ML20213E413

Forwards Reactor Fuel Section Input to Supplemental SER Re Waterside Corrosion & Fuel Rod Bowing.Issues Resolved

ML20213E413
Person / Time
Site:	Columbia
Issue date:	04/14/1983
From:	Rubenstein L Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
References
CON-WNP-0583, CON-WNP-583 NUDOCS 8305020059
Download: ML20213E413 (4)

Text

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APR o G33 MEi!ORANDU!! FOR: T. M. fiovak, Assistant Director for Licensing, DL

• L. S. Rubenstein, Assistant Director FROM:

for Core and Plant Systems, DSI '

SUBJECT:

SSER INPUT FOR WNP-2 C0flCERNING WATERSIDE CGRROSION AND ROD BOWING Plant Name: WPFSS Nuclear Project, Unit 2 Docket !.! umber: 50-397 Licensing Stage: Cperating License Responsible Branch: Licensing Branch #2 Project l'anager: R. Auluck DSI Review Branch: Core Perfomance Description of Review: Supplemental Safety Evaluation Reytew Status: Complete The Reactor Fuels Section of the Core Perfomance Branch has prepared the enclosed input for WNP-2 SSER No. 4. The input concerns (1) water-side corrosion for which a request for additional infomation had been issued in August 1982, and (2) fuel rod bowing, which had been identi-fled as a confirmatory issue in our March 1982 SER. Upon consideration of a recent submittal from WPPSS on waterside corrosion, and upon completion of our review of GE's generic rod bowing report, we conclude that these issues have been resolved for WN?-2 and that no further infomation is required. The basis for this conclusion is discussed in the enclosure. 4 erftawt2 M

m. 6. W A L. S. Rubenstein, Assistant Director for Core and Plant Systems, DSI

Enclosure:

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uck A. Schwencer L. Rubenstein

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ME!10RANDUM FOR: T. fl. Novak, Assistant Director for Licensing, DL FROM: L. S. Rubenstein, Assistant Director for Core and Plant Systems, DSI

SUBJECT:

SSER INPUT FOR WNP-2 CONCERNING WATERSIDE CORROSION Plant Name: WPPSS Nuclear Project, Unit 2 Docket Number: 50-397 Licensing Stage: Operating License Responsible Branch: Licensing Branch #2 Projectftanager: R. Auluck DSI Review Branch: Core Performance Description of Review: Supplemental Safety Evaluation Review Status: Complete The Reactor Fuels Section of the Core Perfomance Branch has nrepared the enclosed input for WNP-?. SSER No. 4 The input concerns waterside corrosion for which a request for additional infomation had been issued in August 1982. Upon consideration of a recent submittal from WPPSS on this issue, we conclude that it has been resolved for WNP-2 and that no further infomation is required. The basis for this conclusion is discussed in the enclosure. j

/

, L. S. Rubenstein, Assistant Director

/ for Core and Plant Systems, DSI

Enclosure:

As stated /

[ s DISTRIBUTION:

cc: R. Mattson / Docket Files D. Eisenhut / CPB r/f s R. Auluck / L. Rubenstein N A. Schwencer /

C. Berlinger R. Capra / R. Meyer N

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/ M. Tokar \ \

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l 4.2.3.1 Fuel Systen Damace Evaluation (d) External Corrosion and Crud Builduo Waterside Corrosion Corrosion problems associated with stainless steel cladding in BUP.s, together with a desire to improve neutron economy, led to a change serr.e years ago from stainless steel to Zircaloy cladding material, which has '

good resistance to the hot water and steam environtrent encountered under typical BWR operating conditions (Garzarolli, et al., 1978). In several recent cases, however, cladding failures have been associated with external " waterside" corrosion (e.g., GE Projects Division Memorandum, April 6,1979, and Maury, November 10,1981), and these occurrences have -

been characterized by GE as " crud-induced local corrosion failure" (NEDE-24343-P) . The corrosion is reportedly associated with a variably high copper concentration in the core coolant water and a minor anomaly in the Zircaloy cladding metallurgy (Charnley, December 11, 1979; Engel, October 3, 1980; Smith November 21, 1980; Smith, February 5,1981; and De1 George, December 2,1980). The source of the copper contamination in the affected plants appears to be the copper-bearing main condenser tubes (DelGeorge, February 9, 1981). All the affected plants have copper alloy condenser tubing. It is notable also that virtually all the SWR waterside corrosion failures have involved gadolinia burnable poison rods.

The NRC staff has been following this issue generically, and in a recent meeting with the staff, GE identified (Tokar, October 13, 1982) what were believed to be some factors responsible for the corrosion failures and stated that a change had been made in the manufacturing process to assure that such failures will not occur in newly manufactured fuel bundles. GE's presentation provided an explanation of the problem, and their solution to it appeared plausible (Tokar, October 13,1982).

Further documentation on this subject has been provided in a recent letter from Washingtcn Public Power Supply System (Bouchey, December 23, 1982). This letter confirmed that all susceptible cladding will be eliminated from the WNP-2 environment. We, therefore, conclude that the issue should be considered resolved for UNP-2.

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3-References G. D. 60uchey (WPPS$) letter to A. Schwencer (NRC), " Request for Additional Information on Fuel Rod Corrosion Measures," December 23,1982.

L. Rubenstein (NRC) memorandum for F. Miraglia, "SER on General Electric Fuel Rod Bowing Topical Report.," Parch 8,1983.

NEDE-24284-P:, " Assessment of Fuel Rod Bewing in General Electric Boiling Wa?.er Reactor:," March d, 1983.

M. Tokar (NRC) memorand::m for C. H. Berlinger, "GE Proprietary Presentation on Watersioe Corrosion of Gadolinia Fuel," October 13, 1982.

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