ML20082S842

Freeze Plugging Stainless Steel Pipe-Using Liquid Nitrogen- Repair of Line Between 1LP-41 & 1LP-42

ML20082S842
Person / Time
Site:	Oconee
Issue date:	09/30/1987
From:	Mize J DUKE POWER CO.
To:
Shared Package
ML20082S817	List: ML20082S842
References
PROC-870930, NUDOCS 9109170316
Download: ML20082S842 (11)

Text

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SING LIQUID N1TROCEN -

, (3) PROCEDURE Tittt l'kEtZC PLUGGING - STAINLESS STELL FIPE - U 1

• RIPA1R Or 1.ThE BEWFC.N ILP-41 AND ILP-42 . . _ . . . . . _

g . (4) PREPARED BY 42 @ 4%.- DAT[ Y.*_J O_* k 7 -

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DAlt (9) COVMt NT S (f of p'oteduit reissue end cate whethe' 8thi.t'onal changen, other than prev.oudy app <oved changes, are included, Atieth edd t.onal pages, d nacitary.) AD0lfl0N AL CHANGES INCLUDE D. (lyes 5 No l

i (101 COMPARE D WITH CONTROL COPY .i %DATF f

COMPLt fl0N Illi DAf fi$lPtRFORMtD .M d _ _ . ~ _ . . . . . . - . . - - - . --

l (12) PROCEDURE COMPLtT10N VERiflCAtl0N ledeti1N/A Check hits and;oe tilanks piuaedy aini, seg'ind, daint u 1.0,0 in N'A nr N'R, an appiopiialet di 1 ' N/A Listed enttosures attechedi dYet!JN/A Daia thrvts attached, eumpletrd,ilated and legimil

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• c DUKE p0WER COMPANY OCONEE NUCLEAR STATION FREEZE PLbGGING + STAINLESS STEEL Fil'E USING L10VID NITE 00EN * ,

RETAIR OF LINE BimiEEN ILP 41 AND ILP 42 1.0 Purpose To provide instructions for safely f reece plugging stainless steel pipe -

using liquid Nitrogen. This procedure is for fresting three inc'. piping lietween LP 41 and I.P 42 to allow the repair of a leak in the pljing.

2.0 feferonecs I,etter from R.A. Harris, Design !!ngineering, to R. Leatherwood, dated 9 29 8* (See Enclosure 13.4).

3.0 Personnel Roaultements

- 3.1 Hinimum of one person quellfled to this procedure.

3.2 Ref er to Section 111 of Station Work Roquest.

4.0 Safety Considerattons

^

4.1 Equipment Clearance and Isolatton 4.1.1 Permisalon to releano equipment for m.ilntenance shall be granted by Unit Shift Supervisor. .

4.1.2 Personnel performing this proceduie should to best of their ab!!Ity verify safe conditinn of equipmont on which maintenance la to be perfo mod Ag verify nato positions of valves, breakers, etc.

4.2 He' alt h I'hyalen Considernt lons

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4.2.1 Heaponsible Supervisor will casure Technicians understand

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1. Iago 2 of II 4.3 Spocle! 5.1fety Considerations

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for protection of workers andreequipment.Respo provJded

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Responsible Supervisor at all times at freeze s}JJQ Q ensure Technician is posted

4. 3. .l eal area when line is froton.

Pipe any should shock JO tmpact beforces.adequately supported 63o $1 subjected 4.3.4 Dye penetrant examination j surface freero s., at freeze seal loc!!QG be performed on pipe ation, prior to performing defects greater ealing than to ensure 1 inch..pipe surface is free of linear .

4.3.$

considerations for freeting of vetor EQ thawing of ice.

' A.

When v.ater frooses, it.. expands. 4 Since coefficient of temperature much contractio temperature of ico will'actually loosen ic instead of making it tightet B.

Thawing produces reverse effects of 4.L$. A. Ice will expand as temperatuto increases point. i.p to molting

• Therefore to minimite possibility of over stressing pipe, thawing of ice plug should be as rapid as possible without affecting pipe pl syster components.

radiant heaters, or warm air blowers, can be us speed.up thawing.

4.3.6 Fr-tr 'e saal

.gh pipes.should be made when @ vater is flowing 4 .3.7 Line should expansion. be vented, while being frcten, to all ow for 4.3.8 Normal be reducedoperating as much anpressure jossible. h @ temperature s em should of sy t 4.3.9 JJ component. la removed O

' involving applications of heat (such aJ replaced by any method brazing). selected frecto scaling sareas veldingshall OJ b e lucated.

at leaststress.

thermal 21 inchen to ensure from heat heated does Nsections o to minimit to minimite amount of refrigerant needed R melt ice t plug. EQ .

o maintain tro that metal temperature at weld lotntplug. Beforo veldin is teiluirog be a minimua, of 60 F.

