ML21214A134
| ML21214A134 | |
| Person / Time | |
|---|---|
| Site: | 07201032 |
| Issue date: | 08/02/2021 |
| From: | Holtec |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML21214A130 | List: |
| References | |
| 5018089 | |
| Download: ML21214A134 (6) | |
Text
ATTACHMENT 2 TO HOLTEC LETTER 5018089 Table 3.4.18 STRESS RESULTS FOR HI-TRAC VW VERSION P - NORMAL HANDLING Item Calculated Value (ksi) Allowable Limit (ksi) Safety Factor Bottom Lid Bolts - 57.5 Tensile Stress 12.07 4.76 Bottom Lid Bolts - 23.8 Shear Stress on Bolt Threads 4.35 5.46 Bottom Lid Bolts - 23.8 Shear Stress on Bolt 12.9 1.84 Bottom Lid -
3.12 13.2 4.23 Internal Thread Shear Stress Table 3.4.19 STRESS RESULTS FOR ANCHORAGE IN HI-STORM FW VERSION E - LEVEL A Safety Allowable Force Calculated Force Item Factor Fa (lbf) Fc (lbf) Fa / Fc Under TensionUnder Tension 153,982153982 138,000129345 1.121.19 Anchor Bolt Thread ShearThread Shear 175,406175406 138,000129345 1.271.36 Compression Thread Shear 241,275 138,000 1.75 Block Nut Thread ShearThread Shear 240,064141250 138,000129345 1.741.09 HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Revision 7.C 3-152 PAGE 1 OF 6
ATTACHMENT 2 TO HOLTEC LETTER 5018089 Table 3.4.20 STRESS RESULTS FOR ANCHORED HI-STORM FW VERSION E - LEVEL D Allowable Force Calculated Force Safety Factor Item Fa (lbf) Fc (lbf) Fa / Fc Under Tension 215,575 157,314 1.37 Anchor Bolt Thread Shear 356,470 157,314 2.27 Compression Thread Shear 361,912 157,314 2.30 Block Nut Thread Shear 487,871 157,314 3.10 Table 3.4.21 STRESS RESULTS FOR ANCHORED HI-STORM FW VERSION E - LEVEL D Allowable Calculated Safety Stress Stress Factor Item a (psi) c (psi) a / c Under TensionUnder Tension 40,300 24,130 1.67 Base PlateBase Under Tension + Bending Under 60,400 24,130 2.50 Plate Tension + Bending Under ShearUnder Shear 29,400 12,065 2.44 Under TensionUnder Tension 40,300 12,410 3.25 Other Plate Under Tension + Bending Under MembersOther 60,400 12,410 4.87 Tension + Bending Plate Members Under ShearUnder Shear 29,400 6,205 4.74 Table 3.4.22 SAFETY FACTOR FOR HI-STORM FW VERSION E LID DURING TORNADO WIND AND MISSILE IMPACT Part Induced Stress - ksi Allowable Stress -ksi Safety Factor Closure Lid Bolts 5.8 50.4 8.69 HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Revision 7.C 3-153 PAGE 2 OF 6
ATTACHMENT 2 TO HOLTEC LETTER 5018089
[3.4.27] Carette and Malhotra, Performance of Dolostone and Limestone Concretes at Sustained High Temperatures, Temperature Effects on Concrete, ASTM STP 858, 1985, p. 38-67.
[3.4.28] Holtec Report HI- 2188720R0, Structure Calculation Package for HI-STORM FW Anchor System, Revision 10.
[3.4.29] Holtec Report HI- 2200647, Analysis of the Postulated Drop and Missile Impact Events for the Loaded HI-STORM FW Version E Cask and the Loaded HI-TRAC VW System, Revision 30.
[3.4.30] Topical report of Bechtel Power Corporation, BC-TOP-9A, "Design of structures for missile impact", Revision 2.
[3.6.1] Visual Nastran 2004, MSC Software, 2004.
HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Revision 7.C 3-275 PAGE 3 OF 6
ATTACHMENT 2 TO HOLTEC LETTER 5018089 SFSC Heat Removal System B 3.1.2 BASES APPLICABLE The thermal analyses of the SFSC take credit for the decay heat SAFETY from the spent fuel assemblies being ultimately transferred to the ANALYSIS ambient environment surrounding the OVERPACK. Transfer of heat away from the fuel assemblies ensures that the fuel cladding and other SFSC component temperatures do not exceed applicable limits. Under normal storage conditions, the inlet and outlet air ducts are unobstructed and full air flow (i.e., maximum heat transfer for the given ambient temperature) occurs.
