ML18152A253
| ML18152A253 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 04/14/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18152A254 | List: |
| References | |
| NUDOCS 9404220091 | |
| Download: ML18152A253 (22) | |
Text
ATTACHMENT 1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE SECOND TEN-YEAR INTERVAL INSERVICE INSPECTION ADDITIONAL REQUESTS FOR RELIEF
1.0 INTRODUCTION
FOR VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNITS 1 AND 2 DOCKET NUMBERS:
50-280, AND 50-281 The Technical Specifications for Surry Power Station, Units 1 and 2 state that the inservice inspection and testing of the American Society of Mechanical Engineers (ASME) Code Cl ass 1, 2, and 3 components sha 11 be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable Addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).
10 CFR 50.55a(a) (3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed alternatives would provide an acceptable level of qu~lity and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulties without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4),
ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry, and materials of construction of the components.
The regulations require that inservice examination of components and system pressure tests conducted during the first ten-year interval comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) on the date twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein.
The applicable edition of Section XI of the ASME Code for the Surry Power Station, Units 1 and 2 second ten-year inservice inspection (ISi) interval is the 1980 Edition, through Winter 1980 Addenda.
The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME
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Code incorporated by reference in 10 CFR 50.SSa(b) subject to the limitations and modifications listed therein and subject to Commission approval.
Pursuant to 10 CFR 50.SSa(g)(S), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement.
After evaluation of the request, pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law, will not endanger life, property, or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed.
In a letter dated August 11, 1993, and two letters dated October 8, 1993, the licensee, Virginia Electric and Power Company, submitted requests for relief from Code requirements that were determined to be impractical, for the Surry Power Station, Units 1 and 2 second ten-year interval inservice inspection (ISI) program plan.
2.0 EVALUATION AND CONCLUSIONS The staff, with technical assistance from its contractor, the Idaho National Engineering Laboratory (INEL), has evaluated the information provided by the licensee in support of its additional requests for relief regarding the second ten-year ISi interval for Surry Power Station, Units 1 and 2.
Based on the information submitted, the staff adopts the contractor's conclusions and recommendations presented in the Technical Evaluation Summary attached. Pursuant to 10 CFR 50.55a(g)(6)(i), relief is granted for Requests for Relief SR-005 (Units 1 and 2), No. 24 (Unit 2), and SR-021 Parts 1, 2, 3, and 4 (Unit 2). Such relief is authorized by law and will not endanger life, property, or the common defense and security, and is otherwise in the public interest. Relief has been granted giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Requests for Relief No.
24 (Unit 2), Nos. 25 and 26 (Unit 2), Nos. 28 and 29 (Unit 1) are denied.
2
e ATTACHMENT 2 TECHNICAL EVALUATION
SUMMARY
OF THE SECOND TEN-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF
1.0 INTRODUCTION
FOR VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNITS 1 AND 2 DOCKET NUMBERS:
50-280 AND 50-281 By a letter dated August 11, 1993 and two letters dated October 8, 1993, the licensee, Virginia Electric and Power Company, requested relief from the requirements of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Section XI.
The Idaho National Engineering Laboratory (INEL) staff has evaluated the information provided by the licensee in support of these requests in the following section.
2.0 EVALUATION The information provided by the licensee in support of the requests for relief has been evaluated and is documented below. Surry Power Station's second IO-year inservice inspection (ISI) interval began December 22, 1982 for Unit I and May 1, 1983 for Unit 2.
Based on these dates, the applicable edition of Section XI of the ASME Code for the second IO-year ISI interval is the 1980 Edition through Winter 1980 Addenda (80W80) for both units.
To complete the Code-required examinations for the interval, the second IO-year ISI interval was extended by one year for both units as permitted by the Code.
e A.
Request for Relief No. SR-005, 10/8/93 Revision {Units 1 and 2),
Examination Category B-B, Items B2.11 and B2.12, Pressurizer Circumferential and Longitudinal Shell-to-Head Welds Code Requirement:
Table IWB-2500-1, Examination Category B-B, Items B2.11 and B2.12, require 100% volumetric examination as defined by Figures IWB-2500-1 and 2, respectively of all pressurizer circumferential shell-to-head welds and one foot of an intersecting longitudinal weld.
