ML22006A362
| ML22006A362 | |
| Person / Time | |
|---|---|
| Site: | 99902086 |
| Issue date: | 01/06/2022 |
| From: | Flemig J Holtec |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML22007A108 | List: |
| References | |
| EPID L-2020-TOP-0056, HDI-IPEC-22-002, HI-2200750 | |
| Download: ML22006A362 (63) | |
Text
Krishna P. Singh Technology Campus, 1 Holtec Blvd., Camden, NJ 08104 Telephone (856) 797-0900 Fax (856) 797-0909 Page 1 of 3 January 6, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Docket No. 99902086 - Holtec Spent Fuel Pool Heatup Calculation Methodology
Subject:
Submittal of U.S. Nuclear Regulatory Commission Draft Safety Evaluation by the Office of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology identifying information proprietary to Holtec International HDI Spent Fuel Pool Heat Up Calculation Methodology Docket No. 99902086
References:
- 1. Letter from Holtec to U.S. NRC, Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, (ADAMS Accession No. ML20280A524) dated September 29, 2020
- 2. Letter from Holtec to U.S. NRC, Response to Request for Additional Information-Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, (ADAMS Accession No. ML21148A289) dated May 28, 2021.
- 3. Letter from Holtec to U.S. NRC, Revised Response to Request for Additional Information-Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, (ADAMS Accession No. ML21228A262) dated August 16, 2021.
- 4. Letter from Holtec to U.S. NRC, Response to Request for Additional Information 10-Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, (ADAMS Accession No. ML21291A161) dated October 18, 2021.
- 5. Letter from Holtec to U.S. NRC, Submittal of Topical Report, Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, Revision 2. Including Site-Specific Calculations for NRC Review (ADAMS Accession No. ML ML21356B704) dated December 22, 2021
Dear Sir or Madam:
In Reference 1, Holtec Decommissioning International, LLC (HDI) submitted a Holtec International Topical Report providing a methodology for calculating Spent Fuel Pool heat up for
Krishna P. Singh Technology Campus, 1 Holtec Blvd., Camden, NJ 08104 Telephone (856) 797-0900 Fax (856) 797-0909 Page 2 of 3 NRC review and approval. Holtec believes the methodology will enhance safety by reducing the zirconium fire risks in the spent fuel pool.
In References 2, 3 and 4, Holtec provided responses to Requests for Additional Information (RAI) concerning the Topical Report.
In Reference 5, Holtec submitted revision 2 to the Holtec International Topical Report providing a methodology for calculating Spent Fuel Pool heat up for NRC, including site-specific calculations for NRC review. provides a proprietary version of the draft safety evaluation for the Holtec Topical Report, HI-2200750, Revision 0. Enclosure 1 contains information proprietary to Holtec and is therefore supported by an affidavit signed by Holtec which is provided in Enclosure 3. The draft safety evaluation for the Holtec Topical Report, HI-2200750, Revision 0 provided in Enclosure 1 includes appropriate markings identifying those portions that are proprietary. The proprietary information bracketed in Enclosure 1 is requested to be withheld under 10 CFR 2.390 as supported by the affidavit provided in Enclosure 3. provides a non-proprietary, redacted version of the draft safety evaluation.
If you have any questions, please contact me at 856-797-0900 ext. 3578.
Sincerely, Jean A. Fleming VP, Regulatory and Environmental Affairs Holtec Decommissioning International Jean A.
Fleming Digitally signed by Jean A. Fleming Date: 2022.03.23 14:48:57 -04'00'
Krishna P. Singh Technology Campus, 1 Holtec Blvd., Camden, NJ 08104 Telephone (856) 797-0900 Fax (856) 797-0909 Page 3 of 3
Enclosures:
- Draft Safety Evaluation by the Office of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology (Holtec Proprietary Withhold Information from Public Disclosure pursuant to 10 CFR 2.390) : Draft Safety Evaluation by the Office of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision ), Holtec Spent Fuel Pool Heat Up Calculation Methodology (Non-Proprietary) : Affidavit Pursuant to 10 CFR 2.390 to Withhold Information from Public Disclosure cc: Robert Lucas, NRC, NRR/DORL/LLPB Dennis Morey, NRC, NRR/DORL/LLPB Ekaterina Lenning, NRC, NRR/DORL/LLPB Christopher Regan, NRC, NMSS/DFM Zahira Cruz Perez, NRC, NMSS/DWUP
HDI-IPEC-22-002 :
Draft Safety Evaluation by the Office of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology (Holtec Proprietary Withhold Information from Public Disclosure pursuant to 10 CFR 2.390)
SUBMITTED SEPARATELY
HDI-IPEC-22-002 :
Draft Safety Evaluation by the Office of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology (Non-Proprietary)
U. S. NUCLEAR REGULATORY COMMISSION 1
DRAFT SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION 2
FOR THE TOPICAL REPORT HI-2200750, REVISION 0, 3
4 HOLTEC SPENT FUEL POOL HEAT UP CALCULATION METHODOLOGY 5
6 HOLTEC DECOMMISSIONING INTERNATIONAL 7
8 HOLTEC INTERNATIONAL 9
10 DOCKET: 99902086 11 12 EPID: L-2020-TOP-0056 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 Enclosure 49
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION TABLE OF CONTENTS 1
2 1.
INTRODUCTION...................................................................................................... 4 3
2.
REGULATORY EVALUATION................................................................................. 5 4
Applicable Regulations.......................................................................................... 5 5
Applicable Guidance.............................................................................................. 5 6
Acceptance Criteria................................................................................................ 6 7
3.
TECHNICAL EVALUATION..................................................................................... 6 8
Scenario Identification Process............................................................................. 6 9
3.1.1.
Structured Process................................................................................................... 7 10 3.1.2.
Scenario Progression............................................................................................... 7 11 3.1.3.
Phenomena Identification and Ranking..................................................................... 8 12 3.1.4.
Initial and Boundary Conditions................................................................................ 8 13 Documentation....................................................................................................... 9 14 Evaluation Model Assessment............................................................................ 10 15 3.3.1.
Evaluation Model Applicability..................................................................................10 16 3.3.1.1.
Previously Reviewed and Accepted Codes and Models..........................................10 17 3.3.1.2.
Single Version of the Evaluation Model....................................................................10 18 3.3.1.3.
Physical Modeling....................................................................................................11 19 3.3.1.4.
Level of Detail in the Model......................................................................................19 20 3.3.1.5.
Simplifying and Averaging Assumptions..................................................................23 21 3.3.1.6.
Equations and Derivations.......................................................................................24 22 3.3.1.7.
Field Equations........................................................................................................25 23 3.3.1.8.
Code Tuning............................................................................................................25 24 3.3.2.
Evaluation Model Verification...................................................................................25 25 3.3.2.1.
Numerical Solution...................................................................................................25 26 3.3.3.
Evaluation Model Validation.....................................................................................26 27 2.1.
2.2.
2.3.
