line breaks 
(HELBs), but also during a reactor's normal operation. The petitioners 
argued that the 1979 Three Mile Island accident and laboratory testing 
have shown that moisture intrusion and submergence of electrical cables 
and wires significantly increase the probability of failure, which also 
causes the failure of connected components such as emergency core 
cooling system motors and pumps, valves, controls, and instrumentation. 
The petitioners asserted that the safety implications from the failure 
of a safety-related cable inside containment submerged by an accident, 
outside containment submerged by a high energy line break, or outside 
containment submerged by nature, are identical--the safety function is 
lost.
    NRC Response to Issue 1: The regulations at Sec.  50.49, 
``Environmental qualification of electric equipment important to safety 
for nuclear power plants,'' are applicable to electrical equipment 
located outside containment as well as inside. The January 21, 1983, 
Federal Register notice of the final Sec.  50.49 rule (48 FR 2730) made 
this clear by noting that nuclear power plant equipment important to 
safety must be able to perform its safety functions throughout its 
installed life, and that this requirement applies to equipment inside 
as well as outside containment. (See 48 FR 2731.) The Q&A referenced by 
the petitioners is itself premised on the applicability of Sec.  50.49 
to important to safety electrical equipment outside of containment. 
Regardless of its location inside or outside containment, if any 
important to safety electrical equipment is near enough to a high 
energy line (e.g., steam line, feedwater, blow-down, charging, or 
letdown lines) that the equipment's performance could be adversely 
affected by a rupture of that line, Sec.  50.49 requires that the 
equipment be qualified to withstand any environmental conditions that 
may result from such an event. Section 50.49 was established to impose 
additional requirements beyond those established by Sec.  50.65, 
``Requirements for monitoring the effectiveness of maintenance at 
nuclear power plants;'' 10 CFR part 50, appendix A, ``General Design 
Criteria [GDC] For Nuclear Power Plants;'' \1\ and 10 CFR part 50, 
appendix B, ``Quality Assurance Criteria for Nuclear Power Plants and 
Fuel Processing Plants.'' The additional requirements in Sec.  50.49 
apply to important to safety electrical equipment that could be subject 
to postulated design basis events (DBEs) that could affect: (1) The 
integrity of the reactor coolant pressure boundary; (2) the capability 
to shut the reactor down safely and keep it safe; or (3) the capability 
to prevent or mitigate accidents that could result in potential

[[Page 11683]]

