[Federal Register Volume 79, Number 250 (Wednesday, December 31, 2014)]
[Notices]
[Pages 78912-78915]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-30718]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-313, 50-368, 72-13, and 72-1014; NRC-2014-0270]
Independent Spent Fuel Storage Installation, Entergy Operations,
Inc.; Arkansas Nuclear One, Units 1 and 2
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 an October 2, 2014, request from Entergy
Operations, Inc., (Entergy or licensee) from the requirement to comply
with the terms, conditions, and specifications in Section 2.1 of
Appendix B of the Technical Specifications for certificate of
compliance (CoC) No. 1014, Amendment No. 5.
DATES: Notice of issuance of exemption given on December 31, 2014.
ADDRESSES: Please refer to Docket ID NRC-2014-0270 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-2014-0270. Address
questions about NRC dockets to Carol Gallagher; telephone: 301-287-
3422; 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: Chris Allen, Office of Nuclear
Material Safety and Safeguards, telephone: 301-287-9225, email:
[email protected]; U.S. Nuclear Regulatory Commission, Washington,
DC 20555.
SUPPLEMENTARY INFORMATION:
I. Background
Entergy is the holder of Facility Operating License Nos. DRP-51 and
NPF-6, which authorize operation of ANO, Units 1 and 2, in
Russellville, Arkansas, pursuant to part 50 of title 10 of the Code of
Federal Regulations (10 CFR). The licenses provide, among other things,
that the facility is subject to all rules, regulations, and orders of
the NRC now or hereafter in effect.
Under subpart K of 10 CFR part 72, a general license has been
issued for the storage of spent fuel in an independent spent fuel
storage installation (ISFSI) at power reactor sites to persons
authorized to possess or operate nuclear
[[Page 78913]]
power reactors under 10 CFR part 50. Entergy is licensed to operate a
nuclear power reactor under 10 CFR part 50, and authorized under the 10
CFR part 72 general license to store spent fuel at the ANO ISFSI. Under
the terms of the general license, Entergy stores spent fuel using the
Holtec International (Holtec) HI-STORM 100 System CoC No.1014 at ANO.
II. Request/Action
While performing drying operations on a loaded Holtec HI-STORM 100
Model 24 Multi-Purpose Canister (MPC-24), serial number MPC-24-060,
Entergy detected Krypton-85 (Kr-85) gas. Kr-85 gas is a fission product
gas and its presence may indicate fuel rods with greater than pinhole
leaks or hairline cracks. Section 2.1 of Appendix B of the Technical
Specifications for the HI-STORM 100 CoC No. 1014 specifies that only
intact fuel assemblies, which is defined as fuel assemblies without
known or suspected cladding defects greater than pinhole leaks or
hairline cracks and which can be handled by normal means, are
authorized for loading into an MPC-24 canister. Entergy stated that
although all fuel assemblies loaded into MPC-24-060 were tested
subsequent to their final operating cycle using standard, accepted
methods (i.e., in-mast sipping and ultrasonic testing), and were
visually inspected for indications of rod damage, assembly damage, or
other potential issues before being loaded into the canister, a fuel
assembly with a defect greater than a pinhole leak or hairline crack
may have been loaded into MPC-24-060.
By letter dated October 2, 2014, as supplemented October 14 and
November 7, 2014 (ADAMS Accession Nos. ML14279A246, ML14289A239, and
ML14311A121, respectively), Entergy requested an exemption from the
following requirements to allow storage of MPC-24-060 in its current,
as-loaded, condition at the ANO ISFSI:
10 CFR 72.212(a)(2), which limits the storage of spent
fuel to casks approved in subpart K of 10 CFR part 72.
10 CFR 72.212(b)(11), which states, in part, that the
``licensee shall comply with the terms, conditions, and specifications
of the CoC . . .''
III. Discussion
Pursuant to 10 CFR 72.7, the Commission may, upon application by
any interested person or upon its own initiative, grant exemptions from
the requirements of the regulations of 10 CFR part 72 as it determines
are authorized by law and will not endanger life or property or the
common defense and security and are otherwise in the public interest.
