ML22331A009
| ML22331A009 | |
| Person / Time | |
|---|---|
| Site: | HI-STORE |
| Issue date: | 09/27/2021 |
| From: | Maheedhara R Holtec |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML22331A002 | List: |
| References | |
| 5025076 HI-2177591 | |
| Download: ML22331A009 (1) | |
Text
Nuclear Power Division 5025
Sponsoring Company Project No.
HI-2177591 2 27 Sep 2021
Company Record Number Revision No. Issue Date
Report Non-Proprietary
Record Type Proprietary Classification
Nuclear No
Quality Class Export Control Applicability
Record
Title:
THERMAL EVALUATIONS OF HI-STORM UMAX AT HISTORE CIS FACILITY
Prepared by: Reviewed by: Approved by:
R.0aheedhara Sep 1.Varma Sep (.0ayer Sep
Signature histories are provided here for reference only. Company electronic signature records are traceable via the provided Verification QR Code and are available for review within the secure records management system. A valid Verification QR Code and the presence of this covering page indicates this record has been approved and accepted.
Proprietary Classification
This is a non-proprietary version of a proprietary company report.
Export Control Status
Not applicable.
Table of Contents 1.0 Introduction....................................................................................................................................... 1 1.1 Quality Essentials Applicable to this Report...................................................................................... 2 2.0 Methodology and Assumptions...................................................................................................... 12 3.0 Inputs............................................................................................................................................... 19 4.0 Acceptance Criteria......................................................................................................................... 20 5.0 Computer Codes and Calculation Files........................................................................................... 20 6.0 Results and Conclusions................................................................................................................. 24 6.1 Maximum Temperatures............................................................................................................. 24 6.2 Maximum MPC Cavity Pressures............................................................................................... 25 6.3 Differential Thermal Expansion.................................................................................................. 25 6.4 Effect of Sustained Wind............................................................................................................ 28 6.5 Thermal Evaluations of Sub-Design Basis Heat Load................................................................ 30 6.6 Fire Accident Condition.............................................................................................................. 30 6.7 Off-Normal and Accident Conditions......................................................................................... 31 7.0 References....................................................................................................................................... 53
Summary of Revisions
Revision 0: Initial revision.
Revision 1: Report is revised to make the following changes:
- Additional information regarding convergence criteria and numerical residuals are added.
- Thermal evaluations for partial duct blockage and complete duct blockage scenarios are performed.
- Thermal evaluation of HI-STORM UMAX at higher ambient temperature is performed.
- Differential thermal expansions are computed for all normal, off normal and accident scenarios.
All changes are marked by revision bars on the right.
Revision 2: Report is revised to document thermal evaluatio ns of 1x12 and 1x25 arrays of HI -
STORM UMAXcasks under sustained wind conditions.
Report HI-2177591 Page i Project 5025 1.0 Introduction This report documents the site-specific thermal evaluations of HI-STORM UMAX System [1]
deployed for long-term storage at HI-STORE CIS facility [2]. The calculations presented in this report support the evaluations related to UMAX in Chapter 6 of HI-STORE SAR [2]. HI-STORM UMAX, certified in the USNRC docket # 72-1040 [3], [16] is an underground vertical ventilated system with openings for air ingress and egress and internal air flow passages for ventilation cooling of loaded MPC.
It is designed to have an MPC sitting inside a thick steel divider shell. The divider shell is insulated to reduce the transmission of decay heat from the MPC to the down-coming cool air in the annular gap between divider shell and container shell (CEC). Large inlet passageway allows air flow from the ambient environment to the annular space between MPC shell and divider shell, through [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]. The cooling air rises through the annulus between the divider shell and the MPC enclosure vessel due to the chimney effect created by the transfer of heat from the MPC shell to the air. The [
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390 ] Large gap between the MPC lid and the VVM closure lid allows efficient heat dissipation from the MPC lid.
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Two different types of MPCs, MPC-37 and MPC-89, that are licensed previously for storage in HI-STORM FW [4] and HI-STORM UMAX [3] are allowed for storage in UMAX cavity at HI-STORE [1]. The MPCs deployed in HI-STORM UMAX cavity are exactly the same as those previously approved in HI-STORM FW FSAR [4] and HI-STORM UMAX FSAR [3].
With respect to normal storage in the HI-STORM UMAX Version C cavities at HI-STORE, it is recognized that the maximum heat load in any canister cannot exceed the limit in the transport cask that will be used to bring the canisters to the HI-STORE CIS site. These canisters are already backfilled with helium and some already under dry storage at power plants from where they are transported to the HI-STORE facility. As the heat removal capacity of the ventilated HI-STORM UMAX system is substantially in excess of the (unventilated) transport cask (viz., HI-STAR 190 [5]) that will be used to fetch the canisters, the peak cladding temperatures are expected to remain well below the normal, off-normal and accident conditions of storage postulated in NUREG-1567 [6] and NUREG-1536 [7]. The maximum allowable decay heat for storage in MPC-37 and MPC-89 are provided in Tables 1.1 and 1.2 respectively. Initial helium backfill range to which these canisters were backfilled is provided in Tables 1.3 and 1.4.
The interim storage of the canisters will occur in the HI-STORM UMAX Version C VVMs. The thermal-hydraulic configuration of the HI-STORM UMAX Version C VVMs at HI-STORE is essentially identical to Version B that is certified in the HI-STORM UMAX ECO [16].
