[Federal Register Volume 81, Number 154 (Wednesday, August 10, 2016)]
[Notices]
[Pages 52910-52912]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-18979]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-482; NRC-2016-0162]


Wolf Creek Generating Station; Use of Optimized 
ZIRLOTM Fuel Rod Cladding Material

AGENCY: Nuclear Regulatory Commission.

ACTION: Exemption; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an 
exemption in response to a January 27, 2016, request, as supplemented 
on May 19, 2016, from Wolf Creek Nuclear Operating Corporation (WCNOC 
or the licensee) in order to use Optimized ZIRLOTM fuel rod 
cladding material at Wolf Creek Generating Station (WCGS).

DATES: The exemption was issued on August 2, 2016.

ADDRESSES: Please refer to Docket ID NRC-2016-0162 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly-available information related to this document 
using any of the following methods:
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2016-0162. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: [email protected]. For technical questions, contact 
the individual listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly-available documents online in the 
ADAMS Public Documents collection at http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and 
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS, 
please contact the NRC's Public Document Room (PDR) reference staff at 
1-800-397-4209, 301-415-4737, or by email to [email protected]. The 
ADAMS accession number for each document referenced in this document 
(if that document is available in ADAMS) is provided the first time 
that a document is referenced.
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.

FOR FURTHER INFORMATION CONTACT: Carl F. Lyon, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001; telephone: 301-415-2296, email: [email protected].

SUPPLEMENTARY INFORMATION:

I. Background

    The licensee is the holder of Renewed Facility Operating License 
No. NPF-42, which authorizes operation of WCGS. The license provides, 
among other things, that the facility is subject to all rules, 
regulations, and orders of the NRC now or hereafter in effect. The 
facility consists of a pressurized-water reactor located in Coffey 
County, Kansas.

II. Request/Action

    Pursuant to Sec.  50.12 of title 10 of the Code of Federal 
Regulations (10 CFR), ``Specific exemptions,'' the licensee requested 
by letter dated January 27, 2016, as supplemented by letter dated May 
19, 2016 (ADAMS Accession Nos. ML16033A470 and ML16161A509, 
respectively), an exemption from specific requirements of 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,'' to allow the use of fuel rod cladding with 
Optimized ZIRLOTM alloy for future reload applications. The 
regulations in 10 CFR 50.46 contain acceptance criteria for the ECCS 
for reactors fueled with zircaloy or ZIRLOTM fuel rod 
cladding material. In addition, 10 CFR part 50, appendix K, requires 
that the Baker-Just equation be used to predict the rates of energy 
release, hydrogen concentration, and cladding oxidation from the metal/
water reaction. The Baker-Just equation assumes the use of a zirconium 
alloy, which is a material different from Optimized ZIRLOTM. 
The licensee requested the exemption because these regulations do not 
have provisions for the use of fuel rod cladding material other than 
zircaloy or ZIRLOTM. Because the material specifications of 
Optimized ZIRLOTM differ from the specifications for 
zircaloy or ZIRLOTM, a plant-specific exemption is required 
to support the reload applications for WCGS.
    The exemption request relates solely to the cladding material 
specified in these regulations (i.e., fuel rods with Zircaloy or 
ZIRLOTM cladding material). This exemption would provide for 
the application of the acceptance criteria of 10 CFR 50.46 and 10 CFR 
part 50, appendix K, to fuel assembly designs using Optimized 
ZIRLOTM fuel rod cladding material. In its letter dated 
January 27, 2016, as supplemented by letter dated May 19, 2016, the 
licensee indicated that it was not seeking an exemption from the 
acceptance and analytical criteria of these regulations. The intent of 
the request is to allow the use of the criteria set forth in these 
regulations for application of the Optimized ZIRLOTM fuel 
rod cladding material.

III. 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. Under 10 CFR 50.12(a)(2), 
special circumstances include, among other things, when application of 
the specific regulation in the particular circumstance would not serve, 
or is not necessary to achieve, the underlying purpose of the rule.

