ML17325A073
| ML17325A073 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 04/30/1987 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Harold Denton NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| AEP:NRC:0967I, AEP:NRC:967I, NUDOCS 8705050166 | |
| Download: ML17325A073 (25) | |
Text
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I REQULATORY XFQRNATIQN DISTRIBUTION BY El'l'R IDB>
ACCESSION NBR: 8705050166 DQC. DATE.: 87/04/30 NOTARIZED:
NO DOCKET 0 FACIL: 50-315 Donald C.
Cool Nuclear Pouer Plant>
Unit 1>
Indiana 5
05000315 AUTH. NANE AUTHOR AFFILIATIQN ALEXICH l'l. P.
Indiana Cc Nichigan Electric Co.
RECIP. NAl'lE RECIPIENT AFFILIATION Document Control Branch (Document Control'Desk)
SUBJECT:
Responds to 870420 telcon U/D Wigginton 8c C Tinkler re util 870210 request for ice condenser surveillance'interval extension for abaci)itg Cycle DISTRIBUTION CODE:
AOOID COPIES RECEIVED: LTR i ENCL /
SIIE: /5 TITLE:
QR Submittal:
General Distribution NOTES:
RECIPIENT ID CODE/NANE PD3-3 LA llIQQINQTQN D INTERNAL: ARN/DAF/LFNB NRR/DEBT/ADB
/ILRB REQ FILE 01 EXTERNAL: EQM BRUBKEp S NRC PDR CQPIEB LTTR ENCL 0
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1 RECIPIENT ID CODE/NAl'1E PD3-3 PD NRR/DEBT/ADE NRR/DOEA/TSB OGC/HDS1 LPDR NBIC COPIES LTTR ENCL 5
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TOTAL NUl'lBER OF COPIEB REQUIRED:
LTTR 18 ENCL 15
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INDIANA8 MICHIGAN ELECTRIC COMPANY P.O. 80X 16631 COLUM8US, OHIO 43216 April 30, 1987 AEP:NRC:0967I Donald C.
Cook Nuclear Plant Unit No.
1 Docket No. 50-315 License No.
DPR-58 ICE CONDENSER SURVEILLANCE INTERVAL EXTENSION FOR UNIT 1 CYCLE 9 U.S. Nuclear Regulatory Commissi'on Attn:
Document Control Desk Washington, D.C.
20555 Attn:
H. R. Denton
Dear Mr. Denton:
This letter responds to the April 20, 1987 telephone conversation with Messrs.
David Wigginton and Charles Tinkler of your staff.
Mr. Tinkler asked a number of questions regarding our February 10, 1987 request (AEP:NRC:0967H) for an ice condenser surveillance interval extension for Unit 1 Cycle 9.
The responses to those questions are given below.
Question 1.
Were the ice weight calculations extrapolated to July 1,
- 1987, or July 31, 1987?
Response
The ice weight calculations were extrapolated to July 31, 1987.
Question 2.
What is the date to which the surveillance interval extension is needed'?
Response
Question 3.
We request an extension to July 31, 1987.
How does the most recent weighing compare with the five most recent weighings?
Response
We have compared the most recent weight losses with the four previous weight losses and also with the average of the five most recent weight losses.
Twenty-five percent of the bays and seventeen percent of the row groups had ice loss significantly greater in the most recent interval than in the previous intervals, at the 958 confidence level.
These larger ice losses would not be expected in the present operating cycle, since few air-handling units have been out of operation recently.
This is discussed further in the response to Question 4.
8705050i66 870430 PDR ADOCK QQQ0031g PDR
AEP:NRC:0967I Question 4.
What maintenance has been performed over previous weighing intervals'E
Response
Although no major maintenance has been done in recent cycles, we have checked the number of air-handling units that were turned off and out of service during the most recent periods of plant operation.
There are 60 air-handling units available by design.
These units are frequently referred to as 30 pairs of 2 units, though each unit is independent with its own air intake, motor, and glycol chiller.
The average number of units that were turned off during a particular month of operation is tabulated below.
0 eratin Period Month ear Avg No. of Air Handling Units Turned Off 6/86
- 4/87 12/85
- 6/86 9/85
- 12/85 6/85
- 9/85 8/84
- 4/85 8/83
- 8/84 4/87 3/87 2/87 1/87 12/86 11/86 10/86 9/86 8/86 7/86 6/86 6/86 5/86 4/86 3/86 2/86 1/86 12/85 12/85 11/85 10/85 9/85 9/85 8/85 7/85 6/85 4/85 3/85 2/85 1/85 12/84 11/84 10/84 9/84 8/84 8/84 7/84 6/84 5/84 3
2 3
4 5
3 5
4 4
3 8
13 8
7 4
1 3
3 6
2 4
7 7
5 5
10 2
1 unavailable 1
1 1
2 3
3 5
5 3
3
I
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1
AEP:NRC:09671 e 4/84 3/84 2/84 1/84 12/83 11/83 10/83 9/83 4
3 3
6 4
6 3
There is some overlap in the operating periods, which results in different averages in the same month.