When 50% or less of the inlet and outlet vent area is blocked (i.e.,
50% to 100% of the vents are open), the heat removal system is considered operable, the blockage is considered a partial blockage, and the system is subject to off-normal condition limits in FSAR Tables 2.2.1 and 2.2.3. When greater than 50% of the inlet or outlet vent area is blocked (i.e., <50% of the vents are open), the heat removal system is considered inoperable, the blockage is considered a complete blockage and consistent with the HI-STORM FW FSAR, is considered an accident condition. As such, the system is subject to accident condition limits in FSAR Tables 2.2.1 and 2.2.3.
Analyses have been performed for the complete obstruction of half, and all inlet air ducts. Blockage of half of the inlet air ducts reduces air flow through the OVERPACK annulus and decreases heat transfer from the MPC. Under this off-normal condition, no SFSC components exceed the short term temperature limits.
The complete blockage of all inlet air ducts stops normal air cooling of the MPC. The MPC will continue to radiate heat to the relatively cooler OVERPACK. With the loss of normal air cooling, the SFSC component temperatures will increase toward their respective short-term temperature limits. None of the components reach their temperature limits over the duration of the analyzed event.
(continued)
HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Rev. 7.C 13.A-18 PAGE 4 OF 6
ATTACHMENT 2 TO HOLTEC LETTER 5018089 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 at least 50% of the inlet air ducts available for air flow (i.e., unblocked) 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.
The intent of this LCO is to address those occurrences of air duct 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 8-hour 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 site-specifically as required by Section 3.4.10 of Appendix B to the CoC.
APPLICABILITY The LCO is applicable during STORAGE OPERATIONS. Once an OVERPACK containing an MPC loaded with spent fuel has been placed in storage, the heat removal system must be operable to ensure adequate dissipation of the decay heat from the fuel assemblies.
ACTIONS A note has been added to the ACTIONS which states that, for this LCO, separate Condition entry is allowed for each SFSC. This is acceptable since the Required Actions for each Condition provide appropriate compensatory measures for each SFSC not meeting the LCO. Subsequent SFSCs that don't meet the LCO are governed by subsequent Condition entry and application of associated Required Actions.
(continued)
HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Rev. 7.C 13.A-19 PAGE 5 OF 6
ATTACHMENT 2 TO HOLTEC LETTER 5018089 SFSC Heat Removal System B 3.1.2 BASES ACTIONS A.1 (continued) Although the heat removal system remains operable, the blockage should be cleared expeditiously. If temperature measurements are used to declare operability, no inspection of the vents is required, but if any blockage is identified, it should be removed.
B.1 If the heat removal system has been determined to be inoperable, it must be restored to operable status within eight hours. Eight hours is a reasonable period of time (typically, one operating shift) to take action to remove the obstructions in the air flow path.
C.1 If the heat removal system cannot be restored to operable status within eight hours, the innermost portion of the OVERPACK concrete may experience elevated temperatures. Therefore, dose rates are required to be measured to verify the effectiveness of the radiation shielding provided by the concrete. This Action must be performed immediately and repeated every twelve hours thereafter to provide timely and continued evaluation of the effectiveness of the concrete shielding. As necessary, the system user shall provide additional radiation protection measures such as temporary shielding. The Completion Time is reasonable considering the expected slow rate of deterioration, if any, of the concrete under elevated temperatures.
C.2.1 In addition to Required Action C.1, efforts must continue to restore cooling to the SFSC. Efforts must continue to restore the heat removal system to operable status by removing the air flow obstruction(s) unless optional Required Action C.2.2 is being implemented.
This Required Action must be complete in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The Completion Time is consistent with the thermal analyses of this event, which show that all component temperatures remain below their short-term temperature limits up to 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> after event initiation.
(continued)
HOLTEC INTERNATIONAL COPYRIGHTED MATERIAL REPORT HI-2114830 Proposed Rev. 7.C 13.A-20 PAGE 6 OF 6