RNP-RA/03-0071, Status Update for NRC Bulletin 88-09, Thimble Tube Thinning in Westinghouse Reactors.

Status Update for NRC Bulletin 88-09, Thimble Tube Thinning in Westinghouse Reactors.

ML031480728
Person / Time
Site:	Robinson
Issue date:	05/02/2003
From:	Baucom C Progress Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-88-009, RNP-RA/03-0071
Download: ML031480728 (2)

Text

-4 Progress Energy Lb NRCB 88-09 Serial: RNP-RA/03-0071 MAY 27 2003 United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261/LICENSE NO. DPR-23 STATUS UPDATE FOR NRC BULLETIN 88-09, THIMBLE TUBE THINNING IN WESTINGHOUSE REACTORS Ladies and Gentlemen:

By letter dated July 26, 1988, the NRC issued Elulletin (NRCB) No. 88-09, Thimble Tube Thinning in Westinghouse Reactors. NRCB 8 8-09 required establishment and implementation of a thimble tube inspection program. The response for H. B. Robinson Steam Electric Plant (HBRSEP), Unit No. 2, was provided to the NF:C by letter dated February 8, 1991, which confirmed that an inspection program had been established.

The nominal inspection frequency for eddy current inspection of the thimble tubes at HBRSEP, Unit No. 2, has been every other refueling outage, which is approximately every 3 years. By letter dated January 20, 1999, the NRC was informed that as a result of inspections performed during the preceding six (6) operating cycles, the planned inspections for Refueling Outage (RO) 19 would be deferred to RO-20. That letter also stated that the future inspection intervals would be adjusted (shortened or lengthened) based on the results of the inspection program.

The NRC responded by letter dated January 27,2000, that the deferral of the planned inspections was reasonable and to please keep the NRC updated on the results of the thimble tube inspection program and the results for the ensuing RO-20.

In response to this request, the following status update is hereby provided:

The most recent eddy current inspection of the HBRSEP, Unit No. 2, thimble tubes was performed on April 16,200l. The inspection was performed in accordance with HBRSEP, Unit No. 2, procedure EST-108, Flux Thimble Eddy Current Inspection (Specified Refueling Outages). The thimble for core location G-07 had a 40% outer wall wear indication in the vicinity of the fuel assembly bottom nozzle. Inner wall indication was 0% wear through. HBRSEP, Unit No. 2, has double walled thimbles, with the inner wall being the Reactor Coolant System pressure boundary.

Progress Energy Carolinas, Inc.

Robinson Nuclear Plant 3581 West Entrance Road HartwIle, SC 29550

United States Nuclear Regulatory Commission Serial: RNP-RA/03-0071 Page 2 of 2 Eddy current inspection of the thimbles has been performed during RO-13 (January 1991), RO-15 (October 1993), RO-17 (September 1996), and RO-20 (April 2001). The inspection of the thimbles has indicated no detectable degradation of the inner wall. No significant changes have been made to alter the flow characteristics in the vessel that would impact the fretting mechanism that could cause degradation of the inner wall of the thimbles. Therefore, based on the existing configuration of the thimbles and the previous inspection results, the frequency of eddy current inspection of the thimble tubes is being changed from every other refueling outage to every third refueling outage.

This information is being provided in response to the NRC request to provide the results of the thimble tube inspection program and the results for RO-20. There is no response or review requested for this submittal. The results of thimble eddy current inspections will continue to be reviewed after each inspection and the inspection frequency will be further adjusted as deemed appropriate based on the results of these inspections.

If you have any questions concerning this matter, please contact me.

Sincerely, C. T. Baucom Supervisor - Licensing/Regulatory Programs CAC/cac c: L. A. Reyes, NRC, Region II NRC Resident Inspector, HBRSEP C. P. Patel, NRC, NRR

Text

-4 Progress Energy Lb NRCB 88-09 Serial: RNP-RA/03-0071 MAY 27 2003 United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261/LICENSE NO. DPR-23 STATUS UPDATE FOR NRC BULLETIN 88-09, THIMBLE TUBE THINNING IN WESTINGHOUSE REACTORS Ladies and Gentlemen:

By letter dated July 26, 1988, the NRC issued Elulletin (NRCB) No. 88-09, Thimble Tube Thinning in Westinghouse Reactors. NRCB 8 8-09 required establishment and implementation of a thimble tube inspection program. The response for H. B. Robinson Steam Electric Plant (HBRSEP), Unit No. 2, was provided to the NF:C by letter dated February 8, 1991, which confirmed that an inspection program had been established.

The nominal inspection frequency for eddy current inspection of the thimble tubes at HBRSEP, Unit No. 2, has been every other refueling outage, which is approximately every 3 years. By letter dated January 20, 1999, the NRC was informed that as a result of inspections performed during the preceding six (6) operating cycles, the planned inspections for Refueling Outage (RO) 19 would be deferred to RO-20. That letter also stated that the future inspection intervals would be adjusted (shortened or lengthened) based on the results of the inspection program.

The NRC responded by letter dated January 27,2000, that the deferral of the planned inspections was reasonable and to please keep the NRC updated on the results of the thimble tube inspection program and the results for the ensuing RO-20.

In response to this request, the following status update is hereby provided:

The most recent eddy current inspection of the HBRSEP, Unit No. 2, thimble tubes was performed on April 16,200l. The inspection was performed in accordance with HBRSEP, Unit No. 2, procedure EST-108, Flux Thimble Eddy Current Inspection (Specified Refueling Outages). The thimble for core location G-07 had a 40% outer wall wear indication in the vicinity of the fuel assembly bottom nozzle. Inner wall indication was 0% wear through. HBRSEP, Unit No. 2, has double walled thimbles, with the inner wall being the Reactor Coolant System pressure boundary.

Progress Energy Carolinas, Inc.

Robinson Nuclear Plant 3581 West Entrance Road HartwIle, SC 29550

United States Nuclear Regulatory Commission Serial: RNP-RA/03-0071 Page 2 of 2 Eddy current inspection of the thimbles has been performed during RO-13 (January 1991), RO-15 (October 1993), RO-17 (September 1996), and RO-20 (April 2001). The inspection of the thimbles has indicated no detectable degradation of the inner wall. No significant changes have been made to alter the flow characteristics in the vessel that would impact the fretting mechanism that could cause degradation of the inner wall of the thimbles. Therefore, based on the existing configuration of the thimbles and the previous inspection results, the frequency of eddy current inspection of the thimble tubes is being changed from every other refueling outage to every third refueling outage.

This information is being provided in response to the NRC request to provide the results of the thimble tube inspection program and the results for RO-20. There is no response or review requested for this submittal. The results of thimble eddy current inspections will continue to be reviewed after each inspection and the inspection frequency will be further adjusted as deemed appropriate based on the results of these inspections.

If you have any questions concerning this matter, please contact me.

Sincerely, C. T. Baucom Supervisor - Licensing/Regulatory Programs CAC/cac c: L. A. Reyes, NRC, Region II NRC Resident Inspector, HBRSEP C. P. Patel, NRC, NRR