ML20115C348
| ML20115C348 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/01/1996 |
| From: | Shell R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-96-001, IEB-96-1, NUDOCS 9607110298 | |
| Download: ML20115C348 (6) | |
Text
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-4 RA Tennessee Valley Authonty, Post Othce Bw 2000 Soddy-Darsy Tennessee 37379 July 1,1996 U.S. Nuclear Regulatory Commission f
ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
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Docket No. 50-328 Tennessee Valley Authority
)
SEQUOYAH NUCLEAR PLANT (SON)- NRC BULLETIN 96-01," CONTROL ROD INSERTION PROBLEMS" REPORT
Reference:
TVA letter to NRC dated April 5,1996, Sequoyah Nuclear Plant (SON) and Watts Bar Nuclear Plant (WBN) Response To NRC Bulletin 96-01, " Control Rod insertion Problems" Dated March 8,1996 TVA is providing the control rod drop times and drag force data for the recent Unit 2 Cycle 7 refueling outage as committed in response to NRC Bulletin 96-01. The data for the end-of-cycle rod drop tests are included as an enclosure to this letter. Two variances were noted during the testing. First, control rods in fuel assemblies V19 and V78 did not rebound following the drop. The drop times for these two rods were 1.21 secorids and 1.23 seconds, respectively. The measured drop times are well below the 2.7 second acceptance criteria listed in Technical Specification 3.1.3.4.
These fuel assemblies are not rodded during the current Cycle 8 operation. Second, the rod drop time trace for fuel assembly U48 appeared to be anomalous in the guide tube prior to entry into the dashpot region. The drop time was 1.21 seconds. Fuel l
assembly U48 is not being used as part of the Cycle 8 core.
l As a separate matter, a new rod cluster control assembly (RCCA) could not be removed from a previously discharged Westinghouse Electric Corporation standard fuel assembly. TVA had attempted to remove the RCCA to support eddy current testing for RCCA clad wear and cracking. This fuel assembly has been residing in the spent fuel pool since October 1991 and has a burnup of 47,111 MWD /MTU. The g
RCCA was placed in this fuel assembly in May 1993. TVA will be working with Westinghouse to resolve this issue.
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DR ADOCK 05000328 PDR
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U.S. Nuclear Regulatory Commission Page 2 July 1,1996 l
Please direct questions concerning this issue to Bill Ludwig at (423) 843-7460.
l Sincerely, -
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R. H. Shell Manager i
l SON Site Licensing l
'c e befpre me l
vorpp and subsc the ~ l - day of hivi 1996 ffn 1 L
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Nota //PUblic '
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My Commission Expires M4
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Enclosure 1
cc (Enclosure)-
Mr. R. W. Hernan, Project Manager Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike l
Rockville, Maryland 20852-2739 j
NRC Resident inspector
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Sequoyah Nuclear Plant J
2600Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 l.
Regional Administrator l
U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711 3
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n ENCLOSURE ROD CLUSTER CONTROL ASSEMBLY (RCCA)
DROP TIMES AND DRAG TEST RESULTS l
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I Sequoyah Unit 2 l
I RCC/ Drag Test And Drop Time Results l
The following is a key for the notes on the column marked "Coruments."