A. 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 is not necessary to achieve the underlying purpose of the 
rule. The underlying purpose of 10 CFR 50.46 and 10 CFR part 50, 
appendix K, is to establish acceptance criteria for ECCS performance. 
The regulations in 10 CFR 50.46 and 10 CFR part 50, appendix K, are not 
directly applicable to Optimized ZIRLOTM, even though the 
evaluations described in the following sections of this exemption show 
that the intent of the regulation is met. Therefore, since the 
underlying purposes of 10 CFR 50.46 and 10 CFR part 50, appendix K,

[[Page 52911]]

are achieved through the use of Optimized ZIRLOTM fuel rod 
cladding material, the special circumstances required by 10 CFR 
50.12(a)(2)(ii) for the granting of an exemption exist.

B. Authorized by Law

    This exemption would allow the use of Optimized ZIRLOTM 
fuel rod cladding material for future reload applications at WCGS. As 
stated above, 10 CFR 50.12 allows the NRC to grant exemptions from the 
requirements of 10 CFR part 50. The NRC staff has determined that 
granting the licensee's proposed exemption would 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.

C. No Undue Risk to Public Health and Safety

    Section 50.46 requires that each boiling or pressurized light-water 
nuclear power reactor fueled with uranium oxide pellets within 
cylindrical zircaloy or ZIRLOTM cladding must be provided 
with an 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 10 CFR 50.46(b). The underlying 
purpose of 10 CFR 50.46 is to establish acceptance criteria for 
adequate ECCS performance. As previously documented in the NRC staff's 
safety evaluation dated June 10, 2005 (ADAMS Package Accession No. 
ML051670395), of topical reports submitted by Westinghouse Electric 
Company (Westinghouse), and subject to compliance with the specific 
conditions of approval established in the safety evaluation, the NRC 
staff found that Westinghouse demonstrated the applicability of these 
ECCS acceptance criteria to Optimized ZIRLOTM. The NRC staff 
found that the Westinghouse topical report demonstrates the 
applicability of these ECCS acceptance criteria to Optimized ZIRLO\TM\, 
subject to the compliance with the specific conditions of approval 
established therein. The NRC staff reviewed the licensee's January 27, 
2016, application, as supplemented by letter dated May 9, 2016, against 
these specific conditions and found that the licensee was in compliance 
with all of the applicable conditions. The NRC staff's review of these 
specific conditions for WCGS can be found in ADAMS under Accession No. 
ML16179A293. Ring compression tests performed by Westinghouse on 
Optimized ZIRLOTM (see WCAP-14342-A & CENPD-404-NP-A, dated 
July 2006 (ADAMS Accession No. ML062080569), demonstrate an acceptable 
retention of post-quench ductility up to 10 CFR 50.46 limits of 2200 
degrees Fahrenheit and 17 percent equivalent clad reacted. Furthermore, 
the NRC staff concluded that oxidation measurements provided by the 
licensee by letter LTR-NRC-07-58 from Westinghouse to the NRC, ``SER 
Compliance with WCAP-12610-P-A & CENPD-404-P-A, Addendum 1-A, 
`Optimized ZIRLOTM,' '' dated November 6, 2007 (public 
version in ADAMS under Accession No. ML073130560), illustrate that 
oxide thickness and associated hydrogen pickup for Optimized 
ZIRLOTM at any given burnup would be less than both 
zircaloy-4 and ZIRLOTM. Hence, the NRC staff concludes that 
Optimized ZIRLOTM would be expected to maintain better post-
quench ductility than ZIRLOTM. This finding is further 
supported by an ongoing LOCA research program at Argonne National 
Laboratory, which has identified a strong correlation between cladding 
hydrogen content (caused by in-service corrosion) and post-quench 
ductility.
    In addition, the provisions of 10 CFR 50.46 require the licensee to 
periodically evaluate the performance of the ECCS, using currently 
approved LOCA models and methods, to ensure that the fuel rods will 
continue to satisfy the 10 CFR 50.46 acceptance criteria. In its letter 
dated January 27, 2016, the licensee stated that for LOCA scenarios, 
where the slight difference in Optimized ZIRLOTM material 
properties relative to standard ZIRLOTM could have some 
impact on the overall accident scenario, plant-specific LOCA analyses 
using Optimized ZIRLOTM properties will demonstrate that the 
acceptance criteria of 10 CFR 50.46 have been satisfied. Granting the 
exemption to allow the licensee to use Optimized ZIRLOTM 
fuel rod cladding material in addition to the current mix of fuel rods 
does not diminish this requirement of periodic evaluation of ECCS 
performance. Therefore, the underlying purpose of the rule will 
continue to be achieved for WCGS.
    Paragraph I.A.5 of 10 CFR part 50, appendix K, states that the 
rates of energy release, 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 this provision of the rule would not 
permit use of the equation for the Optimized ZIRLOTM fuel 
rod cladding material for determining acceptable fuel performance. 
However, the NRC staff previously found that metal-water reaction tests 
performed by Westinghouse on Optimized ZIRLOTM (see Appendix 
B of WCAP-12610-P-A & CENPD-404-P-A Addendum 1-A) demonstrate 
conservative reaction rates relative to the Baker-Just equation. 
Therefore, the NRC staff determined that the application of Paragraph 
I.A.5 of 10 CFR part 50, appendix K, is not necessary to achieve the 
underlying purpose of the rule in these circumstances. Since these 
evaluations demonstrate that the underlying purpose of the rule will be 
met, there will be no undue risk to the public health and safety.

