ML16355A263

License Amendment Request - Proposed Change Regarding Partial Length Fuel Rod (PLR) Burnup

ML16355A263
Person / Time
Site:	Limerick
Issue date:	12/20/2016
From:	David Helker Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML16355A263 (13)

Text

Exelon Generation 200 Exelon Way Kennett Souare. PA 19348 www.exeloncorp.com 10 CFR 50.90 December 20, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 2 Renewed Facility Operating License No. NPF-85 NRC Docket No. 50-353

Subject:

License Amendment Request - Proposed Change Regarding Partial Length Fuel Rod (PLR) Burnup In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (Exelon) requests an amendment to Renewed Facility Operating License No. NPF-85 for Limerick Generating Station (LGS), Unit 2.

The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of NRG Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors," for partial length rods that are currently in the LGS Unit 2 Cycle 14 reactor core for the remainder of the current operating cycle. These partial length rods are expected to exceed 62,000 MWD/MTU (which is the current rod peak burnup limit specified in Footnotes 1O and 11 of NRG Regulatory Guide 1.183) prior to the end of the operating cycle. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above the 62,000 MWD/MTU limit. The attachment to this letter provides a description and evaluation of the proposed change.

The proposed change has been reviewed by the LGS Plant Operations Review Committee in accordance with the requirements of the Exelon Quality Assurance Program.

Current projections show that, at the end of the current operating cycle for LGS Unit 2, eight partial length rods will have exceeded the 62,000 MWD/MTU burnup limit. To date, none of the partial length rods have exceeded the burnup limit. However, projections show that the limit will be exceeded on or about March 30, 2017. Therefore, Exelon requests approval of the proposed change by March 17, 2017, to support continued plant operation following the date that the burnup limit will be exceeded. Once approved, the amendment will be implemented prior to exceeding the burnup limit.

License Amendment Request Partial Length Rod Burnup Docket No. 50-353 December 20, 2016 Page2 In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), Exelon is notifying the Commonwealth of Pennsylvania of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

There are no regulatory commitments contained in this letter.

Should you have any questions concerning this letter, please contact Glenn Stewart at 610-765-5529.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 201h day of December 2016.

Respectfully, David P. Helker Manager - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Evaluation of Proposed Change cc: Regional Administrator - NRC Region I w/ attachment NRC Senior Resident Inspector - Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection

ATTACHMENT License Amendment Request Limerick Generating Station, Unit 2 Docket No. 50-353 EVALUATION OF PROPOSED CHANGE

Subject:

Proposed Change to Partial Length Fuel Rod (PLR) Burnup 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedence 4.3 No Significant Hazards Consideration 4.4 Conclusions

6.0 REFERENCES

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 1 of 10 Docket No. 50-353 Evaluation of Proposed Change 1.0

SUMMARY

DESCRIPTION In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (Exelon) requests an amendment to Renewed Facility Operating License No. NPF-85 for Limerick Generating Station (LGS), Unit 2.

The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of NRC Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors," (Reference 1) for partial length rods that are currently in the LGS Unit 2 Cycle 14 reactor core for the remainder of the current operating cycle. These partial length rods are expected to exceed 62,000 MWD/MTU (which is the current rod peak burnup limit specified in Footnotes 10 and 11 of NRC Regulatory Guide 1.183) prior to the end of the operating cycle. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above the 62,000 MWD/MTU limit.

Current projections show that at the end of the current operating cycle for LGS Unit 2, eight (8) partial length rods will have exceeded the 62,000 MWD/MTU burnup limit. To date, none of the partial length rods have exceeded the burnup limit. However, projections show that the limit will be exceeded on or about March 30, 2017. Therefore, Exelon requests approval of the proposed change by March 17, 2017, to support continued plant operation following the date that the burnup limit will be exceeded. Once approved, the amendment will be implemented prior to exceeding the burnup limit.

2.0 DETAILED DESCRIPTION In Reference 2, the NRC issued amendments 185 and 146 to the facility operating licenses for LGS, Units 1 and 2, respectively. The amendments support the application of alternative source term (AST) methodology with respect to the loss-of-coolant accident (LOCA), the fuel handling accident (FHA), and control rod drop accident (CRDA). Exelon's AST analyses for LGS were performed following the guidance in NRC Regulatory Guide 1.183 and 10 CFR 50.67, "Accident source term."

