ML20082K577

Requests Relief from Exam Requirements of ASME Code,Section Xi,For Facility ISI Program

ML20082K577
Person / Time
Site:	Sequoyah
Issue date:	08/21/1991
From:	Joshua Wilson TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9108300122
Download: ML20082K577 (10)

Text

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i Jack L Wdson  !

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August 21, 1991 l I

U.S. Nuclear Regulatory Commission  :

ATTN: Document Control Desk i

Washington, D.C. 20555 Geatlemen [

Docket Nos. 50-327 In the Matter of )

Tennessee Valley Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - REQUEST FOR RELIEF FROM t AMERICAN SOCIETY OF MECHANICAL ENG! VEERS (ASME) SECTION XI REQUIREMENTS -  ;

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IN-SERVICE INSPECTION (ISI) PROGRAM

References:

1. NRC letter to TVA dated February 7,1991, "First 10-Year Interval inservice Inspection Program (TAC.59457) -

Sequoyah Nuclear Plant, Unit 1" ,

2. .NRC letter to TVA dated February 7, 1991, "First 10-Year ,

Interval Inservice Inspection _ Program, Revision 14 ,

(TAC 59458) - Sequoyah Nuclear Plant, Unit 2"

3. NRC letter to TVA dated April 19, 1990, "First 10-Year Interval Inservice inspection Program (TAC 59458) -

Sequoyah Nuclear Plant. Uait 2" ,

By References 1 through 3, NRC transmitted to TVA safety evaluation I reports (SERs) for SQN's ISI program for the first 10-year interval.

• These SERs granted relief f rom specific requirements of the ASME Section XI Code and. provided regulatory approval of SQN's ISI program.

Fursunut to 10 CFR 50.55a(a)(3)(l) and 10 CFR 50.55a(a)(3)(ii), TVA is e requesting relief from the examination requirements of ASME Code,Section XI, for SQN's ISI. TVA's proposed relief request concerns the examination requiremeats for reactor vessel (RV) nozzle-to-vessel welds.

'SQN is currently in the first ten-year inspection interval. The end of '

i the first 10-year inspectian interval is September 15, l994, for SQN Unit I and February 21, 1995, for SQN Unit 2. l

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- PDR ADOCK 05000327- I o PDR

l I 2 U.S. Nuclear Regulatory Commisolon August 21, 1991 TVA proposes to perform additional examinat ons during the ti. ira i

inspection period of the first interval (rycle 6 refueling outage) !n order to establish a new ten-year examication senedule for the seconJ, third, and fourth inspection intervalt. The adjustment in the examination schedule for the second, third, and fourth intervals a' lows the required RV examinations to coincide with removal of the RV core barrel (removal of SQN's core; barrel occurs during the third peiiod within each 10-year inspection interval). The additional examination that TVA is proposing in the first ten-year inspection interval, coupled with the new examination schedule proposed for the second, third, and fourth intervals, continues to meet or exceed the code examination requirements for SQN's RV nozzle-to-vessel welds. In consideratian of TVA's performance of additional examinations during the first interval, and the radiation exposure required to perform inspections under the current Section Xt examination schedule (second, third, and fourtn intervals), it is concluded that compliance with the specified requirements would result in an unnecessary hardship without a compensatir'g increase in the level of quality and safecy.

Enclosure contains the request for relief (151-14) for SQN Unit 1.

Enclosure 2 contains the identical request for relief (ISI-15) for SQN Unit 2. Enclocure 3 contains two TVA commitments for SQN.

TVA requests that NRC response be provided by June 1, 1992, to allow for adequate planning of work activities in SQN's Cycle 6 refueling outages.

Please direct questions concerning this issue to D. V. Goodin at (615) 843-7734 Very truly yours, TENNESSEE VALLEY AUTliORITY r

( .bL S/W J L. Wilson L

Enclosures cc: See page 3 1

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.U.S. Nuclear Regulatory Commission i August 21, 1991  ;

cc-(Enclosures):  !

Mr. D. E. LaBarge, Project Manager .

U.S. Nuclear Regulatory Commission ..

One White. Flint, North-t 11555 Rockville Pike. i Rockville, Maryland 20852 -!

