ML19093B013

Response to Request for Additional Information Concerning High Density Spent Fuel Storage Racks for Surry Units 1 & 2

ML19093B013
Person / Time
Site:	Surry
Issue date:	08/10/1977
From:	Stallings C Virginia Electric & Power Co (VEPCO)
To:	Case E, Reid R Office of Nuclear Reactor Regulation
References
Download: ML19093B013 (3)

Text

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Vepco VIRGINIA ELECTRIC AND POWER COMPANY, RICHMOND, VIRGINIA 23261 August 10, 1977 Mr. Edson G. Case, Acting Director ~

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Serial No. 314/071977 Office of Nuclear Reactor Regulation PO&M/HSM:bep/mc Attn: Mr. Robert W. Reid, Chief Docket Nos. 50-280 Operating Reactors Branch No. 4 50-281 Divisirin of Operating Reactors License Nos. DPR-32 U.S. Nuclear Regulatory Commission DPR-37 Washington~ D. C.

• 20555

Dear Mr. Case:

'RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION

.. HIGH. DENSITY. SPENT FlJEL. STORAGE. RACKS

. SURRY.POWER STATION UNITS l AND 2 The attached information concerning the High Density Spent Fuel Storage Racks for Surry Uni ts l and 2 is being provi de*d in response to your letter of July 19, 1977.

Very truly yours,

~-fYl, v11-~-~

c.. M. Stallings Vice Presid~nt - Power Supply and Production Operations Attachments cc: Mr. James P. O'Reilly Office of Inspection & Enforcement Region II

" e.

In your May 20, 1977 proposal in regard to increasing the Question l:

capacity for spent fuel storage you state that you per-formed the criticality calculations assuming a uranium-235 enrichment of 3.5 percent. Please convert this number to the number of grams of uranium-235 per axial centimeter of fuel assembly that was used in the criticality calculations.

We will require this number of grams of uranium~235 per axial centimeter of assembly to be specified a~-a Technical Specification limit on fuel assemblies that are to be placed in these high density storage racks.

Response

A uranium-235 enrichment of 3.5 percent corresponds to 44 grams of uranium-235 per axial centimeter of fuel assem-bly. This is the vc.lue which should be used as the Technical Specification nominal limit.*

Question 2: Provide the*:change in the "kx, in this high density storage lattic~ with a small change in the thickness of the stain-less steel .and state the type and composition of the stain-less steel in the racks.

Response

The fuel rack wall thickness will be between 0.090 and

.0.095 inches. All calculations were performed, however, with a wall thickness of 0.085 inches to ensure a conserva-tive keff value. Perturbation ~heory analysis of an increase in wall thickness from 0~085,inche~ to 0.090 inches gives a decrease in keff of 0.003.~'It should be noted that due to the assumptions used in these criticality calculations, speci-fically the rack configuration is infinite in all directions, keff is equivalent to k.:,, for these calculations. Type 304 stainless steel (ASTM A240) will be used in the construction of- these fuei racks. The nominal composition of this steel used in the criticality calculation is listed below:

Element Percent Iron 68.18 Nickel 9.49 Chro'mium 21.45 Manganese 0.20 Cobalt 0.15

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• Question 3:

e Provide the change in the ko:, in this high density storage lattice with a small ~h~nge in the urinium-235 enrich~ent.

Response

An increase in the Uranium-235 enrichment of 0.2 w/o*

results in an increase in the keff of 0:012.

• Question 4: Provide the flow rate of the component cooling water through the shell side of the spent fuel pool heat exchanger. *

Response

The maximum flow.rate of. the component cooling water throu~h th~ shell side of the spent fuel exchanger is 1322 gpm.

ThE actual flow rate is controlled based on cooling water temperature and the fuel pool water tempe~ature.* Using these methods.the spent fuel pool temperature has been maintained at -95°F.

,./