ULNRC-03850, Forwards Response to Request for Addl Info Re Plant Fuel Pool Rerack

Forwards Response to Request for Addl Info Re Plant Fuel Pool Rerack

ML20249C647
Person / Time
Site:	Callaway
Issue date:	06/25/1998
From:	Passwater A UNION ELECTRIC CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-MA1113, ULNRC-03850, ULNRC-3850, NUDOCS 9806300489
Download: ML20249C647 (4)

Text

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. Unies flectric one Ameren Plaza 1901 Chouteau Avenue Po Box 66149 St. Louis, MO b3166-0149

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, June,25, 1998 U. S. Nuclear Regulatory Commission ATTN

Document Control Desk Mail Station Pl-137 Washington, D. C. 20555 ULNRC-03850 TAC NO. mal 113 Gentlemen:

$YL DOCKET NUMBER 50-483 CALLAWAY PLANT

[ RESPONSE TO NRC RAI LETTER

_CALLAWAY SPENT FUEL POOL RERACK

Reference:

1. ULNRC-3742, dated February 24,1998 2 ULNRC-3337, dated May 27,1998

3. NRC Request for AdditionalInformation Letter, dated June 4,1998, from K. M. Thomas to G. L. Randolph Reference 1 provided the original submittal of an amendmer.t request to revise the Callaway technical specifications to support modification to increase the spent fuel pool capacity at the Callaway Plant. Reference 2 transmitted revisions to original submittal Chapters 4 and 5 of the Licensing Report to reflect a re-assessment of the proprietary classification of proprieta

• versus non-proprietary material. Reference 3 transmitted a request for additional information. The response to the request is being provided as an enclosure to this letter.

If there are questions on the Enclosure or if additional information is j required, please contact us. /

/

Very truly yours, YOJ Alan C. Passwater Manager, Licensing & Fuels DJW/jdg Enclosure 9806300489 980625 /

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I 1 I .. l STATE OF MISSOURI ) i

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l Alan C. Passwater, of lawful age, being first duly sworn upon oath says that he is Manager, Licensing and Fuels fj (Nuclear) for Union Electric Company; that he has read the i foregoing document and knows the content thereof; that he has executed the same for and on behalf of said conpany with full power and authority to do so; and that the facts therein stated are true and correct to the best of his l knowledge, information and belief.

By Alan C. Passwater Manager, Licensing and Fuels Nuclear SUBSCRIBED and sworn'to before me this , day of de , 1998. I f \

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-cc: M. H.. Fletcher

-Professional Nuclear Consulting, Inc.

. 19041 Raines Drive Derwood, MD 20855-2432 Regional Administrator l U.S. Nuclear Regulatory Commission

. Region IV 611.Ryan Plaza Drive {

Suite 400-l Arlington, TX 76011-8064 LSenior-Resident-Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Kristine.M; Thomas (2)

Office of Nuclear Reactor Regulation ,

.U.S.. Nuclear Regulatory Commission- )

-1' White. Flint, North, Mail Stop 13E16 11555 Rockville Pike Rockville, MD 20852-2738 Manager, Electric Department Missouri Public Service Commission P.O. Box 360 i

. Jefferson City, MO 65102- )

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-Ron Kucera I Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102 Denny Buschbaum

-TU-Electric P.O. Box 1002

-Glen Rose, TX 76043 1

Pat Nugent Pacific Gas & Electric ]

Regulatory Services P.O. Box 56 Avila Beach, CA'93424, ,

ULNRC-03850 o TAC NO. MA 1113 ENCLOSURE IkESPONSE TO REOUEST FOR ADDITIONAL INFORMATION (RAD OUESTION:

Although Boral neutron absorbers are not expected to exhibit significant corrosion in the spent fuel pool environment, some corrosion will occur. This corrosion will be especially pronounced for the fresh Boral panels, when they are still unprotected by the aluminum oxide film. How does Callaway plan to ensure that the neutron absorbing capability of the Boral panels will not be degraded after exposure to borated water in the spent fuel pool?

RESPONSE

Boral is a hot-rolled cermet of alun.inum and boron carbide, clad in aluminum. Boral is very strong, stable, and highly corrosion resistant. A strongly adhering film of impervious hydrated aluminum oxide passivates the surface of the aluminum typically within a few days of being placed in water (either borated or demineralized). The corrosion layer only penetrates the surface of the aluminum cladding a few microns during this passivation process. There is no na loss of aluminum cladding during the passivation process.

The neutron absorbing property of Boral is due to the Boron-10 isotope in the boron carbide. As noted above, the boron carbide is clad in aluminum. Corrosion of Boral affects only the aluminum. The neutron absorbing capability of Boral (i.e., the boron carbide) is not affected by the corrosion process. The boron carbide in the central matrix of the cermet is chemically stable in either borated or demineralized water, and exhibits no corrosion.

Boral coupons that were exposed to spent fuel pool environments have not exhibited any degradation in the neutron absorbing capability. Therefore, no special corrosion measures are necessary to protect the neutron absorbing capability of the Boral panels after exposure to borated water in the spent fuel pool.

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