I NRC Resident Inspector l Sequoyah Nuclear Plant [

2600 Igou Ferry Read  ;

Soddy Daisy, Tennessee '37379 -;

Mr. B. A. Wilson, Project Chief A U.S. L Nuclear Regulatory Commission -  ;'

Region II L101 Marietta Street, NW, Suite'2900. i Atlanta, Georgia. 30323 i

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• ENCLOSURE 1 Request for Relief ISI-14-(Unit 1)

Components: Reactor Vessel (RV) Outlet Nozzle-To-Vessel Welds, RV Nozzle Inside Radius Section, and RV Nozzle-To-Safe End Welds

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Class: American Society of Mechanical Engineers (ASME) Code Class 1 Inspection Re. qui remen t s : Table IWB-2500-1 Examination Category B-D, Full Penetration Welds of Nozzles in Vessels - Inspection Program B Item No. B3.90 Nozzle-to-Vessel Welds Item No. B3.100 Nozzle Inside Radius Section Footnote 3 (1st Inspection Interval) "At least 25%

but not more than 50% (credited) of the nozzles shall be examined by the end of 1st inspection period and remainder by the end of inspection interval."

Footnote 4 (Successive Inspection Intervals 2nd, 3rd, and 4th) - "At least 25% but not more than 50%

(credited) of the nozzles shall be examined by the end of 1st inspection period and the remainder by the end of 3rd inspection period of each inspection interval."

Footnote 5 (Deferral of Inspection to End of Interval)

- "If examinations are conducted f rom inside the component and the nozzle weld is examined by straight beam ultrasonic method from the nozzle bore the remaining examinations required to be conducted from the shell inside diameter may be performed at or near the end of each inspection interval."

Examination Category B-F, Pressure Retaining Dissimilar Metal Welds Item No. B5.10 Nozzle to Safe End Welds Footnote 2 (Successive Inspection Intervals 2nd, 3rd, 4th) "For the reactor vessel nozzle safe-ends, the examinations may be performed coincident with the vessel nozzle examinations required by Examination Category B-D."

Basis for Relief: Sequoyah Naclear Plant (SQN) is a four-loop pressurized water reactor with f our inlet and f our outlet RV nozzles.

The RV nozzle-to-vessel welds and inside radius sectione are ultrasonically examined from the RV inside diameter using automated inspection devices. With the RV core barrel in place, the outlet nozzles are accessible for ,

examination from the nozzle bere only. The inlet nozzles I are inaccessible for examination until the core barrel is I removed.

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. 2 SQN is in the second period of the first ten ear inspection interval. During the first period, the accessible volum(s of the nozzle-to-vessel we'.d3 and inside radiua sections on SQN's four outlet norztes were ultrasonically examined f rom the nozzle hore. The remaining examinations for the four inlet and four cutlet nozzles are to be completed during the third aeriod, thus satisfying the requirements of Table Ik'B-2500-1, Examination Category B-D, Item Nas. B3.90 and B3.100 Footnotes 3., 4, and 5.

1!k In addition to the RV nozzle examinations, LLe RV nozzle-to-saf e end welds nre ultrasonically ctamined using an automated inspection device when the nozzle is examined frcm the bore. During the first period, the nozzle-to-safe end welds on four outlet nozzles were ultrasonically examined from the itiside diameter and surf ace examined f rom the outside diameter. The nozzle-to-safe end welds on the four inlet nozzles will be similarly examined during the third inspection period. This will satiafy tae requirements of Table IWB-2500-1, Examination Category B-F.

Item No. 85.10, Footnote 2.

The ASME Cade provides for the continuation of the first and third period examinations during the sectnd, third, and fourth inspection intervals, thus establishing a ten-year examination frequency. TVA proposes to alter the inspection schedule by perf orming an additional examination of the RV nozzle-to-vessel welds and inside radius sections for SQN's four outlet nozzles during the third inspection period of the first inspection interval. In addition, the neazle-to-safe end welds for the outlet nozz.es would also be examined during the third inspection period of the first interval. Performance of these additional examinations will thereby establish a new ten-year examination schedule for the second, third, and fourth inspection intervals.

The ten-year examination frequency required by the code would continue to be maintained. Additional benefits include:

• Onc-time installation and removal of the automated inspection device from the RV flange rather than twice during an inspection interval.

+ Perf ormance of additional RV outlet nozzle examinations during the first inspection interval.

• Performance of additional RV outlet nozzle-to-safe end weld examinations during the first inspection interval.