Except for a few cases with a large number of units off, there seems to be no overt trend of fewer units off in recent cycles.
The present operating cycle (6/86-4/87) seems to have fewer units off than did the previous cycle (12/85-6/86)--4 compared to 5.6.
Other units that were operating may have had varying amounts of ice buildup on the air intake that reduces efficiency.
Quantification of the ice buildup or reduced efficiency was not available.
The dates of the six most recent weighings are 06/02/86 to 06/05/86 12/03/85 to 12/06/85 09/03/85 to 09/04/85 04/15/85 to 07/19/85 07/25/84 to 08/27/84 07/18/83 to 09/12/83 The dates of the refueling outages are Question 5.
Response
06/27/87
- (Scheduled)
None in 1986 04/06/85
- 11/17/85 None in 1984 07/16/83
- 10/24/83 Has there been any maintenance or ice replenishment since the last weighing2 1,
There has been no'ajor maintenance and no ice replenishment since the last weighing.
Air-handling units were discussed in response to Question 4.
Ice was replenished during the refueling outages of April 6, 1985 to November 17, 1985 and July 16, 1983 to October 24,,1983.
Ice is not added during ordinary surveillances, only during refueling outages.
Question 6.
During the recent 'shutdown did plant personnel check to determine whether the Row 1 and Row 9 baskets were -frozen in place'P
Response
During the recent shutdown (April 8, 1987 to April 20, 1987) we did not check to determine whether Row 1 and Row 9 baskets were frozen in place.
Due to the short outage period it 'was not possible to prepare to perform a T/S ice weighing without unnecessarily delaying our return to power.
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AEP:NRC:09671
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Question 7.
Why is it appropriate to use the average ice weight and subtract from it the upper limit of the 95% confidence interval of the average weight loss per yearV What would be the effect of using the lower 95% confidence limit of the ice weight and subtract from that the average weight loss per yearV
Response
To support our request for the surveillance extension we needed to determine the expected or average ice weight loss per year at a 95% confidence level.
The weight loss then is the statistical var'iable determined from "as-left" and "as-found" weighings.
The weight loss is the difference between the as-left and as-found weights, normalized to a weight loss/yr.
These as-left and as-found weighings were treated as paired observations for each bay.
The average ice weights were treated as data.
This method of paired observations is discussed in R.
E. Walpole's text, Introduction to Statistics, 2nd edition, and is quite appropriate for this analysis.
We did not believe there was reason to consider any additional statistical methods such as the lower 95% confidence level of ice weight and average weight loss.
Responding to the staff's
- request, however, we have repeated the analysis using this technique and found that the projected ice weights for each bay and row-group are greater than the T/S limit of 1220 pounds.
This technique is not as conservative as the method we used originally because the standard deviation of the ice weights is much less than the standard deviation of the ice weight losses.
We have also subtracted the most, recent weight loss from the average ice weights.
All ice weights projected to July 31, 1987 remained above the 1220 pound T/S limit.
Furthermore, when the most recent ice weight losses were subtracted from the lower 95% confidence limit of ice weights there were two bays and one row group below the 1220 T/S limit, but none below the 1098 weight allowed by the T/S Bases.
The projected ice condenser weight is greater than the minimum required for safe operation.
The total ice weight extrapolated to July 31, 1987 was always greater than 2,590,000 pounds regardless of averaging technique.
This is far greater than the 2,371,450 pound minimum required by T/Ss.
The results of all these new calculations are in Attachment 1.
Question 8:
Have there been any events at the plant since June 1986 such as the inadvertent opening of the lower inlet doors that would lead us to believe that the next surveillance will be different from any past surveillance or average of past surveillancesV
Response
Our April 29, 1987 telephone conversation with D.
C.
Cook Plant ice condenser personnel indicated there have been no significant events such as door openings or defrosting that would affect melting or ice weights on the next surveillance.
Air-handling units were discussed in response to Question 3.
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AEP:NRC:0967I Based on numerous ice weight samples and calculations, we are convinced that the Unit 1 ice condenser will have more than sufficient ice mass, with proper distribution, to completely mitigate the consequences of the design-basis accident.
The calculations used to support our previous submittal (AEP:NRC:0967H) treated any ice weight gains as zero ice weight losses instead of negative weight losses.
