ML20216J171
| ML20216J171 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/08/1997 |
| From: | Jeffery Wood CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 2482, NUDOCS 9709170182 | |
| Download: ML20216J171 (10) | |
Text
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o CENTEREOR ENERGY M01 N State Route 2 419-249 2300 John K. Wood O.* Hartu. OH 43449 FAL 419-3218337 Vice Presdent Nucleaf Davis-Besso Docket Number 50-346 License Number NPF-3 Serial Number 2482 September 8, 1997 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 l
Subject:
Request for Relief from certain American Society of Mechanical Engineers (ASME)
Code Requirements for Inservice Inspection for the Davis-Besse Nuclear Power Station Ladies and Gentlemen:
In the Federal Register, dated August 8,1996 (61 FR 41303), the NRC amended its regulations to incorporate by reference the 1992 Edition and Addenda of Subsections IWE and IWL of Section XI of the ASME Code. Subsections IWE and IWL give the requirements for inservice inspection (ISI) of Class CC (concrete containments), and Class MC (metallic containments).
The Davis-Besse Nuclear Power Station (DBNPS) containment vessel is a free standing metallic structure which was constructed in accordance with ASME Section Ill, Subsection B for Nuclear Vessels,1968 Edition including the Summer 1969 Addenda The rules of Subsection IWL are not applicable to the DBNPS Containment Vessel.
The purpose of this letter is to request relief pursuant to 10CFR50.55a and (g)(5)(iii) from certain requirements of Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. The requests for relief deal with the following: visual examination of containment penetration seals and gaskets; bolt torque or tension testing of containment penetration bolting; requirements for nondestructive examination procedures and qualification of nondestructive examination personnel; and containment repairs and replacements. Details concerning the requested relief are provided in the attached Relief Requests RR-El, RR-E2, RR-E3 and RR-E4.
Relief Request RR-El requests relief from Section XI of the ASME Code,1992 Edition,1992 Addenda Code items E5.10 and E5.20 which require visual examination of seals and gaskets en t
ai-locks, hatches and other devices required to assure containment integrity.
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' Docket Number 50-346 License b' umber NPF-3 Serial Number 2482
. Page 2, Toledo Edison proposes to examine these seals and gaskets in accordance with Examination Category E-D of the 1995 Edition of Section XI.
Relief Request RR-E2 requests relief from Section XI of the ASME Code,1986 Edition, Code Item E8.20 which requires a bolt torque or tension test for bolted connections that have not been disassembled and reassembled during the inspection interval. Toledo Edison proposes that the adequacy of the bolted joints for electrical penetrations, the Personnel llatch and the Emergency Escape 11atch will be verified through the performance of 10CFR50 Appendix J, Type B testing.
Relief Request RR-E3 requests relief from ASME Section XI,1992 Edition,1992 Addenda, j
Subsection IWA-2200 requirements for nondestructive examination procedures and subsection 3
IWA-2300 requirements for the qualificatien of nondestructive test personnel. Toledo Edison proposes to utilize examination procedures written to the requirements of 1986 Edition, no addenda, of ASME Section XI. Toledo Edison also proposes that personnel performing non-destructive examination (NDE) will be qualified to the 1986 Edition, no addenda, of ASME s
Section XI.
Relief Request RR E4 requests relief from ASME Section XI,1992 Edition,1992 Addenda, Subsection IWE, Subsection IWA-4000 for containment repairs and replacements. Toledo Edison proposes that repairs / replacements to the containment vessel will be in accordance with the requirements of 1986 Edition, no addenda of ASME Section XI and preservice examinations will be conducted in accordance with the requirements of Subsection IWE of the 1992 Edition, 1992 Addenda of ASME Section XI, Should you have any questions or require additional infomiation, please contact Mr. James L.
Freels, Manager - Regulatory Affairs, at (419) 321-8466.
