B16616, Application for Amend to License NPF-49,changing TS Bases Section 3/4.9.7 to Reword Section to Be Consistent W/Revised Impact Load Analysis for Spent Fuel Racks
| ML20141H152 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 07/14/1997 |
| From: | Mcelwain J NORTHEAST NUCLEAR ENERGY CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20141H156 | List: |
| References | |
| B16616, NUDOCS 9707220052 | |
| Download: ML20141H152 (3) | |
Text
.
Northeast "M" F"'r "d- (""" *'h **'"'"'d#'"
N6 clear Energy uaision, Noci,, po.r siation Northeast Nuclear Energy Company e.O. ILx 128 Waterford, CT OM85-0128 (860) 447-1791 Fax (8u)) 44+-42??
The Northeast Utilitica System JUL I 419W Docket No. 50-423 B16616 Re: 10CFR50.59 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Millstone Nuclear Power Station, Unit No. 3 Chanae to Technical Specification Bases Section 3/4.9.7 (PTSCR 3-26-97)
Northeast Nuclear Energy Company (NNECO) is providing the NRC Staff with changes to Technical Specification (TS) Bases Section 3/4.9.7 (Crans Travel - Spent Fuel Storage Areas) for information only. These changes were reviewed and approved by the Millstone Unit No. 3 Plant Operating Review Committee on June 17,1997, in accordance with the provisions of 10CFR50.59.
Description of Chance The change to TS Bases Section 3/4.9.7 is to reword the section to be consistent with the revised impact load analysis for the spent fuel racks. The need to revise the j
analysis was a result of an investigation into an inconsistency between the Technical Specifications and the Final Safety Analysis Report (FSAR) for Millstone Unit No. 3
)
regarding the weight of one fuel assembly with a Rod Cluster Control Assembly (RCCA) and its associated handling tool.
Supolemental Information
/
In a letter dated January 9,1997, the NRC Staff transmitted a request for additional information concerning an inconsistency between the Technical Specifications and Final Safety Analysis Report for Millstone Unit 3 regarding the weight of a spent fuel assembly and its associated handling tool. The inconsistency was that TS 3.9.7 and its bases seem to imply that the combined weight of one fuel assembly, RCCA and associated handling tool is 2200 pounds, while the FSAR states that the combined weight is 2000 pounds.
The review, performed for the February 6,1997 NNECO response to the staff request for additional information, determined that a design impact load analysis for the spent fuel racks did not exist for loads up to the TS limit of 2200 pounds. Additionally, a discrepancy was noted between the Bases of TS 3.9.7 and FSAR Section 15.7.4.1. The TS bases states: 1) in the event the load is dropped on stored spent fuel, the activity
!!!!!!!!!!h!k!!!!,$l!h!!!
AN O
p PDet -
, a v v e.
U.S. Nucibcr Rsgulatory Commission 1
B16616\\Page 2.
1 release will be limited to_ that ' contained in a single fuel assembly, and 2) this assumption is consistent with the release assumed in the safety analysis. The.FSAR fuel handling accident analysis assumes. failure of all the fuel rods in the dropped assembly and 50 fuel rods in an additional assembly.
NNECO committed in the February 6,1997 letter to complete the investigation, resolve the inconsistencies, determine the safety significance and submit a supplemental report.
The change request to the FSAR committed to in the letter has been incorporated and forwarded to the NRC Staff as part of NNECO's July 1,1997 Revision 10 to the Final Safety Analysis Report and Addendum 2 to the Annual Report.
NNECO has determined that the combined weight of a fuel assembly, RCCA and handling tool is approximately 2t:30 pounds, which is consistent with the FSAR. The weight limit specified in TS 3.9.7 originated from the spent fuel bridge operating manual, which states that the. overload setpoint should be set at 2000 i 200 pounds.
l Personnel developing the initial TS for Unit 3 determined that a TS limit of 2200 pounds 1
was. appropriate.
The Westinghouse specification for the spent fuel racks only analyzed for a load drop up to the weight of one fuel assembly and RCCA,1616
. pounds.
Westinghouse has recently determined the effects of' dropping a fuel assembly with a weight of 2400 pounds on the spent fuel racks and concluded that Keff would remain less than 0.95. The value of 2400 pounds includes a 200 pound margin f
beyond the TS limit of 2200 pounds.
The design basis fuel handling accident analysis assumes the failure of all the fuel rods 1
in the dropped assembly and an additional 50 fuel rods in a second assembly.
Westinghouse has also provided a letter stating that they had previously performed a test for another utility in which they dropped a fuel assembly through 20 feet of water onto a surface similar to a spent fuel pool floor, and experienced no fuel rod failures.
During fuel handling in the spent fuel. pool, the travel height above the racks is approximately 12 inches and the maximum travel height above the floor is approximately 15 feet. These travel heights are established by the length of the spent r
fuel handling tool and the upper limit for the hoist. The kinetic energy of a. fuel
]
. assembly dropped from 12 inches above the racks or 15 feet above the floor is less than a fuel assembly dropped 20 feet, therefore it.) number of expected failed fuel rods in an actual fuel handling accident is bounded by the assumed number of failed fuel J
rods in the design basis accident.
1 1
U.S. Nucir:r R:gulatory Commission B16616\\Page 3 if yo'u have any questions, please contact Mr. D. Smith at (860) 437-5840.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY FOR: M. H. Brothers Vice President - Millstone Unit No. 3 BY:
M pohn P. McElWain Recovery Officer - Millstone Unit No.1 j
Commitments - NONE
, - Marked Up Bases Page
, - Retyped Bases Page cc-H. J. Miller, Region i Administrator W. D. Travers, PhD., Director, Special Projects Office J. W. Andersen, NRC Project Manager, Millstone Unit No. 3 A. C. Cerne, Senior Resident Inspector, Millstone Unit No. 3 t
N 1
4
+-