D. Consistent With the Common Defense and Security

    The licensee's exemption request is only to allow the application 
of the aforementioned regulations to an improved fuel rod cladding 
material. In its letter dated January 27, 2016, as supplemented by 
letter dated May 19, 2016, the licensee stated that all the 
requirements and acceptance criteria will be maintained. The licensee 
is required to handle and control special nuclear material in these 
assemblies in accordance with its approved procedures. This change to 
the plant configuration is not related to security issues. Therefore, 
the NRC staff determined that this exemption does not impact common 
defense and security.

E. Environmental Considerations

    The NRC staff determined that the exemption discussed herein meets 
the eligibility criteria for the categorical exclusion set forth in 10 
CFR 51.22(c)(9) because it is related to a requirement concerning the 
installation or use of a facility component located within the 
restricted area, as defined in 10 CFR part 20, and the granting of this 
exemption involves: (i) No significant hazards consideration, (ii) no 
significant change in the types or a significant increase in the 
amounts of any effluents that may be released offsite, and (iii) no 
significant increase in individual or cumulative occupational radiation 
exposure. Therefore, in accordance with 10 CFR 51.22(b), no 
environmental impact statement or environmental assessment need be 
prepared in connection with the NRC's consideration of this exemption 
request. The basis for the NRC staff's determination is discussed as 
follows with an evaluation against each of the requirements in 10 CFR 
51.22(c)(9).
Requirements in 10 CFR 51.22(c)(9)(i)
    The NRC staff evaluated the issue of no significant hazards 
consideration,

[[Page 52912]]

using the standards described in 10 CFR 50.92(c), as presented below:

