ML19276D398
| ML19276D398 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs, 07201032, 07200078  |
| Issue date: | 10/03/2019 |
| From: | David Gudger Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards |
| References | |
| Download: ML19276D398 (9) | |
Text
Exelon Generation@
200 Exelon Way Kennett Square. PA 19348 www.exeloncorp.com 10 CFR 72.7 October 3, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Director, Division of Spent Fuel Storage and Transportation Office of Nuclear Material Safety and Safeguards Washington, DC 20555-0001 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 Calvert Cliffs Nuclear Power Plant Independent Spent Fuel Storage Installation, NRC Docket No. 72-8 license No. SNM-2505 NRC Docket No. 72-78
Subject:
Exemption Request to Load and Store Spent Fuel in HI-STORM FW Spent Fuel Casks Utilizing Amendment 1, Revision 1 to CoC No. 1032 The Holtec International, Inc., (Holtec) HI-STORM FW dry cask storage (DCS) system is designed to hold and store spent fuel assemblies for independent spent fuel storage installation (ISFSI) deployment. The system is listed in 10 CFR 72.214 as Certificate of Compliance (CoC) Number (No.) 1032. This system is planned for use by Exelon Generation Company, LLC (Exelon) at the Calvert Cliffs Nuclear Power Plant (CCNPP), in accordance with 1O CFR 72.210, "General license issued."
In accordance with 1O CFR 72.7, "Specific exemptions," Exelon is requesting NRC approval of an exemption from the requirements contained in the CoC for the HI-STORM FW spent fuel casks. Specifically, Appendix B, Table 2.1-2, Class 14x14C has a fuel pellet diameter of~ 0.3805 inches. Calvert Cliffs Nuclear Power Plant (CCNPP) has fuel that meets all other requirements of Class 14x14C, except the fuel pellet diameter is 0.3810 inches.
Exelon has evaluated the proposed exemption and concluded loading the fuel pellets with slightly different diameters does not impact the criticality control, shielding, structural, confinement, or thermal design functions of the loaded casks.
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.
Exemption Request to Load and Store Spent Fuel in HI-STORM FW Spent Fuel Casks October 3, 2019 Page2 The attachment to this letter describes the need and justification for the issuance of an exemption, as well as a safety analysis and environmental assessment of the proposed action.
Exelon requests approval of the proposed exemption by December 31, 2020 to support development of fuel loading documentation for the early Summer of 2021 spent fuel loading campaign.
There are no regulatory commitments in this submittal.
If you should have any questions regarding this submittal, please contact Enrique Villar at 61 0-765-5736.
Respectfully, p},,.,._ .-J T .,,l_ .) yv-David T. Gudger Acting Director - Licensing Exelon Generation Company, LLC
Attachment:
1O CFR 72.7 Exemption Request, Calvert Cliffs Nuclear Power Plant Independent Spent Fuel Storage Installation cc: Regional Administrator, NRC Region I NRC Senior Resident Inspector NRC Project Manager D. A. Tancabel, State of Maryland
Attachment 1 10 CFR 72.7 Exemption Request, Calvert Cliffs Nuclear Power Plant Independent Spent Fuel Storage Installation
1O CFR 72.7 Exemption Request, Attachment 1 Calvert Cliffs Nuclear Power Plant Page 1of6 Independent Spent Fuel Storage Installation
- 1) Introduction The Holtec International, Inc., (Holtec) HI-STORM FW dry cask storage (DCS) system is designed to hold and store spent fuel assemblies for independent spent fuel storage installation (ISFSI) deployment. The system is listed in 1O CFR 72.214 as Certificate of Compliance (CoC) Number (No.) 1032. This system is planned for use by Exelon Generation Company, LLC (Exelon) at the Calvert Cliffs Nuclear Power Plant (CCNPP), in accordance with 1O CFR 72.210, "General license issued."
During the 2021 CCNPP spent fuel loading campaign (SFLC), Exelon will load and store HI-STORM FW spent fuel casks utilizing Amendment 1 Revision 1 to Coe No. 1032. In CoC No. 1032, the NRG has approved the use of the (Holtec) Multipurpose Canister (MPC)-37 to store PWR spent fuel assemblies. Specifically, Appendix B to Coe No.1032, "Approved Contents and Design Features," contains Table 2.1-2, "Fuel Assembly Limits," which gives dimensions, including fuel pellet diameter, for different fuel assembly arrays/classes
- 2) Request for Exemption Holtec CoC No. 1032, Amendment 1 Revision 1, Appendix B, Table 2.1-2, for Class 14x14C limits the fuel pellet diameter to s 0.3805 inches. CCNPP has fuel that meets all other requirements of Class 14x14C, except that the fuel pellet diameter is >0.3805 inches.