Section 3 of Reference 1 provides an AST that is acceptable to the NRC, and indicates that once approved, the AST assumptions or parameters specified in the positions described in Section 3 become part of the facility's design basis. After the NRC has approved an implementation of an AST, subsequent changes to the AST require NRC review under 10 CFR 50.67.

The LGS AST analyses used the core inventory release fractions for the gap release and early in-vessel damage phases for the design basis accident (DBA) LOCA that are listed in Table 1 of Reference 1. For the FHA and CRDA events, the LGS analyses used the fractions of the core inventory assumed to be in the gap for the various radionuclides in Table 3 of Reference 1.

These release fractions were used in conjunction with the fission product inventory calculated with the maximum core radial peaking factor.

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 2 of 10 Docket No. 50-353 Evaluation of Proposed Change The discussion of release fractions in Reference 1 is annotated with the following footnote:

10 The release fractions listed here have been determined to be acceptable for use with currently approved LWR fuel with a peak burnup up to 62,000 MWD/MTU. The data in this section may not be applicable to cores containing mixed oxide (MOX) fuel.

In addition, Table 3 in Reference 1 is annotated with the following footnote:

11 The release fractions listed here have been determined to be acceptable for use with currently approved LWR fuel with a peak burnup up to 62,000 MWD/MTU provided that the maximum linear heat generation rate does not exceed 6.3 kw/ft peak rod average power for burnups exceeding 54 GWD/MTU. As an alternative, fission gas release calculations performed using NRC-approved methodologies may be considered on a case-by-case basis. To be acceptable, these calculations must use a projected power history that will bound the limiting projected plant-specific power history for the specific fuel load. For the BWR rod drop accident and the PWR rod ejection accident, the gap fractions are assumed to be 10% for iodines and noble gases.

On March 12, 2015, it was determined that LGS Unit 2 Cycle 14 core design will not meet the Regulatory Guide 1.183 limit for peak rod exposure of 62,000 MWD/MT for certain partial length rods (Issue Report 2454608). Subsequently, it was determined that an analytical solution to resolve the issue was not going to be successful; therefore, on June 7, 2016, Issue Report 2679181 was initiated under Exelon's Corrective Action Program. A solution was implemented to insert near-edge control rods to suppress the pin exposures such that the leading pin exposures would not exceed the 62,000 MWD/MT requirement. A technical evaluation was performed to provide a new set of control rod patterns to reduce the peak rod exposures below the Regulatory Guide limit. As a result of the rod pattern adjustment an increasing trend in moisture carryover has been identified.

The technical evaluation identified a contingency action to perform a rod pattern adjustment to restore the rod pattern to the original cycle management report rod patterns if elevated moisture carryover was identified. This contingency is required, and as a result, the expected peak pin exposure for the affected partial length rods will exceed the 62,000 MWD/MTU limit if left unaddressed. For LGS Unit 2, the affected fuel bundles are currently expected to exceed the burnup limit on or about March 30, 2017.

The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of RG 1.183 for the partial length rods that are currently in the LGS Unit 2 Cycle 14 reactor core for the remainder of the current operating cycle, which is currently scheduled to end in April 2017.

The fuel bundles containing the partial length rods are in their last cycle of operation; therefore, this condition will be eliminated from the reactor core once the fuel bundles are removed from the operating core after Cycle 14 is complete. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above 62,000 MWD/MTU.

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 3 of 10 Docket No. 50-353 Evaluation of Proposed Change

3.0 TECHNICAL EVALUATION

The partial length rod is a fuel rod that is shorter than a full length rod, and is located in the bottom portion of the reactor core. It has less uranium content and, as a result of the axial power distribution due to voiding in the top of the core, it experiences higher rod-average exposure. However, it is similar to the corresponding segment of the full length rod.

Essentially, the segment is the same as a full length rod, except it has the top portion of uranium removed. Using this equivalence aspect and a gap fraction calculation procedure, a comparative analysis was performed to determine the impact on the FHA and CRDA analyses, and to demonstrate whether or not a partial length rod is bounded by a full length rod.

Fuel rod data shows that a total of four (4) GNF2 fuel bundles have partial length rods that are projected to exceed 62,000 MWD/MTU by the end of Cycle 14. Each fuel bundle has two (2) partial length rods for a total of eight (8) rods that are projected to reach a maximum burnup of 62,130 MWD/MTU.

A review of the power and burnup history for the bundle with the highest partial length rod burnup from beginning of life to the projected end of Cycle 14 was performed. The burnup profile of the partial length rods (PLRs) was compared to the average of the same lower axial segment of the full length rods (FLRs). In this case, the maximum FLR was compared to determine if the PLRs are bounded by the worst FLR.

