ML031000719
| ML031000719 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 04/04/2003 |
| From: | Katz P Constellation Energy Group |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MB7752, TAC MB7753 | |
| Download: ML031000719 (12) | |
Text
Peter E. Katz Vice President Calvert Cliffs Nuclear Power Plant Constellation Generation Group, LLC 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 495-4455 410 495-3500 Fax Constellation v wEnergy Group April 4, 2003 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
SUBJECT:
Document Control Desk Calvert Cliffs Nuclear Power Plant UnitNos. 1 & 2; DocketNos. 50-317 & 50-318 Response to Request for Additional Information Regarding Interim Inspection Requirements for Reactor Pressure Vessel Head (TAC Nos. MB7752 and MB7753)
REFERENCES:
(a)
Letter from Mr. P. E. Katz (CCNPP) to Document Control Desk (NRC),
dated February 18, 2003, Response to Issuance of Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors (b)
Letter from Mr. S. J. Collins (NRC) to Holders of Licenses for Operating Pressurized Water Reactors, dated February 11, 2003, Issuance of Order Establishing Interim Inspection Requirements for Reactor Pressure Vessel Heads at Pressurized Water Reactors (EA-03-009)
(c)
Letter from Mr. G. S. Vissing (NRC) to Mr. P. E. Katz (CCNPP), dated April 2, 2003, Calvert Cliffs Nuclear Power Plant, Unit No. 2 - Request for Additional Information Regarding the Response of March 13, 2003, to the Nuclear Regulatory Commission (NRC) Request for Additional Information (RAI) dated February 28, 2003, Regarding the Relaxation of the Order of February 11, 2003 (TAC Nos. MB7752 and MB7753)
By letter dated February 18, 2003 (Reference a), Calvert Cliffs Nuclear Power Plant, Inc. submitted a request for relaxation from the inspection requirements of Section IV.C(l)(b)(1) of Reference (b). This letter provides Calvert Cliffs Nuclear Power Plant's response to the April 2, 2003, letter (Reference c) request from the Nuclear Regulatory Commission for additional information regarding that relaxation request. The requested information and our responses are contained in Attachment (1) to this letter.
Document Control Desk April 4, 2003 Page 2 Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, for P. E. Katz Vice President Calvert Cliffs Nuclear Power Plant PEK/JKK/bjd
Attachment:
(1)
Response to NRC Request for Additional Information cc:
J. Petro, Esquire J. E. Silberg, Esquire Director, Project Directorate I-1, NRC G. S. Vissing, NRC H. J. Miller, NRC Resident Inspector, NRC R. I. McLean, DNR
ATTACHMENT (1)
RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION Calvert Cliffs Nuclear Power Plant, Inc.
April 4, 2003
ATTACHMENT (1)
RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION NRC Request 1:
Please provide a tabular listing of the maximum operating stress (across the cross-section) from the top of the J-groove weld to 2 inches above the weld. How does the yield strength of the nozzle material used in the calculations compare to the strength of the Calvert Cliffs nozzles, and what impact does the yield strength difference have on the calculated residual stresses?
CCNPP Response:
A tabular listing is provided as Enclosure (1). This enclosure describes the axial and hoop stresses at the nodes of the finite element model used to produce the color figures that were provided in the first set of request for additional information questions. For reference in correlating the node numbers to their position in the model, please use the attached Figure 1, which shows the node-numbering scheme used in the models. In general, nodes increase from 1 to 5 through the nozzle wall from inside diameter (ID) to outside diameter (OD), nodes increase by 100's axially, and increase by 10000's circumferentially. The tabulation provides the axial and hoop stresses at the ID and OD surfaces. The stresses are reported only at nodes, so the stress at the 2-inch elevation is not provided. Instead, the stress at the node closest to the 2-inch elevation is provided.
The model used to calculate the stresses was performed for the 42 ksi yield strength material used to fabricate the control element drive mechanism penetrations in Calvert Cliffs Unit 1. According to the contractor who performed the finite element model analysis, the residual stresses at the nozzle surfaces should scale with the material yield strength, therefore, the tabulated stresses would all be proportionally slightly lower for Calvert Cliffs Unit 2 Control Element Drive Mechanism penetrations, which have yield strengths of 37.5 ksi.
NRC Request 2:
Is the primary impediment to effective examination at elevations higher than 0.75 inches above the J-groove weld due to the counterbore step in the nozzles or the expansion points in the guide sleeves?