Therefore, in accordance with 10 CFR 72.7, "Specific exemptions," Exelon is requesting NRG approval of an exemption from the following requirements, which will enable Exelon to load and store the fuel, in a Holtec MPC-37.
- 10 CFR 72.212(b)(3), which states the general licensee must "[e]nsure that each cask used by the general licensee conforms to the terms, conditions, and specifications of a Coe or an amended CoC listed in§ 72.214."
- The portion of 10 CFR 72.212(b)(11) which states that" The licensee shall comply with the terms, conditions, and specifications of the Coe .... "
Because of potential future plans, and the criticality design of the system is unchanged between amendments, Exelon would also like this exemption to apply to Amendments 4 and 5 of Coe No. 1032, once approved.
- 3) Basis for Approval of Exemption Request In accordance with 1O CFR 72.7, the NRG may, upon application by any interested person or upon its own initiative, grant such exemptions from the requirements of the regulations in this part 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.
a) Authorized by Law This exemption would allow Exelon to load and store CCNPP fuel that is not currently part of the approved contents in the MPC-37. The NRG issued 10 CFR 72.7 under the authority granted to it under Section 133 of the Nuclear Waste Policy Act of 1982, as amended, 42 U.S.C. § 10153. Section 72.7 allows the NRG to grant exemptions from the requirements of
10 CFR 72.7 Exemption Request, Attachment 1 Calvert Cliffs Nuclear Power Plant Page 2 of 6 Independent Spent Fuel Storage Installation 1O CFR Part 72. Granting the proposed exemption provides adequate protection to public health and safety, and the environment. As described 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.
b) Will not Endanger Life or Property or the Common Defense and Security Exelon has evaluated loading and storing the fuel with a slightly larger pellet diameter in an MPC-37. This evaluation concluded that the proposed loading configuration does not impact the criticality control, shielding, structural, confinement, or thermal design functions of the loaded MPC-37, as described in the Safety Analysis section below. Therefore, the proposed exemption does not endanger life or property or the common defense and security. In addition, Exelon has determined that neither the proposed action nor the alternative to the proposed action will have an adverse impact to the environment.
c) Otherwise in the Public Interest Due to site work being performed in late 2019 and early 2020, CCNPP site leadership decided in July 2019 that a SFLC in 2020 cannot be supported. Exelon must load three casks in 2021 to avoid losing full core offload capability. Approval of this exemption request is required to support an early Summer 2021 the spent fuel loading campaign.
It is in the public's interest to grant an exemption, since dry storage of the CCNPP fuel assemblies places them in an inherently safe, passive system, and the exemption would permit this storage without the unnecessary burden and impact of requesting and approving a license amendment.
The requested exemption does not create a new accident precursor or result in an increase in the probability of any postulated accident. Nor will the requested exemption result in an increase in the consequences of postulated accidents. The requested exemption does not result in any change to the types or amounts of effluents that may be released offsite. There is no significant increase in occupational or public radiation exposure. Therefore, the requested exemption does not result in undue risk to public health and safety.
- 4) Safety Analysis The Holtec HI-STORM FW DCS system (i.e., a loaded MPC, stored within a HI-STORM overpack) provides criticality control, shielding, heat removal, and confinement functions, independent of any other facility structures or components. The structural design of the cask system also maintains the integrity of the fuel during storage.
The MPC design requires certain limits on spent fuel parameters, including fuel type, assembly weight, initial enrichment, total uranium weight, maximum burnup, maximum decay heat, minimum cooling time, and physical condition to safely store the spent fuel. These limitations are included in the thermal, structural, radiological, and criticality evaluations for the cask.
