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The following was received via facsimile:
… The following was received via facsimile:</br>A recent inspection of near 'End-of-Life' Marathon Control Rod Blades (CRB) at an international BWR/6 has revealed crack indications. The CRB assemblies in question were manufactured in 1997. GE Hitachi Nuclear Energy (GEH) continues to investigate the cause(s) of the crack indications. Once the cause of the crack indications is determined, GEH will evaluate the nuclear and mechanical lifetime limits of the Marathon Control Rod Blade design in light of the new inspection data, and make revised lifetime recommendations, if necessary.</br>This 60-day interim notification, in accordance with 10CFR Part 21.21(a)(2), is sent for all plants that are D lattice, BWR/2-4 or S lattice, BWR/6 plants. Since there have been no reported cracking occurrences in C lattice assemblies to date, these CRBs are tentatively eliminated from the investigation. C lattice, BWR/4-5 plants have been included on Attachment 2 for identification. Should the results of the investigation implicate the C lattice plants, the final resolution to this 10CFR Part 21 evaluation will include the C lattice plants.</br>The D lattice and S lattice plants in the US that are affected by this notification include Nine Mile Point, Unit 1; Millstone, Unit 1; Fitzpatrick; Pilgrim; Vermont Yankee; Grand Gulf; River Bend; Clinton; Oyster Creek; Dresden, Unit 2; Dresden, Unit 3; Peach Bottom, Unit 2; Peach Bottom, Unit 3; Quad Cities, Unit 1; Quad Cities, Unit 2; Perry, Unit 1; Duane Arnold; Cooper; Monticello; Brunswick, Unit 1; Brunswick, Unit 2; Hatch, Unit 1; Hatch, Unit 2; Browns Ferry, Unit 1; Browns Ferry, Unit 2; and Browns Ferry, Unit 3.</br>* * * UPDATE FROM DALE PORTER TO ERIC SIMPSON VIA FAX AT 1556 ON 12/1/2010 * * *</br>In August 2010, GE Hitachi (GEH) performed the planned inspection of four near 'End-of-Life' CRBs at 'Plant O.' The inspection revealed crack indications on all four Control Rod Blades (CRBs). The observed cracks are much more numerous, and have more material distortion than previously observed. Further, the cracks occur at a much lower reported local B-10 depletion than previously observed, with cracking predominantly starting at approximately 40% local depletion, whereas previous inspections observed cracking only above 60% local depletion.</br>The cracks at 'Plant O' are also more severe, in that they resulted in missing capsule tube fragments from two of the inspected CRBs. A lost parts analysis performed for 'Plant O' determined that there is no negative affect on plant performance due to the missing tube fragments.</br>At this point in the investigation, no causal or contributing factors unique to the 'Plant O' CRBs, nor their operation, has been identified.</br>Including the inspections at 'Plant O,' GEH has now completed the visual inspection of 97 irradiated Marathon CRBs, with 10 showing crack indications. As 'Plant O' is an S lattice design, all crack indications are still confined to D and S lattice applications, with no crack indications on C lattice designs. When considering only D and S lattice applications that are near 'End-of-Life' depletion limits, 10 of 23 control rod inspections have revealed crack indications.</br>Notified R1DO (Schmidt), R2DO (Shaeffer), R3DO (Ring), R4DO (Powers) and Part 21 Group.</br>* * * UPDATE FROM DALE PORTER TO JOHN SHOEMAKER VIA FACSIMILE AT 0934 EST ON 02/15/2001 * * * </br>Subject: Part 21 Reportable Condition Notification: Design Life of D and S Lattice Marathon Control Blades </br>GE Hitachi Nuclear Energy (GEH) has completed its evaluation of the cracking of Marathon Control Rod Blades (CRB) at an international BWR/6. This issue was initially reported on October 20, 2010 as GEH letter MFN 10-327 (Reference 1). Additional information was provided on December 1, 2010 as GEH letter MFN 10-351 (Reference 2). </br>GEH has determined that the design life, of D and S lattice Marathon Control Blades may be less than previously stated. The design life if not revised, could result in significant control blade cracking and could, if not corrected, create a substantial safety hazard and is considered a reportable condition under 10 CFR Part 21.21 (d). Marathon C lattice Control Blades are not affected by this condition. The information contained in this document informs the NRC of the conclusions and recommendations derived from GEH's investigation of this issue.</br>Notified R1DO (Ferdas), R2DO (McCoy), R3DO (Kozak), R4DO (Gaddy) and Part 21 Group.O (Kozak), R4DO (Gaddy) and Part 21 Group.
