ML20247R622

Submits follow-up Activity in Which Four Fuel Assemblies Containing Fuel Rods W/Alternate Clad Surface Processes Will Be Inserted Into Facility Initial Core.No New Matls Introduced to Reactor Environ

ML20247R622
Person / Time
Site:	Limerick
Issue date:	06/02/1989
From:	Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8906070274
Download: ML20247R622 (3)

Text

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PHILADELPHIA ELECTRIC: COMPANY.

l 2301 MARKET STREET.

P O. BOX 8699 PHILADELPHIA A, PA.19101 (215)841 4500 m,.... mu#=h- JUN 021989 U.S. Nuclear Regulatory Conmission Docket ~No.: 50-353 Attn: Doctment Control Desk Washington, D.C. 20555

Subject:

Limerick Generating Station, Unit 2 Minor Fuel Assembly Revision

Reference:

(1) PECo submittal to NRC dated 4/3/89 re: LGS Unit 1 Fuel Failures.

(2) General Electric Standard Appilcation for Reactor Fuel, NEDE-24011-P-A-9, 9/88.

Gentlemen:

In Reference 1, Philadelphia Electric Company (PECo) Identified the results of our evaluation of the Limerick Generating Station (LGS)

. Unit 1 fuel failures which occurred during cycle 2 operation. The failures were due to crud Induced. localized corrosion (CILC) which is believed to have been caused by the. synergistic effect of less than expected corrosion resistance of the cladding and early cycle chemical transients in conjunction with increasing levels of copper input to the reactor water. This letter identifies, for your Information, a follow-up activity in which four (4) fuel assemblies which contain.

fuel rods with alternate clad surface processes will be inserted into the LGS Unit.2 initial core. The four fuel asserrbi tes of concern have identical nuclear, mechanical and hydraulle properties as the standard 2.48 wt % U-235 enriched bundles previously scheduled for loading in Cycle 1, with the only difference being that up to 12 fuel rods in each assembly have cladding material. manufactured by alternate clad surface processes. These processes have been previously used in manufacturing assemblies loaded at other reactors. The assemblies are being loaded to derronstrate the ccmparable corrosion resistance of these fuel rods with alternate clad surface processes. Loading of these assemblies does not require Technical Specifications (TS) changes and'is bounded by the current safety analyses.

The assemblies will be loaded into Limerick 2 Cycle 1 as part of a test to demonstrate the corrosion resistance of cladding material manufactured with alternate surface finish processes. The assenbiles will replace four of the standard 2.48 wt % U-235 enriched fuel bundles scheduled for loading in Cycle 1. The only difference from the standard bundles is that each assembly contains up to 12 special pre-oxide filmed fuel rods. The rods with special processing are from the 8 3.8 wt % U-235 enriched rods and the 14 3.3 wt % U-235 enriched 00 8906070274 PDR 890602 '

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s rods in these bundles ~. The remaining 3.8 and 3.3 wt % rods will be manufactured by the current process to provide a basis for comparison. The specially processed rods have been manufactured with autoclaved tubing.

The assemblies satisfy the fuel rod thermal-mechanical criteria described in the Limerick 2 Safety Analysis Report and in GESTAR-II (Reference 2) when operated within the Maximum Average. Planar Linear Heat Generation Rate (MAPLHGR) Ilmits estabitshed for the standard 2 A8 wt % bundle design. No new materials are introduced to the reactor environment. In addition, the clad surface finishing processes used for the assemblies have been previously used in manufacturing fuel assenblies for other reactors. As previously mentioned, the process changes being tested are such that comparable corrosion resistance is expected relative to the production fuel.

Therefore, assumptions regarding corrosion rates in the cladding mechanical analyses conservatively bound the expected corrosion rates of these assemblies.

If there are any questions' or concerns regarding this Information, please let me know.

Sincerely, I.

/

cc: W. T. Russell, USNRC, Administrator, Region I T. J. Kenny, USNRC, Senior Resident Inspector, LGS R. J. Clark, USNRC, Project Manager, LGS EG/DLM/001

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S26-1 S. J. Kowalski 525-1 E. J. Bradley S23-1 E. P. Fogarty S7-1 J. M. Madara, Jr.' 57-1 G. A. Hunger, Jr. S7-1 D. P..Helker S7-1 R. M. Krich S7-1 D. B. Fetters N4-1 L. B. Pyrlh N2-1 A. J. Marie N2-1 H. D. Honan N2-1 G. M. Lei tch LGS MC 200 P. J. Duca, Jr. LGS MC A5-1 C. R. Endriss LGS MC A2-1 A. S. MacAlnsh LGS MC SB3-4 M. S. Iyer BPC/SF DAC NG-8

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