[Federal Register Volume 70, Number 199 (Monday, October 17, 2005)]
[Notices]
[Pages 60375-60379]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E5-5689]
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NUCLEAR REGULATORY COMMISSION
[Docket No. 50-255]
Nuclear Management Company, LLC, Palisades Plant; Exemption
1.0 Background
Nuclear Management Company, LLC (NMC) is the holder of Facility
Operating License No. DPR-20, which authorizes operation of the
Palisades Nuclear Plant (PNP). The license provides, among other
things, that the facility is subject to all rules, regulations, and
orders of the Nuclear Regulatory Commission (NRC or Commission) now or
hereafter in effect.
The facility consists of a pressurized-water reactor located in
VanBuren County in Michigan.
2.0 Request/Action
Title 10 of the Code of Federal Regulations 10 CFR part 50, Section
50.68(b)(1) specifies requirements for handling and storing spent fuel
assemblies during cask loading, unloading, and handling operations.
Section 50.68(b)(1) sets forth the following requirement that must be
met, in lieu of a monitoring system capable of detecting criticality
events:
Plant procedures shall prohibit the handling and storage at any
one time of more fuel assemblies than have been determined to be
safely subcritical under the most adverse moderation conditions
feasible by unborated water.
NMC is unable to satisfy the above requirement for handling the 10
CFR part 72 licensed contents of the Transnuclear (TN) NUHOMS[reg]-32PT
storage system. Section 50.12(a) allows licensees to apply for an
exemption from the requirements of 10 CFR part 50, if special
circumstances are demonstrated. NMC's letter of June 21, as
supplemented August 25, 2005, requested a license exemption from the
requirements of 10 CFR, part 50, Section 50.68(b)(1) for handling and
storing spent fuel assemblies during cask loading, unloading, and
handling operations for PNP. NMC stated in its letters that complying
with 10 CFR 50.68(b)(1) is not necessary for handling the 10 CFR part
72 licensed contents of the cask system to achieve the underlying
purpose of the rule. Additionally, NMC contends that complying with the
rule in this case will result in undue hardship.
3.0 Discussion
Pursuant to 10 CFR 50.12, ``Specific Exemption,'' 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. These circumstances include the special circumstance listed in
10 CFR 50.12(a)(2)(iii), where ``Compliance would result in undue
hardship or other costs that are significantly in excess of those
contemplated when the regulation was adopted, or that are significantly
in excess of those incurred by others similarly situated.''
In its exemption supplement of August 25, 2005, NMC provided a
justification for satisfying the hardship special circumstance. The
staff agrees with NMC that due to the short duration between the March
23, 2005, issuance of Regulatory Issue Summary (RIS) 2005-05,
``Regulatory Issues Regarding Criticality Analyses for Spent Fuel Pools
and Independent Spent Fuel Storage Installations'' (ADAMS ML043500532),
and the scheduled October 2005 cask loading campaign at PNP,
insufficient time exists for NMC to perform the required analyses
necessary to demonstrate compliance with 10 CFR 50.68. RIS 2005-05
identified an acceptable methodology for demonstrating compliance with
the 10 CFR 50.68(b)(1) requirements during cask loading, unloading, and
handling operations in pressurized water reactor SFPs. The staff has
determined that a hardship claim may be acceptable for licensees that
have previously scheduled loading campaigns commencing before March 31,
2006 (1 year after the issuance of the RIS). Therefore, the staff
concludes that pursuant to 10 CFR 50.12(a)(2)(iii), NMC has provided
sufficient justification to support a conclusion that undue hardship
would occur if NMC were required to postpone its scheduled cask-loading
campaign until it could comply with 10 CFR 50.68.
However, since NMC's justification is based on the time needed to
perform the necessary analyses, the staff has determined that NMC must
comply with the regulations within an appropriate amount of time. In
its exemption supplement, NMC proposed that the exemption remain valid
until July 31, 2006. This will provide enough time for NMC to perform
the necessary analyses and submit a license amendment request (LAR) to
comply with 10 CFR 50.68. If NMC submits an LAR by July 31, 2006, this
exemption will remain in effect until such time as the NRC staff either
approves or denies the LAR. In this case, the NRC staff finds it
acceptable to leave the exemption in effect because it will allow NMC
to unload any previously loaded cask should it become necessary.