In addition to the requirements from which Entergy requested exemption,
the NRC determined exemption from the following requirements would be
necessary to authorize Entergy's proposal:
10 CFR 72.212(b)(3), which requires that each cask used by
the general licensee conforms to the terms, conditions, and
specifications of a CoC listed in Sec. 72.214.
10 CFR 72.212(b)(5)(i), which requires written evaluations
be performed before use that a loaded cask will conform to the terms,
conditions, and specifications of a CoC listed in Sec. 72.214.
10 CFR 72.214, which lists the casks approved for storage
of spent fuel under conditions specified in their CoCs.
Authorized by Law
This exemption would allow the licensee to store MPC-24-060 (loaded
with spent nuclear fuel assemblies which are not authorized per Section
2.1 of Appendix B of the Technical Specifications for CoC No. 1014,
Amendment No. 5) in its as-loaded configuration at the ANO ISFSI. The
provisions in 10 CFR part 72 from which Entergy requested an exemption,
as well as the provisions considered by the NRC, require the licensee
to comply with the terms, conditions, and specifications of the CoC for
the approved cask model that it uses.
Section 72.7 allows the NRC to grant exemptions from the
requirements of 10 CFR part 72. Issuance of this exemption is
consistent with the Atomic Energy Act of 1954, as amended, and not
otherwise inconsistent with NRC regulations or other applicable laws.
As explained below, the proposed exemption will not endanger life or
property, or the common defense and security, and is otherwise in the
public interest. Therefore, the exemption is authorized by law.
Will Not Endanger Life or Property or the Common Defense and Security
The requested exemption would allow the licensee to store MPC-24-
060 (loaded with spent nuclear fuel assemblies which are not authorized
per Section 2.1 of Appendix B of the Technical Specifications for CoC
No. 1014, Amendment No. 5) in its as-loaded configuration at the ANO
ISFSI.
In support of its exemption request, the licensee submitted Holtec
Report HI-2146265, ``Justification for ANO Exemption Request for
Loading of Damaged Fuel in MPC-24,'' Rev. 0 (ADAMS Accession No.
ML14279A246). Holtec stated that the most likely source of the Kr-85
gas was a single breached rod in one fuel assembly and that it is
unlikely that the cladding defects would allow fuel pellets to be
released into the canister cavity. Nevertheless, as discussed further
below, Holtec assumed in its thermal, criticality, and shielding
analyses that multiple breached fuel rods had been loaded into MPC-24-
060 and that fuel pellets had been released into the canister cavity.
Based upon the fact that only trace amounts of Kr-85 gas were detected
after the initial alarm annunciation, NRC staff concludes that these
are conservative assumptions and therefore finds them acceptable.
The Holtec report asserted that, since the damaged fuel rods do not
contact either the HI-STORM overpack or the HI-TRAC transfer cask, they
will have no impact on the structural performance of either the HI-
STORM overpack or the HI-TRAC transfer cask. Also, the normal, off-
normal, and accident condition pressures and temperatures specified in
Tables 2.2.1 and 2.2.3 of Revision 7 of the HI-STORM Final Safety
Analysis Report (FSAR) are not exceeded as a result of the damaged fuel
rods (ADAMS Accession No. ML110250163). Furthermore, the report stated
that the stresses in the overpack and the transfer cask due to normal
and off-normal handling events remain as calculated in the HI-STORM
FSAR since the dead weight of the loaded casks and their centers of
gravity are unaffected by the damaged fuel rods. In addition, the
impact decelerations experienced by the cask as a result of either a
handling accident or a hypothetical tip-over event are not increased,
and the stability of the cask under design basis natural phenomena
events (i.e., tornado winds, earthquake, etc.) continues to be assured.