Licensee's Code Relief Request:
The licensee requested relief from performing the volumetric examination of circumferential shell-to-head Weld 1-07 and longitudinal shell-to-head Weld 1-15 on Unit 1 Pressurizer
- l-RC-E-2, and circumferential shell-to-head Weld 1-07 and longitudinal shell-to-head Weld 1-02 on Unit 2 Pressurizer #2-RC-E-2.
A summary of the coverage was provided by the licensee as follows:
1-07
( 45°)
1 51%
88%
79%
79%
(60°)
1 93%
35%
79%
79%
1-15* ( 45°)
1 54%
33%
26%
26%
(60°)
1 74%
54%
26%
26%
1-07
( 45°)
2 16%
3.6%
26%
26%
(60°)
2 28%
47%
26%
26%
1-02**(45°)
2 100%
100%
100%
100%
(60°)
2 100%
100%
100%
100%
-- Coverage of accessible length (approx. 5 inches)
- -- Coverage of accessible length (approx. 7.5 inches) 2&5 -- Axial scan 7&8 -- Circumferential scans 2
Licensee's Stated Basis for Requesting Relief:
"The pressurizer is covered with an insulation support ring (Attachment 1).
8 The insulation support ring is 6 inches wide where it interferes with the examination. This ring prevents complete volumetric coverage of both the upper shell-to-head weld and [the] intersecting longitudinal weld. Total removal of the insulation support ring is considered impractical due to the high anticipated exposure levels estimated at 18.4 man-rem.
Partial removal of the support ring at the mechanical connection would allow some increase in coverage near the mechanical connection, where the support ring could be spread apart.
However, the actual areas of the weld made accessible to this coverage is estimated to be very small in relation to the overall weld length, because the insulation support structure is rigid, interconnected with cross supports, and welded to the supports for the safety valves and power operated relief valves.
The intersection of the circumferential shell-to-head and longitudinal welds is physically located behind one of these supports.
Examination coverage of this area would not be improved by partial removal at the mechanical connection.
"Any removal of the mechanical connection and spreading apart of the insulation support structure would increase the risk of misalignment problems and warping of the structure. This risk coupled with the marginal increase in examination coverage, makes partial removal of the insulation support structure also impractical.
"No extended beam path examinations can be performed, since the pressurizer is a clad vessel."
Licensee's Proposed Alternative Examination:
No alternative to the Code requirements was proposed.
The Code-required volumetric examinations were performed to the extent practical.
Evaluation: The Code-required volumetric examination of the pressurizer circumferential and longitudinal shell-to-upper head welds is restricted by insulation support rings and support brackets that obstruct access to the examination area.
The licensee estimates that complete removal of these obstructions would require in excess of 18 man-rem per unit.
Partial removal by spreading the rings at the mechanical connections is possible, but would not increase coverage significantly. Therefore, volumetric examination of the subject welds is impractical to perform to the extent required by the Code.
In order to meet the Code requirements,
- a.
Not included in this report.
3
B.
e e
the obstructions would have to be removed.
Imposition of this requirement would cause excessive radiation exposure, and would cause a considerable burden on the licensee.
Based on the licensee's estimates, it appears that a reasonable portion of the welds is being examined.
In addition, the lower head-to-shell welds are also receiving the Code-required volumetric examination.
Since these welds are similar in design and are exposed to similar conditions, the examination of these welds provides additional assurance of structural integrity of the pressurizer upper shell-to-head welds and reasonable assurance that the operational readiness of the pressurizers has been maintained.
Considering the impracticality of performing the 100% volumetric examination of the subject welds, and the extent of examinations that were performed on the pressurizers, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
Request for Relief No. 28 {Unit 1) and No. 25 {Unit 2), Subarticle IWA-4400 and Paragraph IWA-5214, System Pressure Testing for Repairs Made by Welding Code Requirement:
Article IWA-4400, Pressure Test, states that after repairs by welding on the pressure retaining boundary, a system pressure test shall be performed in accordance with IWA-5000.
Paragraph IWA-5214(b} for repairs and replacements states:
"The test pressure and temperature for a system hydrostatic test subsequent to the component repair or replacement shall comply with the system test pressure and temperature specified in IWB-5222, IWC-5222, and IWD-5223, as applicable to the system which contains the repaired or replaced components."
Licensee's Code Relief Request:
The licensee requested relief from performing the Code-required system hydrostatic pressure test following welded repairs or installation of replacement items by welding.
4
Licensee's Stated Basis for Requesting Relief:
"IWA-4000 and IWA-5214 require a hydrostatic pressure test in accordance with IWB-5000, IWC-5000, or IWD-5000 following welded repairs or installation of replacement items by welding.