However, if NMC does not submit a license amendment by July 31, 2006,
this exemption will expire, and NMC will not be able to load, unload,
or handle dry shielded canisters (DSCs) in the spent fuel pool (SFP).
In its exemption supplement, NMC committed to complete supporting
criticality analyses and submit a LAR to allow credit for burnup to
meet the requirements of 10 CFR 50.68(b)(1) in July 2006 or earlier.
The NRC staff also evaluated NMC's request to determine if NMC has
provided reasonable assurance that it can conduct the proposed cask
loading, unloading, and handling activities in a safe and effective
manner. PNP's Technical Specifications (TSs) currently permit NMC to
store spent fuel assemblies in high-density storage racks in its SFP.
In accordance with the provisions of 10 CFR 50.68(b)(4), NMC takes
credit for soluble boron for criticality control, and ensures that the
effective multiplication factor (keff) of the SFP does not
exceed 0.95 if flooded with borated water. Section 50.68(b)(4) also
requires that if credit is taken for soluble boron, the keff
must remain below 1.0 (subcritical) if flooded with unborated water.
However, NMC is unable to satisfy the requirement to maintain the
keff below 1.0 with unborated water at all times, which is
also the requirement of 10 CFR 50.68(b)(1). Therefore, NMC's request
for exemption from 10 CFR 50.68(b)(1) proposes to permit NMC to perform
spent fuel loading, unloading, and handling operations related to dry
cask storage without being subcritical under the most adverse
moderation conditions feasible by unborated water.
Appendix A, ``General Design Criteria (GDC) for Nuclear Power
Plants,'' of 10 CFR, part 50, lists the minimum design
[[Page 60376]]
requirements for nuclear power plants. According to GDC 62,
``Prevention of criticality in fuel storage and handling,'' PNP must
have physical systems or processes to limit the potential for
criticality in the fuel handling and storage system. Section 5.1.7.3 of
PNP's Updated Final Safety Analysis Report (UFSAR) describes PNP's
compliance with GDC 62. Section 5.1.7.3 specifically references the
design of the spent fuel storage racks to maintain a geometrically safe
configuration that provides spacing and neutron poisons sufficient to
maintain a keff of less than 1.0 when flooded with unborated
water.
Section 50.68 of 10 CFR part 50, gives NRC requirements for
maintaining subcritical conditions in SFPs. Section 50.68 specifies
criticality-control requirements that, if satisfied, ensure that an
inadvertent criticality in the SFP is an extremely unlikely event.
These requirements include appropriate, conservative criticality
margins during handling and storage of spent fuel. Section 50.68(b)(1)
states, ``Plant procedures shall prohibit the handling and storage at
any one time of more fuel assemblies than have been determined to be
safely subcritical under the most adverse moderation conditions
feasible by unborated water.'' Specifically, 10 CFR 50.68(b)(1)
requires NMC to maintain the SFP in a subcritical condition during
handling and storage operations without crediting the soluble boron in
the SFP water.
NMC received a license to construct and operate an Independent
Spent Fuel Storage Installation (ISFSI) at PNP. The ISFSI permits NMC
to store spent fuel assemblies in large concrete dry storage casks
(Horizontal Storage Modules). As part of its ISFSI loading campaigns,
NMC transfers spent fuel assemblies to a DSC in the cask pit area of
the SFP. NMC performed criticality analyses of a fully-loaded DSC with
fuel having the highest permissible reactivity. It determined that a
soluble-boron credit was necessary to ensure that the DSC would remain
subcritical in the SFP. NMC is thus unable to satisfy the requirement
of 10 CFR 50.68(b)(1) to ensure subcritical conditions during handling
and storage of spent fuel assemblies in the pool with unborated water.
