[Federal Register Volume 87, Number 61 (Wednesday, March 30, 2022)]
[Notices]
[Pages 18400-18402]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-06619]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. STN 50-528, STN 50-529, and STN 50-530; NRC-2022-0058]
Arizona Public Service Company; Palo Verde Nuclear Generating
Station, Units 1, 2, and 3
AGENCY: Nuclear Regulatory Commission.
ACTION: Exemption; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an
exemption in response to a January 14, 2022, request from Arizona
Public Service Company (the licensee), as supplemented by letter dated
February 22, 2022. The licensee requested an exemption from NRC
regulations to remove the diverse auxiliary feedwater actuation system
using the risk-informed process for evaluations for Palo Verde Nuclear
Generating Station, Units 1, 2, and 3.
DATES: The exemption was issued on March 23, 2022.
ADDRESSES: Please refer to Docket ID NRC-2022-0058 when contacting the
NRC about the availability of information regarding this document. You
may obtain publicly available information related to this document
using any of the following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2022-0058. Address
questions about Docket IDs in Regulations.gov to Stacy Schumann;
telephone: 301-415-0624; 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 https://www.nrc.gov/reading-rm/adams.html. To begin the search, 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 request for the exemption was
submitted by letter dated January 14, 2022, as supplemented by letter
dated February 22, 2022, and are available in ADAMS under Accession
Nos. ML22014A415 and ML22053A212, respectively.
NRC's PDR: You may examine and purchase copies of public
documents, by appointment, at the NRC's PDR, Room P1 B35, One White
Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. To make
an appointment to visit the PDR, please send an email to
[email protected] or call 1-800-397-4209 or 301-415-4737, between
8:00 a.m. and 4:00 p.m. (ET), Monday through Friday, except Federal
holidays.
FOR FURTHER INFORMATION CONTACT: Siva P. Lingam, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-1564, email: [email protected].
SUPPLEMENTARY INFORMATION: The text of the exemption is attached.
Dated: March 24, 2022.
[[Page 18401]]
For the Nuclear Regulatory Commission.
Siva P. Lingam,
Project Manager, Plant Licensing Branch IV, Division of Operating
Reactor Licensing, Office of Nuclear Reactor Regulation.
Attachment: Exemption
NUCLEAR REGULATORY COMMISSION
Docket Nos. STN 50-528, STN 50-529, and STN 50-530
Arizona Public Service Company, Palo Verde Nuclear Generating Station,
Units 1, 2, and 3 Exemption
I. Background
Arizona Public Service Company (APS, the licensee) is the holder of
Renewed Facility Operating License Nos. NPF-41, NPF-51, and NPF-74,
which authorize operation of Palo Verde Nuclear Generating Station,
Units 1, 2, and 3 (Palo Verde), respectively. The licenses provide,
among other things, that the facility is subject to all rules,
regulations, and orders of the U.S. Nuclear Regulatory Commission (NRC)
now or hereafter in effect. The facility consists of pressurized-water
reactors (PWRs) located in Maricopa County, Arizona.
II. Request/Action
By application dated January 14, 2022, as supplemented by letter
dated February 22, 2022 (Agencywide Documents Access and Management
System (ADAMS) Accession Nos. ML22014A415 and ML22053A212,
respectively), APS, pursuant to Title 10 of the Code of Federal
Regulations (10 CFR) Section 50.12, ``Specific exemptions,'' requested
an exemption from certain requirements of 10 CFR 50.62, ``Requirements
for reduction of risk from anticipated transients without scram (ATWS)
events for light-water-cooled nuclear power plants,'' for Palo Verde.
