ML24136A193

Attachment 4: Proposed HI-STORM Umax FSAR Amendment 5

ML24136A193
Person / Time
Site:	HI-STORM 100
Issue date:	04/18/2024
From:	Holtec
To:	Office of Nuclear Material Safety and Safeguards
Shared Package
ML24136A188	List: ML24136A189 ML24136A191 ML24136A192 ML24136A193 ML24136A194
References
5021076
Download: ML24136A193 (1)

Text

of the VVM. For an example of the rigging required to handle the HI-STORM UMAX VVM Closure Lid, see Figure 9.2.3.

9.2.2 Preparation for MPC Transfer

The required equipment/devices that participate in the transferring of the MPC into dry storage are, as a minimum:

1. Equipment to remove and install the VVM Closure Lid;

2. The vertical cask transporter (VCT) or equivalent load handling devices with redundant drop protection features;

3. The loaded transfer cask containing the MPC;

4. The Mating Device; and

5. MPC lifting and handling devices.

Prior to staging the Mating Device and the transfer cask on the recipient VVM cavity, the storage cavity shall be inspected for absence of debris, water, animals or insect nests, and the like. A general checklist for performing the pre-staging inspection of the VVM cavities is provided below:

1. The painted surfaces shall be inspected for corrosion and chipped, cracked, or blistered paint.

2. All lid surfaces shall be relatively free of dents, scratches, gouges, or other damage.

3. Lid lifting points shall be inspected for dirt, debris, and general condition.

4. Vent openings shall be free from obstructions.

5. Vent screens shall be available, intact, and free of holes and tears. Versions B1 and B2 should confirm appropriate cover plates are installed in accordance with the drawings.

6. Temperature monitoring elements, if used, shall be inspected for availability, function, calibration, and provisions for mounting to the VVM outlet air passage.

HI-STORM UMAX VVM Main Body

1. Cooling passages shall be free from obstructions.

2. The interior cavity shall be free of debris, litter, tools, and equipment.

3. Painted surfaces shall be inspected for corrosion, and chipped, cracked or blistered paint.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 9-7 9.3 ACTIVITIES PERTAINING TO ISFSI OPERATIONS

The HI-STORM UMAX System heat removal is by totally passive means. As discussed in Chapter 10, surveillance of the HI-STORM VVM assembly to ensure its continued effectiveness involves the following principal activities:

1. Check for intrusion of foreign objects that may impair the systems thermal performance during normal operations and in the wake of an extreme environmental phenomenon including severe flood.

2. Check for corrosion damage to the steel parts, namely the CECs (oldest or most vulnerable VVM shall be inspected).

3. Check for structural damage to the ISFSI after an earthquake.

4. Perform the heat removal operability surveillance as specified the CoC.

5. Perform ISFSI Security Operations in accordance with the host sites security plan.

Routine maintenance on the HI-STORM UMAX System will typically be limited to cleaning and touch-up painting of the exposed steel surfaces, repair, and replacement of damaged vent screens, and removal of vent blockages (e.g., leaves, debris), if any (See Table 10.4.1 and 10.4.2 for specific requirements). The heat removal system operability surveillance should be performed after any event that may have an impact on the safe functioning of the HI-STORM UMAX system. These include, but are not limited to, wind storms, heavy snow storms, fire inside the ISFSI, seismic activity, flooding of the ISFSI, and/or observed animal, bird, or insect infestations. The responses to these conditions involve first assessing the dose impact to perform the corrective action (inspect the HI-STORM VVM cavity, clear the debris, check for any structural damage of the ISFSI pad, and/or replace damaged vent screens); perform the corrective action; and verify that the system is operable (check ventilation flow paths as applicable and radiation blockage capability. Cover plates that are a part of the lid design are not considered blockages). In the unlikely event of significant damage to the ISFSI, possibly from a Beyond-the-Design Basis earthquake, the situation may warrant removal of the MPC, and repair or replacement of the damaged ISFSI areas. Section 9.4 may be used as guidance for unloading the MPC from the HI-STORM UMAX.

