[Federal Register Volume 72, Number 192 (Thursday, October 4, 2007)]
[Notices]
[Pages 56801-56802]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-19666]
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NUCLEAR REGULATORY COMMISSION
[Docket No. STN 50-456]
Exelon Generation Company, LLC; Braidwood Station, Unit 1;
Exemption
1.0 Background
Exelon Generation Company, LLC (Exelon, the licensee) is the holder
of Facility Operating License No. NPF-72, which authorizes operation of
Braidwood Station, Unit 1. The license provides, among other things,
that the facility is subject to all rules, regulations, and orders of
the Nuclear Regulatory Commission (NRC, the Commission) now or
hereafter in effect.
The facility consists of two pressurized-water reactors located in
Will County in Illinois.
2.0 Request/Action
Title 10 of the Code of Federal Regulations (10 CFR), Part 50,
section 50.46,
``Acceptance criteria for emergency core cooling systems for
light-water nuclear power reactors,'' requires, in part, ``that each
boiling or pressurized light-water nuclear power reactor fueled with
uranium oxide pellets within cylindrical Zircaloy or ZIRLO cladding
must be provided with an emergency core cooling system (ECCS) that
must be designed so that its calculated cooling performance
following postulated loss-of-coolant accidents conforms to the
criteria set forth in paragraph (b) of this section.'' 10 CFR Part
50, Appendix K, ``ECCS Evaluation Models,'' requires, among other
items, that the rate of energy release, hydrogen generation, and
cladding oxidation from the metal/water reaction shall be calculated
using the Baker-Just equation. 10 CFR 50.46 and 10 CFR Part 50,
Appendix K make no provisions for use of fuel rods clad in a
material other than Zircaloy or ZIRLO.
The Braidwood, Unit 1 core consists of a combination of
Westinghouse-designed VANTAGE 5 and VANTAGE+ fuel assemblies. Each
fuel assembly has 264 fuel rods arranged in a 17 by 17 array. The
licensee intends to insert up to eight fuel assemblies containing
AREVA NP Inc. (AREVA) modified Advanced Mark-BW(A) (Advanced Mark-
BW(A)) fuel. These assemblies will be placed in nonlimiting
locations of the core during Cycles 15, 16,
[[Page 56802]]
and 17. The Advanced Mark-BW(A) fuel assemblies are similar in
design to the Advanced Mark-BW fuel assemblies using the approved M5
alloy for the cladding, structural tubing, and grids. The Advanced
Mark-BW fuel design was approved in a topical report BAW-10239(P)-A,
entitled ``Advanced Mark-BW Fuel Assembly Mechanical Design Topical
Report'' (Advanced Mark-BW Topical Report).
The licensee requested an exemption from the requirements of 10
CFR 50.46 and 10 CFR Part 50, Appendix K to allow the use of fuel
rods clad with AREVA's M5 alloy. The M5 alloys are proprietary
alloys and chemically different from Zircaloy or ZIRLO fuel cladding
materials which are approved for use. Therefore, a plant specific
exemption from these regulations is required to support the use of
the eight Advanced Mark-BW(A) fuel assemblies for Braidwood Station,
Unit 1.
In summary, the licensee has requested an exemption from the
requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix K, to
allow the use of fuel assemblies containing Advanced Mark-BW(A) fuel
design.
3.0 Discussion
Pursuant to 10 CFR 50.12, the Commission may, upon application
by any interested person or upon its own initiative, grant
exemptions from the requirements of 10 CFR Part 50 when (1) The
exemptions are authorized by law, will not present an undue risk to
public health or safety, and are consistent with the common defense
and security; and (2) when special circumstances are present. These
circumstances include the special circumstances that application of
the regulation in 10 CFR 50.46 and 10 CFR Part 50, Appendix K is not
necessary to achieve the underlying purpose of the rule.
Authorized by Law
This exemption would allow the licensee to load fuel assemblies
containing Advanced Mark-BW(A) fuel at Braidwood Station, Unit 1. As
stated above, 10 CFR 50.12 allows the NRC to grant exemptions from
the requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix K. The
NRC staff has determined that granting of the licensee's proposed
exemption will not result in a violation of the Atomic Energy Act of
1954, as amended, or the Commission's regulations. Therefore, the
exemption is authorized by law.
No Undue Risk to Public Health and Safety
The underlying purposes of 10 CFR 50.45 is to establish
acceptance criteria for ECCS performance. Previously, the approved
Advanced Mark-BW Topical Report demonstrated the acceptability of
the M5 cladding under loss of coolant accident (LOCA) conditions.
