ML18153A099
| ML18153A099 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 01/14/1997 |
| From: | Mary Anderson IDAHO NATIONAL ENGINEERING & ENVIRONMENTAL LABORATORY |
| To: | Mclellan T NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML18153A100 | List: |
| References | |
| CON-FIN-J-2229 TAC-M95138, NUDOCS 9701230138 | |
| Download: ML18153A099 (8) | |
Text
.
TECHNICAL LETTER REPORT ON THE THIRD 10-YEAR INSERVICE INSPECTION INTERVAL REQUESTS FOR RELIEF
1.0 INTRODUCTION
FOR SURRY POWER STATION UNIT 2 VIRGINIA ELECTRIC AND POWER COMPANY DOCKET NUMBER:
50-281 By letter dated February 7, 1996, Virginia Electric and Power Company submitted Requests for Relief SR-14 through SR-17 for Surry Power Station, Unit 2~
In a letter dated August 29, 1996, the Nuclear Regula-tory Commission (NRC) requested additional information to support the evaluation of these requests.
In a letter dated October 11, 1996, the licensee submitted additional information to clarify their submittal.
The INEL staff has evaluated the subject requests for relief in the following section.
2.0 EVALUATION
.The Code of record for the Surry Power Station, Unit 2, third IO-year inservice inspection (ISi) interval is the 1989 Edition of the American Society of Mechanical Engineers (ASHE) Boiler and Pressure Vessel Code,Section XI.
The. information provided by the licensee in'support of the requests for relief from Code requirements has been evaluated, and the bases for disposition are documented below.
A.
Request for Relief SR-14, Examination Category C-F-1, Item cs~21, Cl.ass 2 Piping Circumferential Welds Code Requirement: Table IWC-2500-1, Examination Category C-F-1, Item CS.21 requires 100% volumetric and surface examina-tion of Class 2 piping circumferential welds as defined by Figure IWC-2500-7.
ENCLOSURE 2
e e
2 Licensee's Code Relief Request:
Pursuant to 10 CFR50.55a(g)
(S)(iii}, the licensee requested relief from performing the volumetric examination to the extent required by the Code on Weld 3"-CH-381-1503-3-04A.
Licensee's Basis for Requesting Relief (as stated):
"The component listed is a three inch pipe to valve body weld.
This weld is located on the upstream side of the discharge check valve
- for the "A" charging pump.
The component listed above has been examined to the extent practical as required by the Code.
Due to interferences from a branch connection and an adjacent valve body the reduction in coverage of volumetric examination is detailed in Table SR-14~11*
The required surface examination had no limita-tions. Figure SR-14-1 is provided detailing the limitations experi-enced."
Licensee's Proposed Alternative Examination (as stated):
"It is proposed that the examination completed at the reduced coverage be counted as meeting the Code preservice requirements."
Evaluation: The Code requires 100% volumetric and surface examina-tion of the subject Class 2 piping weld.
However, a branch connec-
. tion adjacent to the weld limits scanning from the pipe side and the valve configuration limits scanning from the valve side, precluding 100% volumetric examination. Therefore, the Code-required volumet-ric examination to the extent required by Code is impractical for the subject weld.
To satisfy this Code requirement, redesign of the weld joint would be necessary.
Imposition of this requirement would cause a considerable burden on the licensee.
The licensee obtained greater than 71% volumetric coverage of the Code-required examination volume.
This is a significant portion of the Code-required volume.
In addition, the licensee obtained 100%
surface examination coverage.
Based on the percent of Code-required volumetric coverage obtained, in combination with the surface 1Tables and figures are not included with this evaluation.
e 3
examination, it is reasonable to conclude that degradation, if present, would have been detected, providing reasonable assurance of structural integrity. Therefore, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
B.
Request for Relief SR-15, Examination Category C-A, Items Cl.IO and Cl.20, Class 2 Vessel Welds Code Requirement: Table IWC-2500-1, Examination Category C-A, Items Cl.IO and Cl.20 require 100% volumetric examination of Class 2 vessel shell circumfer.ential and head circumferential welds as defined by Figure IWC-2500-1.
Licensee's Code Relief Request:
Pursuant to 10 CFR50.55a(g)
(S)(iii), the licensee requested relief from performing the volumetric examinations to the extent required by the Code for Letdown Heat Exchanger Welds 1-01 and 1-02.
Licensee's Basis for Requesting Relief (as stated):
"One third of the welds listed above have been examined to the extent practical as required by the Code.
