ML18038B185
| ML18038B185 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/09/1995 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9503140144 | |
| Download: ML18038B185 (16) | |
Text
P R.IC)R.I "EY'ACCELERATED RIDS PROCESSING REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9503140144 DOC.DATE: 95/03/09 NOTARIZED: NO DOCKET FACIL:50-259 Browns Ferry Nuclear Power Station, Unit 1, Tennessee 05000259 50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee 05000296 AUTH.NAME AUTHOR AFFXLIATION SALAS,P.
Tennessee Valley Authority RECIP.NAME RECXPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Requests relief from ASME Section XI re boiler
& PV code.
Plant seeks approval to utilize ASME Code Cases N-416-1 N-498-1.
DISTRIBUTION CODE:
A047D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:
P 0
~ R RECXPIENT ID CODE/NAME PD2-4 WILLIAMS,J.
INTERNAL: ACRS FI-B~CEN~ZER00'RR7DE7E ME B OGC/HDS3 EXTERNAL LITCO BROWN I B NOAC COPIES LTTR ENCL 1
1 1
1 6
6 1
1 1
1 1
0 1
1 1
1 RECIPIENT ID CODE/NAME PD2-4-PD AEOD/SPD/RAB NRR/DE/EMCB NUDOCS-ABSTRACT RES/DSIR/EIB LITCO RANSOME,C NRC PDR COPIES LTTR ENCL 1
1 1
1 1
1 1
1 1
1 1
1 1
1 D
0 U
NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE iVASTE!CONTACTTIIE DOCUMENTCONTROL DESK, ROOM P I -37 (EXT, 504-2083 ) TO E LI i%IINATE YOUR NAME FROM DISTRIBUTIONLISTS I'OR DOCUMENTS YOU DON"I'EED!
TOTAL NUMBER OF COPXES REQUIRED:
LTTR 20 ENCL 19
Tennessee Valley Authority. Post Office Box 2000, Decatur. Alabama 35609 March 9, 1995 10 CFR 50.55a(g) (5) (iii)
U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos.
50-259 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN) - UNITS 1~
2 I AND 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)
SECTION ZI INSERVICE SYSTEM PRESSURE TEST (SPT)
PROGRAM - RELIEF REQUESTS SPT-8 AND SPT-9 In accordance with the provisions of 10 CFR 50.55a(g)(5)(iii),
TVA requests relief from the ASME Section XI Boiler and Pressure Vessel Code as follows.
TVA requests appr'oval to utilize ASME Code Cases N-416-1, "Alternate Pressure Test Requirement for Welded Repairs or Installation of Replacement Items by Welding, Class 1, 2, and 3,Section XI, Division 1,"
and N-498-1, "Alternative Rules for 10-Year System Hydrostatic Testing for Class 1, 2, and 3 Systems,Section XI, Division 1,"
as alternatives to the ASME Section XI Code requirements.
As outlined in the enclosed Request for Reliefs, TVA has determined that the ASME Code required hydrostatic testing is impractical for BFN and that the proposed alternative requirements will provide an acceptable level of quality and safety.
ASME Code Case N-416-1 addresses the use of a system leakage test as an alternative in lieu of performing the code required hydrostatic pressure test on the pressure retaining boundary of Class 1, 2, and 3 components for welded repairs y4003.3 e50S<40<44 e5OZ09 PDR ADOCK 05000259 p
U.S. Nuclear Regulatory Commission Page 2
March 9, 1995 or installation of replacement items by welding.
, In addition to the requirements of ASME Code Case N-416-1, TVA will perform additional nondestructive examinations on Class 3 butt and socket welds.
'r ASME Code Case,,N-498-1 utilizes leakage (Class 1) and pressure (Class 2 and
- 3) tests, in conjunction with other requirements, as an acceptable alternative to 10-year hydrostatic pressure tests.
The alternative requirements of ASME Code Cases N-416-1 and N-498-1 have been approved by the ASME Boiler and Pressure Vessel Code Committee and the Board of Nuclear Codes and Standards.
Additionally, NRC has approved similar requests for the use of ASME Code Case N-416-1 at other plants including the TVA Sequoyah Nuclear Plant (NRC Safety Evaluation Report dated December 15, 1994).