"In past situations, our utility has been required to defer or ask relief from ASME Section XI hydrostatic tests following repair or replacement activities due to various reasons, which identified a basis of impracticality. This ranged from boundary valve isolation problems to incorporation of the steam generators in the test boundary.
These situations have necessitated, in some cases, immediate communication with, and approval from, the NRC so that start-up delays or LCO conditions could be avoided. Test deferrals, like those associated with the steam generator, eventually must be conducted, and are considered inordinately burdensome, consideri~g that the IO-year hydrostatic tests have been eliminated for Class I and 2 systems with the approval in Regulatory Guide 1.147, Code Case N-498, "Alternative Rules for IO-Year Hydrostatic Pressure Testing for Class 1 and 2 Systems,Section XI, Division 1." The Code has recognized that alternative rules should be available to hydrostatic testing to allow an option to the owner.
They have developed Code Case N-416-1, "Alternative Pressure Test Requirement for Welded Repairs or Installation of Replacement Items by Welding."
This Code Case as of this writing has been passed by Section XI and has been,sent up to Main Committee for approval. Accordingly, it is considered impractical to maintain only the hydrostatic test option."
Licensee's Proposed Alternative Examination:
As an alternative to the Code-require hydrostatic pressure test, the licensee has stated:
- iin situations following welded repairs or installation of replacement items by welding, when the hydrostatic test required by IWA-4000 or IWA-5214 is not performed, the following alternative requirements shall be applied:
- 1) NOE shall be performed in accordance with the methods *nd acceptance criteria of the applicable Subsection of the 1989 Edition of ASME Section III. Additionally, where no construction NOE is required on partial and full penetration welds greater than 1 inch nominal pipe size, these welds shall receive a surface examination as a minimum.
- 2) Prior to, or immediately upon return to service, a VT-2 visual examination shall be performed in conjunction with a system pressure test, using the 1989 Edition of Section XI, in accordance with IWA-5000, at nominal operating pressure and temperature.
- 3) Use of the alternative shall be documented on the NIS-2 Form.
"If the original Code Case N-416 was used to defer a Class 2 hydrostatic test, the deferred test may be eliminated when the requirements of this alternative testing have been met.
11 5
e Evaluation:
The Code requires a system hydrostatic test for repairs made by welding on pressure retaining systems.
The licensee is requesting relief from the Code-required system hydrostatic pressure test for repairs made by welding, and cites Code Case N-416 and N-498 to support this request.
The NRC has approved both of these Code Cases by incorporation into Regulatory Guide 1.147, Revision 9.
Code Case N-416 allows deferral of the hydrostatic test for Class 1 and 2 systems until the regularly scheduled system hydrostatic test for repair areas that cannot be isolated.
Code Case N-498 eliminates routine hydrostatic pressure testing during the IO-year ISi interval under certain conditions.
This request for relief is generic without a listing of the specific components for which relief is requested.
In addition, the impracticality or the burden of the Code requirement has not been justified. Since the regulations do not provide for the granting of generic relief requests, it is recommended that relief be denied.
C.
Request for Relief No. 29 (Unit 1} and No. 26 (Unit 2}, Examination Category B-P, Item B15.51, System Hydrostatic Test, as Modified by Code Case N-498, for Class 1 Safety Injection (SI} Piping Code Requirement:
Table IWB-2500-1, Examination Category B-P, Item B15.51, requires a system hydrostatic test in accordance with IWB-5222 for Class 1 pressure retaining piping.
6
e Licensee's Code Relief Request:
The licensee requested relief from performing the Code-required system hydrostatic test, as modified by Code Case N-498, for Class 1 SI piping between the following valves:
Unit 1 l-Sl-79, l-Sl-235, and l-Sl-241 l-Sl-82, l-Sl-236, and l-Sl-242 l-Sl-85, l-Sl-237, and l-Sl-243 l-Sl-88 and l-Sl-238 l-Sl-91 and l-Sl-239 l-Sl-94 and l-Sl-240 Unit 2 2-Sl-79, 2-SI-235 and 2-Sl-241 2-Sl-82, 2-Sl-236 and 2-Sl-242 2-SI-85, 2-SI-237 and 2-Sl-243 2-Sl-88, 2-SI-226, 2-SI-227 and 2-Sl-238 2-Sl-91, 2-Sl-226, 2-SI-227 and 2-Sl-239 2-Sl-94, 2-SI-226, 2-Sl-227 and 2-Sl-240 Licensee's Stated Basis for Requesting Relief:
"The double check valve combination prevents pressurization of the area in between the check valves when conducting pressure tests on the primary system."