Therefore, its heat rejection capacity would be virtually identical under identical conditions to
Report HI-2177591 Page 1 Project 5025 that analyzed and certified in [3] under all operation modes. However, the Design Basis heat load and the ambient temperature metrics for the HI-STORE ISFSI are less challenging than those for which the system is certified in [3]. Therefore, it is expected that the heat rejection performance of the canisters at the HI-STORE ISFSI will have even greater margins to the regulator-prescribed limit than that established in [3]. To ascertain this, long-term storage of canisters in HI-STORM UMAX with site-specific conditions from Table 1.5 is evaluated in this report.
1.1 Quality Essentials Applicable to this Report
This section contains quality related information on this document in conformance with the provisions in Holtec's Quality Assurance program.
1.1.1 Document Classification and QA Protocol
This document is classified as Safety Significant under Holtec Internationals quality assurance system. In order to gain acceptance as a safety-significant document in the companys quality assurance system, this document is required to undergo a prescribed review and concurrence process that requires the preparer and reviewer(s) of the document to answer a long list of questions crafted to ensure that the document is purged of all errors of any material significance. A record of the review and verification activities is maintained in electronic form within the companys network to enable future retrieval and recapitulation of the programmatic acceptance process leading to the acceptance and release of this document under the companys QA system. Among the numerous requirements that this document must fulfill, as applicable, to muster approval within the companys QA program are:
- The preparer(s) and reviewer(s) are technically qualified to perform their activities per the applicable Holtec Quality Procedure (HQP).
- The input information utilized in the work effort is drawn from referencable sources. Any assumed input data is so identified.
- All significant assumptions are stated.
- The analysis methodology is consistent with the physics of the problem.
- Any computer code and its specific versions used in the work are formally admitted for use within the companys QA system.
- The format and content of the document is in accordance with the applicable Holtec quality procedure.
- The material content of the calculation package is understandable to a reader with the requisite academic training and experience in the underlying technical disciplines.
Report HI-2177591 Page 2 Project 5025 Once a safety significant document, such as this calculation package, completes its review and certification cycle, it should be free of any materially significant error and should not require a revision unless its scope of treatment needs to be altered. Except for regulatory interface documents (i.e., those that are submitted to the NRC in support of a license amendment and request), editorial revisions to Holtec safety-significant documents are not made unless such editorial changes are deemed necessary by the Holtec Project Manager to prevent erroneous conclusions from being inferred by the reader. In other words, the focus in the preparation of this document is to ensure correctness of the technical content rather than the cosmetics of presentation.
In accordance with the foregoing, this Calculation Package is prepared pursuant to the revisions of Holtec Quality Procedures HQP 3.0 and 3.2, which require that all analyses utilized in support of the design of a safety-related or important-to-safety structure, component, or system be fully documented such that the analyses can be reproduced at any time in the future by a specialist trained in the discipline(s) involved. HQP 3.2 sets down a rigid format structure for the content and organization of Calculation Packages that are intended to create a document that is complete in terms of the exhaustiveness of content. The Calculation Packages, however, lack the narrational smoothness of a Technical Report, and are not intended to serve as a Technical Report.
Because of its function as a repository of all analyses performed on the subject of its scope, this document will require a revision only if an error is discovered in the computations or the equipment design is modified. Additional analyses in the future may be added as numbered supplements to this Package. Each time a supplement is added or the existing material is revised, the revision status of this Package is advanced to the next number and the Table of Contents is amended. Calculation Packages are Holtec proprietary documents. They are shared with a client only under strict controls on their use and dissemination.
This Calculation Package will be saved as a Permanent Record under the companys QA System.
1.1.2 Quality Validation Questionnaire
The questionnaire below is a distilled version of the vast number of questions that the preparer and reviewer of a Holtec safety-significant report must answer and archive in the Company's network to gain a VIR number (the identifier of QA pedigree in Holtec's electronic configuration control system).
An affirmative answer (unless the question is "not applicable" or NA) to each of the following questions by the preparer of the report (or editor of a multi-author document) is an essential condition for this document to merit receiving a QA validated status.
Report HI-2177591 Page 3 Project 5025
Response
Criterion Yes or No 1 Are you qualified per HQP 1.0 to perform the analysis documented in Yes this report?
Are you aware that you must be specifically certified if you use any 2 Category A computer code (as defined in HQP 2.8 in the preparation Yes
of this document?
3 Are you fully conversant with the pertinent sections of the applicable Yes Specification invoked in this report?
4 Is the input data used in this work fully sourced (i.e., references are Yes provided)?
5 Are you fully conversant with the user manual and validation manual Yes of the code(s) used in this report, if any?
6 Are Category A computer code(s) (if used) listed in the Company's Yes "Approved Computer program list"?
7 Are the results clearly set down and do they meet the acceptance Yes criteria set down in the governing Specification?
Are you aware that you must observe all internal requirements on 8 needed margins of safety published in Holtec's internal memos, if Yes applicable (which may exceed those in the reference codes and standards or the specification)?
9 Have you performed numerical convergence checks to ensure that the Yes solution is fully converged?
10 Is it true that you did not receive more than 10 quality infraction points Yes in the past calendar year or thus far this year?
1.1.3 Computer Codes Used in this Work Holtec International maintains an active list of QA validated computer codes on the Companys network that are approved for use in Safety significant projects. The table below identifies the Code and its version (listed in the ACPL) that has been used in this work effort.