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• l' age 3 of 8 4.3.10 Because of low temperatute.11guld nitrogen can destroy human tissue. , l'recautions SHAlt be taken to cover exposed parts of body vest insulated (non portus) gloves, a f ace shield, 6@ (non porous) protective clothing.

4.3.11 Work area M be adequately ventilated to ensure oxygen content of at least 16 percent by volume. .

4.3.12 When two ice plugs are to be used to isolate a single pipe section, they SHAll be located granter than 30 pipe diameters apart. Algo. E freeze seal shall be applied less than 20 pipe diametera f rots a closed valve OR other component that blocks flow of expansion water as ice plug

• forms.

4.3.13 HTV sealant can F,0I be used on atainless steel pipe.

4.3.14 Under $ circumstances should freeze area include fittings.

4.3.15 Frost line shall be at least 3 inches away from nearest ,

socket veld. .

5.0 Statinn Ststus Determined by Unit Shift Supervisvr in Section II of Station Work Request. " Clearance to Begin Work".

6.0 frercquisites fg(16.1 Verif y Responsible Supervisor has revi wed this pr, cedure AJD marked "N/A" all steps known to be [L01 0 applicable.

[8 66.2 prior to job ntart, contact Unit Shif t Supervisor ands A. Have job recorded on turnover shnet for Unit Supervisor.

B. llave normal operating temperature of system reduced as much as possible.

p C. Have system pressure reduced as much as poqible.

/[tL, $ 6.3 Contact QC prior to job start.

4' person Contacted: N 24T/.,I,_ Dates / n - l ,f '7 k)ahepg- e-- - -

//86.4 Contact lif 'or coveragos IS)RWp # We-lA W perhon t'.ontacted:* M y*IN N Dates M / - F7

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, ': . 5 g Work Roquest is snarked in Section !! that retest M functional verification is required, contact Performare:e M Responsible Group prior to beginning work. h*gggMTg Person Contacteds /fy Dates / M " M 6/6 66(4.6 Sections !!.? M91.3 provide instructions for two dif ferent methods of installing freeze jackets on horleontal pipe. H, application is for horisontal pipe EljJconsult Responsible e' Supervisor 0,R Accountable Engineer to decide which snethod is

• applicable.

Hethod'appileable lf// W/a 40 ($ Z- -_

Forson Contacted / IM _ Dates lo -/- N 7_

$ 6.7 Verify adequate source of liquid nitrogen is available at job atte.

[g(Q.8 llave Responsible ' Supervisor or. designee verify safety considerations. Section 4.0. have been complied with..

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g,(2,,,% 7 Initially identify"A_MD independently' verify correct component'.'

Initial Identifications ,& MM Date /v N 7 ,

independent Verifications b.eli A YI4./4 Date /O - / 7 2 _

l- 7.0 Repair Parts 7.1 Ensure all parts used ats documented in Section IV AfD V of Station Woth Request.

8.0 Speela! Tools

' 8.1 Container to transport liquid nitrogen to job site.

8.2 Container to pour liquid nitrogen into jacket.

8.3 Material to make freatu Jacket.

l 8.4 Fracision Tools:

Type / tined For Serial # Cal . Due Dat o

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9.0 Acceptance Rettuirement s

[. f W 9.1 Component. will be repaired AN@ f reeze plug removed.

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N1)K will be performod on f rocw soal area. ,

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10.0 ;nterf erence it ems N/A 11.0 Procedure C Atrr10N All material used directly on pipe sitAt.1. be compatible with Power Chemistry Haterials Culde OR pipe ESAS be wrapped with material that is acceptable. ,

11.1 Inspection of Pipe Before Freets Scaling. '

/lV _ (Jfq,,ll.1.1 Prior to installing f reete jacket, perfore the followings A. Verif y edge of f rene jacket will be' located =o f rost line will NE advance withlu thies inches of a socket weld.

B. Verify pipe is supported properly no sr.alntenance activities do E apply additional stress to area of .

pipe being frozen.

CAUTION Verification of A. AM B. is a Design Engineeling requirements do E proceed if one ran h2I be tact.

C. H toquirements of p0Tij 0T "A" or "B" can 801 be met, contact Accountable Engineer for resolution.

Person Contacted: Dates Clean surf ace of pipe where f recro nealing will occur.

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[f[All.l.2 Direct QC to perforan NDE of area to be f rozen and verify

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.,,. p y / 89 flava grester than 1 inch exist, and oocument on Enclosure 13.3.