Based on this review, the long PLRs on the non-blade side of the lattice are projected to exceed 62,000 MWD/MTU by the end of Cycle 14, and are the most limiting. These PLRs have a slightly higher projected burnup than the maximum FLR as shown in Figure 1. These PLRs not being bounded by the worst FLR burnup indicates that these rods experienced higher power during their operation. The maximum final burnup of the limiting FLR is projected to be 60,710 MWD/MTU and thus the PLR is only exceeding this burnup by about 2.4%, which is considered minor. The power history of these rods was examined because the power can influence the fission gas release to the gap plenum.

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 4 of 10 Docket No. 50-353 Evaluation of Proposed Change Figure 1 - LIM2, Average Over PLR Fueled Nodes, Projected EOC 14 60.0 50.0 Average Burnup (GWD/ST) 40.0 FLR MAX PLR MAX 30.0 20.0 10.0 0.0 0 500 1000 1500 2000 2500 EFPD A calculation procedure available to assess the gap inventory is specified in ANSI/ANS-5.4-2011, "Method for Calculating the Fractional Release of Volatile Fission Products from Oxide Fuel," (i.e., Reference 3) to assess the gap inventory. In that calculation procedure, the fractional release of fission gases is computed in a radial and axial (nodal) domain that represents the uranium oxide fuel pellet stack. The release fraction is computed as a function of burnup and the power, both of which determine how much gas diffusion out of the pellet stack occurs. The effective release fraction is then computed by a volume and power weighted average of the spatial dependent release fractions. The technical evaluation used this approach to evaluate the gap release fraction of the partial length rod with respect to the full length rod, given operational characteristics inherent to the partial length rods.

Plots of the power history of the maximum PLRs in comparison to the corresponding FLR maximum power shows that the PLRs have several periods where the power is larger than the FLR. Conversely, there are also periods where the power of the PLRs is bounded by the maximum FLR. Integrated, these differences agree with the differences in burnup. The largest power difference is about 2.4%, which is considered minor. The same PLR power profile plotted against the FLR with the maximum final burnup shows that the power of the PLRs are in

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 5 of 10 Docket No. 50-353 Evaluation of Proposed Change no danger of exceeding the 6.3 kw/ft restriction for burnup over 54 GWD/MTU as specified in RG 1.183 footnote 11.

The PLRs that exceed 62,000 MWD/MTU have an active fuel length less than the FLR active fuel length of 150 inches. As a result, the FLRs have significantly more uranium, and therefore, will have nearly that much more radionuclide activity. This increased activity provides margin to any possible minor increase in the gap release in the PLR compared to the corresponding release in the lower axial segment of the FLR. The differences have been evaluated to be less than 2.4% in power and burnup when the PLR is compared to the same lower axial segment of the maximum FLR. Therefore, it is concluded that the RG 1.183 Table 3 non-LOCA gap fractions remain applicable for the LGS AST non-LOCA DBA dose analyses. Also, since all the FLRs are projected to meet RG 1.183 footnote 11 restrictions, it is concluded that the LGS GNF2 bundles affected by this condition meet the intent of the footnote.

In order to ensure the dose consequences of AST non-LOCA DBAs are conservative given the GNF2 PLRs that exceed the RG 1.183 burnup restriction, it is important that the activity release from the rods damaged correspond to the activity of the full length rod. This approach is typically taken as the number of PLRs damaged vs FLRs is typically not specified by the fuel vendor. This approach also ensures that effectively the release is bounding regardless of how many PLRs are involved.

A review of the LGS non-LOCA DBA dose analyses of record was performed. The FHA models the release from GE 8x8 fuel. The GE 8x8 fuel was retained as the design basis fuel damage because it is most limiting. In the analysis of record, the release from GNF2 fuel was assessed against the 8x8 release. This assessment effectively substitutes the activity of a PLR with a FLR by assuming the number of fuel pins in the bundle is equal to the number of equivalent full length rods rather than the total number of rods in the calculation of the core damage fraction.

The resulting GNF2 core damage fraction was bounded by the 8x8 fuel core damage fraction.

Therefore, there are no changes required to the LGS FHA dose analysis to address the PLR condition.

Similarly, the CRDA analysis of record was reviewed. The GNF2 core damage calculation in the analysis of record effectively substitutes the activity of a PLR with a FLR by assuming the number of fuel pins in the bundle is equal to the number of equivalent full length rods rather than the total number of rods. This results in the bounding core damage fraction as compared to other fuel types that were evaluated. Therefore, there are no changes required to the LGS CRDA dose analysis to address the PLR condition.