CCNPP Response:
The primary impediment to effective examination to the full extent 2 inches above the J-groove weld root is the counterbore step on the ID of the nozzle. The expansion points in the guide sleeves are located above the elevation of the counterbore. At the counterbore, the annular gap between the guide sleeve and the penetration nozzle narrows, from approximately 0.175 to 0.123 inches.
NRC Request 3:
If the guide sleeves are removed, would there be additional geometric constraints on performing the examination required in the Order?
CCNPP Response:
If the guide sleeves were removed, the ID of the nozzle would become accessible for a rotating probe.
We believe it would be possible to acquire data for the full 2 inches required, above the root of the J-groove weld, for nozzles that had their guide sleeves removed.
1
ATTACHMENT (1)
RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION NRC Request 4:
Since the Order allows either ultrasonic testing (UT) examination or a surface examination and you have identified hardship only for the UT examination, what would be the implications of performing a surface examination of the nozzle areas with limited UT coverage to give 100% coverage of all nozzles?
CCNPP Response:
A surface examination of the nozzle ID surface could be accomplished with an eddy current probe if one could be delivered to the location. It is currently not possible to deliver an eddy current probe to the area 2 inches above the J-groove weld. A different inspection contractor could provide the capability to deliver an eddy current probe to the region where access is limited nearly 2 inches above the top of the high side of the J-groove welds. However, the different contractor is not available to perform inspections at Calvert Cliffs during the Spring 2003 outage.
Surface examination could also be accomplished by penetrant testing, however this would require removal of the guide sleeves.
NRC Request 5:
As stated in the response, the inspection contractor's evaluation of 260 cracks in reactor pressure vessel penetrations at other plants showed that all cracks were found located below 0. 75 inch above the weld.
Are the data evaluated inclusive of all data from all inspections by all vendors? Based on the data evaluated, has any analysis been performed to conclude that all 260 indications would still have been detected even if the scope of examination had been only 0.75 inch above the weld? What does industry experience with outside diameter primary water-stress-corrosion cracking (PWSCC) in vessel head penetration (VHP) nozzles indicate about the likelihood for cracking in the region of the VHP nozzle more than 0.75 inch above the top of the J-groove weld?
CCNPP Response:
The inspection contractor's evaluation of 260 cracks in VHP nozzles at other plants was performed on data available only to the contractor. No analysis was performed on data from plants inspected by other contractors.
Therefore, the data evaluated were not inclusive of all data from all inspections by all vendors.
Since all 260 previously identified cracks were located below 0.75 inches above the weld, we conclude, with high confidence, that all 260 indications would have been detected with an examination scope up to 0.75 inches above the weld. However, no analysis has been performed since such an analysis would require re-evaluation of the entire inspection data sets from previously inspected plants.
