NOC-AE-02001439, Response to Request for Additional Information, Revised Request for Approval of Alternative Approach for Containment Concrete & Tendoc Surveillance (RR-ENG-37)

From kanterella
Jump to navigation Jump to search
Response to Request for Additional Information, Revised Request for Approval of Alternative Approach for Containment Concrete & Tendoc Surveillance (RR-ENG-37)
ML030210116
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 01/06/2003
From: Jordan T
South Texas
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
G25, NOC-AE-02001439, RR-ENG-37
Download: ML030210116 (12)
v • d • e


Text

Nuclear Operating Company South T*rs ,*/eEkdtC G P0 5ar 2S S*feaenhSon HadsmrtA, lcea 77453 *A A January 6, 2003 NOC-AE-02001439 File No.: G25 10CFR50.55a U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Response to Request for Additional Information Regarding Revised Request for Approval of an Alternative Approach for Containment Concrete and Tendon Surveillances (RR-ENG-37)

Reference:

Letter, T. J. Jordan to NRC Document Control Desk, "Request for Approval of an Alternative Approach for Containment Tendon Surveillances (RR-ENG-37)

In accordance with the provisions of 10CFR50.55a(a)(3)(i), the referenced letter from the South Texas Project requested approval of an alternative to ASME Section XI, paragraph IWL 2421(b). This specified the inservice inspection intervals to be applied in examination of containment concrete and unbonded post-tensioning systems, and IWL-2521, which describes the tendon selection process. This letter is in response to questions forwarded from the NRC requesting clarification of points presented previously. The requested information is attached.

If there are any questions, please contact either Mr. Philip Walker at 361-972-8392 or me at 361-972-7902.

Vice President, Engineering & Technical Services PLW

Attachment:

Response to Request for Additional Information Regarding Containment Tendon Surveillance Requirements

NOC-AE-002001439 Page 2 of 2 cc:

(paper copy) (electronic copy)

Ellis W. Merschoff A. H. Gutterman, Esquire Regional Administrator, Region IV Morgan, Lewis & Bockius LLP U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 L. D. Blaylock/W. C. Gunst Arlington, Texas 76011-8064 City Public Service U. S. Nuclear Regulatory Commission Mohan C. Thadani Attention: Document Control Desk U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike R. L. Balcom Rockville, MD 20852 Texas Genco, LP Richard A. Ratliff A. Ramirez Bureau of Radiation Control City of Austin Texas Department of Health 1100 West 49th Street C. A. Johnson Austin, TX 78756-3189 AEP Texas Central Company Cornelius F. O'Keefe Jon C. Wood U. S. Nuclear Regulatory Commission Matthews & Branscomb P. O. Box 289, Mail Code: MN1 16 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704

Attachment NOC-AE-02001439 Page 1 of 10 SOUTH TEXAS PROJECT RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING CONTAINMENT TENDON SURVEILLANCE REQUIREMENTS NRC REQUEST:

In reviewing the information in Figure 1 and Tables 1 and2, it is unclear what the actual measuredand predictedtendon forces are. The licensee is requestedto provide Tables showing actual measured pre-stressing forces for each Unit in each direction together with the forces at installation, elastic shortening losses, and slippage, if any, for the tendons selected duringeach priorinspections.

In the Figure,the licensee is requestedto show:

(1) The trend lines (separately,for each Unit, and for U and hoop tendons) based on the inspectionsperformed, (2) Actual measured forces as points above and below the trend lines, and (3) Predictedaverage tendon forces at 40 years.

The licensee is also requested to provide a summary of the method used to construct the trendlines.

SOUTH TEXAS PROJECT RESPONSE:

Supplementary Tables As requested, supplementary tables are provided for each tendon group. The columns in these tables are as follows:

(1) Tendon designation (2) Tendon end (S = "Shop end", F = "Field end")

(3) Surveillance year (1, 5, or 10)

(4) Initial liftoff force measured at installation (kips)

(5) Predicted elastic loss (kips)

(6) Predicted liftoff force at surveillance year (kips)

(7) Measured liftoff force during surveillance.

Columns 8 through 11 are explained under the section on calculation of trend lines.

Slippage is not applicable to the buttonhead-type installation at the South Texas Project.

The supplementary tables also include the average initial liftoff and predicted end-of-life liftoff for each group. These averages are calculated as the average of all tendons in the group, not just the surveillance tendons.