Note:

The inlet vent openings in UMAX Version B1 and B2 use cover plates in accordance with the applicable vent design of the lid. These cover plates can be installed on an existing Version B inlet vent to convert to the other versions.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 9-16 Table 10.1.1 (continued)

HI-STORM UMAX VVM ASSEMBLY INSPECTION AND TEST ACCEPTANCE CRITERIA Function Fabrication Pre-operation Maintenance and Operations Thermal a) Inner shell I.D. and vent size, a) Visual examination a) MPC lid temperature test Acceptance configuration and placement of the insulation shall be performed as shall be verified. and coatings will be discussed in Section performed to verify 10.3 that they are in good condition b) Periodic surveillance b) Air flow paths will shall be performed by be visually either (1) or (2) below, at inspected to ensure the licensees option.

they are clear and This is not applicable to free of FME. This Version B2.

is not applicable to Version B2. (1) Inspection of VVM inlet and outlet air vent openings for debris and other obstructions.

(2) Temperature monitoring.

Cask a) Verification that the VVM a) The VVM a) The VVM identification Identification identification is present in identification shall shall be periodically accordance with the drawings be checked prior to inspected per licensee shall be performed upon loading. procedures and repaired completion of assembly. or replaced if damaged.

Fit-up Tests a) Where closely toleranced a) Lid fit-up with the a) None.

alignment between mating VVM shall be components is required, a verified following component-to-component fit-up placement of shall be performed directly concrete around the whenever practical or using VVM.

templates or other means.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 10-13 too inaccurate to provide meaningful information.) This test is only required to be performed if Holtec intends to submit a license amendment to remove the aggregate heat load penalty currently in the CoC.

After the system has been in storage for at least one week (to reach steady state) and when the ambient is relatively quiescent and the solar heat deposition rate is minimal, the surface temperature of the top of the MPC lid shall be measured at the center and 4 orthogonally disposed peripheral locations.

The measured lid temperature data (at designated measurement points) shall be compared with the results predicted by the FLUENT analysis.

The measured temperatures (in Deg. F) must be no greater than 5% over the corresponding analytically predicted temperatures to be acceptable.

The technical specifications require periodic surveillance of the system air inlet and outlet vents or, optionally, implementation of a HI-STORM UMAX VVM air temperature monitoring program to provide continued assurance of the operability of the HI-STORM UMAX heat removal system.

This requirement is not applicable to Version B2.

iv. Storm Water Control Test

The HI-STORM UMAX VVM is designed to direct storm water and snow/ice melt-off away from the CEC Flange and the Closure Lid where the air passages are located. The engineered rain caps installed on the inlet and outlet serve to keep rain and snow away from the VVM cavity. Moreover, any minor amount of moisture that may intrude into the MPC storage cavity due to wind-driven rain will evaporate in a short period of time due to the continuous movement of heated air in the MPC storage cavity. To verify the effectiveness of the storm water drainage design, a one-time test shall be performed after construction of the first VVM to ensure that the design is effective in directing storm water away from the VVM to the ISFSIs drainage system. The VVM shall be subjected to a water spray that simulates exposure to rainfall of at least 2 inches per hour for at least one hour. At the conclusion of the water spray, the depth of the water (if any) in the bottom of the module cavity shall be measured. Any amount of water accumulation beyond wetting of the Bottom Plate indicates an inadequacy in rain diversion features of the VVM and shall be appropriately corrected. It should be noted that accumulation of water is not injurious to the thermal performance of the system. The only deleterious effect of prolonged exposure to water is the potential for reducing the service life of the preservative on the wetted surface of the Bottom Plate, CEC shell, and other interfacing components.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 10-17 inspection of the air inlet and outlet vents, the thermocouples and associated temperature monitoring instrumentation shall be maintained and calibrated in accordance with the users QA program commensurate with the equipments safety classification and designated QA category.

10.4.4 Pressure Relief Devices

The pressure relief devices used on the water jackets for the HI-TRAC transfer cask shall be confirmed to have been calibrated as specified in the licensing basis FSAR for the HI-TRAC to ensure pressure relief settings are accurate prior to the casks use at a HI-STORM UMAX ISFSI.

10.4.5 Shielding

The gamma and neutron shielding materials in the HI-TRAC and MPC are not subject to measurable degradation over time or as a result of usage. The radiation shielding capacity of the HI-STORM UMAX System is expected to remain undiminished over time. Therefore, unless the VVM is subjected to an extreme environmental event that imparts stresses or temperatures beyond-the-design-basis limits for the system (i.e., prolonged fire or impact from a beyond-the-design basis large energetic projectile) with the plausible potential to degrade the shielding effectiveness of the VVM, no shielding effectiveness tests beyond that required by the plants Radiation Protection Program are required over the life of the HI-STORM UMAX System.

