ML23052A047

Enclosure 5 - Revised Technical Specification Bases (for Information Only)

ML23052A047
Person / Time
Site:	Callaway
Issue date:	02/21/2023
From:	Ameren Missouri
To:	Office of Nuclear Reactor Regulation
Shared Package
ML23052A041	List: ML23052A042 ML23052A043 ML23052A044 ML23052A045 ML23052A046 ML23052A047 ML23052A048 ULNRC-06796, Enclosure 7 - Holtec International Report HI-2230125, Revision 0, Supplemental Criticality Safety Analysis of SFP for Callaway Nuclear Generating Station, Revision 0, Dated February 14, 2023
References
ULNRC-06796, EPID L-2022-LLA-0132
Download: ML23052A047 (1)

Text

Enclosure 5 to ULNRC-06796 Page 1 of 4

ENCLOSURE 5

REVISED TECHNICAL SPECIFICATION BASES (FOR INFORMATION ONLY)

As discussed in Enclosure 1, the following markup of the Technical Specification (TS) Bases for TS 3.7.17 supersedes those provided in Ameren Missouri letter ULNRC-06723, "License Amendment Request Regarding Proposed Technical Specification Changes for Spent Fuel Storage (LDCN 22-0015)," dated August 29, 2022 (ADAMS Accession No. ML22242A122).

3 pages follow this cover page.

Spent Fuel Assembly Storage B 3.7.17

B 3.7 PLANT SYSTEMS

B 3.7.17 Spent Fuel Assembly Storage

BASES

BACKGROUND The High Density Rack (HDR) modules for the fuel storage pool are designed for storage of both new fuel and spent fuel. Region 1 locations are designed to accommodate new fuel with a maximum nominal enrichment of 5.0 wt% U-235. Region 2 locations are designed to accommodate fuel of various initial enrichments which have accumulated minimum burnups within the acceptable domain according to Figure 3.7.17-1, in the accompanying LCO.

Prior to storage of fuel assemblies in the fuel storage pool, overall pool storage configurations are prepared in accordance with administrative controls. The pool layouts include sufficient Region 1 storage to accommodate new and discharged fuel assemblies with low burnup.

Numerous configurations of Region 1 and 2 locations are possible and can occur within the same rack. Rules to governing the storage configuration of Region 1 and 2 assemblies are identified in Specification 4.3.1.1se interfaces are as follows. Rack cells that face each other across a rack-to-rack gap are still considered face-adjacent.

For a given Region 1 location:

1.1 None of the face-adjacent cells may be a Region 1 location.

1.2 A minimum of two of the face-adjacent cells must be empty.

1.3 A maximum of two of the remaining face-adjacent cells may be Region 2 locations. See also Rule 2.3.

1.4 If both of the remaining face-adjacent cells are Region 2 locations, then Rule 2.1 is restricted to one Region 1 location for those cells.

For a given Region 2 location:

2.1 A maximum of two of the face-adjacent cells may be Region 1 locations. See also Rule 1.4.

2.2 The remaining face-adjacent cells may be Region 2 locations or empty.

2.3 If two face-adjacent cells are Region 1 locations, then Rule 1.3 is restricted to one Region 2 location for those cells.

In the most efficient form, these storage configuration rules create a checkerboard pattern in Region 1, alternating between empty and Region 1 locations in face-adjacent cells, and a uniform pattern in Region 2, designating all cells as Region 2 locations, allowing for irregular boundaries between them.

CALLAWAY PLANT B 3.7.17-1 Revision 2 Spent Fuel Assembly Storage B 3.7.17

BASES

BACKGROUND The water in the fuel storage pool normally contains soluble boron, which (continued) results in large subcriticality margins under actual operating conditions. In accordance with 10 CFR 50.68(b)(4) (Ref. 3), the HDR design maintains the fuel storage pool in a subcritical condition during normal operations with the fuel storage pool racks fully loaded, k eff < 1.0 when flooded with unborated water and keff 0.95 when flooded with borated water, all for 95% probability at a 95% confidence level.

APPLICABLE Accidents can be postulated that could increase the reactivity of the fuel SAFETY storage pool which are unacceptable with unborated water in the fuel ANALYSES storage pool. Examples include misloading fuel into cells for which it is not approved (violating TS 3.7.17 and/or Specification 4.3.1.1) or mislocating fuel outside of designed locations altogether (adjacent to or on top of the HDRs). The double contingency principle states, "process designs should incorporate sufficient factors of safety to require at least two unlikely, independent, and concurrent changes in process conditions before a criticality accident is possible" (Ref. 4). Since a loss of soluble boron is an unlikely event that is independent from such postulated accident conditions, credit for borated water during those accidents is allowed. The negative reactivity effect of the soluble boron compensates for the increased reactivity caused by such a postulated accident.

Accident analyses provided in FSAR, Appendix 9.1A (Ref. 1) demonstrate the storage pool maintains subcriticality with k eff 0.95 during these accident occurrences.

The configuration of fuel assemblies in the fuel storage pool satisfies Criterion 2 of 10 CFR 50.36(c)(2)(ii).

LCO The restrictions on the placement of fuel assemblies within the fuel storage pool, in accordance with Figure 3.7.17-1 orand Specification 4.3.1.1, in the accompanying LCO, preserve the assumptions used in the analyses as described in Reference 1.

APPLICABILITY This LCO applies whenever any fuel assembly is stored in the fuel storage pool.

ACTIONS A.1

Required Action A.1 is modified by a Note indicating that LCO 3.0.3 does not apply.

(continued)

CALLAWAY PLANT B 3.7.17-2 Revision 2 Spent Fuel Assembly Storage B 3.7.17

BASES

ACTIONS A.1 (continued)

When the configuration of fuel assemblies stored in the fuel storage pool is not in accordance with Figure 3.7.17-1, or Specification 4.3.1.1, the immediate action is to initiate action to make the necessary fuel assembly movement(s) to bring the configuration into compliance with Figure 3.7.17-1 or Specification 4.3.1.1.

If unable to move irradiated fuel assemblies while in MODE 5 or 6, LCO 3.0.3 would not be applicable. If unable to move irradiated fuel assemblies while in MODE 1, 2, 3, or 4, the action is independent of reactor operation. Therefore, inability to move fuel assemblies is not sufficient reason to require a reactor shutdown.

SURVEILLANCE SR 3.7.17.1 REQUIREMENTS This SR verifies by administrative means that the initial enrichment, cooling time, and burnup of the fuel assembly is in accordance with Figure 3.7.17-1 in the accompanying LCO. For fuel assemblies in the unacceptable range of Figure 3.7.17-1, performance of this SR will ensure compliance with Specification 4.3.1.1. The burnup of each spent fuel assembly stored in Region 2 shall be ascertained by analysis, and independently verified prior to storage in Region 2. Shuffling of fuel within a Region does not require performance of this surveillance.

REFERENCES 1. FSAR, Appendix 9.1A, Spent Fuel Storage Rack Analysis.

2. Deleted.

3. 10 CFR 50.68(b)(4).

4. NEI 12-16, Rev. 4, Guidance for Performing Criticality Analyses of Fuel Storage at Light-Water Reactor Power Plants, as endorsed by Regulatory Guide 1.240, Rev. 0.

CALLAWAY PLANT B 3.7.17-3 Revision 2