[Federal Register Volume 70, Number 146 (Monday, August 1, 2005)]
[Notices]
[Pages 44122-44123]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-15125]


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NUCLEAR REGULATORY COMMISSION

[Docket No. 50-313]


Entergy Operations, Inc., Arkansas Nuclear One, Unit 1; Exemption

1.0 Background

    Entergy Operations, Inc. (licensee) is the holder of Renewed 
Facility Operating License No. DPR-51 which authorizes operation of the 
Arkansas Nuclear One, Unit 1 (ANO-1) nuclear power plant. The license 
provides, among other things, that the facility is subject to all 
rules, regulations, and orders of the Nuclear Regulatory Commission 
(NRC, Commission) now or hereafter in effect.
    The facility consists of a pressurized water reactor located in 
Pope County, Arkansas.

2.0 Request/Action

    Title 10 of the Code of Federal Regulations (10 CFR) 50.46, 
``Acceptance criteria for emergency core cooling systems for light-
water nuclear power reactors,'' requires, among other items, that 
``[e]ach 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 [(LOCAs)] conforms to 
the criteria set forth in paragraph (b) of this section.'' Appendix K 
to 10 CFR Part 50, ``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. The regulations at 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. Since the chemical composition 
of the M5 alloy differs from the specifications for zircaloy or ZIRLO, 
a plant-specific exemption is required to allow the use of the M5 alloy 
as a cladding material at ANO-1. Therefore, by letter dated September 
30, 2004, the licensee requested the use of the M5 advanced alloy for 
fuel rod cladding at ANO-1.

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.

Authorized by Law

    This exemption results in changes to the operation of the plant by 
allowing the use of the M5 alloy as fuel cladding material in lieu of 
zircaloy or ZIRLO. As stated above, 10 CFR 50.12 allows the NRC to 
grant exemptions from the requirements of 10 CFR part 50. In addition, 
the granting of the licensee's exemption request 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 50.46 and 10 CFR part 50, 
appendix K, are to ensure that facilities have adequate acceptance 
criteria for the ECCS, and to ensure that cladding oxidation and 
hydrogen generation are appropriately limited during a LOCA and 
conservatively accounted for in the ECCS evaluation model, 
respectively. Topical Report (TR) BAW-10227P, ``Evaluation of Advanced 
Cladding and Structural Material (M5) in PWR [pressurized-water 
reactor] Reactor

[[Page 44123]]

Fuel,'' which was approved by the NRC on February 4, 2000, demonstrated 
that the effectiveness of the ECCS will not be affected by a change 
from zircaloy fuel rod cladding to M5 fuel rod cladding. In addition, 
TR BAW-10227P demonstrated that the Baker-Just equation (used in the 
ECCS evaluation model to determine the rate of energy release, cladding 
oxidation, and hydrogen generation) is conservative in all post-LOCA 
scenarios with respect to M5 advanced alloy as a fuel rod cladding 
material. Based on the above, no new accident precursors are created by 
using M5 fuel cladding, thus, the probability of postulated accidents 
is not increased. Also, based on the above, the consequences of 
postulated accidents are not increased. In addition, the licensee will 
use NRC-approved methods for the reload design process for ANO-1 
reloads with M5 cladding. Therefore, there is no undue risk to public 
health and safety due to using M5 cladding.

Consistent With Common Defense and Security

    The exemption requested results in changes to the operation of the 
plant by allowing the use of the M5 alloy as fuel cladding material in 
lieu of zircaloy or ZIRLO. This change to the fuel material used in the 
plant has no relation to security issues. Therefore, the common defense 
and security is not impacted by this exemption request.

Special Circumstances

    Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii), 
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 ensure that facilities 
have adequate acceptance criteria for the ECCS. On February 4, 2000, 
the NRC staff approved TR BAW-10227P in which Framatome demonstrated 
that the effectiveness of the ECCS will not be affected by a change 
from zircaloy fuel rod cladding to M5 fuel rod cladding. The analysis 
described in the TR also demonstrated that the ECCS acceptance criteria 
applied to reactors fueled with zircaloy fuel rod cladding are also 
applicable to reactors fueled with M5 fuel rod cladding.
    The underlying purpose of 10 CFR part 50, appendix K, paragraph 
I.A.5, is to ensure that cladding oxidation and hydrogen generation are 
appropriately limited during a LOCA and conservatively accounted for in 
the ECCS evaluation model. Appendix K requires that the Baker-Just 
equation be used in the ECCS evaluation model to determine the rate of 
energy release, cladding oxidation, and hydrogen generation. In TR BAW-
10227P, Framatome demonstrated that the Baker-Just model is 
conservative in all post-LOCA scenarios with respect to the use of the 
M5 advanced alloy as a fuel rod cladding material, and that the amount 
of hydrogen generated in an M5-clad core during a LOCA will remain 
within the ANO-1 design basis.
    The M5 alloy is a proprietary zirconium-based alloy comprised of 
primarily zirconium (~99 percent) and niobium (~1 percent). The 
elimination of tin has resulted in superior corrosion resistance and 
reduced irradiation-induced growth relative to both standard zircaloy 
(1.7 percent tin) and low-tin zircaloy (1.2 percent tin). The addition 
of niobium increases ductility, which is desirable to avoid brittle 
failures.
    The NRC staff has reviewed the licensee's advanced cladding 
material, M5, for PWR fuel mechanical designs as described in TR BAW-
10227P. In the safety evaluation for TR BAW-10227P dated February 4, 
2000, the NRC staff concluded that, to the extent specified in the 
staff's evaluation, the M5 properties and mechanical design methodology 
are acceptable for referencing in fuel reload licensing applications. 
Therefore, since the underlying purposes of 10 CFR 50.46 and 10 CFR 
part 50, appendix K, paragraph I.A.5 are achieved through the use of 
the M5 advanced alloy as a fuel rod cladding material, the special 
circumstances required by 10 CFR 50.12(a)(2)(ii) for the granting of an 
exemption from 10 CFR 50.46 and 10 CFR part 50, appendix K exist.

Summary

    The staff has reviewed the licensee's request to use the M5 
advanced alloy for fuel rod cladding in lieu of zircaloy or ZIRLO. 
Based on the staff's evaluation, as set forth above, the staff 
concludes that the exemption is authorized by law, will not present an 
undue risk to public health and safety, and is consistent with the 
common defense and security. In addition, the staff concludes that the 
underlying purposes of 10 CFR 50.46 and 10 CFR part 50, appendix K are 
achieved through the use of the M5 advanced alloy. Therefore, pursuant 
to 10 CFR 50.12(a), the staff concludes that the use of the M5 advanced 
alloy for fuel rod cladding is acceptable and the exemption from 10 CFR 
50.46 and 10 CFR part 50, appendix K is justified.

4.0 Conclusion

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
50.12(a), 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 Entergy Operations, Inc. an 
exemption from the requirements of 10 CFR 50.46 and 10 CFR part 50, 
appendix K to allow the use of M5 cladding at ANO-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 (70 FR 37126).
    This exemption is effective upon issuance.

    Dated at Rockville, Maryland, this 25th day of July 2005.

    For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. 05-15125 Filed 7-29-05; 8:45 am]
BILLING CODE 7590-01-P