Accordingly, NMC identified the need for an exemption from the 10 CFR
50.68(b)(1) requirement to support DSC loading, unloading, and handling
operations, without being subcritical under the most adverse moderation
conditions feasible by unborated water.
The NRC staff evaluated the possibility of an inadvertent
criticality of the spent nuclear fuel at PNP during DSC loading,
unloading, and handling. The NRC staff has established a set of
acceptance criteria that, if met, minimize the potential for an
inadvertent criticality event. In lieu of complying with 10 CFR
50.68(b)(1), the NRC staff determined that an inadvertent criticality
accident is unlikely to occur if NMC meets the following five criteria:
Criterion 1--The cask criticality analyses are based on the
following conservative assumptions:
--No credit is taken for fuel-related burnable absorbers.
--All fuel assemblies in the cask are unirradiated and at the
highest permissible enrichment.
--The cask is assumed to be flooded with moderator at the
temperature and density corresponding to optimum moderation.
--Only 75 percent of the Boron-10 in the fixed poison panel inserts
is credited.
Criterion 2--NMC's ISFSI TSs require the soluble boron
concentration to be equal to, or greater than, the level assumed in the
criticality analysis. TS surveillance requirements specify periodically
verifying the concentration both prior to, and during, loading and
unloading operations.
Criterion 3--Radiation monitors, as required by GDC 63,
``Monitoring Fuel and Waste Storage,'' are provided in fuel storage and
handling areas to detect excessive radiation levels and to initiate
appropriate safety actions.
Criterion 4--The quantity of other forms of special nuclear
material (e.g., sources, detectors, etc.) to be stored in the cask will
not increase the effective multiplication factor above the limit
calculated in the criticality analysis.
Criterion 5--Sufficient time exists for plant personnel to
identify and terminate a boron dilution event prior to achieving a
critical boron concentration in the DSC. NMC must provide the following
to demonstrate that it can safely identify and terminate a boron
dilution event:
--A plant-specific criticality analysis to identify the critical
boron concentration in the cask based on the highest reactivity loading
pattern.
--A plant-specific boron dilution analysis to identify all
potential dilution pathways, their flowrates, and the time necessary to
reach a critical boron concentration.
--A description of all alarms and indications available to promptly
alert operators of a boron dilution event.
--A description of plant controls that NMC will implement to
minimize the potential for a boron dilution event.
--A summary of operator training, and procedures that will be used,
to ensure that operators can quickly identify and terminate a boron
dilution event.
In RIS 2005-05, the NRC identified an acceptable methodology for
demonstrating compliance with the 10 CFR 50.68(b)(1) requirements
during cask loading, unloading, and handling operations in pressurized
water reactor SFPs. The NRC staff has determined that licensee
implementation of this methodology will eliminate the need to grant
future exemptions for cask storage and handling evolutions. NMC
submitted its exemption request on June 21, 2005, 3 months after the
issuance of the RIS. Since the exemption request was submitted after
the issuance of the RIS, and an acceptable methodology for complying
with the regulation exists, the staff has determined that it is not
appropriate to approve the exemption based on the 50.12(a)(2)(ii)
special circumstance related to the underlying purpose of the rule.
In its August 25, 2005, supplement, NMC contends that due to the
short duration available between the March 2005 issuance of the RIS,
and the October 2005 planned cask loading campaign, an undue hardship
exists. Section 50.12 of 10 CFR provides for a special circumstance
that allows the staff to review an exemption request based on undue
hardship. Specifically, 10 CFR 50.12(a)(2)(iii) states the following:
Compliance would result in undue hardship or other costs that
are significantly in excess of those contemplated when the
regulation was adopted, or that are significantly in excess of those
incurred by others similarly situated.