The examinations were limited due to interferences from the non-regenerative heat exchang-er inlet nozzle and a component support. Similar restrictions are expected for the remaining two thirds. The anticipated reduction in coverage of the volumetric examination is detailed in Table SR-15 2.
Figure SR-15-1 is provided detailing the limitations experi-enced."
Licensee's Proposed Alternative Examination (as stated):
"It is proposed that the examination completed at the reduced coverage and scheduled examinations at the coverage stated in Table SR-15-1 be counted as meeting the Code requirements."
Evaluation:
The Code re~uires 100% volumetric examination of the subject Class 2 vessel shell and head circumferential welds.
2Tables and Figures are not included *with this evaluation.
4 However, an inlet nozzle adjacent to the welds and the welded support limit scanning, precluding 100% volumetric examination.
Therefore, volumetric coverage to the extent required by the Code is impractical.
To satisfy the coverage requirements of the Code, design modifications would be required.
Imposition of this require-ment would cause a considerable burden on the licensee *
. The licensee completed greater than 71% volumetric examination on a.
one-third segment of each of the welds.
In addition, the licensee proposes to examine the remaining two-thirds of the subject welds to the extent practical. The licensee anticipates similar volumetric coverages for the remaining two-thirds of the welds.
The volume examined, in combination with that expected to be examined, is a significant portion of the Code-required volume.
As a result, it is reasonable to conclude that patterns of degradation, if existing, will be detected, providing reasonable assurance of the structural integrity of the subject welds.
The licensee proposes to volumetrically examine the subject welds to the extent practical. Considering the coverages obtained for the
- one-third segments of the welds examined and the anticipated similar coverages for the remaining two-thirds of the welds, reasonable assurance of structural integrity is provided. Therefore, it is recommended that rel i_ef be granted for the subject welds pursuant to 10 CFR 50.55a(g)(6)(i). If the actual volumetric coverage obtained for each weld does not meet or exceed 70% volumetric coverage, the licensee shall submit for additional relief.
C.
Request for Relief SR-16, Examination Category C-A. Item Cl.20, Class 2 Vessel Welds Code Requirement: Table IWC-2500-1, Examination Category C-A, Item Cl.20 requires 100% volumetric examination of Class 2 vessel head circumferential welds as defined by Figure IWC-250-0-1.
J
e 5
Licensee's Code Relief Request:
Pursuant to 10 CFR50.55a(g)
(S)(iii), the licensee requested relief from performing the volumetric examination to the extent required by the Code for the "A" Seal Water Injection Filter, Weld 1.01.
Licensee's Basis for Requesting Relief (as stated):
"The component listed above is the lower head to shell weld of the "A" seal water injection filter. One third, 0" to 12", of the component listed above has been examined to the extent practical as required by the Code.
Due to interferences from a support leg the reduction in coverage of the volumetric* examination is detailed in Table SR-16-13
- Figure SR-16-1 is provided detailing the limita-tions experienced.
Interferences were encountered when the remain-ing two thirds of the weld was examined during the second interval.
It is anticipated that the same limitations will exist when the remaining two thirds of the weld are examined during the third inspection interval."
Licensee's Proposed A)ternative Examination (as stated):
"It is proposed that the examination completed at the reduced coverage be counted as meeting the Code requirements.
The remaining two thirds will be examined to the extent practical. The estimated coverage for the remaining two thirds is expected to be similar to the coverage presented in Table SR-16-1."
Evaluation:
The Code requires 100% volumetric examination of the subject Class 2 vessel circumferential weld.
However, due to interferences from the support leg, ultrasonic scanning is limited, thereby precluding 100% volumetric examination. Therefore, volumet-ric coverage to the extent required by the Code is impractical for the subject weld.
To sat~sfy the coverage requirements of the Code, design modifications would be required.
Imposition of this require-ment would cause a considerable burden on the licensee.
The licensee obtained greater than 71% volumetric examination coverage on a one-third segment of the weld.
In addition, the licensee proposes to examine the remaining two-thirds of the subject 3Tables and figures are not included with this evaluation.
e 6
weld to the extent practical. The licensee anticipates similar volumetric coverages for the remaining two-thirds of the welds.
The volume examined, in combination with that expected to be examined, is a significant portion of the Code-required volume.
As a result, it is reasonable to conclude that patterns of degradation, if existing, will be detected, providing reasonable assurance of the structural integrity of the subject weld.