The re-evaluation would need to be performed in a double blind experiment with modifications to the raw data to limit coverage to 0.75 inch above the weld. It is difficult to get operating plants' permission to have third parties independently modify, then re-analyze their inspection data.
Calvert Cliffs has no plans to perform this analysis.
Industry experience with outside diameter PWSCC in VHP nozzles is indicated on the attached figure "Vertical Distance from Weld Root to Lower End of Flaw" (Figure 2), which shows the approximate location of circumferential cracks identified in previous inspections by this inspection contractor.
2
ENCLOSURE 1)
RESPONSE TO NRC REQUEST #1:
Table of Maximum Operating Stress
ENCLOSURE (1)
Residual Plus Operating Stresses for Penetration Nozzle at 11 Degree Angle Nozzle ID Nozzle OD Inches Hoop Stress Axial Stress Node above Hoop Stress Axial Stress 1401 abgrove (psi)
(psi)
Node___
abgove (psi)
(psi) 1401 0
44967 13194 1405 0
59923 11842 1501 0.24 40275 25636 1505 0.239 38296
-5770.8 1601 0.6 32582 30660 1605 0.6 12965
-23711 1701 1.074 30205 28429 1705 1.124
-3496.1
-22493 1801 1.438 12543 17213 1805 1.697
-3401.9
-5062 11401 0
44843 13263 11405 0
59720 11531 11501 0.24 39714 25416 11505 0.241 37292
-6774.5 11601 0.596 32451 30322 11605 0.597 13117
-23486 11701 1.065 27644 27850 11705 1.087
-1697.9
-22453 11801 1.408 9914.4 15581 11805 1.685
-3441.5
-5067.8 21401 0
44217 12258 21405 0
59522 11309 21501 0.242 40437 25545 21505 0.241 35252
-8930.8 21601 0.594 36443 31588 21605 0.593 14712
-22724 21701 1.343 20651 20972 21705 0.997
-1531.3
-24011 21801 1.671 2213 9157.1 21805 1.672
-5031.1
-6247.4 31401 0
43998 11126 31405 0
58343 9450.9 31501 0.242 40789 23678 31505 0.242 33152
-10738 31601 0.59 38030 30289 31605 0.59 15521
-22645 31701 1.249 19386 19304 31705 0.868
-3039.5
-25575 31801 1.659 196.17 7302.3 31805 1.659
-5352
-7135.1 41401 0
43810 9143.4 41405 0
57819 7120.2 41501 0.243 40397 19766 41505 0.243 31362
-11171 41601 0.587 38763 28569 41605 0.718 6287.1
-25725 41701 1.14 24222 21922 41705 1.042 3374.5
-14752 51401 0
43904 6452 51405 0
58326 5099.2 51501 0.244 42564 18305 51505 0.243 27978
-17543 51601 0.583 39996 26830 51605 0.567 7212
-27629 51701 1.031 29203 22694 51705 1.033
-1446.2
-17249 51801 1.633 3551.8 6163.6 51805 1.632
-5546.9
-3016.8 61401 0
43980 3867.6 61405 0
59574 3734.7 61501 0.244 44455 17830 61505 0.245 27975
-20562 61601 0.579 41052 25828 61605 0.439 3548.8
-32138 61701 0.937 33450 21973 61705 1.026
-1505.2
-16999 61801 1.621 5137.7 5796.3 61805 1.62
-5180.7
-1538 71401 0
44440 2692.6 71405 0
61287 4021.3 71501 0.246 42857 14965 71505 0.245 25113
-23487 71601 0.577 42456 26424 71605 0.576 6438.1
-27576 71701 0.872 37899 24136 71705 1.018
-1630.4
-14836 71801 1.61 6014.9 6073.7 71805 1.609
-5716
-1567.6 81401 0
44742 2557.9 81405 0
61918 4004 81501 0.247 42700 14623 81505 0.246 25809
-23552 81601 0.574 42880 26499 81605 0.574 5517.9
-27972 81701 0.843 38527 24055 81705 1.012
-2011
-14950 81801 1.6 6078.7 6114.5 81805 1.598
-5644.4
-1410.9
ENCLOSURE (1)
Residual Plus Operating Stresses for Penetration Nozzle at 29 Degree Angle Nozzle ID Nozzle OD Node above Hoop Stress Axial Stress Node above Hoop Stress Axial Stress Node____
abgove (psi)
(psi)
Node_
abgrove (psi)
(psi) 1401 0
44112 24613 1405 0
54871 23576 1501 0.254 37098 32056 1505 0.255 35765 13626 1601 0.658 30565 33813 1605 0.661 13959
-14412 1701 1.193 23506 29806 1705 1.198
-6440.7
-22835 1801 1.899 11508 19714 1805 1.907
-10838
-8107.7 11401 0
41852 23866 11405 0
53606 23646 11501 0.253 35736 31229 11505 0.255 36054 14583 11601 0.646 29732 33750 11605 0.649 14144
-11479 11701 1.168 22092 29152 11705 1.173
-3780.5