Report HI-2177591 Page 4 Project 5025 Generic Report & ACPL Information Generic Report # invoked in this Calc Package, N/A if applicable Code name (must be listed in the ACPL) FLUENT Code version # (must be approved in the ACPL) 14.5.7, 18.1, 2021R1
[PROPRIETARY INFORMATION [PROPRIETARY WITHELD PER 10CFR2.390] INFORMATION WITHELD PER 10CFR2.390]
[PROPRIETARY INFORMATION [PROPRIETARY WITHELD PER 10CFR2.390] INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 5 Project 5025 Table 1.1: MPC-37 Allowable Decay Heat Load Patterns [2]
Maximum Decay Heat Total Canister Heat Load Pattern Region (Note 1) Load per Assembly (kW) (kW)
(Note 2)
1 0.38 1 2 1.7 31.82 3 0.50 1 0.42 2 2 1.54 32.02 3 0.61 1 0.61 3 2 1.23 32.09 3 0.74 1 0.74 4 2 1.05 32.06 3 0.8 1 0.8 5 2 0.95 32.04 3 0.84 1 0.95 6 2 0.84 31.43 3 0.8 Note 1: For basket region numbering scheme refer to Figure 1.1.
Note 2: Sub-Design Basis Heat Load is defined as 80% of the design basis heat load in every storage location defined herein.
Report HI-2177591 Page 6 Project 5025 Table 1.2: MPC-89 Allowable Decay Heat Loads [2]
Maximum Decay Heat Total Canister Heat Load Pattern Region (Note 1) Load per Assembly (kW) (kW)
(Note 2) 1 0.15 1 2 0.62 32.15 3 0.15 1 0.18 2 2 0.58 32.02 3 0.18 1 0.27 3 2 0.47 32.03 3 0.27 1 0.32 4 2 0.41 32.08 3 0.32 1 0.35 5 2 0.37 31.95 3 0.35 Note 1: For basket region numbering scheme refer to Figure 1.2.
Note 2: Sub-Design Basis Heat Load is defined as 80% of the design basis heat load in every storage location defined herein.
Report HI-2177591 Page 7 Project 5025 Table 1.3: Initial MPC Helium Backfill Specification Requirements for Design Basis Heat Loads [2], [5]
MPC Type Pressure Range (Note 1)
MPC-37 > 39.0 psig and < 46.0 psig
MPC-89 > 39.0 psig and < 47.5 psig Note 1: Helium used for backfill of MPC shall have a purity of > 99.995%. The pressure range is based on a reference temperature of 70oF.
Table 1.4: Initial MPC Helium Backfill Specification Requirements for Sub -Design Basis Heat Loads [2], [5]
MPC Type Pressure Range (Note 1)
MPC-37 > 39.0 psig and < 50.0 psig
MPC-89 > 39.0 psig and < 50.0 psig Note 1: Helium used for backfill of MPC shall have a purity of > 99.995%. The pressure range is based on a reference temperature of 70oF.
Note 2: Sub-Design Basis Heat Load is defined as 80% of the design basis heat load in every storage location defined in Tables 1.1 and 1.2 for MPC-37 and MPC-89 respectively.
Report HI-2177591 Page 8 Project 5025 Table 1.5: Thermally Significant Parameters for the HI-STORM UMAX ISFSI at HI-STORE CIS Facility
Thermally Significant ISFSI parameter Value [2]
Maximum Aggregate Heat Load, kW Tables 1.1 and 1.2 Normal Ambient Temperature, oF 62 Elevation, ft 5000 (Note 1)
Minimum Ambient Temperature, oF -11 Off-normal Ambient Temperature, oF 91 Accident Ambient Temperature, oF 108 Note 1: Elevation above sea level adopted for thermal evaluations conservatively bounds the site maximum elevation of 3540 feet [2].
Report HI-2177591 Page 9 Project 5025 3-1 3-2 3-3
3-4 2-1 2-2 2-3 3-5
3-6 2-4 1-1 1-2 1-3 2-5 3-7
3-8 2-6 1-4 1-5 1-6 2-7 3-9
3-10 2-8 1-7 1-8 1-9 2-9 3-11
3-12 2-10 2-11 2-12 3-13
3-14 3-15 3-16
Legend
Region-
Cell ID
Figure 1.1: MPC-37 Region-Cell Identification
Report HI-2177591 Page 10 Project 5025 3-1 3-2 3-3
3-4 3-5 3-6 2-1 3-7 3-8 3-9
3-10 3-11 2-2 2-3 2-4 2-5 2-6 3-12 3-13
3-14 2-7 2-8 2-9 2-10 2-11 2-12 2-13 3-15
3-16 3-17 2-14 2-15 1-1 1-2 1-3 2-16 2-17 3-18 3-19
3-20 2-18 2-19 2-20 1-4 1-5 1-6 2-21 2-22 2-23 3-21
3-22 3-23 2-24 2-25 1-7 1-8 1-9 2-26 2-27 3-24 3-25
3-26 2-28 2-29 2-30 2-31 2-32 2-33 2-34 3-27
3-28 3-29 2-35 2-36 2-37 2-38 2-39 3-30 3-31
3-32 3-33 3-34 2-40 3-35 3-36 3-37 Legend
Region-3-38 3-39 3-40 Cell ID
Figure 1.2: MPC-89 Region-Cell Identification
Report HI-2177591 Page 11 Project 5025 2.0 Methodology and Assumptions Thermal evaluations of MPC-89 are bounded by MPC-37 under heat load patterns provided in Tables 1.1 and 1.2 as has been demonstrated in Section 3.3 of HI-STAR 190 SAR [5].