Licensee's Proposed Alternative Examination:
During performance of the Class 1, Code Case N-498 pressure test, the areas described above will be tested at a pressure 100 psig less than the RCS normal operating pressure to prevent any "uncontrollable dilution" of the primary system during testing. This alternative is to replace the provisions listed in the current Relief Request 1 of the second IO-year interval ISi programs for Surry Units 1 and 2.
Evaluation: The Code requires a system hydrostatic test of Class 1 piping at a test pressure above normal operating pressure.
Code Case N-498, "Alternative Rules for IO-Year Hydrostatic Pressure Testing for Class 1 and 2 Systems,Section XI, Division l," provides alternatives to the system hydrostatic test as follows:
(1) "A system leakage test {IWB-5221) shall be conducted at or near the end of each inspection interval, prior to start-up.
7
D.
(2) The boundary subject to test pressurization during the system leakage test shall extend to all Class 1 pressure retaining components within the system.
(3) Prior to performing VT-2 visual examination, the system shall be pressurized to nominal operating pressure for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for insulated systems and 10 minutes for noninsulated systems.
The system shall be maintained at nominal operating pressure during the performance of the VT-2 visual examination."
Code Case N-498 has been approved by the NRC by incorporation into Regulatory Guide 1.147, Revision 9, "Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1."
In SERs dated January 24, 1984 (Unit 1) and January 24, 1986 (Unit 2),
relief was granted based on a proposed alternative test pressure of 2335 psig, which appears to be above normal operating pressure. This previous proposal demonstrates that pressure testing of the subject portions of the Class I SI system is practical, and should still be considered acceptable.
The licensee is using Code Case N-498 as an alternative to the IO-year system hydrostatic test, which is acceptable if all the requirements of the Code Case are met.
However, the licensee has proposed an alternate pressure test at 100 pounds less than operating pressure, which does not meet the alternative requirements of the Code Case.
This should not be considered acceptable.
If the requirements of the Code Case can not be met, the Code-required system hydrostatic test should be performed.
Therefore, it is recommended that relief be denied.
Request for Relief No. 24 (Unit 2). IWA-4400, Pressure Test Requirements for Repairs of Pressure Retaining Components by Welding Code Requirement:
IWA-4400(a) requires a system hydrostatic test in accordance with IWA-5000 for repairs made by welding on the pressure retaining boundary.
8
Licensee's Code Relief Request:
The licensee requested relief from performing the Code-required hydrostatic pressure testing following repair by welding for the following Class 2 components in the main steam (MS) and feedwater (FW) systems.
Valve 2-FW-30*
3"-WAPD-109-601 A
Valve 2-MS-84 6"-SHP-145-601 A
Valve 2-MS-119 4"-SHP-138-601 B
Valve 2-MW-61*
3"-WAPD-111-601 B
Valve 2-MS-155 6"-SHP-147-601 C
- - Downstream weld only Licensee's Stated Basis for Requesting Relief:
"Surry Unit 2 utilized Code Case N-416, Alternate Rules for Hydrostatic Testing of Repair or Replacement of Class 2 Piping,Section XI, Division 1, on the components identified above.
This Code Case defers the hydrostatic test required by IWA-4400 of ASME Section XI until the next regularly scheduled system hydrostatic test (IWC-5000) for that system.
"The identified components were replaced under the rules of ASME Section XI.
IWA-4400 of the Code requires that a hydrostatic test be conducted on certain welded repairs or replacements. These replacements cannot be hydrostatically tested without also hydrostatically testing the connecting steam generator, as no intermediate isolation exists.
"Prior to NRC and Code approval of Code Case N-416, relief requests were routinely written and approved for these type situations. The relief requests were based upon the difficulties associated with steam generator hydrostatic testing. The test cannot be conducted at ambient conditions due to fracture prevention concerns associated with the Surry steam generators. The Surry steam generators are required to be a minimum of 150 degrees Fon the secondary side and a minimum of 180 degrees Fon the primary side, which results in difficult monitoring and controlling requirements. Additionally, normal problems, such as test boundary isolation, internal boundary leakage, placing spring hanger stops for dead weight loading concerns, and test pump size requirements further increase the difficulties associated with this particular test. The test pressure of 1356 psig also requires gagging or removal of Main Steam Safety valves, which initially lift at 1085 psig.
