ML20093P005
| ML20093P005 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 10/23/1995 |
| From: | Saccomando D COMMONWEALTH EDISON CO. |
| To: | NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9510300081 | |
| Download: ML20093P005 (5) | |
Text
Osmmonweahh litNin O>mpany I 4G3 Opm Place -
Downers Grove,11. 60515 October 23,1995 Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk
Subject:
Teleconference between Commonwealth Edison Company and the Nuclear Regulatory Commission dated October 18,1995, regarding the Increase in the Interim Plugging Criteria for Byron Unit I and Braidwood Unit i Steam Generators NRC Docket Numbers:50-454 and 50-456
Reference:
Teleconference between the Nuclear Regulatory Commission and the Commonwealth Edison Company dated October 18,1995 In the Reference teleconference the Nuclear Regulatory Commission (NRC) discussed several items with the Commonwealth Edison Company (Comed) pertaining to the request to increase the interim plugging criteria for Braidwood Unit I and Byron Unit I steam generators. The conversation focused on clarification of items previously docketed. Attached clarifies the remaining items.
Please address any comments to this office.
Sincerely, C
U r
Denise M. Sacco o
Senior Nuclear Licensing Administrator Attachment ec:
D. Lynch, Senior Project Manager-NRR R. Assa, Braidwood Project Manager NRR G. Dick, Byron Project Manager-NRR S. Ray, Senior Resident Inspector-Braidwood j
H. Peterson, Senior Resident Inspector-Byron H. Miller, Regional Administrator-Rill Office of Nuclear Safety-IDNS Kinla\\bybwd\\stgen\\iperest 65i0300001 951023 I\\
DR ADDCK 05000454 PDR A 1:nicom company -
] Y, ATTACHMENT
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Byron Unit 1 Cycle 8 Length '
The length of Byron Unit 1 Cycle 8 is estimated to be 1.186 Effective Full Power Years.'
Cycle 8 -is currently scheduled to begin on May 13,'1996, following the BIR07-refuel outage, and to end on September 9,1997, for the start of BIR08 refel outage. Table 1 L from the October 11,1995, Comed listed the Byron Unit 1 and Braidwood Unit I gre 'h.
l rates and cycle lengths. This table has been revised to include the estimated length of J
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Unit 1 Cycle 8 and is attached as Table 1.-
' Fractional Indications in Voltage Distribution iThe voltage distribution used for the Byron Unit 1 and Braidwood Unit I leakage and burst probability analyses for the next operating cycle will include all the indications left in service for which the rotating pancake coil (RPC) did not detect degradation (NDD). Therefore, the fraction of RPC NDD indications left in service will be 1.0.
4 Cold Lea Indication Experience Table 2 provides a summary of ODSCC at cold-leg intersections at Braidwood Unit I and 4
Byron Unit 1.
A minimal number of cold-leg indications were indentified in the last three Braidwood Unit 1 inspections (5,10, and 18 indications). The average voltage for each inspection was approximately 0.5 volts, with a maximum voltage of 1.01 volt or less.
To date, Byron Unit I has not experienced ODSCC at cold-leg intersections.
Mid-Cycle Eauation for Unscheduled Outancs j
i For unscheduled mid-cycle steam generator eddy current inspections, the interim pbgging criteria'(IPC) voltage repair limits are determined by equations specified in proposed Technical Specification 4.4.5.4.a.11.f. This specification requires hot-leg indications be repaired to the 3.0 volt IPC limits and cold-leg indications be repaired to limits determined by the given upper and lower voltage repair limit equations. As discussed in the September 1, 1995, 3.0 volt IPC License Amendment Request and in the October 11,'1995 transmittal regarding the October 3 and 4,1995 teleconference, hot-leg indications at tube support plates
..that are adjacent to intersections that cannot pass a 0.610 inch diameter probe are to be repaired to the criteria that applies to the cold-leg (i.e.,1.0 volt IPC in accordance with Generic Letter 95-05). _ Therefore, the voltage repair limits for these indications during -
.. unscheduled mid-cycle inspections will be determined by the mid-cycle equations specified in proposed Technical Specification 4.4.5.4.a.11.f.
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. Cold-Lee Growth Rate Distribution The growth rate to be applied to the cold-leg indications (including hot-leg indications for which the 1.0~ volt repair limit is applicable) will be developed as a bounding growth rate for the cold-leg indications. If, as expected, there is no significant dependence of growth on tube support plate (TSP) elevation or a decrease in growth with elevation, the combined growth distribution for all hot-leg and cold-leg indications is a conservative growth for the cold-leg indications. If an increasing dependence of growth'on TSP elevation is found, such that the cold-leg indications have a larger growth rate than the combined population of indications, a conservative bounding subset of the total growth distribution will be used for the cold-leg indications.
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TABLE 1:
BYRON /BRAIDWOOD UNIT 1 CYCLE LENGTHS AND GROWTH RATES Cycle Maximum Average Length Gowth Gmwth Cycle Outage EFPY (EFPY)
(Volts /EFPY) (Volts /EFPY)
Comment Byron Unit 1 Cycle 5 B1R05 5.671 1.127 2.13 0.28 Cycle 6 BIR06 6.949 1.278 7.72 0.25 10/22/95 Cycle 7A B1P02 7.816 est.
0.867 est.
Outage Start 4/96 Cycle 78 B1R07 8.134 est.
0.318 est.
Outage Start 9/97 i
Cycle 8 B1R08 9.32 est.
1.186 est.
Outage Start Braidwood Unit 1 Cycle 4 A1R04 4.302 1.147 8.51 0.23 _
Cycle SA A1M05 5.016 0.714 5.77 0.4 9/29/95 Cycle SB A1R05 5.522 0.506 Outag3 Start 3/97 Cycle 6 A1R06 6.732 est 1.21est.
Outage Start
- Future Inspection Data not available
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i TABLE 2:
BRAIDWOOD/ BYRON COLD-LEG INDICATIONS 4
Numberof Cold-Leg Bobbin Average Number Number i
Bobbin Vohage Bobbin RPC RPC Station Date Outage ODSCC Range Voltage Inspected Confirmed Braidwood Unit 1 Mar-94 A1R04 5
0.3 - 0.88 '
O.48 5
0 Feb-95 AIM 05 10 0.27- 0.94 0.54 10 2
Oct-95 A1R05 18 0.26 - 1.01 0.48 1
0 Byron UnN 1 Jan-87 thru B1R01 thru None Found Oct-94 BIR06 To Date a
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