[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