3.1.
3.2.
3.3.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION 3.3.3.1.
Validation of the Closure Relationships....................................................................26 1
3.3.3.2.
Validation of the Evaluation Model...........................................................................26 2
3.3.3.3.
Range of Assessment..............................................................................................27 3
3.3.3.4.
Compensating Errors...............................................................................................27 4
3.3.4.
Evaluation Model - Data Applicability.......................................................................28 5
3.3.4.1.
Assessment Data.....................................................................................................28 6
3.3.4.2.
Similarity and Scaling..............................................................................................28 7
3.3.5.
Evaluation Model - Uncertainty Analysis.................................................................29 8
3.3.5.1.
Important Sources of Uncertainty.............................................................................29 9
3.3.5.2.
Experimental Uncertainty.........................................................................................30 10 3.3.5.3.
Calculated and Predicted Results............................................................................30 11 3.3.5.4.
Sensitivity Studies....................................................................................................30 12 3.3.6.
Evaluation Model - Quality Assurance Program.......................................................31 13 3.3.6.1.
Appendix B Quality Assurance Program..................................................................31 14 3.3.6.2.
Quality Assurance Documentation...........................................................................32 15 3.3.6.3.
Independent Peer Review........................................................................................32 16 Conclusions.......................................................................................................... 32 17 3.4.1.
Conditions and Limitations.......................................................................................34 18 4.
REFERENCES....................................................................................................... 34 19 Appendix A Description of Confirmatory Calculations.............................................................37 20 A.1 Recreation of HI-2200750 Method.................................................................................37 21 A.2 Pin by Pin Simulation.....................................................................................................40 22 A.3 References....................................................................................................................52 23 24 3.4.
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- 1. INTRODUCTION 2
3 On September 29, 2020 (later updated by a submittal on October 30, 2020), Holtec International 4
(HI or Holtec) submitted Topical Report (TR) HI-2200750, Revision 0, Holtec Spent Fuel Pool 5
Heat Up Calculation Methodology, (Ref. 1) to the U.S. Nuclear Regulatory Commission (NRC).
6 This TR provides the methodology for describing transient heat up of the assemblies in the 7
spent fuel pool (SFP) following a drain down event in a permanently defueled nuclear power 8
plant.
9 10 The complete list of correspondence between the NRC and Holtec is provided in Table 1 below.
11 This includes request for additional information (RAI) questions, responses to the RAI questions 12 and any other correspondence relevant to this review.
13 14 Table 1: List of Correspondence Author Document Document Date Referenc e
Holtec Initial Submittal September 29, 2020 N/A Holtec Revised Submittal October 30, 2020 1
NRC Completeness Determination December 4, 2020 2
NRC Proprietary Determination December 4, 2020 3
NRC Request for Additional Information - Round 1 March 31, 2021 4
Holtec RAI Responses May 28, 20211 5
Holtec Revised RAI Responses August 16, 2021 6
NRC Request for Additional Information - RAI-10 October 1, 2021 17 Holtec RAI Responses - RAI-10 October 18, 2021 18 15 16 In regard to the staff RAI questions, general information for each RAI including its number, its 17 topic, its associated safety evaluation (SE) section, and the reference(s) of its response are 18 given in Table 2 below.
19 1 Document placed in ADAMS on June 23, 2021.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 5 Table 2: List of RAI Questions OFFICIAL USE ONLY - PROPRIETARY INFORMATION Question Subject Section of SE Reference of
Response
RAI-01 Treatment of near-wall locations 3.1.4 5, 6
RAI-02
Lumped Analysis vs. Pin-by-Pin Analysis 3.3.1.4 5, 6
RAI-03
Radial and Axial Peaking 3.3.1.4 5, 6
RAI-04
Time Step Sensitivity 3.3.5.4 5, 6
RAI-05
Planar Surface Area 3.3.5.1 5, 6
RAI-06
Uncertainty due to emissivity 3.3.5.1 5, 6
RAI-07
Quality Assurance Program 3.3.6.1 5, 6
RAI-08
Comparison to Office of Research (RES) Data 3.3.3.2 5, 6
RAI-09
Variation in Heat Capacity 3.1.4 5, 6
RAI-10
Current NRC Approved Methodology 3.3.1.3 18 2
3
- 2. REGULATORY EVALUATION 4
5 Applicable Regulations 6
7 Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of 8
Production and Utilization Facilities, contains regulations that define requirements for SFPs.
9 These requirements are further specified in the general design criteria (GDC) given in 10 Appendix A to Part 50 including: GDC-61, Fuel Storage and Handling and Radioactivity 11 Control, GDC-2, Design Bases for Protection Against Natural Phenomena, GDC-4, 12 Environmental and Dynamic Effects Design Bases, and GDC-63, Monitoring Fuel and Waste 13 Storage. Holtecs methodology is focused on demonstrating that these regulations are still 14 satisfied following a drain down event in the SFP by demonstrating that the spent fuel 15 temperature remains below a given threshold for a specified time frame.
16 17 Applicable Guidance 18 19 NUREG-1738, Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear 20 Power Plants, provides a technical analysis of the SFP accident risk at decommissioning 21 nuclear power plants (Ref. 7). In Appendix 1.B of that report, the NRC provides the background 22 for the proposed acceptance criteria, which vary based on the conditions experienced by the 23 fuel. The acceptance criterion applicable to the Holtec methodology is that the fuel temperature 24 must not exceed 900 °C prior to 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> following the drain down event. Satisfying this 25 acceptance criterion will ensure that any significant global fuel damage and substantial release 26 of fission products will be avoided.
27 28 To guide the NRC staff in performing its review and assure review quality and uniformity, the 29 NRC created NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports 30 for Nuclear Power Plants (SRP) (Ref. 8). Regulatory guidance for the review of design basis 31 accident evaluation methodologies is provided in Section 15.0.2 of the SRP, Review of 32 Transient and Accident Analysis Methods (Ref. 9). Similar guidance is also set forth for the 33 industry in Regulatory Guide 1.203, Transient and Accident Analysis Methods, dated 34 December 2005 (Ref. 10). While this guidance was specifically developed for reviewing 35 licensing basis accident analysis, it has been noted (Ref. 11) that this guidance is widely 36 applicable to modeling and simulation in general. Therefore, the NRC staff followed the 2.1.
2.2.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 6 guidance presented in SRP Section 15.0.2 but has modified that guidance commensurate with OFFICIAL USE ONLY - PROPRIETARY INFORMATION 2
the risk-significance of the Holtec simulations.
3 4
Acceptance Criteria 5
6 NUREG-1738 provides different acceptance criteria depending on the scenario considered. For 7
the Holtec methodology, the applicable acceptance criterion (as stated in the NUREG and the 8
Holtec submittal) is demonstrating that the spent fuel temperature remains below 900 °C for at 9
least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> following a complete drain down of the SFP. Ensuring this acceptance criterion 10 is satisfied would demonstrate that self-sustained oxidation (that would cause a further increase 11 in the SFP temperatures) will not occur. While Holtecs methodology [
12
] the NRC staff finds that the acceptance criterion provided in 13 NUREG-1738 remains applicable.