Since the NRC staff has determined that it is not appropriate to
grant the exemption based on satisfying the underlying intent of the
rule, it reviewed the exemption request based on the undue hardship
special circumstance in 10 CFR 50.12(a)(2)(iii). In determining the
technical acceptability of NMC's exemption request, the NRC staff
reviewed NMC's criticality analyses submitted to support the ISFSI
license application and its exemption request, and NMC's boron dilution
analysis. For each of the aspects, the NRC staff evaluated whether
NMC's analyses and methodologies provide reasonable
[[Page 60377]]
assurance that adequate safety margins are developed, and can be
maintained, in the PNP SFP during loading of spent fuel into DSCs for
dry cask storage.
3.1 Criticality Analyses
The NRC staff's review of NMC's criticality analyses, as described
in the Standardized NUHOMS[reg] Fuel Safety Analysis Report, dated 6/
30/04 (ADAMS ML051040570), consists of four parts. First, the NRC staff
reviewed the methodology and assumptions NMC used in its criticality
analysis to determine if Criterion 1 was satisfied. NMC stated the
following:
It took no credit in the criticality analyses for burnup or
fuel-related burnable neutron absorbers.
All assemblies were analyzed at the highest permissible
enrichment.
All criticality analyses for a flooded DSC were performed at
temperatures and densities of water corresponding to optimum moderation
conditions.
In its exemption request, NMC provided the results of its optimum
moderation analysis that effectively demonstrated that the optimum
moderation condition had been identified. NMC also said that it
credited 90 percent of the Boron-10 content for the fixed neutron
absorber in the DSC. NUREG-1536, ``Standard Review Plan for Dry Cask
Storage System,'' states that ``[f] or a greater credit allowance
[i.e., greater than 75 percent for fixed neutron absorbers] special,
comprehensive fabrication tests capable of verifying the presence and
uniformity of the neutron absorber are needed.'' The NRC staff accepted
a 90-percent credit for the fixed neutron absorbers as described in
Section 6 of Appendix M of the Standardized NUHOMS[reg] Final Safety
Analysis Report. Therefore, for the purposes of this exemption, the
staff finds a 90-percent credit acceptable on the basis that it has
previously been reviewed and approved by the NRC. Based on its review
of the criticality analyses and the information submitted in its
exemption request, the NRC staff finds that NMC has satisfied Criterion
1.
Second, the NRC staff reviewed the proposed PNP ISFSI TSs. NMC's
criticality analyses credit soluble boron for reactivity control during
DSC loading, unloading, and handling operations. Since the boron
concentration is a key safety component necessary for ensuring
subcritical conditions in the pool, NMC must have a conservative ISFSI
TS capable of ensuring that sufficient soluble boron is present to
perform its safety function. The ISFSI TSs applicable to the
NUHOMS[reg]-32PT DSC, and attached to the Certificate of Compliance No.
1004, contain the requirements for the minimum soluble boron
concentration as a function of fuel assembly class, DSC basket type,
and corresponding assembly average initial enrichment values. In all
cases, the boron concentration required by the ISFSI TS ensures that
the keff will be below 0.95 for the analyzed loading
configuration. Additionally, NMC's ISFSI TSs contain surveillance
requirements that assure it will verify the boron concentration is
above the required level both prior to, and during, DSC loading,
unloading, and handling operations. Based on its review of the PNP
ISFSI TSs, the NRC staff finds that NMC has satisfied Criterion 2.
Third, the NRC staff reviewed the PNP's UFSAR, and the information
provided by NMC in its exemption request, to ensure that it complies
with GDC 63. GDC 63 requires that licensees have radiation monitors in
fuel storage and associated handling areas to detect conditions that
may result in a loss of residual heat removal capability and excessive
radiation levels and initiate appropriate safety actions. In its
exemption request, NMC stated that its radiation monitoring system
consists of gamma-sensitive detector assemblies in the SFP area, with
audible alarm at the initiating detector and in the main control room.
NMC stated in its exemption request that operations personnel will
investigate the cause of high radiation levels and initiate appropriate
safety actions. Furthermore, NMC's compliance with GDC 63 is described
in its UFSAR, Sections 5.1.7.4 and 9.11.4.4. Based on its review of the
exemption request and the PNP UFSAR, the NRC staff finds that NMC has
satisfied Criterion 3.
