ML20100P390
| ML20100P390 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/01/1996 |
| From: | George Thomas DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9603110171 | |
| Download: ML20100P390 (5) | |
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Telephone (412) 393-6000 IoI*s'o'x E March 1, 1996 l
Shippingport, PA 15077 0004 l
l U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001
Subject:
Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 Proposed Operating License Change Request 229; AdditionalInformation Supporting Alternate Tube Plugging Criterla Implementation This letter provides follow-up information in response to conference calls with the NRC staff on January 17, 1996, and February 22, 1996. Enclosure 1 provides our positions with respect to the probe wear and probe variability issues and provides the requested rotating pancake coil no detectable degradation (RPC NDD) data. The upper voltage repair limit calculation and updated database information are still under development and are expected to be submitted the week of March 4,1996. It is our understanding that the enclosed information is the only remaining information necessary to permit completion of the staffs safety evaluation regarding the subject license change request. Approval of the amendment is requested prior to the start of the Beaver Valley Power Station, Unit No. I eleventh refueling outage which is scheduled to start on i
March 23,1996. An implementation period of up to 60 days is requested following the effective date of this amendment. In any case, it will be implemented prior to startilp from the eleventh refueling outage.
If you have any questions regarding this submittal, please contact Mr. G. A. Kammerdeiner at (412) 393-6855.
l Sincerely,
- fj m.S 080013 Geor8e S. Thomas Vice President Nuclear Planning and Development c:
Mr. L. W. Rossbach, Sr. Resident Inspector Mr. T. T. Martin, NRC Region 1 Administrator g
0 Mr. D. S. Brinkman, Sr. Project Manager
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9603110171 960301
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PDR ADOCK 05000334 P
ENCLOSURE 1 Beaver Valley Power Station, Unit No.1 PROPOSED OPERATING LICENSE CHANGE REQUEST 229 ADDITIONAL INFORMATION PROBE WEAR Duquesne Light Company (DLC) committed to perfonn probe wear checks in accordance with the proposed industry procedure which was pending NRC approval. If approval of this procedure was not obtained prior to perfonning the Unit I refueling outage 11 (IRil), DLC further committed to perform the probe wear checks in accordance with the criteria approved by the NRC at the last Unit 1 outage for implementation of a 1 volt Interim Plugging Criteria. The probe wear criteria from IR10 required replacement of probes whose signal amplitudes did not remain within 15% of their initial amplitudes. Furthermore, in such instances where the probe failed the probe wear check, all tubes tested since the last acceptable probe wear check would be reinspected. This criteria is consistent with the requirements of GL 95-05.
Subsequently, the NRC letter from Brian Sheron (NRR) to Alex Marion (NEI) dated February 9,1996, provided approval of the industry attemative procedure for probe wear criteria subject to modifications noted therein. DLC intends to implement the alternative industry procedure regarding probe wear as detailed in the NEI letter from Alex Marion to Brian Sheron dated February 23, 1996.
This letter acknowledges the NRC modifications to the original attemative industry procedure with the exception of reinspection of all intersections in low row tubes (rows 1-9) where entiy from both the cold leg as well as the hot leg would be required to conduct the reinspection. All tubes with indications above 75% of the repair limit will be reinspected with an acceptable probe when the probe fails the wear check. Non-affected intersections in those subject tubes will be reinspected as permitted by access from the hot leg side unless cold leg entry is required to reinspect indications on the cold leg side that are above 75% of the repair limit.
PROBE VARIABILITY Additionally, the industry methodology will be utilized for new probe variability as approved by the NRC and further acknowledged in the NEI letter dated February 23, 1996.
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ENCLOSURE 1 (continued)
Proposed Operating License Change Request 229 AdditionalInfonnation Page 2 RPC NDD DATA Attached is the requested RPC data for both Beaver Valley Unit 1 (Table 1) and the other referenced plants (Table 2) to support our request to apply a fraction of the unconfirmed RPC NDD indications in the BOC voltage distribution.
The data for Beaver Valley is categorized into 0.1 volt bins by steam generator. The other plant data is categorized into < 1 volt and > 1 volt bins.
As demonstrated by the data in Table 1, the confinnation rate of the most limiting steam generator for RCP NDDs left in service from the previous cycle varies less than 10% as compared to the average for all the steam generators combined. The increased number 1
of data points included in the average confirmation rate of all steam generators provides a better representation of the confirmation rate of the entire spectrum of voltage bins while providing a conservative value for the average confinnation rate for RPC NDD indications above 1 volt which have a more significant contribution to the postulated leakage value.
