ENS 40005
ENS Event | |
|---|---|
07:00 Jul 18, 2003 | |
| Title | Part 21 Report Involving Impact of Fuel Channel Bow on Control Rod Blades |
| Event Description | The following is a portion of text received as a fax:
July 18, 2003 Subject: 60 Day Interim Notification: Impact of Fuel Channel Bow on Control Rod Blade Deviations Reference: Letter from Jason Post (GENE) to USNRC, 'Interim Surveillance Program for Fuel Channel Bow Monitoring', MFN 03-030 Revision 1, April 30, 2003 This communication is to inform you that GE Nuclear Energy (GENE) has been evaluating a potentially reportable condition (PRC) on the impact of fuel channel bow on control rod blades. The original channel bow evaluation for increased fuel channel - control rod blade interference did not consider previously evaluated deviations in the control rod blade. Channel bow can cause increased deflection and stresses in control rod blades, which must be considered in control rod blade deviation evaluations. The PRC evaluation is limited to control rod blades delivered to those plants identified in the referenced letter, where an interim surveillance plan for channel bow monitoring is recommended, because those are the only plants where there is a concern about increased fuel channel - control rod blade interference. As described in the referenced letter, it was determined that BWR/6 and BWR/4 & 5 C-lattice plants with Global Nuclear Fuel (GNF) thick/thin channels potentially have increased channel bow that can cause fuel channel control rod blade interference. An interim surveillance program was provided to augment the surveillance requirements in the plant Technical Specifications until other actions, which mitigate or limit the potential for control rod - fuel channel interference due to channel bow can be identified and implemented. This surveillance program provides early indication of potentially degraded operational performance and assurance that action is taken before reaching excessive levels of control rod interference. This surveillance plan is limited to BWR/6 and BWR/4&5 C-lattice plants with GNF thick/thin channels and GENE control rods. There have been no indications of excessive interference on BWR/2, 3 and 4 D-lattice plants, and as a result, they are excluded from the interim surveillance program. The PRC evaluation was initiated by GENE on May 19, 2003. GENE will not have completed the evaluation by July 18, 2003, when the 60 day evaluation period expires. Therefore, GENE is submitting this 60 Day Interim Notification under 10CFR21.21(a)(2) to inform the NRC that we are working on the issue, and to commit to report the results of the evaluation no later than September 23, 2003. GE Nuclear Energy has identified the following as affected plants: Clinton, Nine Mile Point 2, Fermi 2, Grand Gulf, River Bend, Limerick 1 & 2 and Perry 1.
GE submitted its 60 day update letter which indicated no change from previously submitted information.
This communication is to inform you that GE Nuclear Energy (GENE) has completed the evaluation of the potentially reportable condition (PRC) identified in References 2 and 3 and has concluded that it is NOT a Reportable Condition under 10CFR21. Channel bow can cause increased deflection and stresses in control rod blades. The impact of channel bow on as-designed control rod blades was considered when the surveillance program identified in Reference 1 was developed_ However, the evaluation did not consider known control rod blade deviations from as-designed conditions that had previously been addressed. The evaluation to determine the impact of channel bow on control rod blade deviations, as reported to the NRC in References 2 and 3, has now been completed. The evaluation concluded that the increased loads from channel bow do not impact the structural integrity of control rods with known deviations from as-designed conditions. Therefore, it does not produce a significant safety hazard or lead to violation of a technical specification safety limit. As described in the Reference 1 letter, it was determined that BWR/6 and BVVR/4 & 5 C-lattice plants with Global Nuclear Fuel (GNF) thick/thin channels are potentially susceptible to increased channel bow that can cause increased fuel channel - control rod blade interference. A surveillance program is recommended per Reference 1 for the potentially susceptible 8 plants listed above. This evaluation examines known deviations from the as-designed condition for original equipment manufactured (OEM) control rod blades and for "DuraLife" and "Marathon" replacement blades in the potentially susceptible plants. The PRC evaluation was initiated by GENE on May 19, 2003. GENE reported the results of the evaluation for OEM blades and "DuraLife" replacement blades in Reference 3. GENE has now completed the evaluation applicable to "Marathon" replacement blades. These evaluations indicate that there is no change from the previous information provided in Reference 1. Therefore, GENE is submitting this Final Notification to inform the NRC that the evaluations have been completed, and to report the GENE conclusion that this is NOT a Reportable Condition per 10CFR21. References: 1. Letter from Jason Post (GENE) to USNRC, "Interim Surveillance Program for Fuel Channel Bow Monitoring", MFN 03-030 Revision 1, April 30, 2003 2. Letter from Jason Post (GENE) to USNRC, "60 Day Interim Notification: Impact of Fuel Channel Bow on Control Rod Blade Deviations," MFN 03-045, July 18, 2003 3. Letter from Jason Post (GENE) to USNRC, "60 Day Interim Notification: Impact of Fuel Channel Bow on Control Rod Blade Deviations," MFN 03-103, September 23, 2003 Notified Reg 1 RDO(Rogge), Reg 3 RDO(Lipa), Reg4 RDO(Kennedy), and NRR(Foster) See related events #39634 and 39806 |
| Where | |
|---|---|
| General Electric Company San Jose, California (NRC Region 4) | |
| Organization: | General Electric Company |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+5.22 h0.218 days <br />0.0311 weeks <br />0.00715 months <br />) | |
| Opened: | Jason Post 12:13 Jul 18, 2003 |
| NRC Officer: | Steve Sandin |
| Last Updated: | Nov 18, 2003 |
| 40005 - NRC Website | |
General Electric Company with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 425732006-04-24T04:00:00024 April 2006 04:00:00
[Table view]10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 Notification - Bwr Core Shroud Tie Rod Upper Support Cracking ENS 400052003-07-18T07:00:00018 July 2003 07:00:00 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation Part 21 Report Involving Impact of Fuel Channel Bow on Control Rod Blades 2006-04-24T04:00:00 | |