14 15 NUREG-1738 does not specify whether or not it is the peak or an averaged fuel temperature 16 which must remain below 900 °C for at least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />. The NRC staff considered 17 understanding the acceptance criterion as average fuel temperature but determined such an 18 understanding was not reasonable because the criterion was based on the cladding 19 temperature that causes self-sustained oxidation. For the average fuel temperature to reach 20 900 °C, some portion of the fuel must have been above 900 °C for some time period. The 21 portion of the fuel above 900 °C would be hot enough to experience self-sustained oxidation, 22 which would lead to increased fuel temperatures. [
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] Because the NRC staff did not understand 24 this acceptance criterion as applying to the average spent fuel temperature as consistent with 25 the goal of the criterion, the staff concluded that the acceptance criterion applied to the peak 26 predicted SFP temperature.
27 28
- 3. TECHNICAL EVALUATION 29 30 Holtec has submitted a calculational methodology for simulating the temperature following the 31 drain down event of an SFP. SRP Section 15.0.2 directs the reviewer to examine the evaluation 32 model (EM), which is defined as the calculational framework for evaluating the behavior of the 33 SFP and includes the computer programs, mathematical models, assumptions, and procedures 34 on how to treat the input and the output, as well as many other factors. Based on guidance 35 from the SRP, this review is organized into five categories shown in Table 3.
36 37 Table 3: General Review Categories General Review Categories 3.1 Scenario Identification Process 3.2 Documentation 3.3 Evaluation Model Assessment 38 39 Scenario Identification Process 40 41 The scenario identification process is a structured process used to identify the key figures of 42 merit or acceptance criteria for the modeled accident. It is also used to identify and rank the 43 component and physical phenomena modeling requirements based on their: (a) importance to 2.3.
3.1.
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acceptable modeling of the scenario and (b) impact on the figures of merit for the calculation.
2 Table 4 provides the SRP review criteria topics and the sections providing the NRC staffs 3
review.
4 5
Table 4: Review Categories of the Scenario Identification Process Scenario Identification Process 3.1.1 Structured Process 3.1.2 Scenario Progression 3.1.3 Phenomena Identification and Ranking 3.1.4 Initial and Boundary Conditions 6
7 3.1.1. Structured Process 8
Structured Process The process used for scenario identification should be a structured process.
SRP Section 15.0.2, Subsection III.3c 9
10 The Holtec submittal is focused on analyzing a single identified scenario, the heat-up resulting 11 from the drain down of an SFP. As the scenario is pre-defined, the NRC staff finds that this 12 criterion has been satisfied.
13 14 3.1.2. Scenario Progression 15 Scenario Progression The description of each scenario should provide a complete and accurate description of the scenario progression.
SRP Section 15.0.2, Subsection III.3c 16 17 Unlike many scenarios, the heat-up following an SFP drain down event is well understood as 18 the fuel heats up without any water to act as a coolant. [
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] Because Holtec has described the 22 scenario progression and such progressions are well-understood, the NRC staff finds that this 23 criterion has been satisfied.
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3.1.3. Phenomena Identification and Ranking 2
Phenomena Identification and Ranking The dominant physical phenomena influencing the outcome of the scenario should be correctly identified and ranked.
SRP Section 15.0.2, Subsection III.3c 3
4 In the submittal, Holtec identified the dominant physical phenomena and how those phenomena 5
would be modeled. [
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] Because these phenomena are the dominant phenomena in the scenario 19 and modeling them would result in an accurate or conservative prediction of reality, the NRC 20 staff finds that this criterion has been satisfied.
21 22 3.1.4. Initial and Boundary Conditions 23 Initial and Boundary Conditions The description of each scenario should provide complete and accurate description of the initial and boundary conditions.
SRP Section 15.0.2, Subsection III.3c 24 25 Holtec has provided a description of the initial and boundary conditions of the scenario in its 26 submittal. [
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32 33 The Holtec analysis method is based on [
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22 23 Because Holtec has defined the initial and boundary conditions consistent with the scenario 24 being modeled, the NRC staff finds that this criterion has been satisfied.
25 26 Documentation 27 28 Generally, the documentation for an EM is the focus of seven different review categories.
29 However, the NRC staff did not need such detailed documentation based on two considerations:
30 (1) the simplicity of the Holtec methodology and (2) that Holtec provided sufficient information 31 such that the NRC staff could independently re-create the analysis described in the Holtec 32 methodology. Because the information provided by Holtec was sufficient for the NRC staff to re-33 create the Holtec analysis, the NRC staff finds that the documentation is sufficient to fully 34 describe the Holtec EM.
35 3.2.
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Evaluation Model Assessment 2
3 SRP Section 15.0.2, Subsection III.3.b, contains eight review criteria for EMs. The review 4
criteria topics and the subsections that provide the NRC staffs assessments are listed in 5
Table 5.
6 7
Table 5: Evaluation Model Assessment Categories 8
Subsection 3.3.1 Evaluation Model Applicability 3.3.2 Evaluation Model Verification 3.3.3 Evaluation Model Validation 3.3.4 Evaluation Model - Data Applicability 3.3.5 Evaluation Model - Uncertainty Analysis 3.3.6 Evaluation Model - Quality Assurance Program 9
10 3.3.1. Evaluation Model Applicability 11 12 3.3.1.1.
Previously Reviewed and Accepted Codes and Models 13 Previously Reviewed and Accepted Codes and Models It should be determined if the mathematical modeling and computer codes used to analyze the transient or accident should have been previously reviewed and accepted. If so, the reviewer should confirm that any previous conditions and limitations remain satisfied.
SRP Section 15.0.2, Subsection III.3b 14 15 The previously approved methods for performing this analysis are addressed in Section 3.3.1.3, 16 Physical Modeling. Therefore, this criterion is addressed elsewhere.
17 18 3.3.1.2.
Single Version of the Evaluation Model 19 Single Version of the Evaluation Model All assessment cases should be performed with a single version of the evaluation model.
SRP Section 15.0.2, Subsection III.3d 20 21 Based on the information provided in the TR, the NRC staff confirmed that all assessment cases 22 were performed with a single version of the EM. The NRC staff concludes that this criterion has 23 been satisfied.
24 3.3.
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3.3.1.3.
Physical Modeling 2
Physical Modeling The physical modeling described in the theory manual and contained in the mathematical models should be adequate to calculate the physical phenomena influencing the accident scenario for which the code is used.