[PROPRIETARY INFORMATION
WITHELD PER 10CFR2.390] Thermal analyses of normal storage conditions are carried out [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390] in Chapter 4 of HI-STORM UMAX FSAR [3]. The licensing basis MPC corresponds to MPC-37 with short fuel i.e. [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390] as was demonstrated in Chapter 4 of HI-STORM UMAX FSAR [3] and HI-STORM FW FSAR [4]. The storage cavity depth is made fixed (not variable, as permitted in the general UMAX certification [2]) at two discrete dimensions [1]. MPCs up to a certain maximum height can be placed within Type SL of UMAX Version C while MPCs taller than that will be placed within Type XL. See Table 2.1 which shows the maximum MPC heights allowed in each type and the minimum axial gap between the MPC and UMAX VVM cavity. As can be seen from Table 2.1, axial gap between the tallest MPC and UMAX cavity is still at or below the axial gap used in the licensing basis calculations presented in generic UMAX FSAR [3], [16]. Therefore, this change in depth of UMAX cavity between versions B and C will have no negative impact. This report presents the most limiting thermal scenario i.e. MPC-37 with short fuel placed in UMAX Version C Type SL. The justification on why this scenario is thermally most limiting is provided below:
- a. MPC-37 with short fuel results in highest PCT and component temperatures as demonstrated in Section 4.4 of HI-STORM UMAX FSAR [3].
- b. Active fuel height of short fuel is lowest among short, reference and long fuel assemblies.
For the same heat load, lower active height results in higher heat load density.
- c. Additionally, MPC-37 with short fuel also bounds the MPC-37 with [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390] as has been demonstrated by thermal evaluations in Section 4.5 of HI-STORM FW FSAR [4].
The axial air gap does not have a significant impact on heat dissipation from the MPC, as long as it is large enough to accommodate the airflow from the annular gap between MPC and divider shell to the open channel inside the closure lid. Therefore, the airflow resistance in UMAX version C design is expected to be similar or lower than the UMAX version B design. However, the variation of axial gap in Version C design due to the different MPC heights is expected to have a small effect on the airflow, considering the large gap existing for all MPC heights in version C.
The thermal model is exactly the same as that adopted in HI-STORM UMAX FSAR [16] except the following changes:
Report HI-2177591 Page 12 Project 5025
[PROPRIETARY
INFORMATION
WITHELD PER 10CFR2.390]
For each type of MPC, the model of fuel assembly, basket and MPC vessel follows the same methodology and assumptions presented in Chapter 4 of HI-STORM FW FSAR [4]. The methodology used in this report is essentially same as that in HI-STORM UMAX FSAR [3]. To ensure an adequate representation of the features of MPC-37, fuel basket within MPC-37 and the HI-STORM UMAX system, a quarter-symmetric 3-D geometric model is constructed using the FLUENT CFD code pre-processor (GAMBIT) [10], as shown in Figures 2.1 and 2.2. A 3D -
model is constructed for thermally most limiting MPC i.e. MPC-37 with short fuel. The 3-D model implemented to analyze the HI-STORM UMAX Version C system has the following key attributes:
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 13 Project 5025 The cross-section view of the quarter-symmetric 3-D geometric model is shown in Figure 2.1.
An isometric view is shown in Figure 2.2. The 3-D model has the following major assumptions that render the results conservative. In addition to the assumptions that are relevant to MPC thermal model (presented in Section 4.4 of HI-STORM FW FSAR [4]) and UMAX VVM thermal model (presented in Section 4.4 of HI-STORM UMAX FSAR [3]), following assumptions are made in thermal evaluations presented in this report:
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 14 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Thermal evaluations presented in Chapter 3 of HI-STAR 190 SAR [5] clearly demonstrate that heat load pattern 1 in MPC-37 results in bounding peak cladding temperatures. Therefore, heat load pattern 1 presented in Table 1.1 above is adopted for longterm st-orage evaluations presented in this report.
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 15 Project 5025 Table 2.1: Allowable MPCs in Different Types of UMAX Version C
UMAX Version UMAX Cavity Maximum Allowable Minimum Axial Gap C Type Height (in) [1] MPC Height (in) [1] Between MPC and UMAX Lid (in)
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
XL Note 1: The minimum axial gap between MPC and HI-STORM UMAX in [3] is 21.625 inches [15]. Therefore the minimum axial gap between MPC and UMAX at HI-STORE is larger than that was adopted for licensing basis calculations in generic UMAX FSAR [3].
Report HI-2177591 Page 16 Project 5025 Figure 2.1: [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 17 Project 5025 Figure 2.2: [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 18 Project 5025 3.0 Inputs As mentioned earlier, the MPC model is the same as that previously approved by USNRC in HI-STORM UMAX FSAR [3] and HI-STORM FW FSAR [4]. The principal input data for the storage overpack i.e. HI-STORM UMAX VVM at HI-STORE CIS facility, used in these analyses, are taken from design drawing [1].