This zero weight loss keeps the average weight loss higher, and we believed, would provide a more conservative prediction of ice weight for July 31, 1987.
- However, the zero weight loss approach results in a small standard deviation associated with the average weight loss, and for this reason gives a less conservative prediction of ice basket weight.
The standard deviation associated with treating weight gains as negative weight losses is larger and results in the more conservative calculation, though the average weight loss is smaller.
We have repeated the ice weight predictions based on the average ice basket weight and the upper 95% confidence limit average weight loss, treating the weight gains as negative weight losses.
The results are tabulated in.
Table 1 lists the June 1986 as-left average ice basket weights and the expected weights on July 31, 1987 for each bay.
All bays except Nos.
1, 7,
8, 10, and 24 are expected to have average basket weights above 1220 pounds at the lower 95% confidence level.
Bays 1,
7, 8,
10, and 24 are expected to have average basket weights above 1098 pounds at the lower 95% confidence level.
Table 2 lists the June 1986 as-left average ice basket weights for each row-group required to be weighed by T/S 4.6.5.l.b.2 and the expected weights on July 31, 1987.
All row-groups except Nos. 1-1, 1-2, 2-2, 4-1, 4-2, 4-3, and 9-3 are expected to have average basket weights above 1220 pounds at the lower 95% confidence level.
These anticipated lower ice weights are a result of a statistical anomaly due to some relatively large weight gains in one other surveillance period.
Two of the row-groups are below 1098 pounds at the lower 95% confidence level.
They are Nos.
1-2 (1048 pounds) and Nos. 4-3 (1061 pounds).
We believe these weights, although conservative, would not adversely affect public health and safety since the current FSAR analysis is based on a total ice mass of 2,000,000
- pounds, which corresponds to an average ice basket weight of 1029 pounds.
Table 3 lists the total ice weight expected on July 31, 1987.
The ice condenser is expected to have at least 2,400,000 pounds of ice at the lower 95% confidence level on July 31, 1987.
This is well above the 2,371,450 pound limit of T/S 4.6.5.1.b.2 and 2,000,000 pound limit of the FSAR analysis.
The total ice weights were calculated using the predicted average bay basket weights and the predicted average row-group basket weights at the lower 958 confidence level.
The weights for Rows 3, 5, and 7 were estimated as the average of the two adjacent row-groups.
It was not necessary to repeat calculations which used the most recent ice weight losses, since using a zero weight loss instead of a negative weight loss (gain) is conservative.
There is no standard deviation associated with the most recent weight loss, since it is treated as a
single observation.
AEP:NRC:0967I This document has been prepared following Corporate procedures which incorporate a reasonable set of controls to insure its accuracy and completeness prior to signature by the undersigned.
Very truly yours, M.
. Alexi h Vice President cm Attachment cc:
John E. Dolan W.
G. Smith, Jr.
- Bridgman R.
C. Callen G.
Bruchmann G. Charnoff NRC Resident Inspector
- Bridgman A. B. Davis
- Region III Administrator
Attachment 1 to AEP:NRC:0967I Ice Weight Tables
Attachment 1 to AE..
C:0967I I
Page 1
TABLE 1 Projected Ice Weights per Basket by Bay Based on Lower 95% Confidence Level on Basket Weight
~Ba 1
2 3
4.
5 6
7 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1361 1436 1439 1413 1346 1345 1332 1380 1382 1345 1410 1363 1391 1389 1398 1388 1422 1420 1408 1377 1387 1410 1435 1388 46.021, 3.6 28.5 41.5 28.8 67.6 51.3 54.9 44.5 16.1 37.5 35.5 33.0 21.9 49.2 43.9 23.1 8.0 26.3 42.6 36.5 32.9 116.2 P
1311 1434 1435 1382 1301 1314 1259 1324 1322 1297 1392 1322 1352 1353 1375 1334 1375 1395 1400 1348 1340 1371 1400 1263 Projected Total Ice Weight 2,624,300 A - Average ice weight per basket (lbs) at the lower 95% confidence level.
As-left June 1986.
d Average ice weight loss per basket per year (lbs/yr) over the last 5
surveillances.
P Projected ice weight per basket (lbs) on July 31, 1987.
P A-d(13/12).