Figure 1 and Figure 2 As read from top to bottom, respectively, on the right side of Figure 1, the four lines are:

  • Unit 2 verticals (inverted "U"),
  • Unit 1 verticals (inverted "U"),
  • Unit 2 horizontals (hoop), and
  • Unit I horizontals (hoop).

Attachment NOC-AE-02001439 Page 2 of 10 Tendon loss is typically presented on a semi-log plot, with prestress loss being linear with the log of time. STP prepared Figure 1 using a standard linear scale, resulting in nonlinear trend lines. The labels on the revised Figure 1 included with this response have been enhanced for greater clarity. (There is no change to the data presented in the figure.) Figure 2 has been added to show the same trends against the log of time.

The figures show percent deviation from the predicted value on the vertical axis.

Although the request was to add the actual measured forces and end-of-life predicted average forces to the figure, the South Texas Project believes this information is more appropriately shown in the tables provided.

The South Texas Project believes that the information shown in revised Figure 1, Figure 2, and provided in the supplementary tables, while slightly different from the staff's request, meets the intent of the RAI.

Construction of Trend Unes The trend line is calculated using linear regression analysis. The trend is a straight line, represented by the equation:

Y=a + A3X, where the variables X and Y are defined as:

X = Log (T), and T = time (measured in years), and Y= Deviation from predicted prestress (measured in %).

Data points currently available are from surveillances in years 1, 5, and 10. This means the three possible values of T are 1, 5, and 10, and the corresponding values of X are Log(1), Log(5), and Log(110), which are 0, 0.69897, and 1, respectively.

All tendons were installed using similar methods, but no two were tensioned to precisely the same force. The initial liftoff forces were recorded for all tendons immediately following installation. Additional disparity in tendon forces was introduced due to installation sequencing (elastic losses). The subsequent time-dependent losses (creep, shrinkage, relaxation) are stress-dependent. Since no two tendons have exactly the same stress, itfollows that no two have exactly the same predicted time-dependent loss.

Therefore, predicted liftoff force is calculated individually for each tendon. In order to make meaningful comparisons among tendons and assess trends, converting them to percentage deviation from predicted values normalizes the measured liftoff forces. For example, during the first year surveillance of Unit 1, tendon V1 26-S had a predicted liftoff force of 1376 kips and an actual measured liftoff at 1402 kips. This means the actual liftoff force was 1.89% higher than expected. [(1402 - 1376)/1376 = 0.0189 = 1.89%.]

Hence, for this case, the value of Y used in the regression analysis is 1.890. The corresponding value of X is 0.

The regression constants a and P3 are calculated according to standard statistical formulas:

a = y - ix,

Attachment NOC-AE-02001439 Page 3 of 10 Zx,y,-.x

' 2 axi -n.x.2 i=1 in L in where x = -. X xi, y = F y, and n = number of data points in the group.

n i i=1 Columns 8 through 11 in the supplementary tables are defined as:

(8) X = Log(Time),

(9) Y = Deviation from predicted (expressed as %) where Y = 100 x [(col. 7) - (col. 6)]I(col. 6)

(10) XY =(col. 8) x (col. 9)

(11) X2 =(col. 8) x (col. 8)

The sum of the terms in each of these columns is given at the bottom of each table.

These sums are used to calculate the constants a and P3 for each group, according to the formulas given above. Table 2 in the relief request presents the projected trends in tabular form. Using the Unit 1 horizontals as an illustration, the constant =alpha" was calculated as 2.464 and the constant "Beta" was -3.722. Therefore, the projected deviation from predicted (expressed as %).at year 40 is:

Y=a +13X

= a + Log(7)

= 2.464 + (-3.722)(Log(40))

= 2.462 + (-3.722)(1.602)

= -3.50%.

This means that the Unit 1 horizontals, as a group, are trending toward 3.5% less than the predicted values at year 40. This is shown in Table 1 of the relief request. It is the least satisfactory trend of any of the four groups. To put this projection in perspective, the end-of-life containment design value for rated capacity is 56.5 psi, which is 37%

above the 41.2 psi maximum calculated pressure resulting from a LOCA.

To date, STP has performed 116 tendon liftoff tests (38 verticals and 78 horizontals).

These were distributed among the surveillances as follows:

a 52 at the first year,

  • 40 at the fifth year, and
  • 24 at the tenth year.

Each tendon has two ends, so the 116 liftoff tests convert to surveillances of 58 tendons.