All physical properties of the materials used for the simulation of the fuel assemblies, basket and MPC-37 vessel are specified in Section 4.2 of HI-STORM UMAX FSAR [3]. The physical properties of the common materials present within HI-STORM UMAX, such as carbon steel and concrete are same as that specified in specified in Section 4.2 of HI-STORM UMAX FSAR [3].
The physical properties of insulation are also provided in Section 4.2 of HI-STORM UMAX FSAR [3]. Thermal conductivity of insulation adopted in the thermal evaluations presented in this report [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]presented in the UMAX FSAR [9].
The design ambient temperature used in the analysis of long-term storage is provided in Table 1.5. The bottom of the HI-STORM UMAX overpack base is assumed supported on a subgrade at the same temperature as the ambient temperature (Section 2.7 of HI-STORE SAR [2]). Surface emissivity data for key materials of construction are specified in Reference [2]. The thermal loads and applicable environmental conditions are summarized in Table 1.5.
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
] The effective planar and axial thermal conductivities, density and specific heat capacity of fuel assembly are calculated in Reference [8]. [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390 ]
Report HI-2177591 Page 19 Project 5025 4.0 Acceptance Criteria The acceptance criteria are stated below:
- 1. The fuel cladding temperature for long term storage shall be limited to 400°C (752°F).
- 2. The fuel cladding temperature for short-term operations shall be limited to 400°C (752°F) for high burnup fuel and 570°C (1058°F) for moderate burnup fuel.
- 3. The fuel cladding temperature should be maintained below 570°C (1058°F) for off-normal and accident conditions.
- 4. The internal pressure of the system should remain within its design pressures for normal, off-normal, and accident conditions. The design pressure is specified in Chapter 4 of HI-STORE SAR [2].
- 5. The MPC and UMAX component materials should be maintained within their minimum and maximum temperature criteria under normal, off-normal, and accident conditions.
Material temperature limits are provided in Section 4.4 of Chapter 4 of SAR [2].
5.0 Computer Codes and Calculation Fi les ANSYS FLUENT versions 14.5.7 and 18.1 are used to perform CFD calculations documented in this report. A list of computer files supporting the calculations is provided below:
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 20 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 21 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
ANSYS FLUENT version 2021R1 is used to perform CFD calculations of the sustained wind scenarios. The benchmarking of this version of the program is documented in Attachment A of this report.
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 22 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 23 Project 5025 6.0 Results and Conclusions 6.1 Maximum Temperatures A steady state thermal analysis of the governing thermal configuration (meaning the combination of canister type, heat load pattern and fuel type that produces highest fuel cladding temperature) was performed using the 3-D FLUENT model described in Section 2.0 to quantify the thermal margins under long term storage conditions. To summarize, thermal analyses of the MPC-37 with short fuel under heat load pattern 1 provided in Table 1.1 is performed. Simulation is continued until peak cladding temperature, mass-flow rate and numerical residuals are stabilized and convergence is verified by ensuring that the MPC heat balance and mass balance through the domain is close to 100%. The scaled residuals are shown in Figure 6.1.
The maximum spatial values of the computed temperatures of the fuel cladding, the fuel basket material, the divider shell, the closure lid concrete, the MPC lid, the MPC shell and the average air outlet temperature are summarized in Table 6.1. The following conclusions are reached from the solution data:
- b. The maximum temperatures of all MPC and VVM constituent parts are also below their respective limits set down in Section 4.4 of HI-STORE FSAR [2].
It is therefore concluded that the HI-STORM UMAX system provides a thermally acceptable storage environment for all eligible MPCs under all allowable heat load patterns. It should also be noted that the PCT and other component temperatures are well below the licensing basis results presented in Section 4.4 of generic HI-STORM UMAX FSAR [3]. This confirms the assertion made in Section 1.0 that the heat rejection performance of the canisters at the HI-STORE ISFSI has even greater margins to the regulator-prescribed limit than that established in
[3].
6.1.1 Evaluation of HI-STORM UMAX System under Higher Ambient Temperatures The highest average monthly maximum temperature at the HI-STORE CISF site is 93.62oF per Table 2.3.1 of the FSAR [2]. Steady state thermal evaluation of the HI-STORM UMAX system is performed at a bounding ambient temperature of 94oF using the thermal model described 2.0 of this report. The confinement boundary temperature results from this evaluation are adopted in thermal stress calculations documented in HI-STORE FSAR Chapter 5. The primary results are presented in Table 6.11.
Report HI-2177591 Page 24 Project 5025 6.2 Maximum MPC Cavity Pressures
The MPC from HI-STAR 190 is already filled with dry pressurized helium. During normal storage in UMAX VVM, the gas temperature within the MPC rises to its maximum operating basis temperature. The gas pressure inside the MPC will also increase with rising temperature.
The pressure rise is determined using the ideal gas law. The MPC gas pressure is also subject to substantial pressure rise under hypothetical rupture of fuel rods.
