ML21194A063

Tabulation of Proposed Changes in License Amendment Request

ML21194A063
Person / Time
Site:	Calvert Cliffs
Issue date:	07/13/2021
From:	Marshall M Plant Licensing Branch 1
To:	Rhoades D Exelon Generation Co
Marshall M, NRR/DORL/LPLI, 415-2871
References
EPID L-2021-LLA-0112
Download: ML21194A063 (6)

Text

Tabulation of Proposed Changes in License Amendment Request (Licensee input in red text.)

Description Justification (LAR Page #) (LAR Page #)

Changes Approval Explicitly Requested:

1) Removal of use of shutdown cooling system to support 9 - 16 of 26 spent fuel pool cooling with a full core offload to the spent

1. This implies that the full core discharge for fuel pool. SFPC system capable of being used to remove both normal and abnormal operations. Page the maximum expected decay heat load from 1830 (i.e., 10 indicates that Cases 1 and 2 for abnormal max SFP capacity) fuel assemblies, including a full core operation and Case 3 and 7 for normal discharge. YES operation.

2. One of differences between normal and abnormal operations is the number of the fuel assemblies already in the SFP prior to the discharge and the decay times of the fuel assemblies. This difference is shown by the decay heat of the fuel assemblies already in the SFP prior to the discharge.

1, 3, & 5 of 26

3. For Abnormal operation, on Page 14, Case 1 justifies 2 SFPC loops are OK if the discharge starts 4.36 days after shutdown with maximum SRW temperature of 50 oF and SFP temperature of 150 oF. ILD Calculation will justify the case when 1 SFPC loop is lost and add calculations for more SRW temperature values.

4. For full core offload Normal operations, Case 3 justifies 2 SFPC loops with maximum SRW temperature of 50 oF and SFP temperature of 150 oF. ILD Calculation will justify the case when 1 SFPC loop is lost and add calculations for more SRW temperature values.

2) Increase the spent fuel pool temperature limit from 130 oF 9 - 16 of 26 to 150 oF with a full core offload to the spent fuel pool (i.e.,

1 & 5 of 26 1. See justifications of Question 1.

217 fuel assemblies). YES 2. ILD Calculation will support SFP temperature of 150 oF.

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Tabulation of Proposed Changes in License Amendment Request (Licensee input in red text.)

Description Justification (LAR Page #) (LAR Page #)

3) New Technical Requirements Manual section concerning 1. TRM will include tables for both full core full core offload. YES offload and partial core shuffle for 2 SFPC loops.

2. ILD Calculation will justify the case when 1 Attachment 2 SFPC loop is lost. Then, TRM will include tables for both full core offload and partial core shuffle for the case when 1 SFPC loop is lost.

Changes Not Overtly Identified as a Change Requesting Approval:

4) Simplified approach to take credit for time it takes bulk 9 - 16 of 26 SFP to heat up to 150 oF description YES

1. ILD Calculation does not directly use the decay heat values of the fuel assemblies already in the SFP prior to the discharge, which is determined in the design basis calculation CA06535 Revision 2. Instead, ILD Calculation, for simplicity and convenience, assumes the decay heat values of the fuel assemblies already in the SFP prior to the 5 - 6 of 26 or discharge (See Table 3.1 of the ILD 9 - 12 of 26 calculation).

2. ILD Calculation takes credit of extra decay time due to consideration of SFP heat up (assuming SFP temperature is increased from 92 oF to 150 oF) in the SFP heat balance calculations, which is different from the current UFSAR method (ES200500540-000-0000 assumes SFP temperature is 120 oF for normal operation and 130 oF for abnormal operation) where the SFP heat up is not considered.

5) Increase the spent fuel pool temperature limit from 120 oF 1. See justifications of Question 1 and Question to 150 oF not including a full core offload. YES 3 of 26 4.

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Tabulation of Proposed Changes in License Amendment Request (Licensee input in red text.)

Description Justification (LAR Page #) (LAR Page #)

6) Increase in decay heat load from 22.33x106 Btu/hr (for 1. 22.33x106 Btu/hr is the bounding decay heat limited decay time 3.5 days with initial core alteration time determined in the design basis calculation CA06535 Revision 1 for the previous Standard of 3 days after shutdown) to 34.4x106 Btu/hr (for limited and VAP fuel assemblies.

decay time 7 days with initial core alteration time of 6 days 2. 34.4x106 Btu/hr is the bounding decay heat after shutdown). YES determined by using the design basis calculation CA06535 Revision 2 for all fuel 3 of 26 types (the previous Standard and VAP fuel and the current Framatome fuel assemblies).

3. However, ILD Calculation assumes conservative decay heat values of the fuel assemblies already in the SFP prior to the discharge based on the decay heat results in CA06535 Revision 2. See justification #2 of Question 4.