11.2 Treeze Jacket Installation on llortrontal Pipo (Hethod I) 11.2.1 Vrap i inch to 2 inch thick layer of tape aruund pipa at both ende of" freeze seal location. Tape SilAIL tempty with Power Chemistry Haterials Guide requirements. '

f/k 1.oondly fit a piece of material much as heavy cardboard.

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/ metal.(heavy duty altuninum foll). or rAnvas around f recro area. AR mark places to cut t wo gas vents A3 liquid

} inlot holn.

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' page 6 of d NDE:

Center hole should t>e approximately 1/2 inch.

AND 2 outer holes just largo enough (appiontmately 1/4 inch) to vent vaportred nitregen.

11.2.3 Cut three holes in top gf, cardboard or other material.

4tt NOTE: l'erforminggiollowing ensures pipe w!!! be completoly surrounded.

• II.24' Wrsp cardboard or other enatorial around pipe forming a loose cylinder with masking tape as end support.

A. Secure jacket with wire or string.

B. Keep a tight seal between tape and pipe, hED between tape and cardbaard or other material. )Jr,f do (LOI let material touch pipe.

• DI .2 .5 Wrap 3 layers of 1/2 inch fiberglass or equivalent around

< jacket, extending about 3 inches beyond jacket on each -

side. .

A. Cover insulation with tape.

B. Do EDI compress insulation.

C. 'Make openings through insulativn of about same site as openings on cardboard, or other material for nitrogen injection and venting.

11.3 Freeze Jacket installation on Hortrontal rips (Hithod 2)

Obtain a prefabricated aluminum freeze box.

[gg(tl.3.1 Gv . Lubricate 0 rings with Dow Corning til before securing to

/ M/)..ll.3.2 pipe.

[1141.3.3 place freeze box on pipe as follows:

A. Attach box on line at point *o be f rozen.

B. Clamp box so bon vill romain in a snug position. 6N,2

. seal will be effective.

11.5 Freese Jacket Installation on Vertical pipe 1.4.1 Wr.p a 1/2 inch thick layer of tape areund cach end of

• 4 frowto seal area. Tapn S)MI. comply with Power Chemistry

/ Materialn G' aide requirements.

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11.4.2 Prepare inlet and vent 1-A. Cut a notch in masking tapo at top of pipe to neceive '

liquit inlet tube, which Sils!!, receive 1.tquid Nitroger..

I B. Wrap one or two layers of taps around tube in notch ,

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to hold in pisee.

i C. Similarly install one or two vent tubes. '

4 11.4.3 1.cos31y fit a place of heavy cardboard, metal (heavy duty aluminua foll), or canvas around freeze area.

NOTE: Performing following ensures pipe will be' completely surrounded by refrigerant. ii

• b V-11.4.4 Wrap cardboard or other material around pipe, forming a [

loose c,vlinder with masking tape as end support.

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A. Secure jacket with wire or string.

B. Keep a tight seal between tape Aj@ cardboard or other material, pyI do N.gT let material touch pipe.

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NOTE: Any other equivalent insulation material may be -

used in place of fiberglass.

4.5 Wrap three layers of 1/2 inch fiberglass around jacket, l

4 extending about"3 inches beyond jacket on each side.

~

A. Cover insulation with taoe.

CAUTION l Do N0_I compress insulation.

B. Make openings through insulation of =Sout same slao as openings on cardboard, or other material, for j liquid nitrogen injection and venting.

11.5 Operating 1.tquid Nitrogen Apparatus 1 11.5.I' Slowly pour liquid ~ nitrogen through a funnel into liquid l'

7 inlet. .

CAllTION l Observe special safety considorat ions in Step 4.1.11.

[fe_11.5.2 Keep Jacket flooded wit h liquid nitrogen at least for period indicated in Enclosure I'l.2 no freer.e seat in

' accomplish d. l T FE add nitrogen occautonally to keep jacket flooded UNTIt, repolta are completed.

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p-dl l . 5.+3 Vhen repairs are completed. remove jacket using Section 11.6 of this procedure.

11.6 Removing Freeze Seal N* * ~ %nfo =

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CA CAtrfl0N Ice plug SilALL be completely melte' hafore ' pipe is restored to service.

11 it is {gcI allowed to melt comple.u.y. pressure may build in pipe. OJ ice plug may damage a component,

. A /1 14.6.1 Thaw freeze plug as follows: , ,

t A. Obtain infra red lamps, electric heating tape.

radiant heaters.' OJ warm air blowers, to assist L thawing.

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l BL JJ vertical pip *e heat at upper end of ice plug.

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l C. Heat complete section of piring between freeze seal l

A'D, J repisced component OR piece of pipe.