Enclosure 1 contains TVA's Request for Relief utilizing ASME Code Case N-416-1 (SPT-8).
Enclosure 2 contains TVA's Request for Relief utilizing ASME Code Case N-498-1 (SPT-9).
TVA requests review and approval of the attached Relief Requests by August 11, 1995 in order to implement these changes to support Unit 3 restart which is currently scheduled for January 1996 and the next Unit 2 refueling outage that is currently scheduled for April 1996.
V There are no commitments contained in this letter. If you have any questions, please contact me at (205) 729-2636.
Si a as Manager of Site Licensing Enclosures cc:
See page 3
'I e
AU. S. Nuclear Regulatory Commission Page 3
March 9, 1995 Enclosures cc (Enclosures):
Mr. Mark S. Lesser, Acting Branch Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637
- Athens, Alabama 35611 Mr. J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
ENCLOSURE 1
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1q 2g AND 3 REQUEST FOR RELIEF SPT-8 Systems:
Drawings:,
Components:
Class:
Function:
Impractical Test Requirements:
Various American Society of Mechanical Engineers (ASME)Section XI Various Class 1, 2, and 3 pressure retaining components.
1, 2,
and 3
Pressure retaining boundary ASME Boiler and Pressure Vessel Code Section XI, 1986 Code Edition IWA-4400(a) and IWA-4600(a) require the performance of hydrostatic testing on pressure retaining boundaries of Class 1,
2, and 3
components after repairs by welding or the installation of replacement items by welding.
The applicable editions of Section XI of the ASME Code for System Pressure Tests are the 1974 Edition, through Summer 1975 Addenda'or Units 1
and 3, and the 1986 Edition for Unit 2.
The applicable edition of Section XI of the ASME Code for Repair and Replacement is the 1986 Edition for all three units.
Basis for Relief:
Elevated pressure tests are difficult to perform and often represent a true hardship.
Some difficulties associated with elevated pressure testing include the following:
Hydrostatic testing often requires complicated or abnormal valve line-ups in order to properly vent, fill, and isolate the components requiring testing.
~
~ ~
Relief valves with setpoints lower than the hydrostatic test pressure must be gagged or removed and blind flanged.
This process requires the draining and refilling of the system.
Valves that are not normally used for isolation (e.g.,
normally open pump discharge valves) are often required to provide pressure isolation for an elevated pressure hydrostatic test.
These valves frequently require time consuming seal maintenance in order to allow for pressurization.
The radiation exposure required to perform a hydrostatic pressure test is high in comparison to a system leakage test.
The amount of time required to prepare the volume for hydrostatic pressure testing (i.e.,
installing relief valve gags, performing appropriate valve line-ups, etc.) is significantly large.
Temporary support installation and pinning of spring cans are sometimes needed to compensate for the additional weight added to systems during hydrostatic tests.
The difficulties encountered in performing a hydrostatic pressure test are prohibitive when weighed against the benefits.
Industry experience, which is supported by BFN's experience, shows that most through-wall leakage is detected during system operation as opposed to elevated pressure tests.
Little benefit is gained from the added challenge to the piping system provided by an elevated pressure hydrostatic test (when compared to a system leakage test), especially when one considers that the piping stress experienced during a hydrostatic test does not include the stresses associated with the thermal growth and dynamic loading for design basis events.
The. acceptability of performing nominal operating pressure tests, in lieu of hydrostatic tests, is supported by the recent approval by the Board of Nuclear Codes and Standards of ASME Code Case N-416-1, "Alternative Pressure Test Requirements for Welded Repairs or Installation of Replacement Items by Welding."
This code case allows a system leakage test at nominal operating pressure
- and, temperature to be used in lieu of a hydrostatic
- test, provided that non-destructive examination (NDE) of the weld(s) is performed in accordance with the methods and acceptance criteria of the applicable Subsection of the 1992 Edition of Section III.
TVA considers that, the above guidance is sufficient for Code Class 1 and, 2 components since the code requires volumetric examination of repairs or replacements in Code Class 1 and 2
components.
However, the code only,requires a
surface examination of the final weld pass in Code Class 3 components.
Accordingly, TVA proposes to supplement the examination requirements specified in N-416-1 with additional surface examinations as specified below in the Alternative Testing description.