Very truly yours, N
CAK/dle Attachment cc: A. B. Beach, Regional Administrator, NRC Region 111 A. G. Hansen, DB-1 NRC/NRR Project Manager S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board
=
- Docket Numbcr 50-346 License Number NPF-3 Serial Number 2482 Attachment
' Page'l'of 8 REllEF REQUEST RR-El Component
Description:
52 Containment Electrical Penetration Seals and Gaskets Containment Personnelllatch Seals and Gaskets Containment Escape llatch Seals and Gaskets ASME Code Class:
ASME Section XI,1992 Edition,1992 Addenda, Examination Category E-D Seals, Gaskets, and Moisture Barriers ASME Examination Reauirements; Code item E5.10 requires the visual examination of seals on airlocks, hatches, and other devices that are required to assure containment leak-tight integrity.
Code Item E5.20 requires the visual examination of gaskets on airlocks, hatches, and other devices that are required to assure containment leak-tight integrity.
Basis for Relief:
Code Items E5.10 and E5.20 require that all seals and gaskets be inspected each interval.
The penetrations discussed below contain internal seals and gaskets which cannot be inspected without disassembly of the penetration.
Electrical Penetrations:
Electrical penetrations use a header plate attached to a containment penetration nozzle flange wti redundant 0-rings between the header plate and flange face.
Modules through which electrical conductors pass are installed in the header plate.
One type, manufactured by Amphenol, uses seals and gaskets to assure leak tight integrity. A second type, manufactured by Conax, uses a set of compression fittings. Replacement modules for the Amphenol penetrations use a combination of O-rings and compression fittings. Each penetration is pressurized with dry nitrogen to maintain and monitor integrity and to prevent the intrusion of moisture into the penetration.
Inspection of the seals and gaskets requires the disassembly of the penetration to gain access to the seals and gaskets.
I
' Docket Number 50-346 License Number NPF-3 Serial Number 2482 Attachment Page'2 of 8 Containment Personnel and Emercency Escane llatches The Personnel and Emergency Escape liaiches utilize an inner and outer door with gasket surfaces to ensure a leak tight integrity. These gaskets are not the subject of this relief request.110 wever, the hatches do contain other gaskets and seals such as the handwheel shaft seals, electricil penetrations, blank flanges, and equalizing pressure connections which require disassembly to inspect.
Each of the penetrations addressed in this relief request receive a 10 CFR 50 Appendix J Type B test in accordance with the testing frequencies specified in Appendix J. As noted in 10 CFR 50 Appendix J, the purpose of Type B tests is to measure leakage of containment penetrations whose design incorporates resilient seals, gaskets, sealant compounds, and electrical penetrations fitted with flexible metal seal assemblies.
Physical inspection of the seals and gaskets in these penetrations requites the joints, which are proven adequate through Appendix J testing, be disassembled. For electrical penetrations, this would involve a pre-maintenance Appendix J test, determination of cables at electrical penetrations if e iough cable slack is not available, disassembly of the joint, removal and inspection of the seals and gaskets, reassembly of the joint, re-termination of the cables if necessary, post maintenance testing of the cables, and a post maintenance Appendix J test of the penetration. The work required for the Containment i
Personnel and Emergency Escape Hatches would be similar except for the determination, re-termination, and testing of cables. Not only does this require the use of outage man-hours, but also imposes the risk that equipment could be damaged. The 1995 Edition of Section XI recognizes that disassembly ofjoints to perform these inspections is not warr:mted as Note 1 in Examination Category E-D was modified to state that sealed or gasket connections need not be disassembled solely for performance of examinations.
In addition three of the electrical penetrations are protected from fiie per the reqairements of 10CFR50 Appendix R. This protection would also have to be removed to perform these inspectionc.
Six Amphenol modules were replaced in 1988 with an additional four replaced in 1990.
The seals and gaskets in these modules did not exhibit any degradation after approximately 14 years of sersice.
Alternative Examination:
Seals and gaskets will be examined in accordance with the requirements of Examination Category E-D of the 1995 Edition of Section XI. That is, sealed or gasket connections need not be disassembled solely for performance of examinations.