Specifically, the proposed exemption request would permit Palo Verde
Units 1, 2, and 3 to eliminate the specific requirement of 10 CFR
50.62(c)(1) to provide equipment that is diverse from the reactor trip
system to automatically initiate the auxiliary (or emergency) feedwater
system under conditions indicative of an ATWS. The Palo Verde diverse
auxiliary feedwater actuation system (DAFAS) fulfills this requirement
in 10 CFR 50.62(c)(1), and APS has requested approval to allow
elimination of DAFAS from the current licensing basis for Units 1, 2,
and 3 consistent with the proposed exemption. Palo Verde will continue
to comply with the additional requirement in 10 CFR 50.62(c)(1) to
provide a diverse turbine trip under ATWS conditions.
III. Discussion
The regulation in 10 CFR 50.62(c)(1) states:
Each pressurized water reactor must have equipment from sensor
output to final actuation device, that is diverse from the reactor
trip system, to automatically initiate the auxiliary (or emergency)
feedwater system and initiate a turbine trip under conditions
indicative of an ATWS. This equipment must be designed to perform
its function in a reliable manner and be independent (from sensor
output to the final actuation device) from the existing reactor trip
system.
The regulation in 10 CFR 50.62(c)(1) specifically includes the
requirement to provide equipment that is diverse from the reactor trip
system to automatically initiate the auxiliary (or emergency) feedwater
system under the conditions of an ATWS. The Palo Verde DAFAS fulfills
this requirement. Therefore, the proposed removal of the DAFAS from the
Palo Verde licensing basis requires an exemption from this section of
the regulations.
Pursuant to 10 CFR 50.12, the NRC may, upon application by any
interested person or upon its own initiative, grant exemptions from
requirements of 10 CFR part 50 when: (1) The exemptions are authorized
by law, will not present an undue risk to the public health and safety,
and are consistent with the common defense and security, and (2)
special circumstances, as defined in 10 CFR 50.12(a)(2), are present.
The licensee's submittal identifies in particular that the special
circumstance associated with this exemption request is that continuing
to maintain the DAFAS in the licensing basis for Palo Verde Units 1, 2,
and 3 represents an undue hardship in accordance with 10 CFR
50.12(a)(2)(iii) due to DAFAS' obsolescence.
A. The Exemption Is Authorized by Law
The NRC has the authority under 10 CFR 50.12 to grant exemptions
from the requirements of 10 CFR part 50 upon demonstration of proper
justification. The licensee has requested a partial exemption to the
requirement in 10 CFR 50.62(c)(1) to provide equipment to automatically
initiate the auxiliary (or emergency) feedwater system under ATWS
conditions that is diverse from the reactor trip system. The licensee
will continue to meet all other requirements in 10 CFR 50.62(c)(1). As
discussed below, the NRC staff determined that special circumstances
exist, which support granting the proposed exemption. Furthermore,
granting the exemption would not result in a violation of the Atomic
Energy Act of 1954, as amended, or the NRC's regulations. Therefore,
the exemption is authorized by law.
B. The Exemption Presents No Undue Risk to Public Health and Safety
The NRC staff has concluded in the safety evaluation associated
with this exemption under ADAMS Accession No. ML22054A005 (Enclosure 2)
that the exemption represents low risk, is of minimal safety impact,
and that adequate defense-in-depth and safety margins are preserved.
DAFAS is not credited in the Palo Verde UFSAR Chapters 6 and 15
accident analyses for actuating AFS to remove residual heat. AFAS is
the credited means for initiating AFS in the UFSAR analyses as well as
in the Palo Verde PRA model and will be unaffected by the proposed
removal of DAFAS. In addition, the NRC staff has concluded that it is
acceptable for the licensee to credit existing operator manual actions
within the emergency operating procedures to initiate AFS under ATWS
conditions as defense-in-depth in support of the requested exemption.
Thus, granting this exemption request will not pose undue risk to
public health and safety.