The unique features of the proposed fuel assemblies were evaluated
for effects on the LOCA analysis. The results showed that the
assemblies would not adversely affect the ECCS performance. Since
the eight Advanced Mark-BW(A) fuel assemblies will be located at
non-limiting core locations, the NRC concludes that the LOCA safety
analyses will remain bounding for these assemblies at Braidwood
Station, Unit 1.
Paragraph I.A.5 of 10 CFR Part 50, Appendix K states that the
rates of energy, hydrogen concentration, and cladding oxidation from
the metal-water reaction shall be calculated using the Baker-Just
equation. Since the Baker-Just equation presumes the use of Zircaloy
clad fuel, strict application of the rule would not permit use of
the equation for the advanced zirconium-based and M5 alloys for
determining acceptable fuel performance. The underlying intent of
this portion of 10 CFR Part 50, Appendix K, however, is to ensure
that analysis of fuel response to LOCAs is conservatively
calculated. The approved Advanced Mark-BW Topical Report show that
due to the similarities in the chemical composition of the M5 alloys
and Zircaloy, the application of the Baker-Just equation in the
analysis of the M5 clad fuel rods will continue to conservatively
bound all post-LOCA scenarios. Thus, application of 10 CFR Part 50,
Appendix K, Paragraph I.A.5 is not necessary for the licensee to
achieve its underlying purpose in these circumstances.
Based on the above, no new accident precursors are created by
using the proposed Advanced Mark-BW(A) fuel assemblies at Braidwood
Station, Unit 1, thus, the probability of postulated accidents is
not increased. Also, based on the above, the consequences of
postulated accidents are not increased. Therefore, there is no undue
risk to public health and safety.
Consistent With Common Defense and Security
The proposed exemption would allow the use of Advanced Mark-
BW(A) fuel assemblies at Braidwood Station, Unit 1. This change to
the operation of the plant has no relation to security issues.
Therefore, the common defense and security is not impacted by this
exemption.
Special Circumstances
Special circumstances, in accordance with 10 CFR 50.12, are
present whenever application of the regulation in the particular
circumstances would not serve the underlying purpose of the rule, or
is not necessary to achieve the underlying purpose of the rule. The
underlying purpose of 10 CFR 50.46 is to establish acceptance
criteria for ECCS performance. Since the eight Advanced Mark-BW(A)
fuel assemblies will be located at non-limiting core locations, the
NRC concludes that the LOCA safety analyses will remain bounding for
these assemblies at Braidwood Station, Unit 1. The underlying
purpose of 10 CFR Part 50, Appendix K is to ensure that analysis of
fuel response to LOCAs is conservatively calculated. The approved
Advanced Mark-BW Topical Report show that due to the similarities in
the chemical composition of the M5 alloys and Zircaloy, the
application of the Baker-Just equation in the analysis of the M5
clad fuel rods will continue to conservatively bound all post-LOCA
scenarios. Thus, application of 10 CFR Part 50, Appendix K is not
necessary for the licensee to achieve its underlying purpose in
these circumstances. Therefore, since the underlying purpose of 10
CFR 50.46 and 10 CFR Part 50, Appendix K is achieved, the special
circumstances required by 10 CFR 50.12 for the granting of an
exemption from 10 CFR 50.46 and 10 CFR Part 50, Appendix K exist.
4.0 Conclusion
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 Exelon, an
exemption from the requirements of 10 CFR 50.46 ``that each boiling
or pressurized light-water nuclear power reactor fueled with uranium
oxide pellets within cylindrical Zircaloy or ZIRLO cladding must be
provided with an emergency core cooling system (ECCS) that must be
designed so that its calculated cooling performance following
postulated loss-of-coolant accidents conforms to the criteria set
forth in paragraph (b) of this section,'' and 10 CFR Part 50,
Appendix K that the rate of energy release, hydrogen generation, and
cladding oxidation from the metal/water reaction shall be calculated
using the Baker-Just equation for Braidwood Station, Unit 1.
Pursuant to 10 CFR 51.32, the Commission has determined that the
granting of this exemption will not have a significant effect on the
quality of the human environment (72 FR 52585). This exemption is
effective upon issuance.
Dated at Rockville, Maryland, this 27th day of September 2007.
For the Nuclear Regulatory Commission.
Tim McGinty,
Acting Director, Division of Operating Reactor Licensing, Office of
Nuclear Reactor Regulation.
[FR Doc. E7-19666 Filed 10-3-07; 8:45 am]
BILLING CODE 7590-01-P