The staff reviewed the structural evaluation provided by the applicant
and the basis of its conclusions. Based on its review of the
representations, determinations, and information provided by the
applicant in the above mentioned Holtec report, the NRC staff concludes
continued storage of one or more fuel assemblies with fuel rods having
greater than a pinhole leak, not placed in a damaged fuel container,
and loaded into a HI-STORM 100 MPC-24 will have no impact on the
ability of the HI-STORM overpack, HI-TRAC transfer cask, or the MPC to
withstand pressure loads due to tornado winds, floods, or explosions.
The NRC staff also concludes that there is a reasonable assurance that
the
[[Page 78914]]
overpack and transfer cask's structural performance will meet the
requirements of 10 CFR part 72.
In Chapter 5 of Revision 7 to the HI-STORM FSAR, Holtec stated that
storage of damaged fuel assemblies is identical from a shielding
perspective to storage of intact fuel assemblies (ADAMS Accession No.
ML082401632). Dose rate measurements performed by Entergy which show
that the dose rates for MPC-24-060 are below the limits specified in
the CoC support the results presented in the Holtec FSAR. The shielding
analyses performed for accident conditions in Chapter 5 of Revision 7
to the HI-STORM FSAR simulated four collapsed, damaged fuel assemblies
located on the periphery of an MPC-24. Since there are approximately
208 fuel rods in a fuel assembly, this equates to approximately 832
collapsed fuel rods. The results of these analyses showed that external
dose rates at the bottom of the canister increased by less than 27% and
dose rates at higher locations decreased. Since the number of damaged
fuel rods assumed in the Holtec report is much less than that described
in the FSAR analysis, the applicant stated that the effect on dose for
MPC-24-060 loaded with fuel assemblies having defects greater than
pinhole leaks and hairline cracks would be expected to be less than
that described in the FSAR. Similarly, according to the Holtec report
the postulated relocation of the fuel from a small number of rods would
have a negligible effect on the dose contribution at the site boundary.
Additionally, Chapters 7 and 11 of Revision 7 to the HI-STORM FSAR
shows that leakage is not credible under normal, off-normal, and
accident conditions (ADAMS Accession No. ML082401621 and ML082401626
respectively). The NRC staff reviewed Revision 7 to the HI-STORM 100
FSAR and information provided by the applicant and found that analysis
acceptable to demonstrate the dose rates for MPC-24-060. Based on its
review, the NRC staff finds that storage of fuel assemblies having
greater than pinhole leaks and hairline cracks in the HI-STORM 100 MPC-
24 Storage System will meet the dose rate and exposure limit
requirements in 10 CFR part 20 and 10 CFR part 72.
Holtec assumed one fuel pin per assembly is damaged in each of the
24 assemblies loaded into MPC-24-060. The criticality evaluation
indicated the potential relocation of fuel pellets from damaged fuel
rods in the MPC has a negligible effect on the reactivity of the
system, and the maximum reactivity remains well below 0.95. During
storage operations, the MPC is internally dry, resulting in a low
reactivity and large reactivity margins. For unloading operations,
where the MPC is flooded, confirmatory calculations for possible
relocation of fuel both within and outside of an assembly confirmed
that the effect of fuel relocation on the reactivity of the system is
small even if the MPC is flooded with unborated water. The NRC staff
has reviewed the criticality evaluation and the basis of the
conclusions reached by Holtec in support of Entergy's exemption
request. Based on its review of the representations, determinations,
and information provided, the NRC staff finds that the as-loaded
potentially damaged fuel will not impact the criticality performance of
the HI-STORM 100 MPC-24 Storage System, and therefore, as loaded, MPC-
24-060 will meet the criticality safety requirements of 10 CFR part 72.
The staff also finds that there is no impact on the ability of the
fuel to be retrieved from the canister for the following reasons. A
complete break of a fuel rod on the periphery of a fuel assembly could
affect retrievability; however, this condition was not identified by
the visual inspections performed during loading. Also, the amount of
gas released is not indicative of a complete break of a fuel rod.