Attachment NOC-AE- 02001439 Page 4 of 10 Supplementary Table S- I: Vertical Tendons (U1)

V2 S 1 15811 1376 1402 0 1.890 0 0 V2 F 1 16111 1391 1439 0 3.451 0 0 V4 S 1 16222 1401 1400 0 -0.071 0 0 022 1352 1343 0 -0.66 0 0 V227 S 1 1553 22 1345 1336 0 -0.669 0 0 V227 F 1 1556 22 1346 1325 0 -1.560 0 0 V245 S 1 1591 34 1366 1363 0 -0.220 0 0 V245 F 1 1565 34 1349 1326 0 -1.705 0 0 V126 S 5 1598 11 1350 1385 0.69897 2.593 1.81214 0.48856 V126 F 5 1621 11 1370 1406 0.69897 2.628 1.83671 0.48856 V214 S 5 1598 1 1358 1380 0.69897 1.620 1.13245 0.48856 V214 F 5 1631 1 1378 1392 0.69897 1.016 0.71013 0.48856 V242 S 5 1603 5 1363 1381 0.69897 1.321 0.92307 0.48856 V242 F 5 1608 5 1367 1397 0.69897 2.195 1.53495 0.48856 V248 S 5 1603 9 1354 1359 0.69897 0.369 0.25811 0.48856 V248 F 5 1608 9 1359 1382 0.69897 1.692 1.18395 0.48856 V126 S 10 1598 11 1348 1340 1 -0.593 -0.59347 1 V126 F 10 1621 11 1362 1380 1 1.322 1.32159 1 V129 S 10 15339 47 1286 1290 1 0.31 0.31104

.1 1 V14 F 5 1631 47 1333 1320 1 -0.975 -0.97524 1 V-26 S 10 1598 12 1379 1380 1 0.073 0.07252 1 V230 F 10 1596 -2 1354 1430 1 5.613 5.61300 1

____ 9 0040g' ti 11.592 19.632 115.139 19.908

___________ ____ ge ed)' (E) 0If~ Number of liftoff tests: N = 22 See page 1 of this attachment for an explanation of columns 1 through 7, and page 3 of this attachment for an explanation of columns 8 through 11.

Attachment NOC-AE-02001439 Page 5 of 10 Supplementary Table S-2: Vertical Tendons (U2) ia E P e MeOse V110 S 1 1605 25 1380 1421 0 2.971 0 0 V110 F 1 1605 25 1380 1377 0 -0,217 0 0 V120 S 1 1580 18 1359 1403 0 3.238 0 0 V120 F 1 1630 18 1402 1400 0 -0.143 0 0 V202 S 1 1630 15 1402 1432 0 2.140 0 0 V202 F 1 1640 15 1410 1422 0 0.851 0 0 V236 S 1 1605 4 1396 1382 0 -1.003 0 0 V236 F 1 1520 4 1338 1370 0 2.392 0 0 V110 S 5 1605 25 1348 1412 0.69897 4.748 3.31855 0.48856 V110 F 5 1605 25 1348 1362 0.69897 1.039 0.72593 0.48856 V203 S 5 1610 13 1360 1415 0.69897 4.044 2.82672 0.48856 V203 F 5 1620 13 1361 1407 0.69897 3.380 2.36243 0.48856 V221 S 5 1580 -2 1351 1479 0.69897 9.474 6.62237 0.48856 V221 F 5 1630 -2 1394 1452 0.69897 4.161 2.90820 0.48856 V233 S 5 1580 29 1343 1348 0.69897 0.372 0.26023 0.48856 V233 F 5 1540 29 1309 1338 0.69897 2.215 1.54852 0.48856

_ _ _595 *]*g 't5.592 39.661 20.573 3.908 1 5eg~ Pe-oL umer of liftoff tests: N =16 See page 1 of this attachment for an explanation of columns 1 through 7, and page 3 of this attachment for an explanation of columns 8 through 11.