SRP Section 15.0.2, Subsection III.3b 3
4 In general, modeling an SFP drain down is simulating the heat up of a spent fuel assembly as 5
well as any heat transfer mechanisms which can reduce the heat of that assembly. Thus, one 6
common method to perform this analysis is to model the heat up of the assembly using the 7
assemblys decay heat, conservatively ignoring all possible physical mechanisms that would 8
transfer heat from that assembly. [
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18 19 The NRC staff finds that the physical model and the overall methodology of Holtecs approach 20 would result in a reasonable or conservative estimate of the PCT and is therefore acceptable in 21 determining if the acceptance criteria were satisfied. Further discussion regarding specific 22 aspects of Holtecs assumptions in its heat transfer models [
23 24
] are addressed in Section 3.3.1.4, Level of Detail in the Model, of this SE.
25 Because Holtec is conservatively ignoring multiple heat transfer mechanisms between 26 assemblies, is conservatively ignoring multiple heat sinks, and is accurately or conservatively 27 analyzing each bundle in the SFP, the NRC staff finds that this criterion has been satisfied.
28 29 3.3.1.4.
Level of Detail in the Model 30 Level of Detail in the Model The level of detail in the model should be equivalent to or greater than the level of detail required to specify the answer to the problem of interest.
SRP Section 15.0.2, Subsection III.3b 31 32
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] In view of the 37 foregoing, and particularly considering the conditions and limitations imposed by the staff, the 38 level of detail in the model is adequate to determine if an SFP configuration meets the 39 acceptance criterion, so the NRC staff finds that this criterion has been satisfied.
40 41 3.3.1.5.
Simplifying and Averaging Assumptions 42 Simplifying and Averaging Assumptions The simplifying assumptions and assumptions used in the averaging procedure should be valid for the accident scenario under consideration.
SRP Section 15.0.2, Subsection III.3b 43
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29 30 3.3.1.6.
Equations and Derivations 31 Equations and Derivations The equations and derivations should be correct.
SRP Section 15.0.2, Subsection III.3b 32 33 The main equation used in the Holtec method is the general equation for radiation between two 34 surfaces. Because Holtec is using a form of the equation for radiative heat transfer that is 35 based on first principals and no derivations are necessary, the NRC staff finds that this criterion 36 has been satisfied.
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3.3.1.7.
Field Equations 2
Field Equations The field equations of the evaluation model should be adequate to describe the set of physical phenomena that occur in the accident.
SRP Section 15.0.2, Subsection III.3b 3
4 The main equation used in the Holtec method is the general equation for radiation between two 5
surfaces. Because Holtec is using a form of the equation for radiative heat transfer that is 6
based on first principals, the NRC staff finds that this criterion has been satisfied.
7 8
3.3.1.8.
Code Tuning 9
Code Tuning All code options that are to be used in the accident simulation should be appropriate and should not be used merely for code tuning.
SRP Section 15.0.2, Subsection III.3d 10 11 Because the NRC did not observe the selection of any options that were chosen merely for 12 code tuning, the NRC staff finds that this criterion has been satisfied.
13 14 15 3.3.2. Evaluation Model Verification 16 17 3.3.2.1.
Numerical Solution 18 Numerical Solution The numerical solution should conserve all important quantities.
SRP Section 15.0.2, Subsection III.3d 19 20
[
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25 26 Because Holtec performed an analysis demonstrating that the time step size was appropriately 27 chosen, the NRC staff finds that this criterion has been satisfied.
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3.3.3.1.
Validation of the Closure Relationships 4
Validation of the Closure Relationships The range of validity of the closure relationships should be specified and should be adequate to cover the range of conditions encountered in the accident scenario.
SRP Section 15.0.2, Subsection III.3b 5
6 Holtecs methodology models the radiative heat transfer between fuel assemblies. [
7 8
9 10
] The NRC staff finds that this 11 criterion does not apply.
12 13 3.3.3.2.
Validation of the Evaluation Model 14 Validation of the Evaluation Model Integral test assessments must properly validate the predictions of the evaluation model for the full-size plant accident scenarios. This validation should cover all of the important code models and the full range of conditions encountered in the accident scenarios.
SRP Section 15.0.2, Subsection III.3d 15 16
[
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37
]
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION 1
While validation data of the EM are generally required, there are circumstances where no such 2
data exist, and the NRC staff can still determine that the simulations are credible. One such 3
circumstance is an EM that simulates well-understood phenomena where the uncertainties are 4
fully characterized and can be conservatively treated (one example is given in Ref. 20).
5 Because the phenomena are well understood, because the equation used to model the 6
phenomena accurately describes the physics (i.e., first principles) of radiative heat transfer, 7
because the variables in the equation are known with a high degree of certainty, because it is 8
conservative to ignore the phenomena that are not being modeled, because the assumptions 9
made that reduce the complexity of the model are each conservative in nature, and because of 10 the large number of conservatisms in the methodology, the NRC staff determined that validation 11 data is not required for use of this methodology to calculate PCT in the event of a SFP drain 12 down event. Therefore, the NRC staff finds that this criterion does not apply.
13 14 3.3.3.3.
Range of Assessment 15 Range of Assessment All code closure relationships based in part on experimental data or more detailed calculations should be assessed over the full range of conditions encountered in the accident scenario by means of comparison to separate effects test data.
SRP Section 15.0.2, Subsection III.3d 16 17 In general, there are no closure relationships in Holtecs methodology. [
18 19
] Because there are no closure 20 relationships used in Holtecs methodology, the NRC staff finds that this criterion does not 21 apply.
22 23 3.3.3.4.
Compensating Errors 24 Compensating Errors The reviewers should ensure that the documentation contains comparisons of all important experimental measurements with the code predictions in order to expose possible cases of compensating errors.
SRP Section 15.0.2, Subsection III.3d 25 26 Because there was no comparison to experimental data, the NRC staff finds that this criterion 27 does not apply.
1111
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3.3.4. Evaluation Model - Data Applicability 2
3 3.3.4.1.
Assessment Data 4
Assessment Data Published literature should be referred to for sources of assessment data for specific phenomena, accident scenarios, and plant types.
SRP Section 15.0.2, Subsection III.3d 5
6 Holtec was able to provide assessment data in comparison to predictions of analysis performed 7
by RES. This analysis is discussed in Section 3.3.3.2, Validation of the Evaluation Model, of 8
this SE. Additionally, [
9
] In general, because the NRC staff did not base 10 its acceptance on validation data, the NRC staff finds that this criterion does not apply.
11 12 3.3.4.2.
Similarity and Scaling 13 Similarity and Scaling The similarity criteria and scaling rationales should be based on the important phenomena and processes identified by the accident scenario identification process and appropriate scaling analyses. Scaling analyses should be conducted to ensure that the data and the models will be applicable to the full-scale analysis of the plant transient.
SRP Section 15.0.2, Subsection III.3b 14 15 Because there was no comparison to experimental data, the NRC staff finds that this criterion 16 does not apply.
