ML19221A904

Reg Guide 1.83,Revision 1, Inservice Insp of PWR Steam Generator Tubes

ML19221A904
Person / Time
Issue date:	07/31/1975
From:	NRC OFFICE OF STANDARDS DEVELOPMENT
To:
References
REGGD-01.083, REGGD-1.083, NUDOCS 7907100317
Download: ML19221A904 (5)

Text

..

.v.

Revision 1 U.S. NUCLEAR REGULATORY COMMISSION July 1975 REGULATORY GBE L

i OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 1.83 INSERVICE INSPECTION OF PRESSURIZED WATER REACTOR STE AM GENERATOR TUBES A. INTRODUCTION contammert. His guide desenbes a method wptd's to the NRC staff for implementmg these Gener.! % sign General Design Cutena 14. " Reactor Criolant Pressure Criteria by reducmg the probability and conseqi taes of Bounda ry,'

and 31, " Fracture Prevention of Reactor

. team gener. tor tube fadures through periet inservice Coolant Pressure SoundaryJ of Appendit A," General inspection for early detection of defects aad detenora-tion. His guide applies only to pres urized water Design Criteria for Nuckar Power Plants," to 10 CFR Part 50, "Ucensmg of Production and Utilization reactors (PWRs). De Advisory Committee on Reactor Facihties," require that the reactor coolant pressure Safeguards has been consulted conceming this guide and boundary have an e uiemely low probabthty of has concurred ir, the regulatory position.

abnormal leakage, of rapidly propagatmg failure, and of gross rupture. General Design Criterion 15, " Reactor B. DISCUSSION System Des.gr. requires tha t the reactor 6

Coolant toolant system and assocbted suuhary, control, and f:.e heat transfer area of the steam generators m protecticn systems be designed with sufficient margm to pressunzed water rea. tors can comprise well over 50'5 of ensure that the design conditions of the reactor coolant the area of the tota pnmary system pressure retaining L

pressure boundary are not exceeded during any condi-boundary. The thin-walled steam generator tubag is an important p rt of a major barrier against fission product tion of normal operation, including anticipated opera-o tional occurrences. Furtherrnee. General Design 'nter-release to the environment. The steam generator tubing ion 32. " inspection of leactor Coolant Pressure also acts as a barrier against stear - release to the Boundary," requires that components that are part of containment in the event of a LOCA. To act as an the reactor coolant pressuie boundary be designed to effective barner, this tubireg must be free of cracks, permit periodic inspection and testmg of critical areas to perforations. and general detenoration ne design assess their structural and leaktight integnty.

critena used to estabhsh the uructural integnty of the steam generator tubing should also define the mmimum Fadure' of steam generator tubes. w tuch can be tube wall thitkness reqmred to sustain the pressure and caused by cracking, wastage, and frettmg. wdl release thermalloadmg caused by the worst postulated LOCA in radioactne matenals to the secondary coolant system.

combination with a safe shutdown earthquake.2 Furthermore, serious weakenmg of these tubes from simdar causes could, m the esent ot a loss-of coolant Inadequate control of the secondary coolant chem-accident (LOCA), result m tube fadures that would istry has been identified as one of the principal sources release the energy of the secondary system mto the

' As defined in Appendix A. "Seisrnic and Geologic Siting

, Fadure is defined as full penetranon ef the pretsure boundary Criteria for Nudear Power Mants.' to in CFR Part 100,

" Reactor Site Cntena "

with subsequent leakage u s sis.c USNRC RE GUL ATORY GUIDES co - m.

h viaa.e..a....me5.c.......,i.(..-

"W "

a.v...

cm, a..

... n o. a i o e..

..e.. a -...... i..o.

o.*.,one.c h*"***

,-.,~.o.....e.eu,,

i s, wi r...,,.., pi. -.,, e,.y....c p.,4 o,,*.

c o -........ g., w. in 4,i

..... a o.

....a n, i n.... n......