Attachment 1 to AE RC: 09 67I TABLE 2 Projected Ice Weights Per Basket by Row-Group Based on Lower 9 5 % Confidence Level on Basket Weights
~Row - G o ou l-l 1-2 1-3 2-1 2-2 2-3 4-1 4-2 4-3 6-1 6-2 6-3 8-1 8-2 8-3 9-1 9-2 9-3 1309 1384 1501 1342 1410 1447 1340 1332 1367 1459 1480 1418 1426 1405 1417 1393 1454 1417 63.4 81.3 36.2 30.4 41.6 37.0 52.0 41.6 69.7 20.4 13.5 30.2 51.4 49.0 59.6 35.0 74.4 106.4 1241 1295 1461 1310 1365 1407 1284 1287 1292 1437 1466 1386 1371 1352 1352 1356 1374 1301 Projected Total Ice Weight 2,631,800*
A Average ice weight per basket (lbs) at the lower 95% confidence level.
As-left June 1986.
d Average ice weight loss per basket per year (lbs/yr) over the last 5
surveillances.
P - Projected ice weight per basket (lbs) on July 31, 1987.
P A-d(13/12).
+Averaged Row-Groups 3,
5 and 7 by 2+4, 4+6 and 8+6, respectively.
Attachment 1 to AEP: RC:0967I
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TABLE 3 Pr'ojected Ice Weights Per Basket by Bay Based on Most Recent Ice Weight Loss
~Ba 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1387 1480 1483 1471 1407 1391 1380 1434 1436 1410 1472 1423 1433 1435 1452 1440 1451 1469 1456 1491 1432 1454 1482 1430 1361 1436 1439 1413 1346 1345 1332 1380 1382 1345 1410 1363 1391 1389 1398 1388 1422 1420 1408 1377 1387 1410 1435 1388 d5 226 0
0 10 146 52 78 0
0 88 22 114 122 82 36 88 28 2
28 0
66 62 0
2 Pl 1142*
1480 1483 1461 1248 1334 1295 1434 1436 1314 1449 1299 1300 1347 1413 1344 1420 1466 1425 1491 1360 1386 1482 1428 P2 1117*
1436 1439 1403 1187*
1288 1247 1380 1382 1249 1387 1239 1258 1301 1359 1292 1389 1417 1377 1377 1315 1342 1435 1386 Projected Total Ice Weight 2,692,200 2,592,200 Y
Average ice weight per basket (lbs) as-left June 1986.
A - Average ice weight per basket (lbs) at the lower 95% confidence level.
As-left June 1986.
d5 - Most recent ice weight loss per basket per year (lbs/yr).
Pl Projected ice weight per basket on July 31, 1987 based on Y, Pl-Y-d5(13/12).
P2 Projected ice weight per basket on July 31, 1987 based on A, P2 A-d5(13/12).
- Below 1220 lbs. but above 1098 lbs.
Attachment 1 to AE C:0967I TABLE 4 Projected Ice Weights Per Basket by Row-Group Based on Most Recent Ice Weight Loss
~Row - G woo d5 Pl P2 l-l 1-2 1-3 2-1 2-2 2-3 4-]
4-2 4-3 6-1 6-2 6-3 8-1 8-2 8-3 9-1 9-2 9-3 1397 1437 1578 1392 1439 1467 1356 1352 1391 1469 1502 1445 1451 1430 1441 1447 1484 1450 1309 1384 1501 1342 1410 1447 1340 1332 1367 1459 1480 1418 1426 1405 1417 1393 1454 1417 110 14 0
86 50 0
22 98 0
48 30 36 60 112 34 96 50 16 1277 1421 1578 1298 1384 1467 1332 1245 1391 1417 1469 1406 1386 1308 1404 1343 1429 1532 2,690,700 1189*
1368 1501 1248 1355 1447 1316 1225 1367 1407 1447 1379 1361 1283 1380 1289 1399 1399 2,630,700 Projected Total Ice Weight Y - Average ice weight per basket (lbs) as-left June 1986.
A Average ice weight per basket (lbs) at the lower 95% confidence level.
As-left June 1986.
d5 Most recent ice weight loss per basket per year (lbs/yr).'l Projected ice weight per basket on July 31, 1987 based on Y, Pl Y-(j5(13/12).
P2 Projected ice weight per basket on July 31, 1987 based on A, P2 A-d5(13/12).
~Below 1220 lbs. but above 1098 lbs.
~~Averaged Row-Groups 3,
5 and 7 by 2+4, 4+6 and 8+6, respectively.
Attachment 2 to AEP:NRC:0967I Ice Weight Tables Weight Gains Treated as Negative Losses
Attachment 2 to AEP: RC:0967I Page 1
TABLE 1 Average Ice Weights per Basket by Bay
~Bs No.
1 2
3 4
5 6
7 8
9 10ll 12 13 14 15 16 17 18 19 20 21 22 23 24 Average Ice Weight/
Basket As Left June 1986
~lbs.