17 18 19 20 21 1111
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2 3
4 3.3.29. Evaluation Model - Uncertainty 3.3.29 Important Sources of Uncertainty OFFICIAL USE ONLY - PROPRIETARY INFORMATION Important Sources of Uncertainty The accident scenario identification process should be used in identifying the important sources of uncertainty. Sources of calculation uncertainties should be addressed, including uncertainties in plant model input parameters for plant operating conditions (e.g., accident initial conditions, set points, and boundary conditions). To address these uncertainties, demonstrate that the combined code and application uncertainty should be less than the design margin for the safety parameter of interest in the calculation.
SRP Section 15.0.2, Subsection III.3e 5
6
[
7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
]
35
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2 3.3.30 Experimental Uncertainty OFFICIAL USE ONLY - PROPRIETARY INFORMATION Experimental Uncertainty The uncertainties in the experimental data base should be addressed. Data sets and correlations with experimental uncertainties that are too large when compared to the requirements for evaluation model assessment should not be used.
SRP Section 15.0.2, Subsection III.3e 3
4 Because there was no comparison to experimental data, the NRC staff finds that this criterion 5
does not apply.
6 7
3.3.5.3.
Calculated and Predicted Results 8
Calculated and Predicted Results For separate effects tests and integral effects tests, the differences between calculated results and experimental data for important phenomena should be quantified for bias and deviation.
SRP Section 15.0.2, Subsection III.3e 9
10 Because there was no comparison to experimental data, the NRC staff finds that this criterion 11 does not apply.
12 13 3.3.5.4.
Sensitivity Studies 14 Sensitivity Studies Assessments should be performed where applicable {specific test cases for LOCA to meet the requirements of Appendix K to 10 CFR Part 50 and TMI [Three Mile Island] action items for PWR small-break LOCA}.
SRP Section 15.0.2, Subsection III.3d Appropriate sensitivity studies shall be performed for each evaluation model, to evaluate the effect on the calculated results of variations in noding, phenomena assumed in the calculation to predominate, including pump operation or locking, and values of parameters over their applicable ranges. For items to which results are shown to be sensitive, the choices made shall be justified.
Appendix K to 10 CFR Part 50 A detailed analysis shall be performed of the thermal-mechanical conditions in the reactor vessel during recovery from small breaks with an extended loss of all feedwater.
TMI [Three Mile Island] action items for PWR 15
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 31 In RAI-04, the NRC staff requested Holtec perform a time step sensitivity study to ensure a OFFICIAL USE ONLY - PROPRIETARY INFORMATION 2
decrease in time step would not greatly impact its methods results. In its response (Ref. 5, later 3
modified by Ref. 6), Holtec provided results of that sensitivity study demonstrating that a change 4
in time step would not impact the results of its method. Various other sensitivity studies were 5
also requested and provided in connection with other portions of this SE and have been fully 6
addressed elsewhere. Because Holtec has provided all requested sensitivity studies, this 7
criterion has been satisfied.
8 9
3.3.6. Evaluation Model - Quality Assurance Program 10 11 The Holtec Quality Assurance Program (QAP) covers, in part, the procedures for design control, 12 document control, software configuration control and testing, and error identification and 13 corrective actions used in the development and maintenance of the Holtec EM. The QAP also 14 ensures adequate training of personnel involved with code development and maintenance, as 15 well as those who perform the analyses.
16 17 SRP Section 15.0.2, Subsection III.3.f, contains three review criteria for the QAP. The review 18 criteria topics and the subsection providing the NRC staffs reviews are listed in Table 6.
19 20 Table 6: Quality Assurance Plan Review Categories Subsection 3.3.6.1 Appendix B Quality Assurance Program 3.3.6.2 Quality Assurance Documentation 3.3.6.3 Independent Peer Review 21 22 3.3.6.1.
Appendix B Quality Assurance Program 23 Appendix B Quality Assurance Program The evaluation model should be maintained under a quality assurance program that meets the requirements of Appendix B to 10 CFR Part 50.
SRP Section 15.0.2, Subsection III.3f 24 25 In its TR, Holtec made reference to a number of reports (including NRC reports) that contained 26 information important for Holtecs EM (e.g., material properties for UO2), but which were not 27 generated or maintained under an Appendix B QAP. In response to RAI-07 (Ref. 6), Holtec 28 confirmed that it performed this analysis under its QAP and will also perform any plant specific 29 SFP analysis under the licensees QAP. Because Holtec has confirmed that the analysis will be 30 maintained under a QAP that satisfies the requirements of 10 CFR Part 50 Appendix B, the 31 NRC staff finds that this criterion has been satisfied.
32
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 32 2
32 Quality Assurance Documentation OFFICIAL USE ONLY - PROPRIETARY INFORMATION Quality Assurance Documentation The quality assurance program documentation should include procedures that address all of these areas [design control, document control, software configuration control and testing, and corrective actions].
SRP Section 15.0.2, Subsection III.3f 3
4 Due to the simplicity of the Holtec EM, this criterion is addressed under Section 3.3.6.1, 5
Appendix B Quality Assurance Program, above.
6 7
3.3.6.3.
Independent Peer Review 8
Independent Peer Review Independent peer reviews should be performed at key steps in the evaluation model development process.
SRP Section 15.0.2, Subsection III.3f 9
10 Due to the simplicity of the Holtec EM, this criterion is addressed under Section 3.3.6.1, 11 Appendix B Quality Assurance Program, above.
12 13 Conclusions 14 15 The NRC staff has made the following conclusions based on the referenced evaluations 16 provided in this SE:
17 18 Based on the staffs evaluation in Section 3.1, Scenario Identification Process, the 19 NRC staff has determined that that the accident scenario identification process is a 20 structured process and has been appropriately used to identify the key figures of merit 21 for the SFP drain down event.
22 23 Based on the staffs evaluation in Section 3.2, Documentation, the NRC staff has 24 determined that the documentation provided was sufficient to adequately describe 25 Holtecs methodology for performing the analysis of the SFP drain down event.
26 27 Based on the staffs evaluation in Section 3.3, Evaluation Model Assessment, the NRC 28 staff has determined that:
29 o the EM generated is applicable to the scenario, 30 o Holtec has performed adequate verification analysis for the model, 31 o based on the staffs engineering judgment the model does not need additional 32 validation analysis, 33 o the model has had adequate uncertainty analysis performed, and 34 o the QAP covers all relevant actions in the development and maintenance of the 35 EM.
36 37 3.4.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION 33 The NRC staff identified the following major uncertainties in the Holtec methodology:
2 OFFICIAL USE ONLY - PROPRIETARY INFORMATION 3
There is no experimental data to confirm the credibility of the simulations.
4 5
There is limited data on the decay heat radial and axial peaking factors of the fuel in the 6
SFP.
7 8
It has not been mathematically proven that Holtecs method will always result in 9
analyzing the most limiting configuration.
10 11 There is limited data on the applicability of [
] at the temperatures of interest.12 13 However, as discussed in this SE, the NRC staff concludes these uncertainties are more than 14 offset by the following:
15 16 Holtec is conservatively ignoring any heat transfer from the fuel assemblies to other 17 structures in the SFP. This ensures that the modeled heat in the spent fuel assemblies 18 will be conservatively higher than expected. This includes ignoring convection, 19 conduction, and radiation to the plates separating the fuel assemblies, the SFP walls, 20 and ultimately to the environment.