....v.....,e,%...

.. c.,. m

.4....o.~.o.,,

3......,4c...i.

.... a.u. o, c,.a........*.,.....e...g......

e...+..ac.

c f

...no.....o..w....,v..*...i.......an.....,..no......

y,,,,

,,g

.a. p.o..

.n...< <. m.m.,, s.,........ n... u.. w. e o.,. v.,. a....,.

3 gggm,,g,

o......

...c.~.ao....ne. c...~....e.. n..w. c o

... 3a

,..o..... p.o......m.

,.y.4

... o p... p.,...,.

io c,

...i b'

c a

..~..ee....

n.+

b...a i.-...- o p..... m 8...

..,,...ge.o,....,.,.<.--oo.,,,e,.

.......,~,-........4..

c.....-.4-..

.-.......o......-.......-.......

-...-.u

....~,,4..........-,_.-...-

...o.....~..,-..,a....c.--....,

........,.... _. _,....... -......4......o m.s......,o.......

,,m.,s,.-.-.n....-..

7 007100 y/ 7

.s.

of steam gnerator tube depadauon and tailure lhere is Durmg reactor operauon. steam generator tube leaks evidence that excenne,tcamsde corrosion attack are detected by monitonng the secondary system for otcurs m restrated flow.ueas that pernut high local radioacuvity.nd the presence of boron through instru-concentranon of tree causuc. pimsphates, and impunues ment analysts of steant and blewdown samples ifleaks that nuy enter the steam renerator through condenser are present, they can usually be located by eddy cunent mleakaye Theref ore. secondary water chenustry specifi-exanunation of suspect tubmg. Lddy current cuouna cations must reflect the knutanon of the nutenals m the tion is effectne because it detects the preseme of secondary system, and the supporting auubary chenucal defect-caused vanations m effecuve electnal conduc feed system mus t he desip ed to main tam desired tivity and/or magnetic perraeabihty of the nutenal bemg feedw a ter quab t y to eath steam generator. I ffectne tested. Because the eddy current prohmg tethmque lus momf oring of water themistry with in-hne conunuous excellent sensitivity in nonnugnetic matenals, decreases analy ucal inst r umen ta tion sup plemen te d by plant m effectise conductivity due to a discontmuity in a tube labora t or y sa mphng analysis of steam, condensate wall can be measured duectly by mcreases m cod soltar return, and feedwater is ntcessary at aH times dunng m the probe. Specul eddy cunent probes Jesigned f or operation to ensure ttut water quahty is not degraded scanning tubmg from the inside hase pr oved wn below acceptable Imuts by su,h events as c ondenser effectne in locatmg defect areas m steam genera tor inleakage or themhal f eed syst tm au'.operanon tubes and for assening the useral! tondition of the tubmg in numerous operating PWRs-Mechanical or flow-induced ubranon can cause fret-tmg or latigue da.

' to steam generator tubes, which Radwpaphy is a supplemental method for insenne could also lead to tube fadures mspec' ion of steam geneutor tuhmg AlthouyJi rade opaphy does not provide the speed and lleuhthry of A propam of penod2c unenne mspetoon of steam eddy current methods, it can supplement eddy currcnt generators is essental to mcmtor the mtegnty of the testmg for defect ciuracterization on a knuted baus tubmg. parucuirly if there is endente of mechanial da nu ge or propessne dete, oration caused by made.

leakang tubes, defecove tubes,and tubes that eueed quate deugn. nunufactunng errors, or chenu al imbal.

the Cigang bnut should be taken out of servac by ante. Inservue mstrction of steam grneratuc tubmg can pluypng both ends of the tube at the tube sheet with also proude usetut mformauon regardmg the nature and welded plugs. Vanous methods are used for plugging and cause of any tube depadstion, thereby assisting the

~ 4

"'"'"'7 9..sMied mechamcally or explo-sively, and welding may b: M.,.med manually, auto-ope rat or in taking proper and tunely correctne nuncally, or e xplosnely.

v meas ures.