-19745 11801 1.862 10701 19478 11805 1 87
-9177.7
-7493.2 21401 0
37680 21726 21405 0
49644 21995 21501 0.253 34156 29254 21505 0.254 35976 15441 21601 0.634 28262 32615 21605 0.636 13444
-8115.8 21701 1.144 19330 28370 21705 1.147 1335.7
-15424 31401 0
34175 17626 31405 0
45169 18152 31501 0.252 33358 25733 31505 0.252 34013 13206 31601 0.621 29370 31758 31605 0.623 11420
-8674.7 31701 1.119 19060 26447 31705 1.121 5411.6
-12669 31801 2.218 2119.2 10483 31805 1.916 1350.5
-6171.9 41401 0
33099 11804 41405 0
45281 15215 41501 0.251 34987 22473 41505 0.25 30662 5748.8 41601 0.609 32002 30147 41605 0.609 10322
-11921 41701 1.095 22215 24316 41705 1.095 7242.6
-14377 51401 0
35712 6923 51405 0
48486 11414 51501 0.25 37845 18974 51505 0.249 24365
-9199.8 51601 0.599 35266 26186 51605 0.597 12397
-16451 51701 1.073 23101 19705 51705 1.047 782.01
-20435 51801 1.588 5808.9 7262.8 51805 1.714 736.01
-7238.1 61401 0
39303 1914.6 61405 0
53234 7389.9 61501 0.248 39879 11918 61505 0.248 18441
-20707 61601 0.587 42568 22627 61605 0.678 4197.9
-23134 61701 1.317 26377 14789 61705 1.048 647.4
-13800 61801 1.683 4304.1
-47.106 61805 1.679
-4649.7
-4701.4 71401 0
40773
-1915.8 71405 0
58875 6873.5 71501 0.248 43557 11054 71505 0.247 18066
-30137 71601 0.578 40627 17821 71605 0.422
-2565.1
-34509 71701 1.127 30334 13708 71705 1.028
-5062
-15484 71801 1.653 8033.3
-125.11 71805 1.648
-5584
-1475.5 81401 0
42852
-2356.7 81405 0
60817 6802.8 81501 0.247 45583 10393 81505 0.247 11475
-36398 81601 0.569 42887 20114 81605 0.567 2393.3
-26136 81701 1.041 33074 14892 81705 1.01
-6146.9
-13873 81801 1.626 10705 803.77 81805 1.621
-6662.4
-1105.1
ENCLOSURE (1)
Residual Plus Operating Stresses for Penetration Nozzle at 43 Degree Angle Nozzle ID Nozzle OD Node aIove Hoop Stress Axial Stress Inches Noe boe pi)
(pi)
Noe above HopSrss) Ax siaSrs J-groove (s)ps)J-groove (p)(si 1401 0
42080 34501 1405 0
48401 27917 1501 0.26 37191 35969 1505 0.263 29296 23670 1601 0.741 32465 33711 1605 0.747 7889.5
-2198.1 1701 1.379 26591 28324 1705 1.39
-15958
-14903 1801 2.226 14699 16909 1805 2.244
-12285 711.5 11401 0
37759 32760 11405 0
45551 28512 11501 0.257 34256 34810 11505 0.26 31609 26483 11601 0.72 30732 33698 11605 0.726 11225 2992.4 11701 1.338 24795 27851 11705 1.349
-10695
-8832.3 11801 2.166 16574 19191 11805 2.182
-9690.5 1610.2 21401 0
28128 29286 21405 0
37542 26556 21501 0.255 28684 32973 21505 0.256 33326 31246 21601 0.699 26532 32179 21605 0.703 15169 9274 21701 1.297 21807 27244 21705 1.304
-1244.2
-3254.1 21801 2.104 11339 17267 21805 2.115
-3146.2 538.25 31401 0
22807 25060 31405 0
28468 19539 31501 0.251 23881 28682 31505 0.252 30775 30564 31601 0.677 24396 29871 31605 0.68 15446 7691 31701 1.255 18328 24482 31705 1.26 5053.4
-3887.4 31801 2.041 4169.6 12448 31805 2.048 3720.8
-4300.9 41401 0
22347 17993 41405 0
27967 17211 41501 0.248 25141 23224 41505 0.247 27286 22806 41601 0.657 26468 27283 41605 0.656 12627 480.58 41701 1.216 16925 21035 41705 1.216 6100.6
-8632 51401 0
25135 7642.1 51405 0
35807 18352 51501 0.243 32479 18671 51505 0.243 21.286 6453.6 51601 0.636 30656 24175 51605 0.635 9222.5
-9785.7 51701 1.178 21653 20552 51705 1.499 6393.6
-12003 51801 2.098
-498.65 2614.6 51805 1.919 4076.3
-7878.5 61401 0
31487 622.91 61405 0
43760 15252 61501 0.241 38664 11971 61505 0.239 9976
-19042 61601 0.619 37729 20776 61605 0.615 11389
-16157 61701 1.143 23934 15570 61705 0.899
-4871.3
-21039 61801 1.66 6378.7 2296.6 61805 1.861
-1905.9
-5965 71401 0
36215
-4261.5 71405 0
54224 17178 71501 0.237 41508 5831.9 71505 0.236 9263.3
-30644 71601 0.603 43041 16371 71605 0.487