Some examples of previous correspondence requesting relief and approval follow:
9
VEPCO Letter/ Date Serial# 88-725/ 1/9/89 Serial# 89-636/ 8/29/89 Serial# 87-056/ 2/13/87 e
NRC Letter/ Date Serial# 89-278/ 4/7/89 Serial# 89-734/ 10/1/89 Serial# 88-419/ 6/17/88 11When Code Case N-416 was incorporated into Regulatory Guide 1.147,
'lnservice Inspection Code Case Acceptability-ASME,Section XI, Division l', relief requests were no longer needed, since the hydrostatic test was deferred to the end of the interval hydrostatic test described in table IWC-2500-1.
This appeared to be the minimum hydrostatic testing that could be achieved for the steam generators. Recently in Revision 9 of Regulatory Guide 1.147, you approved Code Case N-498, "Alternative Rules for IO-Year Hydrostatic Pressure Testing for Class 1 and 2 SystemsSection XI, Division 1". This Code Case allows testing of the Class 2 steam generators at nominal operating pressure.
As a result, no hydrostatic test is now required by ASME Section XI on these components under normal circumstances, when incorporating Code Case N-498.
The hydrostatic test of Code Case N-416 is still required to be performed, however.
As described before, the components identified above can only be hydrostatically tested by additionally testing the connecting steam generator. Requiring a full steam generator test only for these replacement activities is considered impractical, due to the difficulties of the test described previously."
Licensee's Proposed Alternative Examination:
The requirements described in Code Case N-416 (a volumetric examination of the full penetration welds and a visual examination (VT-2) at nominal operating pressure) was previously performed and deemed acceptable.
Evaluation:
IWA-4400 requires a hydrostatic pressure test per IWA-5000 for repairs on the pressure-retaining boundary that are made by welding.
For the lines contained in this request, the licensee stated that the hydrostatic pressure test cannot be performed without pressurizing the steam generators.
The licensee also cites difficulties isolating the test boundary, test pump size requirements, concerns with placing spring hanger stops for dead weight loading, and the gagging of valves as the reason for the impracticality.
Exposing the steam generators to excess cycles can reduce their life expectancy. Therefore, the inability to isolate the steam generators from the repair area makes the Code-required hydrostatic pressure test impractical to perform.
In order to perform the system hydrostatic test, the subject system would have to be modified to provide a means of 10
e e
i so 1 at i ng the steam generators.
In,pos it ion of this requirement on the licensee represents a significant burden.
In lieu of the system hydrostatic pressure test, the licensee performed a volumetric examination and a VT-2 visual examination during pressure testing at operating pressure. This alternative ensures the structural integrity of the repair welds and provides reasonable assurance of the operational readiness of the system. Therefore, it is recommended that relief be granted pursuant to 10 CFR 50.55a{g){6){i).
E.
Request for Relief No. SR-021 -- Part 1 {Unit 2), Examination Category 8-A, Item 81.40, Reactor Pressure Vessel {RPV) Head-to-Flange Weld Code Requirement:
Table IW8-2500-l, Examination Category 8-A, Item 81.40, requires 100% surface and volumetric examinations for the RPV head-to-flange weld as defined by Figure IW8-2500-5.
Licensee's Code Relief Request:
The licensee requested relief from performing the volumetric examination of RPV head-to-flange,Weld 1-01
{Drawing# 11548-WMKS-RC-R-l.2) to the extent required by the Code.
The examination coverage achieved is summarized below.
These estimates are based on 1991 and 1993 examination results.
11
e Ultrasonic Examination Coverage Estimates
- ijg)~qf w.J!li/!l!i il!!~~ln!i
1li!;l:j:;:: i!Jl:ii
- at~'it1Wf1¥Bt: ()(?