Fourth, as part of the criticality analysis review, the NRC staff
evaluated the storage of non-fuel related material in a DSC. The NRC
staff evaluated the potential to increase the reactivity of a DSC by
loading it with materials other than spent nuclear fuel and fuel
debris. The approved contents for storage in the NUHOMS[reg]-32PT cask
design are listed in the PNP ISFSI TS Limiting Condition for Operation
(LCO) 1.2.1 ``Fuel Specifications.'' This ISFSI TS LCO restricts the
contents of the DSC to only fuels and non-fissile materials irradiated
at PNP. As such, PNP is prohibited from loading other forms of special
nuclear material (e.g., sources, detectors, etc.) in the DSC.
Therefore, the NRC staff determined that the loading limitations
described in PNP's ISFSI TSs will ensure that any authorized components
loaded in the DSCs will not result in a reactivity increase. Based on
its review of the loading restrictions, the NRC staff finds that NMC
has satisfied Criterion 4.
3.2 Boron Dilution Analysis (Criterion 5)
Since NMC's ISFSI application relies on soluble boron to maintain
subcritical conditions within the DSCs during loading, unloading, and
handling operations, the NRC staff reviewed NMC's boron dilution
analysis to determine whether appropriate controls, alarms, and
procedures were available to identify and terminate a boron dilution
accident prior to reaching a critical boron concentration.
The NRC's letter of October 25, 1996, ``Topical Report Evaluation
of WCAP-14416, Westinghouse Spent Fuel Rack Criticality Analysis
Methodology'' (ADAMS 9610300008), issued a safety evaluation
on licensing topical report WCAP-14416, ``Westinghouse Spent Fuel Rack
Criticality Analysis Methodology.'' This safety evaluation specified
that the following issues be evaluated for applications involving
soluble boron credit:
Events that could cause boron dilution;
Time available to detect and mitigate each dilution event;
Potential for incomplete boron mixing;
Adequacy of the boron concentration surveillance interval.
The criticality analyses performed for the NUHOMS[reg]-32PT DSC are
described in the FSAR for the Standardized NUHOMS[reg] Horizontal
Modular Storage System for Irradiated Nuclear Fuel. NMC used the same
criticality analysis methods, models, and assumptions for its boron
dilution evaluation. These PNP criticality calculations are based on
the KENO V.a code. The calculations determined the minimum soluble
boron concentration required to maintain subcriticality
(keff < 1.0) following a boron dilution event in a
NUHOMS[reg]-32PT DSC loaded with fuel assemblies that bound the PNP
fuel designs (Combustion Engineering 15 x 15 fuel). To ensure that the
calculated critical boron concentrations were bounding for all loading
conditions, NMC employed conservative fuel enrichments in its analysis.
NMC's criticality analyses were based on 3.6 weight-percent Uranium-235
enriched fuel, as opposed to the 3.4 weight percent limit in the
NUHOMS[reg]-32PT DSC TSs. The results of these calculations for the
bounding case indicate that subcriticality is maintained if the soluble
boron concentration remains greater than or equal to 1850 ppm. PNP's
ISFSI TSs
[[Page 60378]]
require NMC to maintain the soluble boron concentration greater than
2500 ppm in the DSC at all times. NMC indicated that proposed Amendment
9 to the NUHOMS[reg] Certificate of Compliance 1004 provides analyses
to support a variable, minimum-required, soluble-boron concentration as
a function of the initial enrichment of the fuel to be stored. NMC
committed in its exemption request to not implement this proposed
change. Instead, NMC will continue to conduct DSC operations at a boron
concentration of greater than or equal to 2500 ppm.
