[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