m\\An.g:l\\ij) %\\@:% tot.re.¢t::ibd l Je~:Ht:flM/fExfilW::::::::: 0 97 Weld Interference n----4-5--+----2---+---2-8_W_e_l_d-----1 from flange
- ------------+-------- and 1 i ft i ng 1 ___
4_5 ______ 5 _____ 9_7_W_e_l_d __ 1 ugs. Li ft i ng 45 7 97 Weld lugs are u----4-5-------8-----9-7_W_e_l_d---i approx. 5" in 11---------------------~ width. 60 2 14 Weld 60 5 97 Weld 60 7 97 Weld 60 8 97 Weld 45 & 60 2 36 Base 45 & 60 5 96 Base 45 & 60 7 84 Base 45 & 60 8 84 Base 0 84 Base Scan Direction Key: 2 - Axial scan from flange side 5 - Axial scan from head side 7 - Circumferential scan, clockwise (looking down on head) 8 - Circumferential scan, counterclockwise (looking down on head) Licensee's Stated Basis for Reguesting Relief: "The 1980 Edition, Winter 1980 Addenda (inclusive) of ASME Section XI in Table IWB-2500-1 and IWC-2500-1 does not allow any limitations to the required volumetric [and surface] examinations. Code Case N-460, Alternative Examination Coverage for Class 1 and Class 2 Welds, allows a reduction in coverage, if it is less than 10%. "The components listed above have been examined to the extent practicable as required by the Code. Due to interferences of other components or weld joint geometry the reduction in coverage for the listed component was greater than 10%. Table SR-021-1 [paraphrased above], 2, 3, 4, and 5 [not applicable] are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided. Alternative components were not substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type of configurations." 12
e e Licensee's Proposed Alternative Examination: No alternative to the Code requirements was proposed. The Code-required volumetric examination was performed to the extent practical. Evaluation: The Code requires 100% surface and volumetric examination of the RPV head-to-flange weld. However, volumetric examination of the subject weld is impractical to perform the extent required by the Code due to limitations caused by component geometry and adjacent lifting lugs. Design modifications of the RPV head would be needed to improve access to the weld and complete the Code-required volumetric examination. Imposition of this requirement would cause a considerable burden on the licensee. The licensee has examined a significant portion of the weld and adjacent base metal. In addition, the Code-required surface examination has been completed. Therefore, any existing pattern of degradation should have been detected by the limited examination, and reasonable assurance of the RPV's operational readiness has been maintained. Considering the impracticality of meeting the Code requirements and the extent of examinations that were completed, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i). F. Request for Relief No. SR-021 (Unit 2) -- Part 2, Examination Category B-J, Item B9.ll, Reactor Coolant System Circumferential Butt Welds Code Requirement: Table IWB-2500-1, Examination Category B-J, Item B9.ll, requires 100% surface and volumetric examinations, as defined by Figure IWB-2500-8, for circumferential welds 4 inch nominal pipe size (NPS) or greater. 13 _j
e e Licensee's Code Relief Reguest: The licensee has requested relief from performing the 100% volumetric examination of the following circumferential welds in the reactor coolant system. Examination Coverage Estimates 1-10 100% 60% 100% Pipe-to-elbow joint (2/11548-WMKS-RC-10-1} configuration 1-12 56% 86% 100% Pipe-to-RCP (3/11548-WMKS-RC-10-1} configuration* 1-13 86% 56% 100% Pipe-to-valve (3/11548-WMKS-RC-10-1} configuration* 1-14 56% 86% 100% Pipe-to-valve (3/11548-WMKS-RC-10-1) configuration* 1-22 99% 61% 100% Valve-to-elbow (3/11548-WMKS-RC-10-1) configuration* Scan Direction and Coverage Key:
- - 2T calibration achieved to maximize coverage.