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1 1
i 1
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Table 1 Beaver Valley Unit 1 Distribution of RPC NDD Indications from 1993 RPC Confirmed in 1995 9
SG A SG B SG C All SGs Combined 1993 RPC NDD Indications 1993 RPC NDD Indications 1993 RPC NDD Indications 1993 RPC NDD Indications l
Voltage No. of 1995 RPC Confinned No. of 1995 RPC Confirmed No.of 1995 RPC Confinned No. of 1995 RPC Confirmed l
Bin Indications Indications Indications Indications l
RPC No. of RPC No. of RPC No. of RPC No. of l
Inspected Indications Confumed Inspected Indications Confmned Inspected Indications Confmned Inspected Indications Confinned (1993 Volts)
In 1995 Continned in 1995 Confinned in 1995 Confirmed in 1995 Confumed 0.1 0
0 0
0 0
0 0
0 0.2 0
0 0
0 0
0 0
0 l
0.3 0
0 0
0 0
0 0
0 0.4 2
2 100 0 %
1 1
100.0 %
0 0
3 3
100.0 %
0.5 3
2 66.7 %
0 0
2 2
100.0 %
5 4
80.0 %
06 3
3 100.0 %
0 0
0 0
3 7
100.0*/.
0.7 3
3 100.0 %
2 1
50.0 %
0 0
5 4
80.0 %
0.8 3
2 66.7 %
3 3
100.0 %
0 0
6 5
83.3 %
0.9 2
1 50.0 %
3 1
33.3 %
0 0
5 2
40.0 %
1 5
2 40.0%
6 1
16.7 %
3 0
0.0%
14 3
21.4 %
l.1 11 6
54.5 %
4 1
25.0 %
1 1
100.0 %
16 8
50.0 %
l 1.2 9
6 66.7 %
4 0
0.0%
2 0
0.0%
15 6
40.0 %
1.3 8
3 37.5 %
4 1
25.0 %
0 0
12 4
33.3 %
1.4 4
2 50.0 %
1 1
100.0 %
2 0
0.0%
7 3
42.9 %
1.5 1
1 100.0 %
1 1
100.0 %
2 1
50.0 %
4 3
75.0 %
1.6 6
2 33.3 %
1 0
0.0*/.
0 0
7 2
28.6 %
1.7 0
0 0
0 1
1 100.0 %
1 1
100.0 %
1.x 4
2 50.0 %
1 1
100.0 %
0 0
5 3
60.0 %
1.9 I
I 100.0 %
0 0
0 0
1 1
100.0 %
2 0
0 0
0 0
0 0
0 2.1 0
0 0
0 0
0 0
0 2.2 0
0 0
0 0
0 0
0
)
2.3 0
0 0
0 0
0 0
0 2.4 0
0 0
0 0
0 0
0 2.5 0
0 0
0 0
0 0
0 4
2.6 1
1 100 0*/.
0 0
0 0
1 1
100.0*4 Total 66 39 59.1 %
31 12 38.7 %
13 5
38.5 %
I10 56 50.9 %
> IV 45 24 53.3 %
16 5
31.3 %
8 3
37.5 %
69 32 46.4 %
5IV 21 15 71.4 %
15 7
46.7 %
5 2
40.0 %
41 24 58.5 %
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Table 2 RPC Confirmation Rates for RPC NDD Indications in the Last Inspection Composite Data for All Steam Generators in Plant i
RPC NDD in First Inspection - Second Inspection Data First Second s I volt Bobbin in 2nd Inspection
> 1 volt Bobbin in 2nd Inspection All Voltages in 2nd Inspection Plant Inspection inspection No. of No. of No. of No. of No. of No. of Indications Indications Percent Indications Indications Percent Indications Indications Percent Cycle / par Cycle / year RPC RPC Confirmed RPC RPC Confinned RPC RPC Confinned Inspected Confirmed Inspected Confirmed Inspected Confirmed Plant A-1 EOC 12 EOC 13 1994 1995 0
0 84 37 44.0 %
84 37 44.0 %
Plant A-2 EOC9 EOC 10 1993 1995 0
0 10 0
0%
10 0
0%
Plant P-1 EOC9 EOC 10 1993 1995 21 18 85.7 %
89 38 42.7 %
110 56 50.9 %
Plant R-1 EOC 7 EOC8 1993 1995 68 0
0%
45 8
17.8 %
113 8
7.1%
Plant EOC4 EOC5A AA-1 1994 1995 21 10 47.6 %
177 71 40.1%
198 81 40.9 %
NOTE:
The data for Plant D-1 were not readily available in a format that would permit categorization into the defined voltage bins by steam generator.
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