7) Decrease in maximum service water temperature from 65 1. ILD Calculation will support the change of the oF (to support decay time of 3.5 days) to 50 oF (to support SRW temperature from 65 oF to 50 oF. See justifications of Question 1.

decay time of 6 days). YES 2. Note that ECP-20-000436 approved the UFSAR 3 of 26 change markup against UFSAR Revision 51:

A maximum SRW temperature of 69 °F is required to support a minimum decay time of 4.5 days for partial core offload of 125 fuel assemblies.

8) Increase from 100 assembly batch reload to 101 assembly 1. 100 assembly batch reload is the one that batch reload. NO yields the bounding decay heat (22.33x106 Btu/hr) determined in the design basis calculation CA06535 Revision 1 for the Previous Standard and VAP fuel assemblies.

2. Similarly, 101 assembly batch reload is the 3 of 26 one that yields the bounding decay heat determined in the design basis calculation CA06535 Revision 2 for all fuel types (the Previous Standard and VAP fuel and the current Framatome fuel assemblies).

9) Change hypothetical sequence of events YES  ?

4 - 6 of 26 3 of 6

Tabulation of Proposed Changes in License Amendment Request (Licensee input in red text.)

Description Justification (LAR Page #) (LAR Page #)

From: To:

84 fuel assemblies from 125 fuel assemblies from Unit 1 after an average of Unit 1 after an average of 1860 days of reactor 1498 days of reactor operation at 2738 MWt operation at 2738 MWt 1. From Here:

and are replaced with 101 fresh fuel assemblies and 24 oldest spent fuel assemblies 84 fuel assemblies 125 fuel assemblies Case ?

removed from Unit 2 after removed from Unit 2 after average of 1860 days of average of 1498 days of irradiation and 365 days irradiation and 365 days after Unit 1 refueling after Unit 1 refueling Case ?

84 fuel assemblies 125 fuel assemblies removed from Unit 2 and removed from Unit 2 and replaced with fresh fuel replaced with 101 fresh fuel assemblies and 24 oldest spent fuel Case ?

assemblies from SFP 84 fuel assemblies 125 fuel assemblies removed from Unit 1 after removed from Unit 1 after average of 1860 days of average of 1498 days of Case ?

irradiation and 365 days irradiation and 365 days after Unit 2 refueling after Unit 2 refueling 84 fuel assemblies 125 fuel assemblies removed from Unit 1 and removed from Unit 1 and Case ?

replaced with fresh fuel replaced with 101 fresh fuel assemblies and 24 Case ?

oldest spent fuel assemblies from SFP 4 of 6

Tabulation of Proposed Changes in License Amendment Request (Licensee input in red text.)

Description Justification (LAR Page #) (LAR Page #)

67 oldest fuel assemblies 12 oldest fuel assemblies assumed to be removed assumed to be removed Case ?

from the pool to allow for from the pool to allow for complete filling of the complete filling of the racks with newer fuel racks with newer fuel 2. Up to here, these are description of how to fill the pool full configuration that yields the bounding decay heat Changes in table load for abnormal operations with Assumes age of 1488 full core offload.

stored fuel assemblies in the SFP are 2 years and the last 125 stored fuel 1. This is an assumption of the decay heat of the existing fuel in the SFP prior to the discharge assemblies have 330 days in ILD Calculation. See Justification 2 of of age Question 4.

Determine acceptable time after shutdown for each SRW temperature to maintain pool at a ILD Calculation will justify the cases with temperature at 150oF different SRW temperature values for full and 75 oF maximum SRW 50 oF maximum SRW partial core offloads and accident with 1 SFPC lost.

temperature is required to temperature is required to support a minimum decay support a minimum decay time of 4.5 days time of 4.5 days So far, ILD Calculation only justifies 50 oF for the maximum SRW temperature and will provide in future more cases to justify the maximum SRW temperature values.

10) Decrease maintaining pool temperature from 155 oF to 1. ILD Calculation justifies 150 °F would be the 150 oF, if one SFPC loop is lost and the remaining SFPC 7 of 26 maximum SFP temperature while removing loop is removing decay heat. YES decay heat for all cases.

Possible Impacts Explicitly Addressed 5 of 6

Tabulation of Proposed Changes in License Amendment Request (Licensee input in red text.)

Description Justification (LAR Page #) (LAR Page #)

11) Structural integrity of the spent fuel pool 16 of 26 16 of 26

12) SFP cooling system/purification system 16 of 26 16 of 26

13) SFP temperature rise on criticality 16 of 26 16 of 26

14) Fuel handling incident and control room dose 17 of 26 17 of 26 6 of 6