ML20117K980

Forwards Application for Amends 153 & 137 to Licenses NPF-10 & NPF-15,respectively,clarifying Figures 3.7.18-1 & 3.7.18-2 by Adding Line at 4.8 Weight % Initial U-235 Enrichment to Show Acceptable Zone Maximum of 4.8 W/O

ML20117K980
Person / Time
Site:	San Onofre
Issue date:	08/30/1996
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20117K981	List: ML20117K980 ML20117K985 ML20117K993
References
NUDOCS 9609120277
Download: ML20117K980 (3)

Text

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$$i sourHtRNcAutoasA l .M EDISON " * " ""

Vice President l

An LDISON INURV4 TION.4L Company i

August 30, 1996 l

l U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

Docket Nos. 50-361 and 50-362 Amendment Application Nos. 153 and 137 Supplement 1, Storing Nuclear Fuel San Onofre Nuclear Generating Station Units 2 and 3

References:

1. Letter from R. M. Rosenblum (Edison) to Document Control Desk (NRC), dated December 6,1995,

Subject:

Amendment i

Application Numbers 153 and 137, (PCN-449), Storing Nuclear Fuel

2. Letter from John T. Larkins (NRC) to Harold B. Ray (Edison) and Gary D. Cotton (SDG&E) dated August 20, 1990,

Subject:

i Exemption to 10 CFR 70.24, " Criticality Accident Requirements," San Onofre Nuclear Generating Station, Units Nos. 2 and 3 (TAC Nos. 77094 and 77095)

3. Letter from F. R. Nandy (Edison) to Document Control Desk (NRC), dated February 16, 1990,

Subject:

Spent Fuel Pool Reracking (TAC Nos. 68308/9) Amendment Application Nos. 78 and 64 (PCN-287)

Enclosed are Amendment Application 153, Supplement 1 and Amendment Application 137, Supplement 1 to Facility Operating Licenses NPF-10 and NPF-15, respectively, for the San Onofre Nuclear Generating Station Units 2 and 3. These amendment application supplements are Supplement 1 to Proposed i Change Notice 449, Storing Nuclear Fuel, (PCN-449, Supp.1) which contains replacement pages for the revised Figures 3.7.18-1 and 3.7.18-2 (Reference 1).

This supplement is being submitted to clarify these figures by adding a line at 4.8 weight percent (w/o) initial U-235 enrichment to explicitly show that the acceptable zone of operation ends at a maximum of 4.8 w/o.

l As discussed with the NRC Project Manager for San Onofre Units 2 and 3, Southern California Edison (Edison) will not move a spent fuel pool gate l except in a safe load path (i.e., no fuel assemblies in the drop zone).

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Document Control Desk Additionally, Edison has reviewed the current 10CFR70.24 exemption (Reference 2) for the requirement of two criticality monitoring systems in the new and spent fuel storage areas of the fuel handling building (one is installed). Edison has determined that revision of the current 10CFR70.24 exemption is not required because, even though the fuel enrichment is being increased from 4.1 w/o to 4.8 w/o, the basis for the current exemption has not changed. The basis for the exemption for the new fuel storage racks is geometric spacing. There is no change to the geometric spacing exemption basis for the new fuel storage racks due to the increase in new fuel enrichment.

The current exemption for the spent fuel pool is based on the use of geometric spacing, boraflex panels, minimum boron concentration of 1850 ppm boron, and I the controlled storage of low burnup fuel in Region II racks. The increase in fuel enrichment has resulted in a change to an assumption in the spent fuel pool misloading criticality analysis. Although the burnup vs. enrichment curves have changed, the control requirements for the storage of low burnup 1 fuel in region II racks remain unchanged from the current exemption. The (

assumption in the postulated misloading fuel criticality analysis in Region II l of the spent fuel pool has changed as noted on pace 7 of Attachment E to PCN 449. This change requires a revision to the Tu inical Specification (TS)

Basis for TS 3.7.17, Spent Fuel Pool Boron Concentration. The Technical Specification Basis change was provided in Atta A ent F to PCN 449, and states, in part:

"Previously, the misloading analyses assumed that Region II was completely filled with un-irradiated 4.1 w/o fuel assemblies. The new analyses assume a worst case misloading of nine (9) un-irradiated fuel l assemblies of 5.1 w/o (bounds 4.8 w/o) in a 3x3 array in the a ton II l spent fuel racks." i A summary of the criticality analyses performed for the high density spent fuel storage racks was submitted to the NRC by Reference 3. These analyses included the burnup vs. enrichment curve to be used for the controlled storage of low burnup fuel in Regicn II. PCN 449 provided the analysis results for the increase in enrichment from 4.1 w/o to 4.8 w/o and a revised curve for the storage of low burnup fuel in Region II.

The current exemption (Reference 2) states:

"The rationale for the requested exemption is the high density spent fuel storage racks. Under the amendments which granted an increase in the capacity of the spent fuel pools, it was recognized that criticality was precluded by the following: (1) geometric spacing; (2) Boraflex panels inserted in the racks; (3) minimum boron concentration in the spent fuel pool of 1850 ppm per Technical Specification 3.9.13; and (4) controlled storage of low burnup fuel in Region II of the spent fuel racks as specified in Technical Specification 5.6.1. These additional measures to preclude criticality provide an acceptable bases to continue the exemption."

Document Control Desk Since the rationale and basis for the current exemption for both the new fuel storage racks and the spent fuel pool areas are still valid, no revision to the exemption is warranted.

If you need additional information on this Technical Specification change request, please let me know.

Sincerely,/

r m. c s

\1 t Enclosure cc: L. J. Callan, Regional Administrator, NRC Region IV K. E. Perkins, Jr., Director, Walnut Creek Field Office, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3 M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3

, H. Kocol, California Department of Health Services J. E. Dyer, Director, Division of Reactor Projects, Region IV