[Federal Register Volume 65, Number 152 (Monday, August 7, 2000)]
[Notices]
[Pages 48256-48258]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-19902]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-327 and 50-328]


Tennessee Valley Authority (Sequoyah Nuclear Plant, Units 1 and 
2); Exemption

I

    The Tennessee Valley Authority (TVA or the licensee) is the holder 
of Facility Operating License No. DPR-77 for operation of the Sequoyah 
Nuclear Plant, Unit 1, and DPR-79 for Unit 2. The licenses provide, 
among other things, that the licensee is subject to all rules, 
regulations, and orders of the U.S. Nuclear Regulatory Commission 
(Commission or NRC) now or hereafter in effect.

[[Page 48257]]

    The Sequoyah units are pressurized water reactors located in 
Hamilton County, Tennessee.

II

    By application dated February 11, 2000, TVA requested an exemption 
from the requirements of Title 10 of the Code of Federal Regulations, 
Section 50.44 (10 CFR 50.44), ``Standard for Combustion Gas Control in 
Light-Water-Cooled Power Reactors,'' 10 CFR 50.46, ``Acceptance 
Criteria for Emergency Core Cooling Systems [ECCS] for Light Water 
Nuclear Power Reactors,'' and 10 CFR Part 50, Appendix K, ``ECCS 
Evaluation Models.'' These regulations set forth requirements for use 
of zircaloy or ZIRLO fuel rod cladding material by specifying 
acceptance criteria for ECCS and the fuel cladding performance 
evaluation for normal operation, anticipated operational occurrences 
and accident conditions. Specifically, 10 CFR 50.46 contains acceptance 
criteria for ECCS for light water nuclear power reactors fueled with 
uranium oxide pellets within cylindrical zircaloy or ZIRLO cladding. 
Further, 10 CFR 50.46 states that ECCS cooling performance following 
postulated loss-of-coolant accidents (LOCA) must be calculated in 
accordance with an acceptable evaluation model. Appendix K to 10 CFR 
Part 50 contains the required and acceptable features for ECCS 
evaluation models. Finally, 10 CFR 50.44 contains requirements for the 
control of hydrogen gas that may be generated after a postulated LOCA 
in light water power reactors fueled with uranium oxide pellets within 
cylindrical zircaloy or ZIRLO cladding. Because TVA proposes to use a 
fuel cladding that is not specified in the rule, TVA sought an 
exemption from these regulations in order to use a newly designed 
cladding and structural material, designated M5, developed by Framatome 
Cogema Fuels (FCF). The licensee's exemption request was submitted in 
conjunction with an application for operating license amendments to 
revise the Sequoyah Unit 1 and 2 Technical Specifications to allow use 
of the M5 alloy for fuel rod cladding. The proposed amendment will be 
issued concurrently with this exemption. Together, the exemption and 
amendments will allow M5 to be used at both Sequoyah units.
    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 and 
safety, and are consistent with the common defense and security, and 
(2) when special circumstances are present. Special circumstances are 
present whenever, according to 10 CFR Part 50.12(a)(2)(ii), 
``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.''