1387 1480 1483 1471 1407 1391 1380 1434 1436 1410 1472 1423 1433 1435 1452 1440 1451 1469 1456 1491 1432 1454 1482 1430" Expected Ice Weight/
Basket July 1987
~lbs 1435 1529 1531 1521 1437 1400 1372 1462 1441 1457 1490 1451 1457 1453 1491 1431 1460 1515 1480 1541 1434 1460 1522 1313 Expected Ice Weight/
Basket at Lower 95%
Conf. Level July 1987
~lbs 1170 1477 1440 1332 1244 1267 1108 1185 1232 1159 1415 1273 1280 1284 1303 1267 1259 1293 1398 1355 1283 1317 1221 1129
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I Attachment 2 to AEP: RC:0967I Page 2
TABLE 2 Expected Average Ice Weights per Basket by Row-Group Row No.
~Gs su Ns.
1-1 1-2 1-3 2-1 2-2 2-3 4-1 4-2 4-3 6-1 6-2 6-3 8-1 8-2 8-3 9-1 9-2 9-3 Average Ice Weight/
Basket As Left June 1986
~lbs 1397 1437 1578 1392 1439 1467 1356 1353 1391 1469 1502 1446 1451 1430 1441 1447 1484 1450 Expected Ice Weight/
Basket July 1987
~lbs 1419 1474 1666 1426 1517 1501 1385 1399 1426 1479 1517 1427 1440 1396 1389 1431 1450 1339 Ice Weight/
Basket at Lower 95%
Conf. Level July 1987
~lbs 1148 1048 1357 1272 1178 1271 1102 1183 1061 1374 1448 1358 1288 1284 1259 1341 1255 1161
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Attachment 2 to AE
- RC:09671 Page 3
TABLE 3 Total Ice Weight Expected on July 31, 1987 Based on Average Ice Basket Wei hts Based on Average Ice Basket Weights at the Lower 95%
ConEidence Level
~B~Ba 2,841,800 2,811,500
~B~Ba 2,480,100 B
Row-Grou 2,422,900
April 29, 1987 DISTRIBUTION:
+Docket-Files ~
PKreutzer DWigginton PDIII-3 r/f DOCKET NO(S). 50-315/316 Mr. John Dolan, Vice President Indiana. and Michigan Electric Company c/o American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, OH 43216
SUBJECT:
DONALD C.
COOK NUCLEAR PLANTS The following documents concerning our review of the subject facility are transmitted for your information.
Notice of Receipt of Application, dated Draft/Final Environmental Statement, dated Notice of Availability of Draft/Final Environmental Statement, dated Safety Evaluation Report, or Supplement No.
dated Environmental Assessment and Finding of No Significant Impact, dated Notice of Consideration of Issuance of Facility Operating License or Amendment to Facility Operating License, dated Q Bi-Weekly Notice; Applications and Amendments to Operating Licenses Involving No Significant Hazards Considerations, dated Apr 22~8~
[see page(s) 3 Exemption, dated Construction Permit No.
CPPR-
, Amendment No.
dated Facility Operating License No.
, Amendment No.
dated Order Extending Construction Completion Date, dated Monthly Operating Report for transmitted by letter dated
+ Annual/Semi-Annual Report-transmitted by letter dated Encl osures:
As stated Office of Nuclear Reactor Regulation cc:
See Next Page OFFICE)
,SURNAME/
DATEP 4/g.g/87-
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NRC FORM 3I8 IIO/80)NRCM 0240 OFFICiAL RECORD COPY
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Mr. John Dolan Indiana and Michigan Electric Company Donald C.
Cook Nuclear Plant CC:
Mr. M. P. Alexich Vice President Nuclear Operations American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43215 Attorney General Department of Attorney General 525 West Ottawa Street Lansing, Michigan 48913 Township Supervisor Lake Township Hall Post Office Box 818 Bridgeman, Michigan 49106 W. G. Smith, Jr., Plant Manager Donald C.
Cook Nuclear Plant Post Office Box 458 Bridgman, Michigan 49106 U.S. Nuclear Regulatory Commission Resident Inspectors Office 7700 Red Arrow Highway Stevensville, Michigan 49127 Gerald Charno ff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, N.W.
Washington, DC 20037 Mayor, City of Bridgeman Post Office Box 366 Bridgeman, Michigan 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, Michigan.48909 Nuclear Facilities and Environmental Monitoring Section Office Division of Radiological Health Department of Public Health 3500 N. Logan Street Post Office Box 30035 Lansing, Michigan 48909 The Honorable John E. Grotberg United States House of Representatives Washington, DC 20515 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 J. Feinstein American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216