04:00:00, 20 October 2010 +
12:54:00, 20 October 2010 +
04:00:00, 20 October 2010 +
The following was received via facsimile:
… The following was received via facsimile:</br>A recent inspection of near 'End-of-Life' Marathon Control Rod Blades (CRB) at an international BWR/6 has revealed crack indications. The CRB assemblies in question were manufactured in 1997. GE Hitachi Nuclear Energy (GEH) continues to investigate the cause(s) of the crack indications. Once the cause of the crack indications is determined, GEH will evaluate the nuclear and mechanical lifetime limits of the Marathon Control Rod Blade design in light of the new inspection data, and make revised lifetime recommendations, if necessary.</br>This 60-day interim notification, in accordance with 10CFR Part 21.21(a)(2), is sent for all plants that are D lattice, BWR/2-4 or S lattice, BWR/6 plants. Since there have been no reported cracking occurrences in C lattice assemblies to date, these CRBs are tentatively eliminated from the investigation. C lattice, BWR/4-5 plants have been included on Attachment 2 for identification. Should the results of the investigation implicate the C lattice plants, the final resolution to this 10CFR Part 21 evaluation will include the C lattice plants.</br>The D lattice and S lattice plants in the US that are affected by this notification include Nine Mile Point, Unit 1; Millstone, Unit 1; Fitzpatrick; Pilgrim; Vermont Yankee; Grand Gulf; River Bend; Clinton; Oyster Creek; Dresden, Unit 2; Dresden, Unit 3; Peach Bottom, Unit 2; Peach Bottom, Unit 3; Quad Cities, Unit 1; Quad Cities, Unit 2; Perry, Unit 1; Duane Arnold; Cooper; Monticello; Brunswick, Unit 1; Brunswick, Unit 2; Hatch, Unit 1; Hatch, Unit 2; Browns Ferry, Unit 1; Browns Ferry, Unit 2; and Browns Ferry, Unit 3.</br>* * * UPDATE FROM DALE PORTER TO ERIC SIMPSON VIA FAX AT 1556 ON 12/1/2010 * * *</br>In August 2010, GE Hitachi (GEH) performed the planned inspection of four near 'End-of-Life' CRBs at 'Plant O.' The inspection revealed crack indications on all four Control Rod Blades (CRBs). The observed cracks are much more numerous, and have more material distortion than previously observed. Further, the cracks occur at a much lower reported local B-10 depletion than previously observed, with cracking predominantly starting at approximately 40% local depletion, whereas previous inspections observed cracking only above 60% local depletion.</br>The cracks at 'Plant O' are also more severe, in that they resulted in missing capsule tube fragments from two of the inspected CRBs. A lost parts analysis performed for 'Plant O' determined that there is no negative affect on plant performance due to the missing tube fragments.</br>At this point in the investigation, no causal or contributing factors unique to the 'Plant O' CRBs, nor their operation, has been identified.</br>Including the inspections at 'Plant O,' GEH has now completed the visual inspection of 97 irradiated Marathon CRBs, with 10 showing crack indications. As 'Plant O' is an S lattice design, all crack indications are still confined to D and S lattice applications, with no crack indications on C lattice designs. When considering only D and S lattice applications that are near 'End-of-Life' depletion limits, 10 of 23 control rod inspections have revealed crack indications.</br>Notified R1DO (Schmidt), R2DO (Shaeffer), R3DO (Ring), R4DO (Powers) and Part 21 Group.</br>* * * UPDATE FROM DALE PORTER TO JOHN SHOEMAKER VIA FACSIMILE AT 0934 EST ON 02/15/2001 * * * </br>Subject: Part 21 Reportable Condition Notification: Design Life of D and S Lattice Marathon Control Blades </br>GE Hitachi Nuclear Energy (GEH) has completed its evaluation of the cracking of Marathon Control Rod Blades (CRB) at an international BWR/6. This issue was initially reported on October 20, 2010 as GEH letter MFN 10-327 (Reference 1). Additional information was provided on December 1, 2010 as GEH letter MFN 10-351 (Reference 2). </br>GEH has determined that the design life, of D and S lattice Marathon Control Blades may be less than previously stated. The design life if not revised, could result in significant control blade cracking and could, if not corrected, create a substantial safety hazard and is considered a reportable condition under 10 CFR Part 21.21 (d). Marathon C lattice Control Blades are not affected by this condition. The information contained in this document informs the NRC of the conclusions and recommendations derived from GEH's investigation of this issue.</br>Notified R1DO (Ferdas), R2DO (McCoy), R3DO (Kozak), R4DO (Gaddy) and Part 21 Group.O (Kozak), R4DO (Gaddy) and Part 21 Group.
MFN 10-327 + and MFN 10-351 +
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00:00:00, 15 February 2011 +
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02:07:50, 2 March 2018 +
12:54:00, 20 October 2010 +
0.371 d (8.9 hours, 0.053 weeks, 0.0122 months) +
04:00:00, 20 October 2010 +
North Carolina + and Vermont +
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