offsite exposures comparable to NRC emergency planning guidelines. As 
the cited GL 82-09 Q&A indicates, a HELB was the most probable such DBE 
involving submergence outside of containment for which the NRC staff 
believed that a power reactor's important to safety electrical 
equipment must be environmentally qualified.
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    \1\ The GDC pertains to water cooled nuclear plants and 
establishes the minimum requirements for their principal design 
criteria (36 FR 3256; February 20, 1971, as amended).
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    The NRC agrees with the petitioners that safety-related cables and 
other electrical equipment must be fully able to function, not only 
within an operating environment affected by a HELB under Sec.  50.49, 
but also over the entire length of its system, even those portions not 
exposed to a HELB. Criterion 18 of 10 CFR part 50, appendix A, requires 
that electric power systems important to safety be designed so that 
important areas and features permit appropriate periodic inspection and 
testing. Example areas and features specified are the following: 
wiring, insulation, connections, and switchboards. Criterion 18 also 
requires the systems to be designed with a capability to test 
periodically the operability and functional performance of the 
components of the systems and the operability of the system as a whole.
    As the petitioners rightly point out, designing the entirety of an 
electrical safety system for inspectability and testability is 
essential because ``[i]t matters little if the portion of a safety-
related cable inside [or] outside containment in a high energy line 
break area survive[s] if another portion of that same cable routed 
underground fails due to submergence.'' It is also important to note 
that the NRC's design and qualification requirements for underground or 
inaccessible wires, cables, and ancillary equipment are inspected and 
enforced. The NRC's inspection procedures direct that inspections of 
electrical equipment at risk of flooding or exposure to moisture be 
conducted annually.
    The NRC disagrees with the petitioners' assertion that GL 82-09 has 
restricted the applicability of Sec.  50.49 regulatory requirements for 
safety-related equipment according to its location. Generic letters do 
not have the legal authority of a final rule promulgated after due 
public notice and comment, as was Sec.  50.49. The Q&A in GL 82-09 does 
not exempt any safety-related equipment that could be submerged, inside 
or outside containment, from the environmental qualifications (EQ) 
requirements of Sec.  50.49. The purpose of the GL 82-09 Q&A cited by 
the petitioners was simply to clarify that under Sec.  50.49, licensees 
must submit information on the EQ of important to safety equipment that 
could be submerged due to a high energy line break outside containment. 
The applicability of Sec.  50.49 is not limited to a HELB, although 
after more than 30 years of operating experience and risk analysis, a 
HELB remains the most probable DBE involving submergence outside 
containment that meets the Sec.  50.49 criteria for the subset of DBEs 
that could result in a severe accident. The clarifying Q&A was 
important because the GL was providing information in the event of a 
HELB, not describing the entire universe of postulated DBEs to which 
Sec.  50.49 could apply.
    Issue 2: Safety-related cable subject to submergence, condensation, 
or moisture located in a ``mild environment'' should not be exempted 
from the environmental qualification requirements of Sec.  50.49.
    The petitioners argued that rulemaking is necessary to ensure that 
electrical cables and wires will be properly qualified for 
environmental conditions they may experience during normal operation 
(i.e., a mild environment) as well as in an accident. The petitioners 
claimed the need for rulemaking and clarification of Sec.  50.49 to 
address cables that may be exposed to non-mild environments during 
normal, abnormal, and accident conditions. The petitioners noted that 
electrical cables and wires ``are prone to accelerated failure rates 
when submerged in water or exposed to high humidity unless designed and 
qualified for these environmental conditions.'' The petitioners stated 
that the NRC prioritized the inspection of cable penetrations after the 
1979 Three Mile Island accident based on the probability of their 
impairment, mostly due to submergence and moisture. The petitioners 
argued that ``[i]f these conditions cause a high probability of 
impairment following an accident, then it is logical to assume that 
these conditions produce a similar outcome in the absence of or prior 
to an accident as well.'' In support of their case for a rulemaking to 
address this impairment, the petitioners also referenced a 1996 study 
by the U.S. Department of Energy (DOE) (ADAMS Accession No. 
ML031140264) and three studies by the Electric Power Research Institute 
(EPRI), ``Plant Support Engineering: Life Cycle Management Planning 
Sourcebooks: Medium-Voltage (MV) Cables and Accessories (Terminations 
and Splices),'' EPRI Product ID: 1013187; ``Plant Support Engineering: 
Aging Management Program Development Guidance for AC and DC Low-Voltage 
Power Cable Systems for Nuclear Power Plants,'' EPRI Product ID: 
1020804; and ``Plant Support Engineering: Aging Management Program 
Guidance for Medium-Voltage Cable Systems for Nuclear Power Plants,'' 
EPRI Product ID: 1020805. The EPRI documents are available for download 
from www.EPRI.com.
    Also in support of their request for rulemaking to extend Sec.  
50.49 requirements to electrical equipment in mild environments, the 
petitioners contended that the NRC's requirements state only that 
safety systems should remain functional and do not provide conditions 
or acceptance criteria for degraded cables.
    NRC Response to Issue 2: The NRC agrees that Sec.  50.49 does not 
apply to reactor cables and electrical equipment exposed to mild 
environments. This section of the rule applies EQ requirements only to 
important to safety cables and electrical equipment that may be exposed 
to non-mild environments during accident conditions. The purpose of the 
final Sec.  50.49 rule (48 FR 2730; January 21, 1983) was to codify 
accepted industry standards and NRC guidance for the EQ of safety-
related electrical equipment, and non-safety-related equipment relied 
on by safety-related equipment, that must perform a safety function 
under DBE conditions.
    The NRC disagrees with the petitioners' assertion that Sec.  50.49 
should be amended to extend EQ requirements to important to safety 
cables and electrical equipment exposed to submergence or moisture 
intrusion in mild environments. The existing rule specifically exempts 
from these requirements equipment exposed only to a ``mild 
environment,'' which is defined in Sec.  50.49(c) as an environment 
that would at no time be significantly more severe than the environment 
that would occur during normal plant operation, including anticipated 
operational occurrences.
    All important to safety equipment whether in mild or non-mild 
environments is subject to the requirements for monitoring the 
effectiveness of maintanence under the maintenance rule (Sec.  50.65). 
Furthermore, all important to safety equipment at plants with 
construction permits issued after May 21, 1971, is also subject to the 
design and quality requirements in 10 CFR part 50, appendix A. In 
addition to the above requirements, all safety-related equipment is 
also subject to the quality assurance requirements of 10 CFR part 50, 
appendix B. Therefore, equipment in mild environments exposed to 
submergence, condensation, and moisture intrusion, the kind of