The MPC maxi mum gas pressure is computed for a postulated release of fission product gases from fuel rods into this free space. The amount of fission gas and fill gas release due to rod rupture is exactly the same as that adopted in HI-STORM UMAX FSAR [3] and HI-STORM FW FSAR [4]*. For these scenarios, the amounts of each of the release gas constituents in the MPC cavity are summed and the resulting total pressures determined from the ideal gas law. A concomitant effect of rod ruptures is the increased pressure and molecular weight of the cavity gases with enhanced rate of heat dissipation by internal helium convection and lower cavity temperatures. As these effects are substantial under large rod ruptures the 100% rod rupture accident is evaluated without any credit for increased heat dissipation under increased pressure and molecular weight of the cavity gases. Based on fission gases release fractions (NUREG 1536 criteria), rods net free volume and initial fill gas pressure, maximum gas pressures with 1%
(normal), 10% (off-normal) and 100% (accident condition) rod rupture are given in Table 6.2.
The maximum calculated gas pressures reported in Table 6.2 are all below the MPC internal design pressures for normal, off-normal and accident conditions specified in Chapter 4 of HI-STORE SAR [2]. It should also be noted that the MPC cavity pressure is also bounded by the licensing basis results presented in Section 4.4 of generic HI-STORM UMAX FSAR [3].
6.3 Differential Thermal Expansion
In this subsection, thermal expansion of free-standing HI-STORM UMAX components in the radial and axial directions is computed for the bounding scenario (i.e. short fuel length). [
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
- The actual values of fission and fill gas are provided in input/output files supporting Reference [12].
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[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 26 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 27 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
6.4 Effect of Sustained Wind
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
Report HI-2177591 Page 28 Project 5025
[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
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[
PROPRIETARY INFORMATION WITHELD PER 10CFR2.390
]
6.5 Thermal Evaluations of Sub-Design Basis Heat Load
Thermal evaluations in Section 3.3.5 of HI-STAR 190 SAR [5] demonstrate that the predicted temperatures and cavity pressures under sub-design basis heat loads is bounded by design maximum heat load scenario. Therefore, the conclusions drawn for design basis heat loads in Sections 6.1 and 6.2 remain applicable to sub-design basis heat loads also.
6.6 Fire Accident Condition The HI-STORM UMAX fire accident is evaluated for the same conditions described in a separate Holtec report that evaluates the effects of VCT fire on HI-STORM FW System [14].
The fire evaluation for limiting MPC-37 with short fuel length stored in HI-STORM UMAX is bounded by the analysis reported in this report [14] due to the following facts:
- The initial PCT and component temperatures of MPC stored in HI-STORM UMAX at HI-STORE are lower than that of the same MPC in the HI-STORM FW system [4].
- HI-STORM UMAX system has much less surface directly exposed to fire than that of the above-ground system.
- Amount of combustibles that can cause a VCT fire is the same.
- The maximum permissible decay heat load for UMAX at HI-STORE is significantly lower than that for HI-STORM FW in [14]
Report HI-2177591 Page 30 Project 5025 Consequently, the conclusion that PCT and components temperatures and MPC pressure are below temperature and pressure limits for the Design Basis Fire event drawn in this fire report
[14] will remain valid for the HI-STORM UMAX system.
The differential thermal expansion of the MPC/HI-STORM UMAX components under the fire accident are computed using the methodology set forth in Section 6.3. The increment in temperatures (Tfire) due to the fire accident is adopted from the thermal report [14] and added to the computed component temperatures from Section 6.1 to obtain respective component temperatures to compute the thermal expansion. The temperature increments are provided in Table 6.10. The computed differential thermal expansion under fire accident are provided in Table 6.9. Restraint free thermal expansion is demonstrated for all components.
6.7 Off-Normal and Accident Conditions The predicted temperatures and MPC cavity pressures presented for all the off-normal and accident conditions in Section 4.6 of HI-STORM UMAX FSAR [3] are bounding due to the following reasons:
- As stated in Section 6.1 of this report, PCT and component temperatures at HI-STORE under long-term storage condition are bounded by those presented for generic UMAX system (Section 4.4 of FSAR [3]).
- As stated in Section 6.2 of this report, MPC cavity pressure at HI-STORE under long-term storage condition is bounded by that presented for MPCs in generic UMAX system (Section 4.4 of FSAR [3]).
- Design basis heat loads (Tables 1.1 and 1.2) at HI-STORE are well below the design basis maximum heat loads in generic FSAR [3].
Off-normal and accident conditions evaluations specific to HI-STORE CISF are discussed in the following sub-sections.
6.7.1 Partial Duct Blockage of Inlets and Outlet
An explicit steady state thermal evaluation is performed for the off-normal condition of partial duct blockage (50% of inlets and 50% of outlet). The thermal model used in the long-term storage evaluation presented in Section 6.1 is adopted with the modification that 50% of inlets and outlets are assumed to be blocked by debris. Simulation is continued until peak cladding temperature, mass-flow rate and numerical residuals are stabilized and convergence is verified by ensuring that the MPC heat balance and mass balance through the domain is close to 100%.
The scaled residuals are shown in Figure 6.2.
Report HI-2177591 Page 31 Project 5025 Results for this evaluation are presented in Table 6.5. The MPC pressure is presented in Table 6.2. The results show that all component temperatures and pressures meet the acceptance criteria presented in Section 4.0 for off-normal conditions.
The results of thermal expansion calculations performed using the methodology described in Section 6.3 are presented in Table 6.6.