III

    TVA proposes to use M5 for fuel rod cladding, fuel assembly spacer 
grids, fuel rod end plugs, the fuel assembly guide, and instrument 
tubes. M5 is an alloy composed of approximately 99 percent zirconium 
and 1 percent niobium, is designed for high fuel rod burnup conditions, 
and exhibits superior corrosion resistance and reduced irradiation-
induced growth. In September 1997, FCF submitted Topical Report BAW-
10227P, ``Evaluation of Advanced Cladding and Structural Material (M5) 
in PWR Reactor Fuel,'' for NRC staff review. The topical report 
justified the use of M5 as cladding and structural material in 
pressurized-water reactor cores and provided the licensing basis for 
the FCF advanced cladding and structural material. In a safety 
evaluation report (SER) dated February 4, 2000, NRC approved Topical 
Report BAW-10227P, concluding that the M5 properties and the mechanical 
design methodology, as defined in BAW-0227P, ``are in accordance with 
SRP [Standard Review Plan] Section 4.2, 10 CFR 50.46, and 10 CFR Part 
50, Appendix K and therefore, are acceptable for reload licensing 
applications up to rod averaged burnup levels of 62,000 MWd/MTU and 
60,000 MWd/MTU for Mark B and Mark-BW fuel designs, respectively.'' The 
staff SER and the approved topical report were published on February 
11, 2000, as BAW-10227P-A. The staff has determined that BAW-10227P-A 
is applicable to Sequoyah because the fuel designs are consistent with 
the requirements of the topical report.
    The underlying purpose of 10 CFR 50.46 is to ensure that facilities 
meet the appropriate acceptance criteria for ECCS. The rule, however, 
expressly applies only to reactors fueled with the use of zircaloy-clad 
or ZIRLO-clad fuel pellets. In its topical report, FCF demonstrated 
that the ECCS acceptance criteria, which are applied to reactors fueled 
with zircaloy- or ZIRLO-clad fuel, are also applicable to reactors 
fueled with M5 fuel rod cladding and structural material. The staff has 
determined that this finding is applicable to Sequoyah because the fuel 
designs are consistent with the requirements of the topical report. 
Thus, the performance of M5-clad material is similar to that of 
zircaloy- and ZIRLO-clad fuel and application of the regulation (i.e., 
using zircaloy or ZIRLO) is not necessary to achieve the underlying 
purpose of 10 CFR 50.46.
    The underlying purpose of 10 CFR 50.44 and 10 CFR Part 50, Appendix 
K, is to ensure that cladding oxidation and hydrogen generation are 
appropriately limited during a LOCA and conservatively accounted for in 
the ECCS evaluation model. These regulations set forth requirements for 
the plants that use either zircaloy- or ZIRLO-clad fuel. Specifically, 
Paragraph I.A.5 of 10 CFR Part 50, Appendix K, requires that the Baker-
Just (B-J) equation be used in the ECCS evaluation model to determine 
the rate of energy release, cladding oxidation, and hydrogen 
generation. This equation conservatively bounds all post-LOCA 
scenarios. In the SE that approved Topical Report BAW-10227P, the NRC 
staff concluded that the B-J correlation is conservative for 
determining high temperature M5 oxidation for LOCA analysis, and that 
the correlation is acceptable for LOCA ECCS analysis up to the 
currently approved burnup levels. The staff has determined that this 
finding is applicable to Sequoyah because the fuel designs are 
consistent with the requirements of the topical report. Therefore, when 
M5 is used as fuel rod cladding and structural material, the B-J 
correlation conservatively bounds post-LOCA scenarios and ECCS 
evaluation model criteria will be met. Application of the rule (i.e., 
the use of zircaloy or ZIRLO) is not necessary to achieve the 
underlying purpose of 10 CFR 50.44 and 10 CFR Part 50, Appendix K.
    Based on this evaluation, the staff has determined that application 
of the criteria in 10 CFR 50.44 and 10 CFR Part 50, Appendix K, 
Paragraph I.A.5, is appropriate given the similarities in the 
performance of M5-clad fuel rods and zircaloy- and ZIRLO-clad fuel. 
Therefore, special circumstances exist to grant an exemption in that 
application of the regulations (i.e., the use of zircaloy or ZIRLO) is 
not necessary to achieve the underlying purpose of the rules cited 
above.

IV

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
Part 50.12, an exemption is authorized by law and will not present an 
undue risk to the public health and safety and is consistent with the 
common defense and security. The Commission has determined that, 
pursuant to 10 CFR 50.12(a)(2)(ii), special circumstances are

[[Page 48258]]

present, as noted in Section III above. Therefore, an exemption is 
hereby granted from the requirements of 10 CFR 50.44, 10 CFR 50.46, and 
10 CFR Part 50, Appendix K, to allow use of the M5 alloy.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will have no significant impact on the 
quality of the human environment (65 FR 20209).
    This exemption is effective upon issuance.

    For the Nuclear Regulatory Commission.
    Dated at Rockville, Maryland this 29th day of July 2000.
John A. Zwolinski,
Director, Division of Licensing Project Management, Office of Nuclear 
Reactor Regulation.
[FR Doc. 00-19902 Filed 8-4-00; 8:45 am]
BILLING CODE 7590-01-P