Have QC perform NDE of area frozen and document'on

, l' )I.6.2 Enclosure 13.3.

12.0 Festorstion 12.1 Verify area' clean and tools properly stored.

12.2 Notify Operations work is complete.

l 13.0 Enclosures

,13.1 Log Sheet 13.2 Trocre Seal Chart

13.3 NDE Data Sheet 13.4 Letter From R. A. Itarris

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1;NCLOSllRE 13.3 #

l NDE DATA SilEST j Copy as needed for additional inspections.

h3TE:

• Determina Duke Class, Insrrvice Inspection Class (ISI), MD Q. A.

Conditton 1 Duke Class 151 Class . A. Condition

• Haterial to'De Test ed %q

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h /d Detpymined Dy /Mh A[he . r*/

PROCEDURE 5 ff. /. 3 _

Test Hoquiromonts: VT -

circle all roqyirements)

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!!:- MT Initial - RT //A - UT (/ggjfMfggfDate

• • Procedure Numbers ANI VT Proc # -

M /@ N Q.C. Inhpector r Dste _ Pass / Tail (circle one)

/M[ NDE Proc # I 8 b'.

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Q.C. Inspector'[A[ [fmi- Date ,,,,,,e s A i

/[a fall (circle one)

NDE Proc # NV &P M//,3 N/. 7 ,

Q.C. Inspector Date . Pass / Fall (circle one)

NDE Proc #

HT Serial Numbers ,,,

Q.C. Inspector _ ,,,, Date Pass / Fall (circle one)

RFJtARKS: ,

• Det ermino Duje Class, inservie nspection Class (ISI), LND Q.A. Condition c- ISI Class Q A. Condition /

Duke Class Material to Be Ested: .5 ~d Determined By: &521*/AY PROCEDURE STEP

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• Test Requirements: VT - PT

• MT - RT - UT (c(rele all requirements)

• • Procedure Numbers ANI/AN!!: Initial /4/QK/M/25 Date VT Proc # _,,,,

W Q.C. Inspector Date Pass / Fall (circle one)

" NDE proc # INN [ k 7

Q.C. Inspector ~~[- N/ Net _ Date # 70-8) QFall (circle one)

NDE Proc # 7['8/d Ah' 9 _,, '

I Q.C. Inspector Date Pass / Fall (circle one)

NDE Proc #

MT Serial Numbers Q.C. Inwpector Date Pass / Fall icircle one)

REMARKS:

Final Q. A. Approvsgi/1)/3/

/hbite M/ b ANI/ANil Review t

[7 Date~ b /I' d

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l.t:GEND

• hecountable Engincor Supply Information 0,_R,Completo

• • Q.A. Technical Support Supply Informatton OR Completc Q.C. Inspector Supply informat ton 0}t Completo 4f e

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I OI I ENCt.0SUR F. 13, i, I.ETTER FROM R. 4. IIARRIS

. MB0( 87 474 September 29, 1997 .

N. 5. Tuckmen. Stattou kanager Oconee Nuclear Station Attn! R. Leatherwood 4

Re: Oconee Nuclear $tstion. Unit 3 1

freeze Plugging File: 05 27K freete plugging of the 3' stainless steel piping between valves (P 41 and l,

.42 ts acceptable provided the following guideltnis are sattsffed l

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1) Stathless steel pfptng requires only a dys penetrant examinati

,reater than i iengtn eirst.

j 2)

The edge of the freeze plug Jacket should be located such that the frost,line does ne' edvance within 3" from a socket veld.

3)

The piping should be supported such that maintenance activttfes

do not apply additional stress to the aret of pipe being froren.

j 1

• 4)

Welding or use of a torch is not allowel within 24 inches froa '

the ecge of the freeze plug.

j

5) The line should be vented while tein1 froren to allow for espans*on.

%The subject ploing should not have a croblee with soltdificetton of boron if flushed with dominereltted water for ten etnutes as we have discussed.

If it is not possible to flush before freef thg, the Itne should be flushed afterward with system water long enough to aswre there is no solletftcation of boron in the pipe.

l If you have any questions, please call Nike Wilter at estenston 3 7056.

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WM b3 k Ib f/' d i, f. Wyne. Chief Engirieer O' c p -* Nchenical 4 Nuclear Ofvisfon 46 . 4 '. \ th.7 4 L .. dr * * . 'in l1 j. . '.

],K \% t' Ei.'d. bn. WI lW f .n.d. .

ly: R. A. Harris t

Supervising Design (ngineer

• J. . . . i t A. le { ,1 *(3 ' g ' N i RAH /tdw cc: J. f. Norris

. M. R. Wilder **

5. 5. Lefler i

o. J. Gilstrao contret Records 1

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