    1. Does the proposed exemption involve a significant increase in 
the probability or consequences of an accident previously evaluated?
    Response: No. The proposed change would allow the use of 
Optimized ZIRLOTM fuel rod cladding material in the 
reactors. The NRC approved topical report WCAP-12610-P-A & CENPD-
404-P-A Addendum 1-A, ``Optimized ZIRLOTM,'' prepared by 
Westinghouse, addresses Optimized ZIRLOTM and 
demonstrates that Optimized ZIRLOTM has essentially the 
same properties as the currently licensed ZIRLOTM. The 
fuel cladding itself is not an accident initiator and does not 
affect accident probability. Use of Optimized ZIRLOTM 
fuel rod cladding material will continue to meet all 10 CFR 50.46 
acceptance criteria and, therefore, will not increase the 
consequences of an accident.
    Therefore, the proposed change does not involve a significant 
increase in the probability or consequences of an accident 
previously evaluated.
    2. Does the proposed exemption create the possibility of a new 
or different kind of accident from any accident previously 
evaluated?
    Response: No. The use of Optimized ZIRLOTM fuel rod 
cladding material will not result in changes in the operation or 
configuration of the facility. Topical Report WCAP-12610-P-A & 
CENPD-404-P-A demonstrated that the material properties of Optimized 
ZIRLOTM are similar to those of standard 
ZIRLOTM. Therefore, the Optimized ZIRLOTM fuel 
rod cladding material will perform similarly to those fabricated 
from standard ZIRLOTM, therefore precluding the 
possibility of the fuel cladding becoming an accident initiator and 
causing a new or different type of accident.
    Therefore, the proposed change does not create the possibility 
of a new or different kind of accident from any previously 
evaluated.
    3. Does the proposed exemption involve a significant reduction 
in a margin of safety?
    Response: No. The proposed change will not involve a significant 
reduction in the margin of safety, because it has been demonstrated 
that the material properties of the Optimized ZIRLOTM are 
not significantly different from those of standard 
ZIRLOTM. Optimized ZIRLOTM is expected to 
perform similarly to standard ZIRLOTM for all normal 
operating and accident scenarios, including both LOCA and non-LOCA 
scenarios. For LOCA scenarios, where the slight difference in the 
Optimized ZIRLOTM material properties, relative to 
standard ZIRLOTM could have some impact on the overall 
accident scenario, plant-specific LOCA analyses using the Optimized 
ZIRLOTM properties demonstrate that the acceptance 
criteria of 10 CFR 50.46 have been satisfied.
    Therefore, the proposed change does not involve a significant 
reduction in a margin of safety.
    Based on the above, the NRC staff concludes that the proposed 
exemption presents no significant hazards consideration under the 
standards set forth in 10 CFR 50.92(c), and, accordingly, a finding 
of no significant hazards consideration is justified (i.e., 
satisfies the provision of 10 CFR 51.22(c)(9)(i)).
Requirements in 10 CFR 51.22(c)(9)(ii)
    The proposed exemption would allow the use of Optimized 
ZIRLOTM fuel rod cladding material in the reactors. 
Optimized ZIRLOTM has essentially the same properties as the 
currently licensed ZIRLOTM. The use of the Optimized 
ZIRLOTM fuel rod cladding material will not significantly 
change the types of effluents that may be released offsite, or 
significantly increase the amount of effluents that may be released 
offsite. Therefore, the provision of 10 CFR 51.22(c)(9)(ii) is 
satisfied.
Requirements in 10 CFR 51.22(c)(9)(iii)
    The proposed exemption would allow the use of the Optimized 
ZIRLOTM fuel rod cladding material in the reactors. 
Optimized ZIRLOTM has essentially the same properties as the 
currently licensed ZIRLOTM. The use of the Optimized 
ZIRLOTM fuel rod cladding material will not significantly 
increase individual occupational radiation exposure, or significantly 
increase cumulative occupational radiation exposure. Therefore, the 
provision of 10 CFR 51.22(c)(9)(iii) is satisfied.
Conclusion
    Based on the above, the NRC staff concludes that the proposed 
exemption meets the eligibility criteria for the categorical exclusion 
set forth in 10 CFR 51.22(c)(9). Therefore, in accordance with 10 CFR 
51.22(b), no environmental impact statement or environmental assessment 
need be prepared in connection with the NRC's proposed issuance of this 
exemption.

IV. Conclusions

    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 WCNOC an exemption from the 
requirements of 10 CFR 50.46 and 10 CFR part 50, appendix K, to allow 
the use of Optimized ZIRLOTM fuel rod cladding material at 
WCGS. As stated above, this exemption relates solely to the cladding 
material specified in these regulations.

    Dated at Rockville, Maryland, this 2nd day of August 2016.

    For the Nuclear Regulatory Commission.
Anne T. Boland,
Director, Division of Operating Reactor Licensing, Office of Nuclear 
Reactor Regulation.
[FR Doc. 2016-18979 Filed 8-9-16; 8:45 am]
 BILLING CODE 7590-01-P