21 22 Holtec is conservatively ignoring any natural convection from the air or steam that would 23 be expected to flow through assemblies following an SFP drain down event. This 24 ensures that the heat in the spent fuel assemblies will be conservatively higher than 25 expected.
26 27 Holtec is conservatively treating the fuel pellet and fuel cladding as a single material.
28 This will result in a conservatively high cladding temperature, as there would normally be 29 a temperature distribution in the fuel pin that would have its peak in the pellet and would 30 decrease as the heat is transferred through the pellet, through the gap, and through the 31 cladding. Holtecs method ignores this temperature gradient and calculates a single 32 lumped clad/fuel temperature that represents the average temperature of the fuel pin 33 and will always be higher than the cladding surface temperature where the acceptance 34 criterion is applied.
35 36 Holtec is conservatively ignoring the neutron absorbing material, which would act as a 37 heat sink and reduce the temperature in the assembly.
38 39 Holtecs analysis methodology is based on radiative heat transfer, which is well 40 understood. Further, the NRC staff has concluded that as the temperatures increase, 41 the methods predictions would become more conservative due to ignoring the impacts 42 of an increasing surface emissivity.
43 44 Holtecs analysis methodology has been confirmed using higher fidelity models.
45 46 Holtecs [
] methodology generally results in a conversative limiting decay heat 47 power for fuel assemblies [
48
]
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Based on the above conclusions, the NRC staff finds that there is reasonable assurance that 2
Holtecs EM (described in Ref. 1, with modifications provided by Refs. 5 and 6) along with the 3
staffs conditions and limitations, conservatively or accurately predicts the PCT following an SFP 4
drain down event, and use of the method is acceptable for ensuring that the acceptance criteria 5
of 900 °C is satisfied.
7 3.4.1. Conditions and Limitations 8
9
- 1) The Holtec methodology is approved with the limitation that the decay heat values -
10 including axial peaking factors - of all assemblies are analyzed in order to determine the most limiting case. [
12
]
13 14 The following three conditions and limitations only apply in situations [
15 16 17
]
18 19
- 2) The Holtec methodology is approved with the condition that the modified form of 20 Equation (26) - as stated in response to RAI-02 and given in Equation (1) in this SE - is 21 used to determine the PCT after applying the method described in Chapter 3 of the TR 22 to determine the average fuel temperature. [
23
]
24 25
- 3) The Holtec methodology is approved with the condition that a [
26
] must be applied to the PCT.
27 28
- 4) The Holtec methodology is approved with the condition that [
29 30 31 32 33
]
34 35 4. REFERENCES 36 37
- 1.
Holtec, HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation 38 Methodology, September 29, 2020 - initial submittal (October 30, 2020 - resubmittal) 39 (Agencywide Documents Access and Management System (ADAMS) Accession 40 Nos. ML20280A525 (Non-Publicly Available) and ML20280A524 (Publicly Available)).
41 42
- 2.
Lenning, E., NRC, email to A. Sterdis, Holtec Decommissioning International (HDI), HI, 43 Completeness determination for Holtec Decommissioning International Topical Report 44 HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology, 45 December 4, 2020 (ADAMS Accession No. ML20329A373 (Transmittal Email),
46 ML20329A368 (Completeness Determination)).
47 48
- 3.
Lenning, E., NRC, email to A. Sterdis, HDI, HI U. S. NRC Proprietary information 49 withholding determination form for the Holtec Decommissioning International Topical 50 Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation I
I I
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Methodology, December 4, 2020 (ADAMS Accession No. ML20329A360 (Transmittal 2
Email), ML20329A364 (Completeness Determination)).
3 4
- 4.
Lenning, E., NRC, email to A. Sterdis, HDI, HI Formal Transmittal of the U.S. Nuclear 5
Regulatory Commission Requests for Additional Information for Holtec Topical Report 6
HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology, 7
March 31, 2021 (ADAMS Accession No. ML21077A102 (Transmittal Email/Publicly 8
Available), ML21077A098 (Non-Publicly Available).
9 10
- 5.
Sterdis, A., HDI, HI to E. Lenning, NRC, Response to Request for Additional Information 11
- Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, May 28, 12 2021, (ADAMS Accession No. ML21148A289 (Non-Proprietary/Publicly Available),
13 ML21174A041 (Proprietary/Non-Publicly Available)).
14 15
- 6.
Sterdis, A., HDI, HI to E. Lenning, NRC, Revised Response to Request for Additional 16 Information - Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical Report, 17 August 16, 2021, (ADAMS Accession No. ML21228A262 (Non-Proprietary/Publicly 18 Available), ML21228A263 (Proprietary/ Non-Publicly Available)).
19 20
- 7.
NUREG-1738 Technical Study of Spent Fuel Pool Accident Risk at Decommissioning 21 Nuclear Power Plants (ADAMS Accession No. ML010430066), 2001.
22 23
- 8.
NRC, NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports 24 for Nuclear Power Plants, June 1987.
25 26
- 9.
NRC, NUREG-0800, Section 15.0.2, Review of Transient and Accident Analysis 27 Methods, December 2005 (ADAMS Accession No. ML053550265).
28 29
- 10.
NRC, Regulatory Guide 1.203, Transient and Accident Analysis Methods, December 30 2005 (ADAMS Accession No. ML053500170).
31 32
- 11.
Kaizer, J. S., Heller, A. K., and Oberkampf, W. L., Scientific computer simulation 33 review, Reliability Engineering and System Safety 138: 210-218, 2015.
34 35
- 12.
Manteufel, R.D. and N.E. Todreas, Effective Thermal Conductivity and Edge 36 Configuration Model for Spent Fuel Assembly, Nuclear Technology, Vol. 105, pp. 421-37 440, March 1994.
38 39
- 13.
Manteufel, R.D., Heat Transfer in an Enclosed Rod Array, Submitted to the Department 40 of Mechanical Engineering in partial fulfillment of the requirements for the degree of 41 Doctor of Philosophy, Massachusetts Institute of Technology, May 1991.
42 43
- 14.
American Nuclear Society, Decay Heat Power in Light Water Reactors, ANSI/ANS 5.1-44 1979, La Grange Park, IL.
45 46
- 15.
NRC, Recommendations for Addressing Axial Burnup in PWR Burnup Credit Analyses, 47 NUREG/CR-6801, March 2003 (ADAMS Accession No. ML031110292).
48 49
- 16.
NRC, Axial Moderator Density Distributions, Control Blade Usage, and Axial Burnup 50 Distributions for Extended BWR Burnup Credit, NUREG/CR-7224, August 2016 51 (ADAMS Accession No. ML16237A100).
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION 1
- 17.