TS surveillance requirements for the NUHOMS[reg]-32PR Cask System
require the boron concentration in the SFP, and in the water to be
introduced in the DSC, to be verified as follows:
Within 4 hours prior to flooding the DSC cavity;
Within 4 hours prior to inserting the first spent fuel
assembly into the DSC;
Reconfirmed at intervals not to exceed 48 hours until such
time as the DSC is removed from the SFP;
NMC's analysis identified all credible potential sources that could
dilute the SFP to critical conditions. NMC determined that the limiting
boron dilution event occurs when water from the fire protection system,
with a maximum flow rate of 210 gpm from a 1.5-inch diameter hose, is
added to the SFP. NMC's calculations show that at least 4 hours will be
available to terminate the event before the DSC water boron
concentration decreases from 2500 ppm to the critical concentration of
1850 ppm, assuming a straight dilution to the SFP overflow limit and a
feed and bleed operation thereafter with instantaneous complete mixing.
The Palisades' SFP is a large rectangular structure filled with
borated water which completely covers the spent fuel assemblies. During
loading, unloading, and handling activities, the DSC is located in a 9
by 9 foot area in the north east corner of the SFP. This area is open
to the SFP, thereby ensuring that thermal currents within the pool will
mix the volume near the DSC with the remainder of the pool.
To demonstrate that sufficient time exists for plant personnel to
identify and terminate a boron dilution event, NMC described all alarms
available to alert operators, and plant controls that will be
implemented. There is no automatic level control system for the SFP;
therefore, the SFP will overflow on an uncontrolled water addition.
However, a high-level alarm in the control room would alert personnel
of a potential boron dilution event within 45 minutes for a 210 gpm
dilution rate; 30 additional minutes will elapse before the pool begins
to overflow. From this point, NMC calculated that at least 3 more hours
are available to mitigate the dilution event before the boron
concentration is reduced to the critical concentration of 1850 ppm.
In its exemption request of June 21, 2005, NMC stated that ``to
ensure defense-in-depth regarding the detection of a boron dilution
event, NMC will revise procedures to include a requirement that
whenever a 32PT DSC is in the SFP and fuel is in the DSC, the SFP level
will be monitored on at least an hourly frequency (via television
monitor or locally) to ensure that the SFP is not overflowing, and that
SFP water level is not unintentionally rising.'' Therefore, should a
boron dilution event occur, the most conservative time for the
individual to detect the event would be when the SFP begins to
overflow. Assuming the pool water level starts just above the low-level
alarm setpoint, then at most 73.3 minutes could elapse since the start
of the dilution. With a limiting value of 210 gpm of unborated water
being added to the pool, there would be 2.96 additional hours to
mitigate and terminate the event. The staff finds that this is
acceptable.
To ensure that operators are capable of identifying and terminating
a boron dilution event during DSC loading, unloading, and handling
operations, NMC stated that operator training will be conducted. NMC
said that during training activities, operators will receive revised
alarm manual procedures, which verify that the SFP boron concentration
is in compliance with the new ISFSI TS limit prior to the loading of a
NUHOMS[reg]-32PR DSC.
Based on the staff's review of NMC's exemption request dated June
21, 2005, and its boron dilution analysis, the staff finds that NMC has
provided sufficient information to demonstrate that an undetected and
uncorrected dilution from the TS required boron concentration to the
calculated critical boron concentration is very unlikely. Based on its
review of the boron analysis and enhancements to the operating
procedures and operator training program, the staff finds NMC has
satisfied Criterion 5.
Therefore, in conjunction with the conservative assumptions used to
establish the TS-required boron concentration and critical boron
concentration, the boron dilution evaluation demonstrates that the SFP
and DSC will remain subcritical during spent fuel loading, unloading
and handling operations.
Accordingly, the NRC staff concludes that since NMC has satisfied
the five criteria, as described in Section 3.0 of this exemption, NMC
has provided reasonable assurance that it can conduct the proposed cask
loading, unloading, and handling activities in a safe and effective
manner.
Section 50.68(b)(1) of 10 CFR was promulgated to require that
adequate controls are in place so that the handling and storage of fuel
assemblies is conducted in a manner that provides reasonable assurance
that the fuel assemblies will remain safely subcritical. Based on the
NRC staff's review of NMC's exemption request, the staff has determined
the following:
NMC has demonstrated that sufficient controls are in place
to provide reasonable assurance that there is no undue risk to public
health and safety given conservative assumptions in the criticality
analysis (Criterion 1).