- Docket Number 50-346 License Number NPF-3 Serial Number 2482 Attachrnent Page'3 of 8 RELIEF REQUEST RR-E2 Comnonent
Description:
Containment Electrical Penetration Flange Bolting - 52 Penetrations Containment Personnel llatch Bolting Containment Escape Bolting ASME Code Class:
ASME Section XI,1992 Edition,1992 Addenda, Examination Category E-G Pressure Retaining Bolting ASME Examination Reauirements:
Code item E8.20 requires a bolt torque or tension test for bolted connections that have not been disassembled and reassembled auring the inspection inten'al.
Basis for Relief:
Code item E8.20 requires that all bolting which has not been disassembled and reassembled during the inspection interval receive a bolt torque or tension test. The test confirms that the bolt torque or bolt tension is within the limits specined for the original design. These limits would include a minimum and maximum torque value within which the bolting torque must fall. This value is determined by the torque value at which the bolt begins to loosen.
Each of the penetrations addressed in this relief request receive a 10 CFR 50 Appendix J Type B test in accodance with the testing frequencies specifie? in Appendix J. As noted in 10 CFR 50 Appendix J, the purpose of Type B tests is to measure leakage of containment penetrations whose design incorporates resilient seals, gaskets, sealant compounds, and electrical penetrations fitted with flexible metal seal assemblies.
Determination of the torque value requires the bolting be untorqued and then retorqued.
This activity is considered maintenance and therefore would require an as-found 10 CFR 50 Appendix J Type B test prior to verifying the torque value and then an as-left Type B test. The performance of the pre-maintenance Type B test in itself proves that the bolt torque is at a value to provide a penetration leak rate that is within acceptable limits. The torque value of the penetration bolting only becomes an issue if the leakage rate is excessive. Once a penetration bolt is torqued, it is not subjected to dynamic, vibration, or thermal forces which would cause its torque to significantly change. Verification of torque values onjoints which are proven adequate through 10 CFR 50 Appendix J Type
' Docket Number 50-346 License Number NPF-3 Serial Number 2482 Attachment Page'4 of 8 B testing results in an increase in outage man hours without any increase in the level of quality or safety.
In addition three of the electrical penetrations are protected from fire per the requirements of 10CFR50 Appendix R. This protection would also have to be removed to perform these inspections.
Testing history has shown that the electrical penetrations, Containment Personnel 1 latch, and Containment Escape llatch have not exhibited excessive leakage due to inadequate l
bolt torque, l
Alternative Examination:
l Bolting in electrical penetrations, the Personnel Hatch, and the Emergency Escape llatch will not be torque tested. The adequacy of the boltedjoints will be verified through the performance of 10 CFR 50 Appendix J Type B testing.
1 l
_a
Docket Number 50 346 License Number NPF-3 Serial Number 2482
. / ttachment
\\
Page'5 of 8 RELIEF REQUEST RR E3 Component
Description:
IWA-2200 Examination Methods IWA-2300 Qualification of Nondestructive Examination Personnel ASME Code Class:
ASME Section XI,1992 Edition,1992 Addenda, Subsection IWE ASME Examination Reauirements:
IWA-2200 provides requirements for nondestructive examination procedures.
IWA-2300 provides requirements for the qualification of nondestructive examination personnel.
Basis for Relief:
In the Federal Register dated August 8,1996, (61FR41303), the NRC amended its regulations to incorporate the 1992 Edition,1992 Addenda of ASME Section XI when performing containment examinations. In addition to the requirements of Subsection IWE, this also imposes the requirements of the 1992 Edition,1992 Addenda of Subsection IWA for containment examinations.
The Davis-Besse Nuclear Pwer Station (DBNPS) Second Ten Year Inservice Inspection Program is written to meet the 1986 Edition, No Addenda, of ASME Section XI including Subsection IWA. Meeting both the 1986 Edition, No Addenda and the 1992 Edition,1992 Addenda of ASME Section XI requires separate procedure examination requirements (one for the IWB, IWC, and IWD examinations per the 1986 Edition, No Addenda of ASME Section XI and one for the IWE examinations per the 1992 Edition, 1992 Addenda of ASME Section XI), and separate personnel qualification requirements.