10 CFR 72.7 Exemption Request, Attachment 1 Calvert Cliffs Nuclear Power Plant Page 3 of 6 Independent Spent Fuel Storage Installation CoC No. 1032, Appendix B, Table 2.1-1,Section I, "MPC MODEL: MPC-37," Item A.1 specifies, as an allowable content fuel assembly (undamaged or damaged) meeting the criteria specified in Table 2.1-2. Table 2.1-2 states (in part) that Assembly Class 14x14C has a fuel pellet diameter s0.3805 inches, whereas CCNPP has fuel assemblies that meet all other criteria of that assembly class, except a fuel pellet diameter of 0.381 O inches. The fuel assemblies to be loaded in the HI-STORM FW System, MPC-37 continue to meet all other fuel parameters, burnup and enrichment limits, and decay heat requirements. The fuel pellet diameter impacts only the criticality analysis, which is evaluated below. Because the fuel assemblies meet all other requirements, and the system is operated in the same manner as described in the HI-STORM FW FSAR, there is no change to the structural, thermal, shielding, or confinement analysis of the system, and those areas are not further evaluated.
Criticality The CCNPP fuel meets all other requirements of Assembly Class 14x14C which is specified in Coe No. 1032, Appendix B, Table 2.1-2, except that the fuel pellet diameter of the CCNPP fuel is 0.3810 inches while the fuel pellet diameter of the assembly class 14x14C is only 0.3805 inches. In Section 6.1 of the HI-STORM FW Final Safety Analysis Report (FSAR),
Assembly Class 14x14C in the MPC-37 canister are analyzed with the associated maximum allowable enrichments and the minimum allowable soluble boron concentrations, and all the maximum kett values are below the regulatory requirement of 0.95. However, increasing the fuel pellet diameter would result in an increase in the fissile material amount and a potential increase of the reactivity. Therefore, the criticality analysis is not bounding for the CCNPP fuel.
Consequently, evaluations have been performed for the revised Assembly Class 14x14C using the increased fuel pellet diameter of 0.381 O inches corresponding to the specifications of CCNPP fuel. The maximum kettValues for the revised Assembly Class 14x14C are only 0.9220 for the maximum allowable enrichments of 4.0 wt% 235 U and 0.9276 for the maximum allowable enrichments of 5.0 wt% 235 U, which are well below the regulatory limit. Sensitivity studies for the revised Assembly Class 14x14C are also performed with both filled and voided guide and instrument tubes, and with both flooded and empty pellet-to-clad gap. Conclusions of these studies remain unchanged when compared with Subsections 6.2.1 and 6.4.7 of the HI-STORM FW FSAR.
Therefore, it is concluded that loading and storing the CCNPP fuel in an MPC-37 canister would not significantly increase the cask reactivity, which would continue to remain below the regulatory limit of 0.95.
Shielding A small variation in heavy metal weight in this fuel assembly (increase from 438 kg to approximately 439.15 kg) is sufficiently covered by conservatism in shielding analyses discussed in HI-STORM FW FSAR. For example, the design basis assembly considers uranium weight of approximately 469 kg (Table 5.2.1 of the HI-STORM FW FSAR) which is greater than the uranium weight of assemblies being loaded.
1OCFR 72.7 Exemption Request, Attachment 1 Calvert Cliffs Nuclear Power Plant Page 4 of 6 Independent Spent Fuel Storage Installation In addition, outside of the CoC approval process, a site-specific shielding analysis is performed to satisfy 1OCFR72.104 which will consider specific fuel assemblies loaded on site. This will be captured in the Calvert Cliffs 72.212 compliance report.
Thermal The fuel pellet diameter is used in the effective fuel thermal conductivity calculations. The small change in fuel pellet diameter has a second order impact on the effective fuel properties. Moreover, a larger fuel pellet diameter decreases the helium gap between the pellet and cladding, thereby reducing the resistance to heat transfer. Additionally, the 14x14C fuel assembly is bounded by the 17x17 fuel assembly adopted in the licensing basis analyses for the Reference Hight MPC-37 to be loaded at CCNPP. Therefore, the 14x14C assembly continues to be bounded by the 17x17 assembly identified in Table 2.1.4 of the HI-STORM FW FSAR.
Structural Fuel pellet diameter is not a critical characteristic for the HI-STORM FW FSAR structural analyses, and further consideration is not required.
Confinement Fuel pellet diameter is not a critical characteristic for the HI-STORM FW FSAR structural analyses, and further consideration is not required.
- 5) Environmental Consideration Exelon has evaluated the environmental impacts of the proposed exemption request and has determined that neither the proposed action nor the alternative to the proposed action will have an adverse impact to the environment. Therefore, neither the proposed action nor the alternative requires any Federal permits, licenses, approvals, or other entitlements.
a) Environmental Impacts of the Proposed Action Although the CCNPP ISFSI is not part of the Protected Area as defined in 1O CFR Part 50; it is a radiologically controlled area with physical protection in accordance 10 CFR 72.182.