[[Page 11684]]

degradation of concern to the petitioners, is subject to several 
existing requirements. For important to safety equipment that could be 
subject to environmental conditions that may result as a consequence of 
a DBE, Sec.  50.49 establishes additional requirements beyond those 
stipulated in Sec.  50.65; 10 CFR part 50, appendix A; and 10 CFR part 
50, appendix B.
    The maintenance rule (Sec.  50.65) establishes requirements for 
monitoring the effectiveness of maintenance at nuclear power plants. 
Under Sec.  50.65(a)(1), licensees are required to monitor the 
condition or performance of structures, systems, or components (SSCs) 
in a manner providing reasonable assurance that the intended SSC 
functions can be fulfilled. Section 50.65(b) describes the types of 
SSCs subject to its requirements. The maintenance rule (Sec.  50.65) 
applies to safety and non-safety SSCs that includes the following: SSCs 
used in the plant's emergency operating procedures or relied upon to 
mitigate accidents or transient unsafe conditions; SSCs whose failure 
could prevent safety-related SSCs from fulfilling their safety-related 
function; or SSCs whose failure could cause a reactor scram (unplanned 
action to stop the fission reaction) or the actuation of a safety-
related system. With this scope, the maintenance rule (Sec.  50.65) 
already covers the equipment specified in the petition (i.e., all 
safety-related cables, wires, splices, connections, and other ancillary 
electrical equipment that may be subjected to submergence and/or 
moisture intrusion). Section 50.65 covers this equipment under any 
normal or unusual operating or post-accident conditions, whether these 
conditions include severe weather, seasonal flooding, or seismic 
events, or whether the SSCs are inside or outside of containment. The 
rule also covers the petitioners' specified systems and components 
whether or not they are exposed to submergence in water, condensation, 
wetting, and other environmental stresses during routine operation and 
infrequent events (e.g., flooding).
    In its April 2012 Regulatory Guide (RG) 1.218, ``Condition-
Monitoring Techniques for Electric Cables Used In Nuclear Power 
Plants'' (ADAMS Accession No. ML103510447), the NRC described a 
programmatic approach and acceptable techniques for monitoring the 
condition of electric cable systems and their operating environments. 
As authority for this guidance, RG 1.218 cited 10 CFR part 50, 
Criterion XI, ``Test Control,'' of appendix B. Criterion XI specifies 
that power reactor licensees must have a program to assure that all 
testing required to show that SSCs will perform satisfactorily in 
service is identified and performed.
    The test program must include, as appropriate, operational tests of 
SSCs during nuclear power plant operation. Test procedures must include 
provisions for assuring that all prerequisites for the given test have 
been met, that adequate test instrumentation is available and used, and 
that the test is performed under suitable environmental conditions. 
Test results under Criterion XI must also be ``documented and 
evaluated'' to ensure that this Criterion's requirements have been 
satisfied. It is important to note that Criterion XI is only one of 18 
criteria that are applicable to a quality assurance program for the 
electrical equipment at issue in this petition. Appendix B criteria 
establish quality assurance requirements for the design, manufacture, 
construction, and operation of all safety-related equipment, and all 
activities affecting its functions, including not only testing, but 
designing, purchasing, fabricating, handling, shipping, storing, 
cleaning, installing, inspecting, operating, maintaining, repairing, 
and modifying this equipment. Criterion XVI, ``Corrective Action,'' 
also requires licensees to have measures assuring that conditions 
adverse to quality are promptly identified and corrected. Examples of 
such conditions are the following: failures, malfunctions, 
deficiencies, deviations, defective material and equipment, and 
nonconformances. For significant conditions adverse to quality, 
including the potential failure of electrical equipment to function as 
designed, licensees must determine the cause of the condition and 
``assure'' that corrective action is taken to preclude a repetition of 
the adverse condition. The identified condition, its cause, and the 
corrective action taken to prevent its recurrence must also be 
documented and the appropriate levels of management informed. In 
addition, for important to safety cables and electrical equipment 
located in an area meeting the definition of a mild environment in 
Sec.  50.49, 10 CFR part 50, appendix A, GDC 4 requires that this 
equipment be designed to manage the conditions it will experience 
during normal operation, maintenance, testing, and postulated 
accidents.
    The NRC does not agree that its existing regulations do not require 
sufficient protection of important to safety electrical equipment 
against expected or potential environmental conditions it experiences 
during its period of service. Regardless of whether a cable, switch, or 
other piece of electrical equipment must be environmentally qualified 
under Sec.  50.49, it must meet maintenance, design, and quality 
assurance requirements established by Sec.  50.65; 10 CFR part 50, 
appendix A; and 10 CFR part 50, appendix B (for safety-related 
equipment), to provide adequate protection for public health and 
safety. And regardless of whether the equipment is environmentally 
qualified, it is subject to the same degree of NRC oversight in the 
form of inspections and enforcement. A rulemaking to require the 
environmental qualification of all electrical equipment exposed only to 
mild environments is, therefore, unnecessary.
    Moreover, the 1996 DOE study and three EPRI studies cited by the 
petitioners are well known to the NRC and do not constitute significant 
new information justifying a rulemaking. The NRC recognized the concern 
regarding the reliability of low-voltage power cable systems at 
reactors that the petitioner references and acted accordingly. Among 
other things, the NRC has revised its inspection procedures to ensure 
annual inspections of underground bunkers and manholes in a continuing 
repeated cycle beginning with those containing the most risk-
significant cables. The NRC also issued RG 1.218, describing a 
programmatic approach and acceptable techniques for monitoring the 
condition of electric cable systems and their operating environments.
    The NRC disagrees with the petitioners' contention that the NRC's 
requirements do not provide conditions or acceptance criteria for 
degraded cables. Any requirement for safety-related systems to remain 
functional for a specified operating life is a design requirement, and 
any failure of the equipment before the end of that operating life 
would be a violation of that design requirement. Therefore, taken 
together, GDC 2, 4, and 18 in 10 CFR part 50, appendix A, the 
maintenance requirements under Sec.  50.65, and the quality assurance 
testing requirements in 10 CFR part 50, appendix B, Criterion XI, 
effectively provide an enforceable acceptance criterion for the 
continued use of cables or any other electrical equipment degrading 
during normal operation. Criterion XI states that the measured rate of 
degradation must not impair the equipment's ability to function in an 
emergency, even if the emergency were to occur on the last day of the 
performance period specified in the equipment's design requirement.