Attachment NOC-AE-02001439 Page 6 of 10 Supplementary Table S-3: Hoop Tendons (Ul)

Ten on 0im Rers o i ~r~t 1H091 S 1 1550 5 1326 1380 0 4.072 0 0 1H091 F 1 1612 5 1367 1378 0 0.805 0 0 1H106 S 1 1579 73 1302 1345 0 3.303 0 0 1H106 F 1 1607 73 1321 1354 0 2.498 0 0 1H130 S 1 1638 55 1368 1383 0 1.096 0 0 1H130 F 1 1582 55 1331 1360 0 2.179 0 0 2H051 S 1 1539 99 1259 1297 0 3.018 0 0 2H051 F 1 1643 99 1329 13211 0 -0.602 0 0 2H054 S 1 1582 24 1335 1376 0 3.071 0 0 2H054 F 1 1589 24 1340 1363 0 1.716 0 0 2H078 S 1 1643 22 1376 1423 0 3.416 0 0 2H078 F 1 1632 22 1369 1373 0 0.292 0 0 2H111 S 1 1607 70 1338 1386 0 3.587 0 0 2H111 F 1 1577 70 1318 1336 0 1.366 0 0 3H005 S 1 1579 53 1315 1402 0 6.616 0 0 3H005 F 1 1562 53 1304 1356 0 3.988 0 0 3H032 S 1 1545 65 1285 1345 0 4.669 0 0 3H032 F 1 1632 65 1343 1365 0 1.638 0 0 1H091 S 5 1550 5 1310 1312 0.69897 0.153 0.10671 0.48856 1H091 F 5 1612 5 1386 1329 0.69897 -4.113 -2.87455 0.48856 1H112 S 5 1579 55 1318 1281 0.69897, -2.807 -1.96221 0.48856 1HI12 F 5 1542 55 1280 1270 0.69897 -0.781 -0.54607 0.48856 2H093 S 5 1607 90 1294 1276 0.69897 -1.391 -0.97229 0.48856 2H093 F 5 1589 90 1302 1270 0.69897 -2.458 -1.71790 0.48856 2H129 S 5 1558 68 1293 1345 0.69897 4.022 2.81102 0.48856 2H129 F 5 1553 68 1289 1213 0.69897 -5.896 -4.12116 0.48856 2H036 S 5 1637 10 1359 1384 0.69897 1.840 1.28582 0.48856 2H036 F 5 1644 10 1364 1381 0.69897 1.246 0.87115 0.48856 2H048 S 5 1643 11 1364 1380 0.69897 1.173 0.81991 0.48856 2H048 F 5 1620 11 1345 1338 0.69897 -0.520 -0.36378 0.48856 1H043 S 10 1634 2 1356 1330 1 -1.917 -1.91740 1 1H043 F 10 1553 2 1306 1320 1 1.072 1.07198 1 1H049 S 10 1610 31 1325 1270 1 -4.151 -4.15094 1 1H049 F 10 1567 31 1298 1330 1 2.465 2.46533 1 1H091 S 10 1550 5 1303 1310 1 0.537 0.53722 1 1H091 F 10 1612 5 1341 1280 1 -4.549 -4.54884 1 2H129 S 10 1558 68 1287 1320 1 2.564 2.56410 1 2H129 F 10 1553 68 1284 1265 1 -1.480 -1.47975 1 1H130 S 10 1638 55 1345 1330 1 -1.115 -1.11524 1 1H130 F 10 1582 55 1310 1290 1 -1.527 -1.52672 1 1H127 S 10 1610 6 1356 1340 1 -1.180 -1.17994 1 41H1i27 F 10 15421 6 1314 1310 1 -0.3041 -0.30441 1

__ I 20.388 27.611 1 -16.248 1 lumber of liftoff tests: N =42 17.863 See page 1 of this attachment for an explanation of columns 1 through 7, and page 3 of this attachment for an explanation of columns 8 through 11.