Expanded damage of breached rod(s) during storage could make handling
of the fuel at a later time more difficult than if it was repackaged at
the current time. However, the only degradation mechanism which could
further damage the fuel is oxidation of exposed fuel pellets. Oxidized
fuel pellets would exert stress on the cladding, potentially causing
further damage and release of fuel pellets. Since the MPC has been seal
welded shut and an inert atmosphere of helium has been introduced into
the cavity, unless there is a breach of containment letting air into
the canister, oxidation of the pellets will not occur. Consequently,
the cladding will not be damaged further and fuel pellets will not be
released. Therefore, NRC staff finds that storage of fuel assemblies
having greater than pinhole leaks and hairline cracks in the HI-STORM
100 MPC-24 Storage System will meet the retrievability requirements of
10 CFR part 72.
As part of its thermal assessment of storage of the damaged fuel in
a HI-STORM 100 MPC-24, Holtec stated that the damaged fuel rods in the
canister would be well below 1% of the total number of fuel rods
(approximately 50 fuel rods). Holtec evaluated the effect of damaged
fuel on the different heat transfer mechanisms while the canister is in
the storage configuration. Holtec stated that the damaged rods would
remain in their correct physical positions within the fuel assembly and
that the fuel assembly geometry is unchanged. Therefore, both the
conduction heat transfer mechanism and the radiation heat transfer
mechanism would not be impacted. Holtec also stated that the resistance
to movement of helium within the fuel assemblies (i.e., the hydraulic
resistance that is also dependent on the fuel geometry) is unaffected.
Consequently, the natural convection heat transfer mechanism, which is
dependent upon the hydraulic resistance, would not be impacted. Even
though Holtec believes the fuel rods are intact, Holtec evaluated the
impact on the natural convection heat transfer mechanism within the
canister from either fuel pellets or pieces of fuel cladding becoming
dislodged from the damaged fuel rods. Holtec stated that, if a fuel
pellet or piece of fuel cladding were to block one of the rod-to-rod
interstitial spaces, the impact on the natural convection heat transfer
would be very small because each interstitial space is connected to
four adjacent rod-to-rod interstitial spaces. Therefore, helium could
easily flow around any blocked rod-to-rod interstitial space. Holtec
also stated that, if a fuel pellet or piece of fuel cladding were to
fall completely out of the fuel assembly and into the bottom region of
the fuel basket, the impact on the natural convection heat transfer
mechanism due to helium circulation would be similarly negligible
because openings in the bottom region of the fuel basket are sized
sufficiently large enough to allow the movement of helium within the
canister.
The NRC staff reviewed Holtec's evaluation on the impact of damaged
spent fuel on the MPC-24 thermal performance discussed above and
determined that it demonstrated that the presence of damaged fuel (to
the extent described in the technical justification) would not affect
the heat transfer characteristics (i.e., conduction heat transfer,
radiation heat transfer, and natural convection heat transfer by helium
circulation). Since the impact on the thermal performance is small and
because the total cask heat load is relatively low as compared to the
design basis heat load, the staff concludes that neither temperature
nor pressure limits in the FSAR would be exceeded. Also, the licensee
characterized all the spent fuel assemblies loaded in MPC-24-060 as low
burnup fuel, which is permitted to reach higher temperatures in storage
than fuel of other burnup levels. The
[[Page 78915]]
HI-STORM 100 system is rated also to store high burnup fuel. As a
result, MPC-24-060 has a large thermal margin. Therefore, based on the
NRC staff's review of Holtec's evaluation and technical justification,
the staff concludes that MPC-24-060 (loaded with the contents described
in the ANO exemption request letter) inside the HI-STORM 100 system
will meet the 10 CFR part 72 thermal requirements.
Based on its review, the NRC staff has reasonable assurance that
Entergy's exemption request for an MPC loaded with fuel assemblies
classified as having defects greater than pinhole leaks and hairline
cracks will meet the thermal, structural, criticality, retrievability
and radiation protection requirements of 10 CFR part 72 and the offsite
dose limits of 10 CFR part 20. Therefore, the NRC staff concludes that
the exemption to allow the licensee to store MPC-24-060 in its as-
loaded configuration will not endanger life or property or the common
defense and security.