Duplicate records to demonstrate compliance with the 1986 Edition, No Addenda, and the 1992 Edition,1992 Addenda, will also be required. This duplication of procedures and records increases the man-hours necessary to maintain the Inservice Inspection Program without providing any increase in quality of the examinations.
Toledo Edison will utilize examination procedures written to the requirements of the 1986 Edition, No Addenda, of ASME Section XI. These procedures will contain the inspection attributes and acceptance criteria required by the Subsection IWE of the 1992 Edition,1992 Addenda of ASME Section XI. These procedures will require that remote l
' Docket Number 50-346
- License Number NPF-3 Serial Number 2482 Attachment
. - Pagd 6 of 8 -
j visual examinations be conducted under illumination and distances which will detect the conditions or indications for which the examination is being performed.
Personnel performing nondestructive exmninations will be qualified to the 1986 Edition,
- No Addenda, of ASME Section XI. The nondestructive examinations required by IWE are not sophisticated, complex examinations. Utilization of personnel qualification requirements of the 1986 Edition, No Addenda of ASME Section XI will ensure that inspection personnel have the necessary skills to perform the examinations required by IWE.
I Alternative Examination:
The requirements ofIWA-2200 and IWA-2300 of the 1986 Edition, No Addenda of ASME Section XI will be used for containment examinatior.s in lieu of IWA-2200 and IWA-2300 of the 1992 Edition,1992 Addenda of ASME Section XI.
1 b
Docket Number 50-346 License Number NPF-3 1
Serial Number 2482 Attachment
' 'Page 7 of 8 RELIEF REQUEST RR E4 Component Descrintion:
IWA-4000 Repair and Replacement Program ASME Code Class:
ASME Section XI,1992 Edition,1992 Addenda, Subsection IWE ASME Examination Reauirements:
Implementation of the 1992 Edition,1992 Addenda of ASME Section XI for examination of Class MC components requires the use of Subsection IWA-4000 of the 1992 Edition, 1992 Addenda of ASME Section XI for repairs and replacements to Class MC components.
Basis for Relief:
In the Federal Register dated August 8,1996, (61FR41303), the NRC amended its regulations to incorporate the 1992 Edition,1992 Addenda of ASME Section XI when performing containment examinations. In addition to the requirements of Subsection IWE, this also imposes the requirements of the 1992 Edition,1992 Addenda of Subsection IWA-4000 for contamment repairs and replacements.
Toledo Edison holds a National Board Nuclear Repair Certificate of Authorization for repairs / replacements to Class 1,2,3, and MC components. This Certificela of Authorization is based on the Davis-Besse Nuclear Power Station (DBNM)
Repair / Replacement program which is written to the requirements of the 1986 Edition, No Addenda, of ASME Section XI. This program requires that repairs and replacements to the containment vessel meet its design specifications and Constrwtion Code requirements. This ensures that the original integrity and quality of the containment vessel will be maintained during repair / replacement activities.
Meeting both the 1986 Edition, No Addenda and the 1902 Edition,1992 Addenda of ASME Section XI requires the maintenance of two separate repair and replacement programs (one for the IWB, IWC, and IWD components per the 1986 Edition, No Addenda of ASME Section XI and one for the containment vessel per the 1992 Edition, 1992 Addenda of ASME Section XI). Duplica'e records to demonstrate compliance with the 1986 Edition, No Addenda, and the 1992 Edition,1992 Addenda will also be required. This duplication of programs and records increases the man-hours necessary to maintain the DBNPS Repair / Replacement Program without providing any increase in quality of containment vessel repairs / replacements.
" Docket Number 50-346 License Number NPF-3 Serial Number 2482
,Attachipent Pagd 8 of 8 Alternative Examination:
The DBNPS Repair / Replacement Program, written to the requirements of 1986 Edition, No Addenda of ASME Section XI, will be used for repairs and replacements to the containment vessel. Presenice examinations will be conducted in accordance with the requirements of Subsection IWE of the 1992 Edition,1992 Addenda of ASME Section -
XI.
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