Radiation monitoring of the ISFSI by the licensee in accordance with 10CFR72.104(c) provides ongoing evidence and confirmation of shielding integrity and performance. If increased radiation doses are indicated by the facility monitoring program, additional surveys of the ISFSI shall be performed to determine the cause of the increased dose rates.

The water level in the HI-TRAC water jacket shall be verified during each loading campaign in accordance with the licensee's approved operations procedures.

The neutron absorber panels installed in the MPC baskets are not expected to degrade under normal long-term storage conditions. Therefore, no periodic verification testing of neutron poison material is required on the HI-STORM UMAX System.

10.4.6 Thermal

In order to assure that the HI-STORM UMAX System continues to provide effective thermal performance during storage operations, surveillance of the air vents (or alternatively, by temperature monitoring) shall be performed in accordance with written procedures for all versions except Version B2.

For those licensees choosing to implement temperature monitoring as the means to verify VVM Assembly heat transfer system operability, a maintenance and calibration program shall be

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 10-20 Table 10.4.1

HI-STORM SYSTEM MAINTENANCE PROGRAM SCHEDULE

Task Frequency VVM cavity visual inspection Prior to MPC loading Divider shell visual inspection Prior to MPC loading Closure Lid visual inspection Prior to MPC loading VVM external surface (accessible) Annually, during storage operation visual examination VVM inlet, and outlet vent screen Monthly and inlet vent cover visual inspection for damage, holes, etc.

VVM inlet and outlet vent Daily unless monitoring is performed using inspection for blockage (Not temperature monitoring equipment applicable to Version B2)

HI-TRAC cavity visual inspection Prior to each handling campaign HI-TRAC TAL visual inspection Prior to each handling campaign HI-TRAC bottom lid bolts and bolt Prior to each handling campaign holes HI-TRAC pressure relief device Per the device manufacturers recommendation.

calibration HI-TRAC water jacket water level During each handling campaign in accordance with visual examination licensee approved operations procedures VVM visual inspection of Annually identification markings VVM Air Temperature Monitoring Per licensees QA program and manufacturers System recommendations VVM inlet plenum inspection for Every five years or following a severe weather event accumulation of FME. that may introduce significant FME material.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 10-22 SFSC Heat Removal System B 3.1.2 BASES LCO The SFSC Heat Removal System must be verified to be operable to preserve the assumptions of the thermal analyses. Operability is defined as either 50% or more of the uncovered inlet and outlet vent duct areas are unblocked and available for flow or when differential temperature requirements are met. Operability of the heat removal system ensures that the decay heat generated by the stored fuel assemblies is transferred to the environs at a sufficient rate to maintain fuel cladding and other SFSC component temperatures within design limits.

This LCO is not applicable to HI-STORM UMAX VERSION B2, because the inlet vent openings are purposely covered to raise the MPC surface temperature while maintaining the fuel cladding temperature below applicable limits.

The intent of this LCO is to address those occurrences of air duct screen blockage that can be reasonably anticipated to occur from time to time at the ISFSI (i.e., Design Event I and II class events per ANSI/ANS-57.9). These events are of the type where corrective actions can usually be accomplished within one operating shift to restore the heat removal system to operable status (e.g., removal of loose debris).

This LCO is not intended to address low frequency, unexpected Design Event III and IV class events (ANSI/ANS-57.9) such as design basis accidents and extreme environmental phenomena that could potentially block one or more of the air ducts for an extended period of time (i.e., longer than the total Completion Time of the LCO). This class of events is addressed by site procedures as required by the CoC.

APPLICABILITY The LCO is applicable during STORAGE OPERATIONS after the lid is installed on the VVM. Once installed, the heat removal system must be operable to ensure adequate dissipation of the decay heat from the fuel assemblies. Prior to lid installation, adequate cooling is available due to the configuration without the lid, which results in larger flow areas than those in the lid and vents.

HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL HI-2115090 Proposed Rev. 8A7 13-A-18