Surveillances periodically verify the boron concentration
before, and during, loading and unloading (Criterion 2).
Radiation monitoring equipment is used to detect excessive
radiation and initiate appropriate protective actions (Criterion 3).
Only fuel authorized by the ISFSI TSs will be loaded and stored in
the ISFSI (Criterion 4).
Boron dilution events have been analyzed, and there are
sufficient monitoring capabilities and time for NMC to identify and
terminate a dilution event prior to achieving a critical boron
concentration in the cask (Criterion 5).
Therefore, the NRC staff concludes that NMC has established
sufficient controls to ensure the fuel assemblies remain subcritical
during loading, unloading, and handling within the SFP and DSC so that
there is no undue risk to public health and safety.
This exemption results in changes to the operation of the plant by
allowing the operation of the new dry fuel storage facility and loading
of the NUHOMS[reg]-32PT DSC.
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 NMC, an exemption from the
requirements of 10 CFR 50.68(b)(1) for the loading, unloading, and
handling of the components of the TN NUHOMS[reg]-32PT
[[Page 60379]]
dry cask storage system at PNP. However, since NMC does not have an
NRC-approved methodology for evaluating changes to the analyses or
systems supporting this exemption request, the NRC staff's approval of
the exemption is restricted to those specific design and operating
conditions described in NMC's June 21, 2005, exemption request. NMC may
not apply the 10 CFR 50.59 process for evaluating changes to specific
exemptions. Any changes to the design or operation of (1) the dry cask
storage system; (2) the SFP; (3) the fuel assemblies to be stored; (4)
the boron dilution analyses; or (5) supporting procedures and controls,
regardless of whether they are approved under the general Part 72
license or perceived to be conservative, will invalidate this
exemption. Upon invalidation of the exemption, NMC will be required to
comply with NRC regulations prior to future cask loadings.
Based upon the review of NMC's exemption request to credit soluble
boron during DSC loading, unloading, and handling in PNP's SFP, the NRC
staff concludes that pursuant to 10 CFR 50.12(a)(2)(iii), NMC's
exemption request is acceptable. However, the NRC staff places the
following limitations/conditions on the approval of this exemption:
1. This exemption is limited to the loading, unloading, and
handling of the DSC for only the TN NUHOMS[reg]-32PT at the PNP.
2. This exemption is limited to the loading, unloading, and
handling in the DSC at PNP of Combustion Engineering 15 x 15 fuel
assemblies, without burnable poison rod assemblies, that had maximum
initial, unirradiated U-235 enrichments less than 3.6 weight percent.
3. This exemption is limited to the one-time only loading,
unloading, and handling of the 7 TN NUHOMS[reg]-32PT cask systems (224
assemblies total) scheduled for the October 2005 cask loading campaign
at PNP.
4. If NMC submits a LAR by July 31, 2006, this exemption will
remain in effect until such time as the NRC staff either approves or
denies the LAR. In this case, the NRC staff finds it acceptable to
leave the exemption in effect because it will allow NMC to unload any
previously loaded cask should it become necessary. However, if NMC does
not submit a license amendment by July 31, 2006, this exemption will
expire, and NMC will not be able to load, unload, or handle DSCs in the
SFP. In its exemption supplement, NMC committed to complete supporting
criticality analyses and submit a LAR to allow credit for burnup to
meet the requirements of 10 CFR 50.68(b)(1) in July 2006 or earlier.
5. During DSC loading, unloading, and handling at PNP, the SFP
soluble boron concentration must be greater than or equal to 2500 ppm
at all times.
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 57899).
This exemption is effective upon issuance.
Dated at Rockville, Maryland, this 6th day of October 2005.
For the Nuclear Regulatory Commission.
Ledyard B. Marsh,
Director, Division of Licensing Project Management, Office of Nuclear
Reactor Regulation.
[FR Doc. E5-5689 Filed 10-14-05; 8:45 am]
BILLING CODE 7590-01-P