[[Page 11685]]

    Guidance for the implementation of this criterion is provided in 
the August 25, 2009, NRC staff regulatory resolution issue protocol, 
``Cable Performance Issues at Nuclear Power Plants'' (ADAMS Accession 
No. ML092220419), which the petitioners cited as documentation of the 
NRC's requirements on cable and wire submergence issues. The NRC staff 
position in that protocol is: (1) Licensees should monitor cables 
within the scope of the maintenance rule (Sec.  50.65) at an 
appropriate frequency to demonstrate that they can perform their design 
functions when called upon; and (2) cables must be designed to fulfill 
their intended design function in the environment to which they are 
subject. Under the protocol, if cables have been exposed to conditions 
for which they are not designed or qualified, the licensee must 
demonstrate, through adequate testing or condition monitoring, that the 
cables can perform their intended design function for the duration of 
the qualified period specified in the license.
    The NRC also inspects underground cables through established 
inspection procedures. In particular, Inspection Procedure (IP) 
Attachment 71111.06, ``Flood Protection Measures'' (ADAMS Accession No. 
ML11244A012), specifically directs NRC inspectors to perform an annual 
review of cables located in underground bunkers or manholes. The IP 
Attachment directs inspectors to select bunkers or manholes subject to 
flooding that contain multiple train or multiple risk-significant 
cables, and inspect those that contain more risk-significant cables 
before inspecting those with less risk-significant cables. The IP notes 
that inspectors should rotate through the bunkers or manholes until all 
are inspected; and then the cycle should be recommenced. The IP 
Attachment also clarifies that these inspections may be in addition to 
those for the aging management programs of plants with renewed 
licenses. Where ``significant moisture'' is identified at such plants, 
inspectors are to verify that the licensee takes action to keep the 
cables dry and assess cable degradation in accordance with the 
licensee's aging management program.
    Issue 3: Although GDC 2 and 4 of the NRC's regulations require that 
cables be able to perform their design function when subjected to 
anticipated environmental conditions, the NRC does not apply these and 
other GDC to the 57 plants with construction permits issued before May 
21, 1971, the effective date of the GDC rule (36 FR 3256; February 20, 
1971).
    Citing the August 25, 2009, NRC staff regulatory issue resolution 
protocol, ``Cable Performance Issues at Nuclear Power Plants,'' the 
petitioners asserted that this statement defined the NRC's governing 
regulations on submerged cable performance as explicitly including GDC 
2 and GDC 4. The GDC 2 requires reactor SSCs that are important to 
safety be designed to withstand the effects of natural phenomena 
without loss of capability to perform their safety functions. The GDC 4 
requires that these SSCs be designed to accommodate the effects of and 
be compatible with the environmental conditions associated with normal 
operation, maintenance, testing, and postulated accidents.
    The petition stated that although these GDC may contain appropriate 
regulatory requirements for the qualification of electrical cables and 
wires, the NRC has determined that these requirements are not to be 
applied to the majority of reactors. The petitioners noted that, at the 
time the petition was submitted, at least 57 of the nation`s 104 
operating reactors had construction permits that were issued prior to 
the effective date of the GDC rule, and that the Commission, through 
guidance to the NRC staff, has determined that the GDC do not need to 
be applied to these 57 reactors.
    NRC Response to Issue 3: The NRC disagrees with the petitioners' 
suggestion that the 57 plants that received construction permits prior 
to May 21, 1971, are not operating safely with appropriately qualified 
important to safety equipment. In 1992, after more than 15 years of 