• An overall reduction in personnel endiction exposure (one automated examination versus two), thus supporting as icw ao reasonably achievable considerations.

l. . . 3 A reductior in the number of times automated devices and associated mate; rials and equipment must be decontaminf ed (reduces generation of radw.aste).

• A cost sav8.1g to TVA of 1.8 million dollars over the 40-year 111e of the plant.

In considerati:n of TVA's performance of additional examinations daring the fIrst Interval and the radiation exposure requi ed to perform inspections under the current Section XI examination schedule (s cor.d. taird, and faurth lutervals), it in concluded that compliance with the specified requirements would result in an unnecessary hardship without a ong>cusallug inc rease in tne level ot quality and safety.

Alternate Inypection: SQN's four RV outlet nozzles will be ultrasonically examined twice during the first inspection interval. The second examination wuuld occur caring the third period.

This includes examination of the outlet norzie-to-vessel welds by the sr.raight bram ultrasonic method from the nozzle bore and examination of the outlet nozzle inner radius sections. These examinations will t'e in addition to the examinationa required to be conducted on the outlet nozzle-to-vessel welds and inner radius section from the RV shell inside dinmeter during the third inspection period.

SQN's four RV outlet norzle-to-safe end welds will also be examined twice during the first inapection interval (third period). The examinations will include an automated ultrasonic exnmination from the inside diameter and a surface examination from the outside diameter.

During the second, third, and fourth inspection intervals, all RV nozzle-to-vessel welds,-Inside radius sectiona, and RV nozzle-to-safe end volds will be examined during the third inspection period.

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ENCLOSURE 2

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Request for Relief ISI-15 (Unit 2)

Components: Reactor Vessel (RV) Outlet Nozzle-To-Vessel Welds,-RV l

. Nozzle.Inside Radius Section, and.RV Nozzle-To-Safe End.

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Welds  ;

Class: American Society of Mechanical 1.ngineers (ASME) Code Class 1 .}

l Inspectio..- ,

Requirements: Table IWB-2500-1 l r

Examination Category B-D. Full Penetration Welds of Noazles in Vessels - Inspection Program B j Item No. B3.90 Nozzle-to-Vessel Welds Item No.-B3.100 Nozzle Inside Radius section .fr Footnotej (1st Inspection Ir.terval) "At least 25%  !

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-but not more'than 50% (creditedY of the. nozzles shall' be examined by the end of 1st inspection period and.-  ;

remainder by the end of inspection interval." )

Footnote 4 (Successive _ Inspection Intervals 2nd,_3rd.  ;

and-4th)- "At least;24 but not more than 50%

(credited) of the noczles shall be examined by the end_. p of 1st inspection period and the remainder by the end -

-of 3rd inspection period of each inspection interval"

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Footnote 5 (Deferral of Inspection to End of Interval) -;

"If examinations.are conducted from1inside the  !

component and the nozzle weld-is examined by straight-

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-beam ultrasonic method from the nozzle bore the  !

remainingJexaminations required to be conducted from l the shell insidel diameter may be performed at or-near [

the end of each inspection interval."  :

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-Examination Category B-F,/ Pressure Retaining Dissimilar- s Metal' Welds l

Item No. B5.10. Nozzle to Safe End Welds j Foo'tnote'2.(Successive Inspection Intervais 2nd, 3rd, -;

i' 4th).-~"For the reactor vessel nozzle safe-ends, the j examinations may be. performed coincident with the -

vesse1 nozzle examinations _ required by= Examination- .I j l Category B-D." j Basis for Relief: 'Sequoyah Nuclear-Plant.(SQN) is a four-loop' pressurized

. water reactor with four inlet and.four outlet RV nozzles. ,

s The: RV nozzle-to-vessel welds and inside radius sections '

are= ultrasonically examined from the RV inside diameter

-using automated. inspection devices. With the RV core

, barrel in place,-the outlet nozzles are accessible for ~

, examination from the nozzle bore only. The inlet nozzles  !

are inaccessible for examination until the core barrel is  !

removed.