6.7.2 Complete Duct Blockage of Inlets and Outlet
An explicit transient thermal evaluation of UMAX Version C adopted at the HI-STORE site under design basis heat load pattern 1 is performed for the accident condition of complete duct blockage (100% of inlets and 100% of outlet). The results from the long-term storage condition presented in Section 6.1 are adopted as the initial conditions for the transient evaluation. The thermal model used in the long-term storage evaluation is then modified to block 100% of inlets and outlets. The transient evaluation is performed for a duration of 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> of complete duct blockage. The component temperatures for the evaluation at the end of the 32-hour duration are presented in Tables 6.7. The MPC pressure is presented in Table 6.2. The time histories of various component temperatures are presented in Figure 6.1. The results show that all component temperatures and pressures meet their acceptance criteria under accident conditions for the duration of 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br />.
The results of thermal expansion calculations performed using the methodology described in Section 6.3 are presented in Table 6.8.
6.7.3 Thermal Expansion under Off Normal and Extreme Ambient Temperatures :
The differential thermal expansion of MPC/HI-STORM UMAX components under off-normal and extreme ambient is computed following the methodology outlined in Section 6.3. The component temperatures under these conditions are obtained by adding the respective ambient temperature rise (T=20oF for off-normal ambient and T=45oF for extreme ambient) to the computed temperatures under normal storage (Section 6.1). The computed differential thermal expansion values between components are presented in Table 6.9. The results demonstrate restraint free expansion under off normal and extreme ambient conditions.
Report HI-2177591 Page 32 Project 5025 Table 6.1: HI-STORM UMAX Normal Long-Term Storage Temperatures for MPC-37 with Short Fuel under Heat Load Pattern 1
Temperature Component TemperatureoC (oF) Limit [3]
oC (oF)
Fuel Cladding 323 (613) 400 (752)
MPC Basket 289 (552) 400 (752)
Basket Periphery 244 (471) 400 (752)
Aluminum Basket Shims 224 (435) 400 (752)
MPC Shell 189 (372) 343 (650)
MPC Baseplate1 151 (304) 400 (752)
MPC Lid 1 187 (369) 400 (752)
Divider Shell 134 (273) 343 (650)
CEC Shell 44 (111) 343 (650)
Closure Lid Concrete 2 69 (156) 177 (350)
Insulation 132 (270) 343 (650)
Average Air Outlet 3 67 (153) -
1 Maximum section average temperature reported.
2 Maximum section average temperature reported.
3 Section average temperature on the cross section area of outlet duct below the outlet vent screen reported.
Reported herein for the option of temperature measurement surveillance of outlet duct air temperature as set forth in the Technical Specifications.
Report HI-2177591 Page 33 Project 5025 Table 6.2: Summary of MPC Cavity Pressure for Limiting MPC -37 with Short Fuel under Heat Load Pattern 1
Gauge MPC Cavity Average Condition Pressure, Temperature oC (oF) psig 1
no rods rupture 88.2 Normal condition 1% rods ruptured 89.2 226 (439)
Off-normal (10% rods ruptured) 98.3
Off-normal (50 of inlets and outlets blocked) 89.7 233 (451)
Accident (100 rods ruptured) 188.7 226 (439)
Accident (100% of inlets and outlets blocked)
(At the end of 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br />) 113.0 346 (655)
Note 1: The MPC pressure reported in this table do not include the effect of wind.
1 The pressures reported in this table are computed assuming the helium backfill pressure is at its upper bound limit (Table 1.3).
Report HI-2177591 Page 34 Project 5025 Table 6.3: Differential Thermal Expansion during Long-Term Storage for Limiting MPC-37 with Short Fuel under Heat Load Pattern 1
Minimum Gap Differential Expansion, Gap Description [1],[13], mm (inch) mm (inch)
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 35 Project 5025 Table 6.4: Summary of MPC Cavity Pressure for Limiting MPC-37 with Short Fuel under Heat Load Pattern 1 under Sustained Wind
Gauge MPC Cavity Average Condition Pressure, Temperature psig 1 oC (oF)
no rods rupture 91.5 Normal condition 1% rods ruptured 92.5 242 (468)
Off-normal (10% rods ruptured) 101.8
Off-normal (50% of inlets and outlet blocked) 92.9 249 (480)
Accident (100% rods ruptured) 195.0 242 (468)
Note 1: The MPC pressure reported in this table includes the effect of wind.
1 The pressures reported in this table are computed assuming the helium backfill pressure is at its upper bound limit (Table 1.3).
Report HI-2177591 Page 36 Project 5025 Table 6.5: HI-STORM UMAX Partial Duct Blockage Temperatures for MPC-37 with Short Fuel under Heat Load Pattern 1
Temperature Component TemperatureoC (oF) Limit [3]
oC (oF)
Fuel Cladding 330 (626) 400 (752)
MPC Basket 297 (567) 500 (932)
Basket Periphery 250 (482) 500 (932)
Aluminum Basket Shims 218 (424) 500 (932)
MPC Shell 190 (374) 427 (800)
MPC Baseplate1 159 (318) 427 (800)
MPC Lid 1 194 (381) 427 (800)
Divider Shell 140 (284) 343 (650)
CEC Shell 44 (111) 343 (650)
Closure Lid Concrete 84 (183) 177 (350)
Insulation 138 (280) 343 (650)