Based on the evaluation performed above, it is concluded that the current LGS FHA and CRDA conservatively model GNF2 PLRs by effectively substituting the activity of the PLR with that of a FLR. Since the power and burnup evaluation concluded that there are no changes required to the RG 1.183 Table 3 non-LOCA gap release fractions, it is concluded that the LGS FHA and CRDA dose analyses are unaffected by the PLR condition and do not require revision.

Exelon has also performed an evaluation to assess the impact of considering the LGS Unit 2 Cycle 14 specific core design on the AST LOCA dose analysis, and to further show that the consequences of a small number of partial length rods in the applicable batch exceeding the 62,000 MWD/MTU peak rod average limit in Footnote 10 of Reference 1 will not cause LOCA

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 6 of 10 Docket No. 50-353 Evaluation of Proposed Change doses to exceed the current analysis of record results. The impact of partial length rods exceeding 62,000 MWD/MTU was determined using the same method of substituting full length rod activity for partial length rod activity. The current analysis of record determined the post-LOCA control room dose is 4.76 rem TEDE, which is the most limiting with respect to the 10 CFR 50.67 limits. Using a LGS Unit 2 Cycle 14 cycle-specific core inventory and substituting the activity of all PLRs in the affected batch with that of FLRs results in a control room dose of 4.56 rem TEDE. Therefore, it is concluded that the small number of LGS Unit 2 Cycle 14 partial length rods that will exceed the 62,000 MWD/MTU limit by the end of the current operating cycle would not result in doses from a LOCA exceeding the current licensing basis results.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria In accordance with 10 CFR 50.67, a licensee may revise its current accident source term by re-evaluating the consequences of DBAs with the AST. In Reference 2, the NRC approved the allocation of AST methodology at LGS with respect to the LOCA, FHA, and CRDA. The guidance associated with the implementation of an AST is provided in NRC Regulatory Guide 1.183 (Reference 1), which states that subsequent changes to the AST require NRC review under 10 CFR 50.67.

Fundamental to the definition of an AST according to Reference 1 are the release fractions. Table 1 of Reference 1 provides core inventory release fractions, by radionuclide groups, for the gap release and early in-vessel damage phases for DBA LOCAs. These fractions are applied to the equilibrium core inventory developed for LGS. Footnote 10 limits the peak burnup to 62,000 MWD/MTU. Table 3 of Reference 1 provides gap release fractions for various volatile fission product isotopes and isotope groups, to be applied to non-LOCA accidents. Footnote 11 of Table 3 limits the peak burnup to 62,000 MWD/MTU provided that the maximum linear heat generation rate does not exceed 6.3 kw/ft peak rod average power for burnups exceeding 54,000 MWD/MTU. As an alternative, fission gas release calculations performed using NRC-approved methodologies may be considered on a case-by-case basis. To be acceptable, these calculations must use a projected power history that will bound the limiting projected plant-specific power history for the specific fuel load. For the BWR rod drop accident and the PWR rod ejection accident, the gap fractions are assumed to be 10% for iodines and noble gases.

Exelon's analyses demonstrate that the radiological consequences of a FHA, CRDA and LOCA are not affected by the proposed change.

4.2 Precedence Letter from B. Vaidya (NRC) to B. Hanson (Exelon), LaSalle County Station, Units 1 and 2 - Issuance of Amendments Re: High Burnup ATRIUM-10 Partial Length Fuel Rods (CAC Nos. MF8442 and MF8443), dated November 18, 2016 (ML16320A182).

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 7 of 10 Docket No. 50-353 Evaluation of Proposed Change 4.3 No Significant Hazards Consideration In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (Exelon) requests an amendment to Renewed Facility Operating License No. NPF-85 for Limerick Generating Station (LGS), Unit 2. The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of NRC Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors," for partial length rods that are currently in the LGS Unit 2 Cycle 14 reactor core for the remainder of the current operating cycle. These partial length rods are expected to exceed 62,000 MWD/MTU (which is the current rod peak burnup limit specified in Footnotes 10 and 11 of NRC Regulatory Guide 1.183) prior to the end of the operating cycle. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above the 62,000 MWD/MTU limit.

