ML18052A811
| ML18052A811 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/19/1986 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18052A812 | List: |
| References | |
| NUDOCS 8612240025 | |
| Download: ML18052A811 (3) | |
Text
consumers Power l'OWERINli NllCHlliAN'S l'ROliRESS General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-1636 December 19, 1986
- Director, Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
EXPANSION OF SPENT FUEL POOL STORAGE CAPACITY - TECHNICAL SPECIFICATION CHANGE REQUEST - ADDITIONAL INFORMATION Kenneth W Berry Director Nuclear licensing Consumers Power Company letter dated October 16, 1986, submitted Revision 1 to the February 20, 1986, Technical Specification Change Request associated with the proposed installation of new spent fuel racks in approximately one half of the Palisades Spent Fuel Pool~ Subsequently, during a November 6, 1986, telephone conference, the NRC staff made inquiries concerning (1) the instal-lation of and the maintenance of the gap between rack modules and between rack modules and the pool walls; (2) the effect of rotational forces on a partially loaded rack during a seismic event; (3) the physical effect on the fuel pool liner by the accidental drop of a fuel bundle straight through a storage location; and (4) additional information with reference to the July 24; 1986 Consumers Power Company response to question llC in the April 25, 1986 NRC letter regarding expansion of the spent fuel pool storage capacity.
The following is our response to those inquiries.
- 1.
The new spent fuel racks will be installed according to administra-tive controls which require the gaps between rack modules and the gaps between rack modules and the pool walls to be measured at the time of installation.
The fuel assembly drop accident and the stuck fuel assembly incident will not cause rack movement.
The rack movement during a seismic event is small enough so that 20 seismic events of the magnitude of an SSE could occur before the rack to rack and rack to wall gaps are significantly reduced.
Thus, it is not 861'2240025 861219.*
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Director, Nuclear Reactor Regulation
- Palisades Plant TSCR - Expansion of Spent Fuel Pool Storage Capacity December 19, 1986 2
necessary to measure the rack to rack and rack to wall gaps after the time of installation.
- 2.
Analysis has shown that the condition of a fully loaded rack produces the maximum loads and rack displacements.
The response of the racks for conditions of partial loading of fuel is less severe than for the fully loaded condition.
There is no significant rotation of a partially loaded rack.
The margins of safety reported in the Safety Analysis Report are the limiting values.
- 3.
Analysis has been performed which shows that if a fuel assembly is dropped straight through a fuel rack storage location so as to impact the rack base plate, the force will not perforate the Spent Fuel Pool liner plate.
- 4.
The drop of a fuel assembly straight through a storage location was analyzed to determine if.the Spent Fuel Pool liner would be perforat-ed.
In order that this same analysis could be used in the future as a reference for the drop of loads which are of the same general configuration (but more dense) than a fuel assembly, the analysis postulated a fuel canister weighing 2,720 lbs in water dropped from a height of 181 inches.
The results of this analysis showed that the pool liner would not be perforated and were evaluated to envelope the postulated fuel assembly drop (1,500 lbs) from a height of 183 inches a*s described in section 4. 6. 4 of the SAR.
Since the above described evaluation has been the subject of recent discussion, another analysis has been done postulating a fuel assembly and handling tool of the same weight (1500 lbs) and drop height (183 inches) -as stated in section 4.6.4 of the SAR.
No credit was taken for the water resistance of the falling fuel assembly.
The maximum velocity of the fuel assembly was approximately 29.5 ft/sec.
The fuel assembly was assumed to impact the rack base plate and the drop energy was dissipated in breaking some of the cell to base plate welds and in deformation of the base plate.
The base plate did not impact the pool floor; and thus the pool liner was not perforated.
Accordingly, with regard to Response No. 3, the fourth paragraph of Section 4.6.4 of the SAR, as revised on October 16, 1986, should be amended to read as follows:
"The third accident condition assumed that the dropped assembly (1500 lbs) fell straight through an empty cell and impacted the rack base plate from a drop height of 183 inches.
The results of this analysis showed that the impact energy is absorbed by the fuel assembly and the rack base plate, the OC1186-0184-NL02
Director, Nuclear Reactor Regulation
- Palisades Plant TSCR - Expansion of Spent Fuel Pool Storage Capacity December 19, 1986 criticality acceptance criterion is not violated, and the spent fuel pool liner is not perforated."
Attachment I.is amended.page 4-11 of the SAR.
It includes Section 4.6.4 as amended.
Kenneth W Berry Director, Nuclear Licensing CC Admi~istrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment OC1186-0184-NL02 3