Exp"nence lus indicated that each steam generator

,nspecuon and repairs of steam generefor tub ng in design fas caucal areas (e g, crevicts, low flow areas, opera ung plants cause some radauon e xposure t and repons that allow steam blankeimg) where attack personnel. C aref ul pre-job punning can assist m mam-and degradation of the steam generator tubes nuy o.ccur

'ami;.,

,du c on expor ures as low as is reasonably nen semn n wa er emnty a pmpe@ nmn ~

a clues able. Temporary shieldmg. de c on ta nun atmn.

tained Mechamcal damage to steam generator tubes may special toolmg, pp and fixtures for remote inspection also occur m areas subject to flow 4nduced ubrat ons and repau, and other deugn and procedural considera-Typically, the number of tubes m these enthal areas is cons such as are outhned m Regulatory G~uide 8.8, less than 20% of the total.

,.Information Relevant to Maintammg Occupauonal n 1.uw as Pracucable (Nuclear The usual shop examinatinn of tubing can be consid-Radution h pusure Reactors)," should be used ta the extent pueneal cred to serve as an adequate baseline examinatico. An onsite preservice inspection of the steam generator De recommendations m this guide are appbcable to tubing should be performed in the ab <en ce of a documented shop or field exanunation. For plants now current "t s pical" on t e-t hr o u eh and t' bend steam operatmg. the initul inspection should sample tubes on generators that have Ni Cr-Fe or stam:ess steel tubmg a random basis unless expenence with similar designs The steam generator tubmg is usuaMv eam! ss, cold and chemistry indicate entical areas Subsequent mspec-drawn, and anneated and n r unufactured and tested in tions should concentrate on any totical areas idenufied accordante with specificatmns of the Amencan Socacty that must defectne tubes wiu be found. This selection s

of Methamcal Engneers and the Amenean Smety for nethod can be expected to resu't m the ratio of tube Testmg ard Matenals.

defects found to total tubes mspected being consider-ably higher than the ratm of defectm tubes to otal The irutul quality ol manuf.actured f ahing is deter-tubes in the steam generator mmed by hydrostatic. eddy cunent, and ultrasonie tests.

The tube-to-tube-sheet welds are mspected visually and by dye penetra.nf then finally leak tested.

• lanes mdicate substantaw thanges from prevmus nwe

%/

126 036 i.8 n

g. The equipment used for eddy current testing C. REGULAf0RY POSITION should be designed so that operators may be sluelded or the eqtupment may be operated remotely to bnut A provam for mservice mspection of steam generator tubmg should be estabbi 1 and should include the operator exposure to radiation.

f ollowing'

h. Personnel engaged in data taking and mterpret-ing the results of the eddy current inspection should be

1. Access for inspection tested and quahtied in accordance with American Society for N o n d es t r u c tive Testing Standard Steam generators or pressunted water reactors SNT-TC-I A and supplements.'

a should be dengs,ed to facibtate mspection of all tt.bes.

The exammations should be performed accord-i.

b. Sufficient access should be provided to perform ing to wntten procedures.

these inspectbns and to plug tubes as requ: red.

c. Pre. job planning should be undertaken to make for mspections that ensure that personnel

a. All tubes in the steam generators should be pr ovismns radiation exposure is maintained as low as is reasonably inspected by eddy current or alternative techniques pnor to service to estabbsh a baseline condition of the tubing.

achievable.

b. For operatm, plants without an initial baseline the first inservice mspection performed

2. Inspection Equipment and Procedures inspection, according to regulatory positions C,4 and C.5 will define

a. Inservice inspection should mclude nondes'ruc-the baseline condition for subsequent inspections.