-8499.5
-33204 71701 1.353 31936 12950 71705 1.106
-5049.2
-10138 71801 1.823 9032.7
-4133.3 71805 1.813
-5407.6
-1099 81401 0
41891
-1095.8 81405 0
56042 17699 81501 0.235 44223 7573.3 81505 0.234 3041
-38712 81601 0.589 42463 17261 81605 0.585
-5543.4
-24629 81701 1.216 33954 13208 81705 1.079
-12184
-11826 81801 1.782 11450
-3706.8 81805 1.771
-6575.6
-598.85
ENCLOSURE (1)
Residual Plus Operating Stresses for Penetration Nozzle at Zero Degree Angle Nozzle ID Nozzle OD Node Dstance Hoop Stress Axial Stress Node asoce Hoop Stress Axial Stress 141J-groove (psi)
(psi)
J-groove (psi)
(psi) 1401 0
47136 9035.8 1405 0
60275 5944.8 1501 0.251 44106 22607 1505 0.25 33457
-15547 1601 0.74 37472 27955 1605 0.604 10395
-23477 1701 1.068 20559 18755 1705 1.068
-2662
-14958 1801 1.674 1289 5355.9 1805 1.673
-3825.2
-278.77 11401 0
47134 9034.8 11405 0
60269 5937.5 11501 0.251 44107 22607 11505 0.25 33460
-15546 11601 0.74 37476 27953 11605 0.604 10403
-23472 11701 1.068 20564 18753 11705 1.068
-2665.7
-14960 11801 1.674 1296.9 5353.1 11805 1.673
-3827.9
-282.63 21401 0
47135 9034.9 21405 0
60269 5936.7 21501 0.251 44107 22605 21505 0.25 33461
-15543 21601 0.74 37476 27952 21605 0.604 10396
-23469 21701 1.068 20567 18752 21705 1.068
-2667.9
-14956 21801 1.674 1301.8 5352.1 21805 1.673
-3822.8
-278.56 31401 0
47135 9035.3 31405 0
60269 5936.6 31501 0.251 44106 22604 31505 0.25 33459
-15545 31601 0.74 37474 27952 31605 0.604 10396
-23473 31701 1.068 20565 18754 31705 1.068
-2667.5
-14961 31801 1.674 1298.6 5355 31805 1.673
-3825
-282.02 41401 0
47134 9035.5 41405 0
60269 5936.7 41501 0.251 44106 22605 41505 0.25 33459
-15546 41601 0.74 37473 27952 41605 0.604 10398
-23472 41701 1.068 20564 18754 41705 1.068
-2665.7
-14961 41801 1.674 1297.3 5355.6 41805 1.673
-3824.8
-282.82 51401 0
47135 9035.3 51405 0
60269 5936.6 51501 0.251 44106 22604 51505 0.25 33459
-15545 51601 074 37474 27952 51605 0.604 10396
-23473 51701 1.068 20565 18754 51705 1.068
-2667.5
-14961 51801 1.674 1298.6 5355 51805 1.673
-3825
-282.02 61401 0
47135 9034.9 61405 0
60269 5936.7 61501 0.251 44107 22605 61505 0.25 33461
-15543 61601 0.74 37476 27952 61605 0.604 10396
-23469 61701 1.068 20567 18752 61705 1.068
-2667.9
-14956 61801 1.674 1301.8 5352.1 61805 1.673
-3822.8
-278.56 71401 0
47134 9034.8 71405 0
60269 5937.5 71501 0.251 44107 22607 71505 0.25 33460
-15546 71601 0.74 37476 27953 71605 0.604 10403
-23472 71701 1.068 20564 18753 71705 1.068
-2665.7
-14960 71801 1.674 1296.9 5353.1 71805 1.673
-3827.9
-282.63 81401 0
47136 9035.8 81405 0
60275 5944.8 81501 0.251 44106 22607 81505 0.25 33457
-15547 81601 0.74 37472 27955 81605 0.604 10395
-23477 81701 1.06 20559 18755 81705 1.068
-2662
-14958 81801 1.674 1289 5355.9 81805 1.673
-3825.2
-278.77
ENCLOSURE (1) 2305 2206 (shelt)
S06t0 106' (she)II 80605 tshc &': te, 140'
'I0 416 ttsbe) tOIll Ntb Downhill Planc Nodes are 0's Series A
Uphill Plane Nodes are 80,000's Series 60005 80001 I
,hat&.
N N Tube Node Series: I'sat Nozzle ID, 's at NozzleO 22O5 Shell Node Series: S's at Shell ID (merged w/nibe OD) in weld region 6's at Shell ID above wveld region 15's at edge of shell section Node Numbers IsCreasC by 100 up she Icnglh of the tube and shell 815 Node Numbers Increase by I along the tube and shell radius 6!6 FIGURE 1 CEDM Nozzle Node Numbering Scheme
ENCLOSURE (1)
Vertical Distance from Weld Root to Lower End of Flaw Circles = Circumferential Flaws (Red: > Toe into weld or > Root) (Yellow: @ Toe) (Green: <
8 7
6 0
(_
0 z
5 4
3 2
1 0 -f
-5 55 115 175 235 295 355 Nozzle Circumference (Degrees)
FIGURE 2 cof