The licensee proposes to volumetrically examine the subject weld to the extent practical. Considering the coverage obtained for the one-third segment of the weld examined and the anticipated similar coverages for the remaining two-thirds of the weld, reasonable assurance of structural integrity is provided. Therefore, it is recommended that.relief be granted for the subject weld pursuant to -
10 CFR 50.55a{g){6){i). If the actual volumetric coverage obtained does not meet or exceed 70% volumetric coverage, the licensee shall submit for additional relief.
D.
Request for Relief SR-17, Examination Category 8-A, Item 81.40, Reactor Pressure Vessel Flange-to-Head Weld Code Requirement: Table IWB-2500-1, Examination Category 8-A, Item 81.40 requires 100% volumetric and surface examination of the reactor pressure vessel head-to-flange weld as defined by Figure IWB-2500-5.
Licensee's Code Relief Request:
Pursuant to 10 CFR~0.55a(g)
(S)(iii), the licensee requested relief *from performing the volumetric examination to the extent required by the Code for reactor pressure vessel head-to-flange Weld 1-01.
Licensee's Basis for Requesting Relief (as stated):
"The component listed above is the reactor head to flange weld.
One third, O" to 179",.of the component listed above.has been examined to the extent practical as required by the Code.
Due to interfer-
7 ences from a lifting lug and geometry of the weld the reduction in coverage of the volumetric examination is detailed in Table SR-17 4.
Figures SR-17-1 and SR-17-2 are provided detailing the limita-tions experienced.
The surface examination had no limitations.
"Limitations were encountered when the remaining two thirds of the weld was examined during the second interval. It is anticipated that the same limitations will exist when the remaining two thirds of the weld are examined during the third interval."
Licensee's Proposed Alternative Examination (as stated):
"It is proposed that the examination completed at the reduced coverage be counted as meeting the Code requirements.
The remaining two thirds will be examined to the extent practical. The estimated coverage for the remaining two thirds is expected to be similar to coverage presented in Table SR-17-1 for 0" to 179"."
Evaluation: The Code requires 100% volumetric and surface examina-tion of the reactor pressure vessel head-to-flange weld.
- However, due to interferences from a lifting lug and the head-to-flange geometric configuration, ultrasonic scanning is limited, thereby precluding 100% volumetric examination. Therefore, volumetric.
coverage to the extent required by the Code is impractical.
To satisfy the coverage requirements of the Code, design modifications
- would be required.
lmpositi~n of this requirement would cause a considerable burden on the licensee.
The licensee obtained greater th~n 87% volumetric examination coverage on a one-third segment of the weld.
In addition, the licensee obtained. 100% surface examination*coverage for the segment examined.
The licensee proposes to examine the remaining two-thirds of the subject weld to the extent pr~ctical and anticipates similar volumetric and surface examination coverages for the remaining two-thirds of the welds.
The volume examined, in combination with that expected to be examined, is a significant portion of the Code-required volume.
As a result, it is reasonable to conclude that 4Tables and Figures are not included with this evaluation.
8 patterns of degradation, if existing, will be detected, providing reasonable assurance of the structural integrity of the subject weld.
The licensee proposes to volumetrically examine the subject weld to the extent practical. Considering the coverage obtained for the one-third segment of the weld examined and anticipated similar coverages for the remaining two-thirds of the weld, which includes 100% surface examination, reasonable assurance of structural integ-rity is provided. Therefore, it is recommended that relief be granted for the subject weld pursuant to 10 CFR 50.55a(g)(6)(i).
If the actual volumetric coverage obtained does not meet or exceed 70%
volumetric coverage, the licensee shall submit for additional relief.
3.0 CONCLUSION
The INEL staff has reviewed Virginia Electric and Power Company's
. Requests for Relief SR-14 through SR-17 for. Surry Power Station, Unit 2.
For Request for ~elief SR-14, it has been determined that the licensee has performed the examinations to the extent practical. Based on the significant coverage obtained, it has been concluded that reasonable assurance of structural integrity is provided. Therefore, it is recom-mended that for Request for Relief SR-14, relief be granted pursuant to 10 CFR 50.55a(g)(6)(i}.
For Requests for Relief SR-15, SR-16 and SR-17, the licensee proposes to examine the subject welds to the extent practical. Based on the coverage obtained for the weld segments examined, in combination with the estimat-ed coverages for the remaining portions that will be examined, reasonable assurance of structural integrity is provided. Therefore, it is recom-mended that for Requests for Relief SR-15 through SR-17, relief be granted pursuant to 10 CFR 50.55a(g}(6)(i}.
If, following the completion of the examinations, the actual volumetric coverage obtained does not meet or exceed the coverage(s} specified in the evaluations, the licensee shall submit for additional relief.
l