2 - Axial scan, 180° from isometric flow direction. 5 - Axial scan, the same direction as isometric flow direction. 7 - Circumferential scan, clockwise. 8 - Circumferential scan, counterclockwise. Licensee's Stated Basis for Reguesting Relief: "The 1980 Edition, Winter 1980 Addenda (inclusive) of ASME Section XI in Table IWB-2500-1 and IWC-2500-1 does not allow any limitations to the required volumetric [and surface] examinations. Code Case N-460, Alternative Examination Coverage for Class 1 and Class 2 Welds, allows a reduction in coverage, if it is less than 10%. The components listed above have been examined to the extent practicable as required by the Code. Due to interferences of other components or weld joint geometry the reduction in coverage for the listed component was greater than 10%. Table SR-021-2 [paraphrased above], 1, 3, 4, and 5 [not applicable] are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided. Alternative components were not substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type of configuration." 14
Licensee's Proposed Alternative Examination: No alternative to the Code requirements was proposed. The Code-required volumetric examinations were performed to the extent practical. Evaluation: The Code requires 100% surface and volumetric examinations of at least 25% of Class I circumferential welds greater than or equal to 4 inch NPS. As reported by the licensee, volumetric examination of the subject welds was limited in at least one of the required scan directions by physical obstructions or component configuration. These limitations make 100% volumetric examination impractical to perform on the subject welds. In order to complete the volumetric examination to the extent required by the Code, design modifications to the weld joints would be needed to provide access to 100% of the examination area. Imposition of this requirement would cause a considerable burden on the licensee. "The licensee has completed a significant portion {>50%) of the Code-required volumetric examinations and 100% of the Code-required surface examinations. In addition, these welds are a small portion of a much larger population of welds that are receiving complete volumetric examination. Therefore, generic degradation would have been detected and reasonable assurance of the operational readiness.of the subject piping system has been provided. Considering the impracticality of performing the 100% volumetric examination and the extent of examinations that are being performed on these and similar welds, it is recommended that relief be granted pursuant to 10 CFR 50.55a{g){6){i). 15 ~-1
G. Request for Relief No. SR-021 (Unit 2) -- Part 3, Examination Category C-A, Items Cl.IO and Cl.30, Steam Generator Circumferential Shell and Tubesheet-to-Shell Welds Code Requirement: Table IWC-2500-1, Examination Category C-A, Item Cl.IO requires 100% volumetric examination of the steam generator circumferential shell welds as defined by Figure IWC-2500-1. Examination is limited to welds at gross structural discontinuities. Item Cl.30 requires 100% volumetric examination of the steam generator tubesheet-to-shell welds as defined by Figure IWC-2500-2. For both items, examinations include essentially 100% of the weld length. In the case of multiple vessels of similar design, size, and service (such as steam generators and heat exchangers), the required examinations may be limited to one vessel, or distributed among vessels. Licensee's Code Relief Request: The licensee has requested relief from performing the 100% volumetric examination of tubesheet-to-shell Weld 2-02 on all three steam generators (Drawing Nos. 11548-WMKS-RC-E-IA.1, -18.1 and -IC.I), and circumferential shell Weld 2-06 on Steam Generators A and C (Drawing Nos. 11548-WMKS-RC-E-IA.l and -IC.I). The required examinations are distributed among the multiple steam generators. Estimates of the examination coverage achieved are based on the 1988 and 1993 examination results and are listed below. 16
Examination Coverage Estimates 111ij111 1 11 1i 1 i~11:111:1 11~:;:~! 1 111111111111 1 1111:111 1r~,11:~, 1 ~ 11~ 1 ~ 1 1:i:1:::i:1n1111 11 111 1! 11 1~:1:i 1 ~1:1::riiiil'iij 111 11111 1 11: 11 1111 111
- 1:
1111 1 2-02 0 96 Hand holes, 2-06 45&60 2 96 bl owdown 45&60 5 80 piping, and 45&60 7 96 nozzles 45&60 8 96 0 45&60 45&60 45&60 45&60 2 5 7 8 96 96 83 96 96 Insulation
- supports, welded pads, and nozzles 2 -
Axial scan transition/tubesheet side of weld 5 - Axial scan shell side of weld 7 - Circumferential scan, clockwise. 8 - Circumferential scan, counterclockwise. Licensee's Stated Basis for Requesting Relief: "The 1980 Edition, Winter 1980 Addenda (inclusive) of ASME Section XI in Table IWB-2500-1 and IWC-2500-1 does not allow any limitations to the required volumetric [and surface] examinations. Code Case N-460, Alternative Examination Coverage for Class 1 and Class 2 Welds, allows a reduction in coverage, if it is less than 10%. "The components listed above have been examined to the extent practicable as required by the Code. Due to interferences of other components or weld joint geometry the reduction in coverage for the listed component was greater than 10%. Table SR-021-3 and -4 [paraphrased above] and 1, 2, and 5 [not applicable] are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided. Alternative components were not substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type of configurations." Licensee's Proposed Alternative Examination: No alternative to the Code requirements was proposed. The Code-required volumetric examinations were performed to the extent practical. 17