analysis, the NRC staff recommended that the Commission retain the 
current policy that no exemptions from or specific backfits for the GDC 
are required for plants with construction permits issued before that 
date. In its September 18, 1992, Staff Requirements Memorandum (SRM) 
(ADAMS Accession No. ML003763736), the Commission endorsed the NRC 
staff's recommendation not to apply the GDC to plants with construction 
permits issued prior to the effective date of the GDC rule. This 
recommendation was based on the documented results of the NRC staff's 
evaluations of representative designs of 10 of the 57 plants against 
the design requirements of a 1975 Standard Review Plan for reactor 
license applications based on the approved GDC.
    The SRM explained that at the time the GDC were promulgated, the 
Commission had stressed that they were not new requirements and were 
promulgated to articulate more clearly the licensing requirements and 
practice in effect at that time. The Commission stated that while 
compliance with the intent of the GDC is important, each plant licensed 
before the GDC were formally adopted was evaluated on a plant-specific 
basis, determined to be safe, and licensed by the NRC. Furthermore, the 
Commission determined that existing regulatory processes were 
sufficient to ensure that plants continue to be safe and comply with 
the intent of the GDC. As the petitioners also noted, the Commission 
went on to say that backfitting these 57 plants to meet the GDC would 
provide little or no safety benefit while requiring an extensive 
commitment of resources. The petitioners have not provided any 
significant, new, or previously unconsidered information to justify a 
new rulemaking or to reverse this NRC position.

III. Reasons for Denial

    The NRC is denying PRM-50-106 because:
    (1) The NRC disagrees with the petitioners' assertion that GL 82-09 
has restricted the applicability of Sec.  50.49 regulatory requirements 
for safety-related equipment according to its location. This regulation 
is applicable to electrical equipment located outside containment as 
well as inside.
    (2) Section 50.49 explicitly excludes important to safety 
electrical equipment subject only to mild environments. The petitioners 
have not provided significant new information sufficient to justify a 
change to this rule. A rulemaking to require the environmental 
qualification of all electrical equipment exposed only to mild 
environments is unnecessary because existing NRC regulations require 
sufficient protection of important to safety electrical equipment 
against expected or potential environmental conditions it experiences 
during its period of service.
    (3) With regard to the reactors that received construction permits 
prior to May 21, 1971, the Commission determined in response to SECY-
92-223, ``Resolution of Deviations Identified During the Systematic 
Evaluation Program'' (ADAMS Accession No. ML12256B290) that these 
plants are operating safely with appropriately qualified important to 
safety equipment, and that no specific backfits of the GDC to these 
plants were required. The petitioners have not provided any 
significant, new, or previously unconsidered information justifying a 
rulemaking to apply the GDC to the 57 reactors that received 
construction permits prior to May 21, 1971.

[[Page 11686]]

IV. Conclusion

    For the reasons cited in this document, the NRC is denying PRM-50-
106. The NRC is denying this petition because the current regulations 
already address environmental qualification in both mild and design 
basis event conditions of electrical equipment located both inside and 
outside of the containment building that is important to safety, and 
the petitioners did not provide significant new or previously 
unconsidered information sufficient to justify rulemaking.

    Dated at Rockville, Maryland, this 29th day of February, 2016.

    For the Nuclear Regulatory Commission.
Annette L. Vietti-Cook,
Secretary of the Commission.
[FR Doc. 2016-05028 Filed 3-4-16; 8:45 am]
 BILLING CODE 7590-01-P