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SQN'is in:the second period of the first ten-year l inspection interval. .During the first period, the accessible volume.-of the nozzle-to-vesdel welds and inside O

radius sections on SQN's four outlet no::zles were-ultrasonically examined from the nozzle bore. Tha i re.naining exan,inations for the four inict and four outlet  ;

. nozzles are to be completed during the third period, thus l satisfying the. requirements of Tcble IWB-2500-1, {

Examination Category B-D, Item Wos. B3.90 and B3.100,  ;

Footnotes 3, 4, and 5. j In addition to the RV norale examinations, the RV nozzle-to-saf e end welds are ultrasc.nically examined using  !

an automated i.upection device when the nozzle is examined  !

from the bore. During the fire period, the nozzle-to-safe end welde on four outlet-nozzlea were ultrasonically _

l examined f roin the inside diameter and surf ace examined f rom l

-the cutside dinmeter. The nor::le-to-saf e end welds on the  !

- four inlet nozzles will be si.nilarly examined during the- I third inspection period. This will satisfy the .

f requirements ci fable IGB-2500-1. Examination Category B-P, '

Item No. B5.10 Footnote 2. [

t The ASME Code provides for the continuation of tbe first 1;

.and' third period examinations during the second, third, and j tourth inspection intervals, thus establishing a ten-year-  !

cxamination frequency. TVA proposes-to alter the  !

inspection: schedule by performing an additional examination.  !

of the RV nozr.le-to-vessel welds and.inside radius sectiona. -f for'SQN's four outlet rozzles during the third luspection ~I period of the-first inspection irterval. In addition, the- ,

nozzle-to-safe end welds for the outlet nozzles wo dd also be. examined'during the tlird' inspection period of the first

. interval. Perf ormance of these additlonal examinat lons ,

-will-thereby estatlish a new ten-year examination schedule  ?!

for the cecond, third, and_ fourth-inspection-intervals.- :l Tbc . ten-year examination f requency required by the codo- '

would continue to.be maintaine'd, Additinnal benefits include:

i One-timo installation and removal of the autonutted

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• l inspection device from the RV flange rather than twice during-an inspection interval.

Performance of additional RV outlet nozzle examinations

-during the first inspection interval.

• Performance of additionat-RV outlet nozzle-to-safe end weld examinations during the fient inspection interval.

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• An overall' reduction in personnel radiation exposure (one automated examination versus two), thus supporting.

, as low as reasonably achievable considerations.

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t l-A reduction in the number of times autonsted devices y . and associated materials and equipment must be I D-iecontaminated (reduces generation of_radwaste).

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• A cost saving to TVA of 1.8 million dollars over the  :

f 40-year life of the plant. [

l In consideration of TVA's perfurnance of additional enaminations durCng the tirst interval and the radiation ,

exposure required tc perfocm inspections under the current  !

6ection XI examination schedule.(second, third, and fourth latervals), it is concluded that compliance with the i specified requirements would result in an unnecessary  ;

E hardship without a compensating. increase in the level of quality and safety.

t p Al te rnate  :

l' Inspection: SQN's four RV outlet nozzles will be ultrasonically exsmined twice during the first inspection interval. The second examination would. occur during the third period, ,

This includes examination of the outlet nozzle-to-vessel welds by the straight' beam ultrasonic method frcm the nozzle bore and examinction of the outlet nozzle inner ,

radius sections. These examinations will be in addition to the examinations required to be conducted on the outlet ,

l nozzle-to-vessel welds and inner radius se: tion f rom the RV l l shell inside diameter during the third-inspection period. l l -SQN's four RV outlet nozzle-to-saic end welds will also be l examined twice during the first inspection interval (third L period). The examinations will include an automated ,

ultrasonic examination from the inside-diameter and a surface exraination from the outside diameter.  ;

l During the second, third, and fourth inupection intervals, 5 all RV nozzle-to-vessel welds and_inside-radius sections,_ }

and'RV nozzle-to-safe end welds will be examined during the  ;

third inspection period, l- ,

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ENCLOSURE 3 TVA Commitments 1, Four reactor vessel (RV) outlet nozzles (nozzle-to-vessel weld and inride radius section) and four RV outlet nozzle-to-safe end welds on Unit 1 will be reexamined (in accordance with the examination methods of Table IWS-2500-1) during the Cycle 6 refueling outage.

2. Four reactor vessel (RV) outlet nozzles (norzie-to-vessel well and inside radius sectien) and four RV outlet nozzle-to-sale end welds on Unit 2 will be reexamined (in accordance w"th the examinc. tion methods of Table IWB-2500-1) during the Cycle 6 refueling cutage.

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