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No Bounce - No recoil noticed on rod drop traces Hump - A camel back hump noticed on rod drop trace (before entering the dashpot region) e Cycle 8 RCCA - Denotes fuel assemblies going under control rods in Cycle 8 l
The following is a key of the fuel assembly identifications (ID)
V - V5H fresh in Cycle 7 (once burned after Cycle 7) l U - V5H twice burned after Cycle 7 l
E - STD thrice burned after Cycle 7 (operated in Unit 1 Cycles 3 and 4 - reinserted from l
Unit 1 - discharged from Unit 1 on March 17,1990) l 4
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Sequoyah Unit 2 EOC 7 l
RCCA Drag Test Results l
Sorted by Burnup Measured Weight Spent Fuel Pit (pounds)
Fuel Thimble Thimble EOC7 Rod Assembly Assembly RCCA Core Dashpot Tube Dashpot Tube Drop Times Burnup ID ID Loc (Max)
(Max)
(Max)
(Max)
(sec)
Comments (MWD /MTU)
E62 107 M02 245 190 70 15 1.29 43235 E23 150 D14 245 185 70 10 1.33 43101 E25 106 B12 240 190 65 15 1.25 43033 E71 132 D02 225 195 50 20 1.34 42939 E40 126 PO4 245 185 70 10 1.24 42851 _
E44 136 B04 230 185 55 10 1.22 42688 E11 118 M14 250 185 75 10 1.31 42679 E68 127 P12 230 190 55 15 1.23 42574 E50 154 H08 250 190 75 15 1.24 40226 U51 137 K10 255 195 80 20 1.19 39931 U43 108 F06 245 205 70 30 1.22 39925 U47 143 K06 240 190 65 15 1.23 39916 U42 102 F10 240 195 65 20 1.20 39892 U45 117 M12 240 190 65 15 1.21 39672 U48 113 M04 245 190 70 15 1.21 Hump 39600 U50 144 D12 240 195 65 20 1.20 39594
- U49 105 D04 240 195 65 20 1.22 39552 V41 114 N07 220 190 45 15 1.21 24372 VS1 123 C09 225 200 50 25 1.21 24353 V38 122 G03 220 195 45 20 1.21 24345 V33 146 C07 250 210 75 35 1.21 24318 V52 134 N09 235 200 60 25 1.19 24312 V83 153 J13 225 190 50 15 1.21 24308 V78 145 D08 260 215 85 40 1.23 No bounce 24302
'V77 138 H12 230 200 55 25 1.20 24284 V35 140 J03 230 195 55 20 1.22 24276 V28 147 G13 230 190 55 15 1.23 24259 V32 115 M08 215 185 40 10 1.23 24236 V49 116 H04 225 195 50 20 1.30 24226 V73 35 H06 225 200 50 25 1.22 23941 V76 124 H10 235 195 60 20 1.19 23939 V75 121 F08 250 200 75 25 1.23 23895 V74 141 K08 230 185 55 10 1.21 23886 V40 104 C05 220 190 45 15 1.21 Cy 8 RCCA 23262 V31 130 N11 220 190 45 15 1.21 Cy 8 RCCA 23245 V79 158 L13 220 190 45 15 1.23 Cy 8 RCCA 23199 V27 109 LO3 225 190 50 15 1.23 Cy 8 RCCA 23198 V39 149 C11 235 195 60 20 1.18 Cy 8 RCCA 23186 V82 128 E13 230 190 55 15 1.23 Cy 8 RCCA 23181 V48 152 E03 225 190 50 15 1.23 Cy 8 RCCA 23153 V26 151 N05 220 190 45 15 1.21 Cy 8 RCCA 23134 V19 129 B08 265 210 90 35 1.21 No bounce 21928 V18 155 H02 220 190 45 15 1.27 21908 V22 111 P08 225 185 50 10 1.20 21885 V13 131 H14 220 190 45 15 1.26 21857
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Sequoyah Unit 2 EOC 7 RCCA Drag Test Results Sorted by Burnup Spent Fuel Pit p nds (pounds)
Fuel Thimble Thimble EOC7 Rod Assembly Assembly RCCA Core Dashpot Tube Dashpot Tube Drop Times Burnup 10 1D Loc (Max)
(Max)
(Max)
(Max)
(sec)
Comments (MWD /MTU) l V11 139 K02 215 185 40 10 1.29 21561 i
V17 142 P10 225 185 50 10 1.21 21404 l
V23 148 K14 210 185 35 10 1.28 21476 V10 119 P06 220 185 45 10 1.23 21469 V09 101 B10 220 190 45 15 1.22 21463 V69 112 F02 225 190 50 15 1.29 21408 V70 125 F14 230 190 55 15 1.31 21401 V72 103 B06 220 185 45 10 1.20 21400 Ave 232 192 57 17 1.23 28933 l
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