tive exanunatwn by eddy 'urrent testing or equivalent techniques. The equipment should be capable oflocating

c. Operating p: ants instituting a major change in and identifymg stress corrosica cracks and tube wall their secondary water chemistry (e.g., phosphate to ihmmng by chemical wastage, mechanical damage, or volatile treatment) should ccnduct a baseline inspection e

other causes before resumption of power operation.

b. The mspection equipmcnt should be sensitive

4. Sample Sekction and Testing enough to detect imperfections 207e or more through the tube wall Selectim and t<'

.g of steam generator tubes should be made on ti e followmg basis:

c. A suitable eddy current mspection system could consist of (1) an mternal sensing probe, (') a

a. The presernce taspection should tnclude all the '

tw o-channt eddy current tester, (3) a newmg oscillo-g, i

scope, (4) a conventional two-channel stnp chart recorder, and (5): magnetic tape data recorder.

g g

should be selected on a random basa except where

d. Examination results and reports should be experience in similar plants with sinular secondary water stored and maintained for the operating Ufe of the chenustry indicates critical areas to be mspected.

faedity.

c. At least 370 of the total number of tcbes in

e. St.ndards consistmg of similar as manufactured each steam generator to be mspected should be tested steam generator tuhmg with known imperfections dunng each mspection (see regulatory positions C.3 and should be used to estabbsh sensitnity and to calibrate C.6).

the equipment. Where practbi, these standards should include reference flaws that simulate the length, depth,

d. All of the steam generators m a given plant and shape of actual imperfections that are charactenstic should be mspected at the first inservice inspection.

Subsequent mspectmns may be bnuted to one steam of past experience.

generator on a rotating schedule encompassing 3% of the

f. The equipment should be capable of examining total tubes of the steam generators in the plant if the the entire leng h of the tubes.'

i

'SNT~TC-I A and Supplements, " Recommended hactise for Nondestructive Testing Personnel Quabfication and Certifica-

' For l' bend dergm. entry for the hot-leg side w ith examinatior-taon." Copies may be obtained from the Amencan Society for from the point of entry completely around the U bend to the top support of the cold teg is considered sufficent to constitut e Nondestructive Testing, 914 Chicago Avenue, Evanston.

Ilhnois 60202.

a tube mspection.

126 03' D

l.83-3

results of the first inspection mdicate that all. team

c. Inspectsons may be made comeident with generators are performmg in a hke manner. (Note:

refueling outages or any shutdown for plant repair and Under some circumstams, the operatmg condidons in maintenance in accordance with the Amencan Socsety one or more specific steam :nerators may be m of Mechanical Engineers Ikuler and Pressure Wssel r

Code,Section XI.*

be more severe than those in ^- other ger ratt.

.ier such circumstances, the samp'e sequwe Uoold be modined to inspect the steam gent.ata with the mmt

d. If two consecutive inspections, not includmg severe conditicc the preservice inspection, result in less than 10% of the tubes with detectable wall penetration p20%) and no

e. Every m.ction O.eque

,o the preserdce significant p10%) further penetration of tubes with inspection should 1%oe all ronpiogeo tubes that previous indications, the inspection frequency should be previously had de'ectable wall puietrations P20%)and extended to 40 month intervals. If it can be demon-should also mc'ade tubes in those areas where experi-str aed through two consecutive inspections that ence has mdicated potent:al problems-T eviously observed der dation has not continued and

,o additional degradaticn has occurred, a 40-month

5. Supplerientary Sampling Requirements inspection interval may be initiated.

a. If the edt y current mspection pursuant to

e. Unscheduled inspections should be conducted regulatory positios C.4.d indicates any tubes with m the event of primary.to-secondary leaks exceeding previously undetected imperfections of 20% or greater technical specifications, a seismic occurrence greater depth, additieaal steam generators, if any, should be than an operating basis earthquake,2 a loss-of<oolant mspected. If previously degradcd tubes edubit signifi-accident requiring actuation of engineered safeguards, or cant DIOT) further wall penetration, additional steam a major steamline or feedwater Une break.