Otherwise in the Public Interest
The information Entergy submitted with its exemption request, and
the Holtec analyses documented in Holtec Report No. HI-2146265,
``Justification for ANO Exemption Request for Loading of Damaged Fuel
in MPC-24,'' Rev. 0, demonstrates that the as-loaded MPC is not
compromised due to the misloaded fuel (ADAMS Accession No.
ML14279A246). If the NRC did not grant this exemption, Entergy would
need to take action to correct the condition by reloading the affected
MPC to be in compliance with CoC No. 1014, Amendment No. 5. This would
involve unloading the spent fuel assemblies from the MPC, performing
inspections of various MPC components, loading different spent fuel
assemblies into the used MPC or a new MPC (if there was damage noted on
the used MPC) in accordance with CoC No. 1014, Amendment No. 5 and
performing the MPC closing procedures.
The licensee estimates that unloading and reloading the MPC would
increase personnel exposures by 600 mRem. In addition, the licensee
states that unloading and reloading would generate radioactive
contaminated material and waste not only during unloading and reloading
operations, but also from disposal of the used MPC (if the MPC were
damaged during the unloading process). The licensee estimates this
action would cost an estimated $300,000 for unloading and reloading
operations. If the MPC was damaged during unloading, the licensee
estimates an additional $750,000 for purchase of a new MPC and $200,000
for disposal of the used MPC. The licensee also states additional
opportunities for design basis accidents, such as a fuel handling
accident, would be introduced if the MPC were unloaded and reloaded.
Because the corrective action would result in increased radiation
exposure to personnel and provides increased opportunities for fuel
handling accidents which could result in radioactive material releases
to the environment, granting the exemption, and allowing MPC-24-060 to
remain in its as-loaded condition, is consistent with the NRC's mission
to protect public health and safety. Therefore, the exemption is in the
public interest.
Environmental Consideration
The NRC staff also considered in the review of this exemption
request whether there would be any significant environmental impacts
associated with the exemption. For this proposed action, the NRC staff
performed an environmental assessment pursuant to 10 CFR 51.30. The
proposed action is the approval of an exemption from the requirements
of 10 CFR 72.212(a)(2), 10 CFR 72.212(b)(3), 10 CFR 72.212(b)(5)(i),
and the portion of 72.212(b)(11) that requires compliance with the
terms, conditions, and specifications of a CoC, and 10 CFR 72.214, but
only to the extent necessary to allow Entergy to store MPC-24-060 in
its current as-loaded configuration at the ANO ISFSI.
The NRC staff performed an environmental assessment and determined
that the proposed action will not significantly impact the quality of
the human environment. The NRC staff concludes that there are no
changes being made in the types or amounts of any radiological
effluents that may be released offsite, and there is no significant
increase in occupational or public radiation exposure as a result of
the proposed action. In addition, the proposed action only affects the
requirements associated with the fuel assemblies already loaded into
the canister and does not affect non-radiological plant effluents, or
any other aspects of the environment. The Environmental Assessment and
the Finding of No Significant Impact were published in the Federal
Register on December 19, 2014 (79 FR 75843).
IV. Conclusion
Based on the foregoing considerations, the NRC has determined
pursuant to 10 CFR 72.7, that the exemption is authorized by law, will
not endanger life or property or the common defense and security, and
is otherwise in the public interest. Therefore, the NRC grants Entergy
a one-time exemption from the requirements in 10 CFR 72.212(a)(2), 10
CFR 72.212(b)(3), 10 CFR 72.212(b)(5)(i), and the portion of 10 CFR
72.212(b)(11) that requires compliance with the terms, conditions, and
specifications of a CoC, and 10 CFR 72.214 for storage of HI-STORM 100
MPC-24-060 at the ANO ISFSI.
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 19th day of December 2014.
For the Nuclear Regulatory Commission.
Mark Lombard,
Director, Division of Spent Fuel Management, Office of Nuclear Material
Safety and Safeguards.
[FR Doc. 2014-30718 Filed 12-30-14; 8:45 am]
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