Lenning, E., NRC, email to Andrea Sterdis, HDI, HI, Email Formal Transmittal of the 2
U.S. NRC Request for Additional Information for HDI Topical Report HI-2200750 3
Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology, October 13, 4
2021 (ADAMS Accession No. ML21280A279 (Transmittal Email/Publicly Available),
5 ML21280A300 (Non-Publicly Available)).
6 7
- 18.
Sterdis, A., HDI, HI, to E. Lenning, NRC, Response to Request for Additional 8
Information 10 - Holtec Spent Fuel Pool Heat Up Calculation Methodology Topical 9
Report, October 18, 2021 (ADAMS Accession No. ML21291A161 (Non-10 Proprietary/Publicly Available), ML21291A165 (Proprietary/Non-Publicly Available)).
11 12
- 19.
Wengert, T.J., NRC, to David Heacock, Dominion Energy Kewaunee, Kewaunee Power 13 Station - Exemptions from certain emergency planning requirements and related safety 14 evaluation (TAC NO. MF2567)," October 27, 2014 (ADAMS Accession No.
15 ML14261A223).
16 17
- 20.
Kaizer, J. S., and Anzalone R., In-Vessel Thermal-Hydraulic Analysis Associated with 18 License Amendment for a Risk-Informed Approach to Address Generic Safety Issue 191 19 and Generic Letter 2004-02, 2017 (ADAMS Accession No. ML17019A003).
20 21
- 21.
NRC, RES/DSA/FSCB 2016-03, Spent Fuel Assembly Heat Up Calculations in Support 22 of Task 2 of User Need NSIR-2015-001, April 2016 (ADAMS Accession No.
23 ML16110A431).
24 25 Principal Contributors: J.S. Kaizer 26 Adam Rau 27 John Grasso 28 29 Date: December 16, 2021
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Appendix A Description of Confirmatory Calculations 2
3 The purpose of this appendix is to describe the confirmatory calculations that were performed 4
by the NRC staff in support of the review of Holtec International (HI) HI-2200750, Revision 0, 5
(Hereafter referred to as HI-2200750). Two sets of calculations were performed. The first set of 6
calculations was a direct re-creation of the calculational method described in HI-2200750.
7 These calculations were initially performed to confirm NRC staffs understanding of the method.
[
9
] These 10 calculations are described in A.1 Recreation of HI-2200750 Method. The second set of 11 calculations were [
12 13 14
] These calculations are described in 15 A.2 Pin by Pin Simulation.
16 17 A.1Re-creation of HI-2200750 Method 18 19 Initially, this model was developed to reproduce Holtecs method in order to verify completeness 20 of description within the TR and facilitate reviewer understanding of the method. To that end, 21 the equations and properties employed are effectively identical to that described in the TR.
22
[
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
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49 50 8 1111
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]
9 10 A.2 Pin by Pin Simulation 11 12 These simulations were performed to [
13 14 15
] using ANSYS Fluent. [
16
]
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[
1 2
] Gambit was used to generate the geometry and 3
the mesh. [
4 5
6 7
]
8 Parameters provided in HI-2200750 were used to facilitate comparison with Holtecs 9
calculations. [
10
] were taken from the publicly available DOE/RW-0184 Vol. 3 (Ref.
11 1).
12 13
[
14 15 16
] Homogenized density and specific 17 heat capacity were calculated using the following equations 18 19
= (2 + )/(2 + )
20 21
,= (2,2 +,)/(2 + )
22 23 Where,,, and represent density, specific heat capacity, volume in an assembly, or 24 mass in an assembly, respectively, of the material named in the subscript. Zircaloy density was 25 taken from Table 5.2, UO2 mass from Table 5.3, and UO2 specific heat from Appendix A of 26 HI-2200750. Zircaloy specific heat capacity was calculated using equation 3-14 with the values 27 listed in Table 5.1 of HI-2200750. Volumes were calculated using the dimensions in Table 5.3.
28 Specific heat capacity of the homogenized material was calculated at the same temperature 29 intervals used in Appendix A of HI-2200750 and linearly interpolated between these intervals.
30 Material density, dimensions, and [
] were modeled as constant with respect to 31 temperature.
32 33
[
34
]
35
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[
1 2
3 4
5 6
7 8
9 10 11 12 13 14 15 16 17 18
]
19 20 Manteufel discussed a similar consideration in Appendix A of his dissertation. Specifically, he 21 evaluated a modified Biot number to determine whether the effect of conduction within a fuel pin 22 needed to be considered. The Biot number is the ratio of the thermal resistance to 23 conduction within the body of an object to the thermal resistance to convection at its surface.
24 25
= /
26 27 Where is the convective heat transfer coefficient, is a characteristic length, and is the 28 thermal conductivity of the material. Smaller Biot numbers indicate that the thermal resistance 29 due to conduction within the body is smaller, and the assumption of uniform temperature within 30 the object is better. In Manteufels application, the relevant comparison was between 31 conduction heat transfer and radiative heat transfer, so Manteufel substituted the convective 32 heat transfer coefficient with an approximated heat transfer coefficient due to radiation.
33 34
= 43 35 36 For PWR applications, Manteufel calculated a Biot number of approximately 0.02 using the 37 worst-case emissivity and thermal conductivity, indicating that the assumption of isothermal rods 38 would not have a significant impact on the solution. However, the maximum temperature 39 considered in his application was 300 °C. In the present application, temperatures can reach 40 900 °C, so more energy will be transferred through radiation, and temperature gradients within 41 the pin will have a greater impact on the solution. Biot numbers between 0.01 and 0.15 were 42 calculated assuming a cladding temperature of 900 °C, depending on whether cladding or fuel 43 properties and dimensions are used. The exact relationship between the magnitude of the Biot 44 number and the [
] is not clear, but generally a Biot 45 number of less than 0.1 has been used to justify the isothermal temperature assumption. For 46
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the majority of the transient, the temperature will be lower than 900 °C, so the Biot number will 2
be less limiting. Because the Biot number for this application remains relatively small, 3
conduction within each pin was not simulated.
4 5
Simulated cases are shown in Table 7. In each case, the power density in each pin is 6
determined by dividing the nominal assembly power by total volume of the fuel pins [
7 8
9 10 11 12 13 14 15 16
] Cases 7, 8, and 9 were run to confirm that the method Holtec proposed in response to 17 RAI-02 would result in a conservative [
18 19 21 22
]
23 24 25 26 27 28 20
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]
1
[
2 3
4 5
Results for all cases are plotted in Figures 17 through 22 and Figures 24 through 26.