Attachment NOC-AE-02001439 Page 7 of 10 Supplementary Table S-4: Hoop Tendons (U2) 1H094 S 1 1535 55 1289 1283 0 -0.465 0 0 1H094 F 1 1620 55 1345 1335 0 -0.743 0 0 1H112 S 1 1535 56 1305 1274 0 -2.375 0 0 1H112 F 1 1580 56 1343 1303 0 -2.978 0 0 1H124 S 1 1580 55 1343 1312 0 -2.308 0 0 11H124 F 1 1580 55 1343 1337 0 -0.447 0 0 2H033 S 1 1520 49 1292 1216 0 -5.882 0 0 2H033 F 1 1550 49 1302 1354 0 3.994 0 0 2H075 S 1 1600 43 1344 1394 0 3.720 0 0 2H075 F 1 1600 43 1344 1398 0 4.018 0 0 2H105 S 1 1540 39 1309 1418 0 8.327 0 0 2H105 F 1 1580 39 1327 1400 0 5.501 0 0 3H005 S 1 1580 101 1296 1355 0 4.552 0 0 3H005 F 1 1550 101 1271 1375 0 8.183 0 0 3H029 S 1 1585 97 1300 1392 0 7.077 0 0 3H029 F 1 1550 97 1271 1319 0 3.777 0 0 3H056 S 1 1570 65 1319 1361 0 3.184 0 0 3H056 F 1 1580 65 1311 1346 0 2.670 0 0 1H055 S 5 1550 3 1310 1325 0.69897 1.145 0.80035 0.48856 1H055 F 5 1540 3 1301 1298 0.69897 -0.231 -0.16118 0.48856 1H106 S 5 1580 56 1304 1308 0.69897 0.307 0.21441 0.48856 1H106 F 5 1570 56 1295 1251 0.69897 -3.398 -2.37488 0.48856 2H018 S 5 1540 10 1301 1421 0.69897 9.224 6.44707 0.48856 2H018 F 5 1620 10 1353 1352 0.69897 -0.074 -0.05166 0.48856 2H045 S 5 1540 47 1278 1356 0.69897 6.103 4.26601 0.48856 2H045 F 5 1570 47 1295 1300 0.69897 0.386 0.26987 0.48856 2H075 S 5 1600 43 1320 1324 0.69897 0.303 0.21181 0.48856 2H075 F 5 1600 43 1320 1338 0.69897 1.364 0.95314 0.48856 3H050 S 5 1610 64 1312 1336 0.69897 1.829 1.27860 0.48856 3H050 F 5 1630 64 1337 1323 0.69897 -1.047 -0.73191 0.48856 2H033 S 10 1520 49 1258 1196 1 -4.928 -4.92846 1 2H033 F 10 1550 49 1277 1280 1 0.235 0.23491 1 2H036 S 10 1600 13 1329 1290 1 -2.935 -2.93454 1 2H036 F 10 1570 13 1311 1310 1 -0.076 -0.07628 1 2H030 S 10 1550 12 1299 1280 1 -1.463 -1.46266 1 2HO3O

  • , .vvv F 10

,v 197n 12 1 11 1q20 1 0v,*vv 1 068RR501 1 14.388 1 47.233 [ 2.641 11.863 Number of liftoff tests: N = 36 See page 1 of this attachment for an explanation of columns 1 through 7, and page 3 of this attachment for an explanation of columns 8 through 11.

Attachment NOC-AE-02001439 Page 8 of 10 Supplementary Table S-5: TREND

SUMMARY

20.388 11.592 14.388 5.592 27.611 19.632 47.233 39.661

-16.248 15.139 2.641 20.573 17.863 9.908 11.863 3.908 42 22 36 16 0.485 0.527 0.400 0.349 0.657 0.892 1.312 2.479

-3.722 1.262 -2.656 3.435 2.464 0.228 2.374 1.279 2.4_6 0.23 2.375 1.28

-0.14 1.11 0.52* 3.68

-1!.26 1.49 -0.28 4.71

-1.91 1.71 -0.75 53

-2.38 1.87 -1.08 5.75

-2.74 1.99 -1.34 6.08

-3.03 2.09 -1.55 6.35

-3.28 2.18 -1.73 6.58

-3.50 2.25 -1.88 6.78

Attachment NOC-AE-02001439 Page 9 of 10 Revised Figure.1: Trend Lines of Lift-Off Test Results (Years 1, 5, and 10) 8

...... ..... ......... .Unit 2 Vertical ii7 6

4 U) 4)

2 0

I 0 0.

r* " '"

.,: "*'t. , I.*,,-".....

b,....

. -,p.....'

'**;:!: .. 4*!

r-: ' -: ..

-2 Unit2lHocop ,'. -V

t:'::'::';*

'*;*"* :"':**'* 4 p..."

': 'i a: * 'Y' *:'i .... .. " ***' ' '**;....":-. ... '"4 *" . . "* *:.0 *.... ... ..... '**4  :'""..

-4

-6 Year of Plant Life

Attachment NOC-AE-02001439 Page 10 of 10 Figure 2: Trendlines of Lift-Off Test Results (Years 1, 5, and 10) 8

(/0

(

"0 a.

I E

Year of Plant Life (Logarithmic)

Retrieved from "https://kanterella.com/w/index.php?title=NOC-AE-02001439,_Response_to_Request_for_Additional_Information,_Revised_Request_for_Approval_of_Alternative_Approach_for_Containment_Concrete_%26_Tendoc_Surveillance_(RR-ENG-37)&oldid=2678542"