The area considered for potential environmental impact as a result of this exemption request is the area in and surrounding the ISFSI.
The interaction of a loaded HI-STORM FW with the environment is through the thermal, shielding, and confinement design functions for the cask system. As described in Section 4, EGC has verified the following conclusions for proposed storage of CCNPP fuel assemblies with increased pellet diameter:
- Steady state fuel cladding temperatures will remain below the ISG-11, Revision 3 limits, since there is no change to the allowable decay heat limits of the fuel.
10 CFR 72.7 Exemption Request, Attachment 1 Calvert Cliffs Nuclear Power Plant Page 5 of 6 Independent Spent Fuel Storage Installation
- Existing radiological evaluations and conclusions in Chapter 5 of the HI-STORM FW FSAR will remain valid, since there is no change to the shielding evaluation as the analysis inputs bound the 14x14C fuel assembly.
- Design aspects of the MPC enclosure vessel (i.e., the confinement boundary) will remain unchanged.
Exelon has also determined that there are no gaseous, liquid, or solid effluents (radiological or non-radiological), radiological exposures (worker or member of the public) or land disturbances associated with the proposed exemption. Therefore, approval of the requested exemption has no impact on the environment.
The proposed exemption does not increase the probability or consequences of accidents, no changes would be made to the types of effluents released offsite, and there would be no increase in occupational or public radiation exposure. Therefore, there are no significant radiological environmental impacts associated with the proposed action. Additionally, the proposed action would not involve any construction or other ground disturbing activities, would not change the footprint of the existing ISFSI, and would have no other significant non-radiological impacts. The ISFSI is located on previously disturbed land, thus, the proposed exemption does not have the potential to create any significant impact on aquatic or terrestrial habitat in the vicinity of the ISFSI, or to threatened, endangered, or protected species. In addition, the proposed exemption does not have the potential to cause effects on historic or cultural properties, assuming such properties are present at the site of the GGNPP ISFSI.
b) Adverse Environmental Effects Which Cannot be Avoided Should the Exemption be Approved Since there are no environmental impacts associated with approval of this exemption, there are no adverse environmental effects which cannot be avoided should the exemption request be approved.
c) Alternative to the Proposed Action In addition to the proposed exemption request, Exelon has considered the alternative action.
Specifically, Exelon would need to request the GoG holder to submit a license amendment request, which the NRG would need to review and approve. While 10 GFR 72.7 does not require a description of "special circumstances," application of the applicable regulations [i.e.,
1OGFR 72.212(b)(3) and (b)(11 )] to the particular circumstances would not serve the underlying purpose of the rule, nor is it necessary to achieve the underlying purpose.
The underlying purpose of 10 GFR 72.212 is to allow reactor licensees to utilize dry fuel storage casks that have previously been found to be safe and appropriately analyzed for use by the cask designer, the cask user, and the NRG. As described above in Section 4, the storage of the fuel assemblies described above in an MPG-37 has been found to be non-safety significant, and in agreement with the underlying purpose of 10GFR 72.212.
1OCFR 72.7 Exemption Request, Attachment 1 Calvert Cliffs Nuclear Power Plant Page 6 of 6 Independent Spent Fuel Storage Installation Exelon currently plans to load the fuel assemblies during the CCNPP 2021 SFLC as part of a program to ensure full core discharge capability is maintained. In order to load the fuel assemblies during the 2021 SFLC campaign, Exelon must start fuel loading package documentation by December 2020.
Based on the amount of time required by NRC to review and approve previous CoC amendment requests (i.e., ranging from 18 months to 27 months), a license amendment request by HOLTEC to amend its currently approved CoC for the HI-STORM FW will not provide adequate time for Exelon to develop the required fuel loading packages. This could potentially result in Exelon having to delay or postpone executing the scheduled loading campaign in early Summer 2021; and therefore, losing the ability to maintain full core discharge capability.
Note that although, this exemption request is made to allow the schedule to accommodate CCNPP, the CoC holder (Holtec), does plan on making this change in the next amendment that is submitted.
d) Environmental Effects of the Alternatives to the Proposed Action There are no environmental impacts associated with the alternative to the proposed action.
e) Conclusion and Status of Compliance As a result of the environmental assessment, EGC concludes that the proposed action, which will allow EGC to load CCNPP spent nuclear fuel in an MPC-37, is in the public interest in that it avoids an unnecessary delay in the safe loading and storage of the CCNPP that would result from the alternative to the proposed action.