6 Simulations were run for a fixed period of 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> to ensure that PCTs exceeded the limit 7
during the simulation time. The limiting temperature, 1173.15 K, is plotted as a black dotted 8
line. [
9 10
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A.3 References 6
7
- 1. DOE/RW-0184, Volume 3, Characteristics of Spent Fuel, High-Level Waste, and Other 8
Radioactive Wastes Which May Require Long-Term Isolation, Appendix 2A, Physical 9
Descriptions of Light Water Reactor Assemblies. https://doi.org/10.2172/5258301 10 Affidavit Pursuant to 10 CFR 2.390 to Withhold Information from Public Disclosure
US. Nuclear Regulatory Commission ATTN: Document Control Clerk Non-Proprietary AFFIDAVIT PURSUANT TO 10 CFR 2.390 1, Jean A. Fleming, being duly sworn, depose and state as follows:
- 1) I have reviewed the information provided in US. Nuclear Regulatory Commission Draft Safety Evaluation by the Of"ce of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology which is sought to be withheld and I am authorized to apply for its withholding.
- 2) The information sought to be withheld is in Enclosure 1 to this letter, US Nuclear Regulatory Commission Draft Safety Evaluation by the Of"ce of Nuclear Reactor Regulation for the Topical Report HI-2200750 Revision 0, Holtec Spent Fuel Pool Heat Up Calculation Methodology. and is proprietary to Holtec International.
- 3) In making this application for withholding of proprietary information of which it is the owner, Holtec International relies upon the exemption from disclosure set forth in the Freedom of Information Act (FOIA), 5 USC Sec. 552(b)(4) and the Trade Secrets Act, 18 USC Sec. 1905, and NRC regulations 10 CFR Part 9.17(a)(4), 2.390(a)(4), and 2.390(b)(1) for trade secrets and commercial or "nancial information obtained from a person and privileged or con"dential (Exemption 4). The material for which exemption from disclosure is here sought is all con"dential commercial information, and some portions also qualify under the narrower de"nition of trade secret, within the meanings assigned to those terms for purposes of FOIA Exemption 4 in, respectively, Critical Mass Energy Proiect v. Nuclear Regulatorv Commission, 975F2d871 (DC Cir. 1992),
and Public Citizen Health Research Group v. FDA, 704F2d1280 (DC Cir. 1983).
- 4) Some examples of categories of information which "t into the de"nition of proprietary information are:
- a. Information that discloses a process, method, or apparatus, including supporting data and analyses, where prevention of its use by Holtecs competitors without license from Holtec International constitutes a
competitive economic advantage over other companies; Page 1 of 5
U.S. Nuclear Regulatory Commission ATTN: Document Control Clerk Non-Proprietary AFFIDAVIT PURSUANT TO 10 CFR 2.390
- b. Information which, if used by a competitor, would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product.
- c. Information which reveals cost or price information, production, capacities, budget levels, or commercial strategies of Holtec International, its customers or its suppliers; (1. Information which reveals aspects of past, present, or future Holtec International customer-funded development plans and programs of potential commercial value to Holtec International;
- e. Information which discloses patentable subject matter for which it may be desirable to obtain patent protection.
The information sought to be withheld is considered to be proprietary for the reasons set forth in paragraphs 4.a and 4b, and 4.0 above.
- 5) The information sought to be withheld is being submitted to the NRC in con"dence. The information (including that compiled from many sources) is of a sort customarily held in con"dence by Holtec International, and is in fact so held. The information sought to be withheld has, to the best of my knowledge and belief, consistently been held in con"dence by Holtec International.
No public disclosure has been made, and it is not available in public sources. All disclosures to third parties, including any required transmittals to the NRC, have been made, or must be made, pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in con"dence. Its initial designation as proprietary information, and the subsequent steps taken to prevent its unauthorized disclosure, are as set forth in paragraphs (6) and (7) following.
- 6) Initial approval of proprietary treatment of a document is made by the manager of the originating component, the person most likely to be acquainted with the value and sensitivity of the information in relation to industry knowledge. Access Page 2 of 5
US. Nuclear Regulatory Commission ATTN: Document Control Clerk Non-Proprietary AFFIDAVIT PURSUANT TO 10 CFR 2.390 to such documents within Holtec International is limited on a need to know basis.
- 7) The procedure for approval of external release of such a document typically requires review by the staff manager, project manager, principal scientist or other equivalent authority, by the manager of the cognizant marketing function (or his designee), and by the Legal Operation, for technical content, competitive effect, and determination of the accuracy of the proprietary designation. Disclosures outside Holtec International are limited to regulatory bodies, customers, and potential customers, and their agents, suppliers, and licensees, and others with a legitimate need for the information, and then only in accordance with appropriate regulatory provisions or proprietary agreements.
- 8) The information classi"ed as proprietary was developed and compiled by Holtec International at a signi"cant cost to Holtec International.
This information is classi"ed as proprietary because it contains detailed descriptions of analytical approaches and methodologies not available elsewhere. This information would provide other parties, including competitors, with information from Holtec Internationals technical database and the results of evaluations performed by Holtec International.
A substantial effort has been expended by Holtec International to develop this information.
Release of this information would improve a competitors position because it would enable Holtecs competitor to copy our technology and offer it for sale in competition with our company, causing us "nancial injury.
- 9) Public disclosure of the information sought to be withheld is likely to cause substantial harm to Holtec Internationals competitive position and foreclose or reduce the availability of pro"t-making opportunities. The information is part of Holtec Internationals comprehensive decommissioning and spent fuel storage technology base, and its commercial value extends beyond the original development cost. The value of the technology base goes beyond the extensive physical database and analytical methodology, and includes development of the expertise to determine and apply the appropriate evaluation process.
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US. Nuclear Regulatory Commission ATTN: Document Control Clerk Non-Proprietary AFFIDAVIT PURSUANT TO 10 CFR 2.390 The research, development, engineering, and analytical costs comprise a substantial investment of time and money by Holtec International.
The precise value of the expertise to devise an evaluation process and apply the correct analytical methodology is dif"cult to quantify, but it clearly is substantial.
Holtec Intemationals competitive advantage will be lost if its competitors are able to use the results of the Holtec International experience to normalize or verify their own process or if they are able to claim an equivalent understanding by demonstrating that they can arrive at the same or similar conclusions.
The value of this information to Holtec International would be lost if the information were disclosed to the public. Making such information available to competitors without their having been required to undertake similar expenditure of resources would unfairly provide competitors with a windfall, and deprive Holtec International of the opportunity to exercise its competitive advantage to seek an adequate return on its large investment in developing these very valuable analytical tools.
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US. Nuclear Regulatory Commission ATTN: Document Control Clerk Non-Proprietary AFFIDAVIT PURSUANT TO 10 CFR 2.390 STATE OF NEW JERSEY )
)
ss:
COUNTY OF CAMDEN
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Jean A. Fleming, being duly sworn, deposes and says:
That she has read the foregoing af"davit and the matters stated therein are true and correct to the best of her knowledge, information, and belief.
Executed at Camden, New Jersey, this [1 M day of January 2022.
Qua 41:57, Jean A. Fleming Holtec Decommissioning International Holtec International VP, Regulatory & Environmental Affairs Subscribed and sworn before me this 9% day of W 2022 SHARON Y. PAGE NOTARY PUBUC OF NEW £RSEY My mum Expim 0mm Page 5 of 5