1 Maximum section average temperature reported.
Report HI-2177591 Page 37 Project 5025 Table 6.6: Differential Thermal Expansion during Partial Duct Blockage Scenario for Limiting MPC-37 with Short Fuel under Heat Load Pattern 1
Gap Description Minimum Gap [13], Differential Expansion, mm (inch) mm (inch)
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 38 Project 5025 Table 6.7: HI-STORM UMAX Complete Duct Blockage Temperatures at the end of 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> for MPC-37 with Short Fuel under Heat Load Pattern 1
Temperature Component TemperatureoC (oF) Limit [3]
oC (oF)
Fuel Cladding 432 (810) 570 (1058)
MPC Basket 404 (759) 570 (1058)
Basket Periphery 363 (685) 570 (1058)
Aluminum Basket Shims 335 (635) 570 (1058)
MPC Shell 319 (606) 570 (1058)
MPC Baseplate2 272 (522) 570 (1058)
MPC Lid 1 262 (503) 570 (1058)
Divider Shell 305 (581) 570 (1058)
CEC Shell 212 (414) 570 (1058)
Closure Lid Concrete 199 (390) 316 (600)
Insulation 303 (577) 570 (1058)
1 Maximum section average temperature reported.
Report HI-2177591 Page 39 Project 5025 Table 6.8: Differential Thermal Expansion during Complete Duct Blockage Scenario for Limiting MPC-37 with Short Fuel under Heat Load Pattern 1
Gap Description Minimum Gap [13], Differential Expansion, mm (inch) mm (inch)
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 40 Project 5025 Table 6.9: Differential Thermal Expansion under Off -normal Ambient, Extreme Ambient and Fire Accident
Differential Differential Differential Minimum Gap Expansion Expansion Expansion Gap Description [1],[13], under Off-under Extreme under Fire mm (inch) normal Ambient, Accident, Ambient, mm (inch) mm (inch) mm (inch)
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 41 Project 5025 Table 6.10: Temperature Increment Due to VCT Fire (adopted from [14])
Component Temperature Increment (K)
MPC Basket 4
Basket Shims 4
MPC Lid 4
MPC Shell 30
Divider Shell 0 Note 1
Note 1: Temperature rise of divider shell is conservatively neglected. This will overestimate the differential thermal expansion between the MPC and VVM components.
Report HI-2177591 Page 42 Project 5025 Table 6.11: Results of HI-STORM UMAX at High Ambient Temperature
Component Peak Temp Bulk Temp (F) (F)
MPC Base 347 311 MPC Lid 416 378 MPC Shell 406 351 MPC Cavity Pressure 92.4 psig
Report HI-2177591 Page 43 Project 5025 Table 6.13: Effect of Wind on Air Mass Flow Rate Through HI-STORM UMAX System Stored in an ISFSI Array
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 44 Project 5025 Table 6.14: Effect of Wind on Inlet Temperatures Note 1 Through HI-STORM UMAX System Stored In An ISFSI Array
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 45 Project 5025 Table 6.15 Differential Thermal Expansion for wind conditions
Gap Description Minimum Gap [13], Differential Expansion, mm (inch) mm (inch)
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Report HI-2177591 Page 46 Project 5025
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Figure 6.1. Scaled Residuals from the 3D Thermal Evaluations for HI-STORM UMAX under Normal Storage.
Report HI-2177591 Page 47 Project 5025
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Figure 6.2. Scaled Residuals from the 3D Thermal Evaluations for HI-STORM UMAX under Partial Duct Blockage Scenario.
Report HI-2177591 Page 48 Project 5025
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Figure 6.3: Time history of Component Temperatures under Complete Duct Blockage Condition
Report HI-2177591 Page 49 Project 5025
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Figure 6.4: Comparison of Inlet Mass Flow Rates by Module Across Arrays of 1x8, 1x12, and 1x25 Casks
Report HI-2177591 Page 50 Project 5025
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Figure 6.5: Comparison of Mass Flow-weighted Average Inlet Temperatures by Module Across Arrays of 1x8, 1x12, and 1x25 Casks
Report HI-2177591 Page 51 Project 5025
[PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
Figure 6.6: Residuals for thermal evaluations of (a) 1x12 and (b) 1x25 cask arrays.
Report HI-2177591 Page 52 Project 5025 7.0 References
[1] [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
[2] HI-STORE SAR, Holtec Report HI-2167374, Revision 0.
[3] HI-STORM UMAX FSAR, Holtec Report HI-2115090, Latest Revision.
[4] HI-STORM FW FSAR, Holtec Report HI-2114830, Latest Revision.
[5] HI-STAR 190 SAR, Holtec Report HI-2146214, Latest Revision.
[6] NUREG-1567, Latest Revision.
[7] NUREG-1536, Latest Revision.
[8] Effective Thermal Properties of PWR Fuel to Support Thermal Evaluation of HI-STORM FW, Holtec Report HI-2094356, Revision 5.
[9] Holtec Engineering Change Order (ECO) 5021-26, Revision 0.
[10] ANSYS FLUENT Computational Fluid Dynamics Software.
[11] Interim Staff Guidance, ISG-11, Revision 3.
[12] Thermal-Hydraulic Evaluation of HI-STORM UMAX, Holtec Report HI-2114807, Latest Revision.
[13] [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
[14] Evaluation of Effects of Tracked VCT Fire on HI-STORM FW System, Holtec Report HI-2135677, Revision 5.
[15] [PROPRIETARY INFORMATION WITHELD PER 10CFR2.390]
[16] Holtec Engineering Change Order (ECO) 5021-24, Revision 0.
Report HI-2177591 Page 53 Project 5025