According to 10 CFR 50.92, "Issuance of amendment," paragraph (c), a proposed amendment to an operating license involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability or consequences of any accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

Exelon has evaluated the proposed change, using the criteria in 10 CFR 50.92, and has determined that the proposed change does not involve a significant hazards consideration. The following information is provided to support a finding of no significant hazards consideration.

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of NRC Regulatory Guide 1.183 for partial length rods which are currently in the LGS Unit 2 Cycle 14 reactor core that are expected to exceed the 62,000 MWD/MTU rod peak burnup limit specified in Footnotes 10 and 11 of NRC Regulatory Guide 1.183 prior to the end of the operating cycle. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above the 62,000 MWD/MTU limit. The proposed change does not involve any physical changes to the plant design and is not an initiator of an accident. The proposed change does not adversely affect accident initiators or precursors, and

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 8 of 10 Docket No. 50-353 Evaluation of Proposed Change does not alter the design assumptions, conditions, or configuration of the plant or the manner in which the plant is operated or maintained. Therefore, the proposed change does not affect the probability of a loss-of-coolant accident. In addition, the proposed change does not affect the probability of a fuel handling accident or control rod drop accident because the method and frequency of initiating activities are not changing.

Analyses have been performed that demonstrate that the power and burnup for a partial length rod is within 2.4% of the power and burnup in the same axial portion of neighboring full length rods, which is minor. Therefore, since the power and burnup of the full length rods comply with the limits specified in Footnotes 10 and 11 of NRC Regulatory Guide 1.183, the partial length rods may operate beyond the 62,000 MWD/MTU burnup limit and meet the intent of NRC Regulatory Guide 1.183. There are no changes in the dose consequences of the analyses of record for the fuel handling accident, control rod drop accident, and loss-of-coolant 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 change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of NRC Regulatory Guide 1.183 for partial length rods which are currently in the LGS Unit 2 Cycle 14 reactor core that are expected to exceed the 62,000 MWD/MTU rod peak burnup limit specified in Footnotes 10 and 11 of NRC Regulatory Guide 1.183 prior to the end of the operating cycle. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above the 62,000 MWD/MTU limit. The proposed change does not introduce any changes or mechanisms that create the possibility of a new or different kind of accident. The proposed change does not install any new or different type of equipment, and installed equipment is not being operated in a new or different manner. No new effects on existing equipment are created nor are any new malfunctions introduced.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No The proposed change would allow the use of the release fractions listed in Tables 1 and 3 of NRC Regulatory Guide 1.183 for partial length rods which are

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 9 of 10 Docket No. 50-353 Evaluation of Proposed Change currently in the LGS Unit 2 Cycle 14 reactor core that are expected to exceed the 62,000 MWD/MTU rod peak burnup limit specified in Footnotes 10 and 11 of NRC Regulatory Guide 1.183 prior to the end of the operating cycle. In addition, the proposed change would revise the LGS licensing basis to allow movement of irradiated fuel bundles containing partial length rods that have been in operation above the 62,000 MWD/MTU limit. Analyses have been performed that demonstrate that the power and burnup for a partial length rod is within 2.4% of the power and burnup in the same axial portion of neighboring full length rods, which is minor. There is no change in the dose consequences of the fuel handling accident, control rod drop accident, or loss-of-coolant accident analyses of record. The margin of safety, as defined by 10 CFR 50.67 and NRC Regulatory Guide 1.183, has been maintained.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above evaluation, Exelon concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92, paragraph (c), and accordingly, a finding of no significant hazards consideration is justified.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

Exelon has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, "Standards for Protection Against Radiation." However, the proposed amendment does not involve: (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22, "Criterion for categorical exclusion; identification of licensing and regulatory actions eligible for categorical exclusion or otherwise not requiring environmental review,"

paragraph (c)(9). Therefore, pursuant to 10 CFR 51.22, paragraph (b), no environmental impact statement or environmental assessment needs to be prepared in connection with the proposed amendment.

6.0 REFERENCES

1. NRC Regulatory Guide 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors," dated July 2000.

License Amendment Request Attachment LGS Partial Length Fuel Rod Burnup Page 10 of 10 Docket No. 50-353 Evaluation of Proposed Change

2. Letter from R. Guzman (U.S. NRC) to C. M. Crane (Exelon Nuclear), "Limerick Generating Station, Units 1 and 2 - Issuance of Amendments Re: Application of Alternative Source Term Methodology (TAC Nos. MC2295 and MC2296)," dated August 23, 2006.

3. ANSI/ANS-5.4-2011, "Method for Calculating the Fractional Release of Volatile Fission Products from Oxide Fuel."