Evaluation: The Code requires volumetric examination of essentially 100% of the length of one of the subject welds. However, physical obstructions prevent access to 100% of the required examination volume, and make the Code requirements impractical to meet. To meet the Code requirements, the steam generators would have to be modified to eliminate the obstructions. This would cause a considerable burden on the licensee. The licensee has examined the entire Code-required volume of a significant portion (>80%) of the length of each weld. Therefore, any existing pattern of degradation should have been detected by the limited examination, and reasonable assurance of the steam generators operational readiness has been maintained. Considering the impracticality of meeting the Code requirements and the extent of examinations that were completed, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i). H. Request for Relief No. SR-021 (Unit 2) -- Part 4, Examination Category C-A. Item Cl.20, Residual Heat Removal Heat Exchanger (RHRHX) Circumferential Head Welds Code Requirement: Table IWC-2500-1, Examination Category C-A, Item Cl.20 requires 100% volumetric examination of the RHRHX circumferential head welds as defined by Figure IWC-2500-1. Examination includes essentially 100% of the weld length. In the case of multiple vessels of similar design, size, and service (such as steam generators and heat exchangers), the required examinations may be limited to one vessel, or distributed among vessels. 18
e Licensee's Code Relief Request: The licensee has requested relief from performing the 100% volumetric ~xamination of RHRHX circumferential head Welds 1-AOl (RHRHX # 02-RH-E-lA) and 1-BOl (RHRHX # 02-RH-E-lB). The required examinations are distributed among two heat exchangers. The estimates of the coverage listed below are based on the 1986, 1988, and 1993 examination results. Examination Coverage Estimates 1;!~ 1 111111111;11111111 11!11~1lliillllillll 1i 1 illlllll !~~l~i~ili}ll~ 1 lll//lil 1l 1 lil il 1ii!11/l~iijl 1 ~ 11~1~i~:11i1ili!~jilt:~:j~;;li~;a~:::1:i:::;:::;:iiii'. 1-AOl/ 45 2 62 Welded supports 1-801 45 5 55 and nozzles 45 7 62 45 8 62 2 -Axial scan bottom side of weld 5 -Axial scan top side of weld 7 -Circumferential scan, clockwise. 8 -Circumferential scan, counterclockwise. 02-RH-E-lA "Weld 1-AOl" 1988 - Examined 44"-88" 02-RH-E-lB "Weld 1-BOl" 1986 - Examined 0"-44" 02-RH-E-lB "Weld 1-BOl" 1993 - Examined 88"-0" Licensee's Stated Basis for Requesting Relief: "The 1980 Edition, Winter 1980 Addenda (inclusive) of ASME Section XI in Table IWB-2500-1 and IWC-2500-1 does not allow any limitations to the required volumetric [and surface] examinations. Code Case N-460, Alternative Examination Coverage for Class 1 and Class 2 Welds, allows a reduction in coverage, if it is less than 10%. The components listed above have been examined to the extent practicable as required by the Code. Due to interferences of other components or weld joint geometry the reduction in coverage for the listed component was greater than 10%. Table SR-021-5 [paraphrased above], 1, 2, 3, and 4 [not applicable] are provided detailing the limitations experienced. Amplifying sketches or drawings are also provided. Alternative components were not substituted for examination due to the mandatory selection requirements of the Code, or because the examination coverage attained was representative of what could be expected for that type of configurations." Licensee's Proposed Alternative Examination: No alternative to the Code requirements was proposed. The Code-required volumetric examinations were performed to the extent practical. 19
'\\.. Evaluation: The Code requires volumetric examination of essentially 100% of the length of at least one of the subject welds. The licensee elected to distribute these examinations among two RHR heat exchangers as allowed by the Code. Of the portions of these welds examined, adjacent components (nozzles and supports) and weld geometry restricted access to portions of the welds. Therefore, complete volumetric examination of the subject portions of welds is impractical. In order to perform the 100% volumetric examination on the selected segments, the RHRHX would require design modifications to allow access for examination. This would represent a significant burden on the licensee. The licensee has performed a significant portion (>60%) of the Code-required volumetric examination. Thus, any pattern of degradation that has occurred would have been detected. In addition, there has been no significant problems with these welds at other, similar plants. Therefore, reasonable assurance of the RHRHX's operational readiness has been maintained. Considering the examinations that were performed and the impracticality of performing the complete Code-required volumetric examination, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
3.0 CONCLUSION
The INEL staff has reviewed the licensee's submittal and concludes that, pursuant to 10 CFR 50.55a(g)(6)(i), the requirements of the Code are impractical and recommends that relief be granted for Requests for Relief SR-005 (Units 1 and 2), SR-021 (Unit 2), Parts 1 through 4, and No. 24 (Unit 2). For Requests for Relief Nos. 25 and 26 (Unit 2) and Nos. 28 and 29 (Unit 1), it is recommended that relief be denied. The request was generic in content, thus, impracticality of the Code requirements were not demonstrated. 20}}