generators should be inspected.

b. If the eddy current mspection pursuant to

7. Acceptance Limits 5

regulatory position C.4.c indicates that more dian 10%

of the inspected tubes have detectable wall penetration

a. As used in this regulatory guide:

p207) or that one or more af the i.nspected tubes have an indication m excess of the pluggng limit (see (1) Imperfection means an exception to the regulatory position C.7.a), an additional 3% of the tubes dimensions, fmish, or contour requ: red by drawing or should be mspected, concentrating on tubes in those specification.

v areas of the tube sheet array w here tubes with imperfec-tions were found. In addition, the rest of the steam (2) Defect means an imperfection of such generators should be mspected accordmg to regulatory severity that the tube is unacceptable for continued pczition C.4.c.

service.

c. If this additional mspection indicates that more (3) Hugging limit means the imperfection than 10% of these additionally inspected tubes have depth at or beyond which pluggng of the tube must be detectable wall penetration P205) or one or more of performed. (Note that the pluggmg brrut is not a depth these additionally inspected tubes has an indication in of penetration within the defect range but rather an excess of the pluggng brnit, additional tubes (no less imperfection depth with conservauve allowances These thn 67 of the total tubes m the steam generator)in the allowances include such consideratior.s as general corro-area of the tube sheet array where tubes with imperfec-sion and measurement error.)

tions were found should be msacted.

(4) Huggmg cntena rneans those calculational

6. Inspection Intervals and analytical procedures used to arnvt. at the plaggmg limit. Unese currently may be submitted by a licensee

a. The Grst mservice inspection of steam genera-for approval by NRC.

to:s should be performed after 6 effective full power neths but before 24 calendar months.

b. If, in the mspection performed under regula-tory position C.4, less than 107 of the tubes mspected

b. Subsequent inservtee inspections should be not have detectable wall pentration P20%) and no tube has less than i 2 nor mme than 24 calendar months after the imperfections that exceed the plugging limit defect, prenous mspection.

plant operation may resume.

'n all in spec tes, previously degraded tubes that exhibit

' Copies nuy be obtained frorn the Arnerican Society of i

ugnificant (>loh thrther wall penetration rnust be included in Methrtical Engineers, tJnited Engineenng Center. 345 East the to'i 47th Street, New York, New York 10017.

/

v 1.83 4 126 038

D. IMPLEMENTATION

c. If, in tr e inspections performed under regula-tory position C.5, less than 107c of the total tubes The purpose of this section is to provide infornuuon inspected have detectable wall penetration f>20%) and to applicants and hcensees regardmg the NRC staff's no more than three tubes exceed the plugging bmit, v

plant operation nuy resume af ter required corrective plans for utilizing this regulatory guide.

measures have been taken.

d. If, in the inspections performed under regula-tory position C.5, more than 107-of the total tubes This guide reflects current regulatory practice. There-inspected have detectable wall penetration (>20%) or fore, except in those cases in which the appbcant more than three of the tubes inspected exceed the proposes an acceptable attemauve method for comply-plugging bnut, the situation should be immediately ing with specified portions of the Comnussion's regula-reported to the Commission in accordance with the bons, the methods descnbed herem will be used by the for resolution and approval of the NRC staff in evaluating an applicant's program for facility lic<

proposed remedial action. Additional samphng and more nspection of steam generator tubes.

frequent irqv crions may be required.

8. Corrective Measu;es Technical specifications for ensuring inspection as All leaking tubes, defective tubes, and tubes with recommended in regulatory position C should be incor-imperfections exceeding the pluggmg limit should be porated in operating licenses, plugged.

s 126 039 e

!.83 5

UNITED STATES p

]

NUCLE AR REGULATORY COMMISSION O

WASHINGTON. O. C.

20556

,O,7,,,,,,,,,,,,,,

jj mu W

o.P,

,A<

k_dM PENALTY POR PalvAtt USE, S300 9

v 126 040 v