Alternate Testing:
As an alternative to the existing Section XI requirements, BFN will utilize the provisions of ASME Code Case N-416-1 along with the following additional NDE requirements for Class 3
components.
When performing repairs by welding or the installation of replacement items by welding on the pressure retaining boundary of Class 3
components, NDE shall be performed in accordance with the methods and acceptance criteria of Subsection ND of the 1992 Edition of Section III.
In addition, when the surface examination method is used in accordance with ND-5222 for a butt or socket weld, an additional surface examination shall be performed on the root (pass) layer.
E1-3
ENCLOSURE 2
TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1~
2g AND 3 REQUEST FOR RELIEF SPT-9 Systems:
Drawings:
Components:
Class:
Function:
Impractical Test Requirements:
Various American Society of Mechanical Engineers (ASME)Section XI Various Class 1,
2, and 3 pressure retaining components.
1, 2,
and 3
Pressure retaining boundary 10-Year System Hydrostatic Testing for Class 1, 2, and 3 Systems.
ASME Boiler and Pressure Vessel Code Section XI, Division 1, Table IWB-2500-1, Category B-P; Table IWC-2500-1, Category C-H; and Table IWD-2500-1, Categories D-A, D-B, and D-C The applicable editions of Section XI of the ASME Code for System Pressure Tests are the 1974 Edition, through Summer 1975 Addenda for Units 1
and 3, and the 1986 Edition for Unit 2.
Basis for Relief:
ASME Code Case N-498 has been accepted by the NRC as listed in Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability ASME Section XI Division 1."
This Code Case allows the use of an inservice leakage test in lieu of'a hydrostatic pressure test when performing the required 10-year pressure test for Class 1 and 2 systems.
ASME Code Case N-498-1 extends the use of this alternate test method to Class 3 systems.
Elevated pressure tests are difficult to perform and often represent a true hardship.
Some difficulties associated with elevated pressure testing include the following:
Hydrostatic testing often requires complicated or abnormal valve line-ups in order to properly vent, fill, and isolate the components requiring testing.
Relief valves with setpoints lower than the hydrostatic test pressure must be gagged or removed and blind flanged.
This process requires the draining and refilling of the system.
Valves that are not normally used for isolation (e;g., normally open pump discharge valves) are often required to provide pressure isolation for an elevated pressure hydrostatic test.
These valves frequently require time'onsuming seal maintenance in order to allow for pressurization.
The radiation exposure required to perform a hydrostatic pressure test. is high in comparison to a system leakage test.
The amount of time required to prepare the volume for hydrostatic pressure testing (i.e.,
installing relief valve gags, performing appropriate valve line-ups, etc.) is significantly large.
Temporary support installation and pinning of spring cans are sometimes needed to compensate for the additional weight. added to systems during hydrostatic tests.
In the case of raw water systems, check valves do not provide good test boundaries.
This requires blanking in order to establish a test boundary that can be pressurized.
The difficulties encountered in performing a
hydrostatic pressure test are prohibitive when weighed against the benefits.
Industry experience, which is supported by BFN's experience, shows that most through-wall leakage is detected during system operation as opposed to elevated pressure tests.
Little benefit 'is gained from the added challenge to the piping system provided by an elevated pressure hydrostatic test (when compared to a system leakage test), especially when one considers that the piping stress experienced during a hydrostatic test does not include the stresses associated with the thermal growth and dynamic loading for design basis events.
ASME Code Case N-498-1 recognizes that inspection for leaks at normal system operating pressure is also adequate for Class 3 systems and components
~
Q
~
~
I in lieu of a hydrostatic test.
This alternative provides for sufficient verification of the pressure retaining boundary integrity without the additional workload associated with the performance of a hydrostatic test.
The acceptability of performing nominal operating pressure tests, in lieu of hydrostatic tests, is supported by the recent approval by the Board of Nuclear Codes and Standards of ASME Code Case N-498-1, "Alternative Rules for 10-Year System Hydrostatic Testing for Class 1, 2, and 3 Systems,Section XI, Division 1."
TVA considers the ASME Code Case N-498-1 requirements to be an acceptable alternative to the 10-year hydrostatic testing requirements.
Alternative Testing:
As an alternative to the existing Section XI require'ments, BFN will utilize the provisions of ASME Code Case N-498-1.
E2-3
N