C. The Exemption Is Consistent With the Common Defense and Security
The proposed exemption will allow the removal of DAFAS from the
licensing basis for Palo Verde Units 1, 2, and 3 as a diverse automatic
actuation of AFS under ATWS conditions satisfying partial requirements
of 10 CFR 50.62(c)(1). The NRC staff has reviewed the exemption request
in the SE associated with this exemption. The NRC concluded in the
associated SE that the licensee's submittal demonstrates that the
reactor protection system, the engineered safety features actuation
system (ESFAS) and AFAS, and the supplemental protection system (SPS)
are designed and maintained with high reliability to preclude ATWS
conditions and are monitored under 10 CFR 50.65, ``Requirements for
monitoring the effectiveness of maintenance at nuclear power plants.''
The NRC staff also concluded that adequate defense-in-depth and safety
margins will be preserved with the removal of DAFAS from the licensing
basis for Palo Verde Units 1, 2, and 3. The licensee will continue to
meet all other requirements in 10 CFR 50.62(c)(1). Further, the
exemption does not involve security requirements and does not create a
security risk. Therefore, the exemption is consistent with the common
defense and security.
[[Page 18402]]
D. Special Circumstances
The licensee has asserted that continuing to maintain DAFAS in the
plant licensing basis represents an undue hardship in accordance with
10 CFR 50.12(a)(2)(iii) due to its obsolescence. DAFAS is no longer
supported by the vendor and spare parts are not readily available for
the system. Significant engineering resources are required to reverse-
engineer parts and frequent fiber optic communications problems often
affect DAFAS system reliability. DAFAS operates on a vendor-supplied
proprietary platform that is unique to Palo Verde. The vendor is no
longer in business and Palo Verde can no longer obtain the Modicon
programmable logic controllers, displays and associated equipment to
maintain DAFAS. Since these replacement parts can no longer be obtained
through generally available sources, the licensee has established that
maintaining or replacing DAFAS in the given circumstances is a
hardship. Furthermore, the Statement of Considerations associated with
10 CFR 50.62(c)(1) (49 FR 26038, dated June 26, 1984) state that the
installation of diverse equipment to trip the turbine and initiate
auxiliary feedwater have only a marginally favorable value/impact for
Combustion Engineering plants such as Palo Verde. The NRC staff has
concluded that the licensee has demonstrated that removal of DAFAS from
the Palo Verde licensing basis represents low risk and only a minimal
safety impact. Therefore, the maintaining or replacing of DAFAS in the
given circumstances is an undue hardship on the licensee. For these
reasons, granting an exemption to allow removal of DAFAS from the Palo
Verde licensing basis supports the claimed special circumstance of
undue hardship.
E. Supplemental Information
For more technical details, refer to the SE associated with this
exemption under ADAMS Accession No. ML22054A005 (Enclosure 2).
F. Environmental Considerations
The NRC staff determined in the associated SE that the exemption
discussed herein meets the eligibility criteria for the categorical
exclusion set forth in 10 CFR 51.22(c)(9) because the granting of this
exemption involves: (i) No significant hazards consideration, (ii) no
significant change in the types or a significant increase in the
amounts of any effluents that may be released offsite, and (iii) no
significant increase in individual or cumulative occupational radiation
exposure. Therefore, in accordance with 10 CFR 51.22(b), no
environmental impact statement or environmental assessment need be
prepared in connection with the NRC's consideration of this exemption
request.
IV. Conclusions
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12, the exemption is authorized by law, will not present an undue
risk to the public health and safety, and is consistent with the common
defense and security. Also, special circumstances are present.
Therefore, the Commission hereby grants APS an exemption from the
specific requirement of 10 CFR 50.62(c)(1) to provide equipment that is
diverse from the reactor trip system to automatically initiate the
auxiliary (or emergency) feedwater system under conditions indicative
of an ATWS. As stated above, APS will continue to meet all other
requirements of 10 CFR 50.62(c)(1) at Palo Verde Units 1, 2, and 3.
Dated at Rockville, Maryland, this 23rd day of March 2022.
For the Nuclear Regulatory Commission.
/RA/
Gregory F. Suber,
Deputy Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. 2022-06619 Filed 3-29-22; 8:45 am]
BILLING CODE 7590-01-P