ML19324C457

Requests Approval for Use of SB-166,UNS N06690 (Alloy 690) Matl in Fabricating Steam Generator Plugs,As Alternative to ASME Boiler & Pressure Vessel Code Section III Requirements, by 891215

ML19324C457
Person / Time
Site:	Calvert Cliffs
Issue date:	11/07/1989
From:	Taylor J BABCOCK & WILCOX CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
JHT-89-235, NUDOCS 8911170127
Download: ML19324C457 (2)

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,y f B&W NUCLEAR TECHNOLOGIES 3HT/89-235 November 7, 1989 3315 Old Forest Road m Boxfosas I ynchbury VA 24506-0935 Telephone:804 385-2000 Telecopy: 804-3BS-3663 o

U. S. Nuclear Regulatory Commission [t?- 3/7 Washington, D.C. 20555 Attention: Document Control Desk

Subject:

B&W Proposal of Alternative to ASME Boiler and Pressure Vessel Code Section III Requirements

Reference:

1) Letter from Mr. G. C. Creel (Baltimore Gas &

Electric) to U. S. NRC Document Control Desk, dated October 27, 1989, " Revision of Proposal of Alternative to ASME Boiler and Pressure Vessel Code Section III Requirements" (copy attached).

Gentlemen:

The purpose of this letter is to request approval for the use of SB-166, UNS N06690 (Alloy 690) material in fabricating steam generator plugs. As noted in the referenced letter, this material possesses superior corrosion resistance to primary water stress corrosion cracking over Alloy 600, the current material that is used for steam generator plugs. The design values that will be used for code calculations will be based on those given in Code Case N-474, approved for SB-163 material, and Code Main Committee Item 88-360, approved December 9, 1988 for all forms of Alloy 690. The information from 88-360 will ha included in the Winter 1989 Addenda of the Section III Appendices.

As material requirements for Alloy 690 are contained within SB-166, this specification, and B&W manufacturing roquirements that are more restrictive, will be adhered to for chemical and mechanical properties.

B&W has requested ASME approval for the application of Alloy 690, Specification SB-166, SB-167, SB-168, and SB-564 material for

l. Section III repairs, and the ASME B&PV Code Committee will be i reviewing this request.

Your approval of this proposal is requested by December 15, 1989 l to allow the use of Alloy 690. The need for this material is

' based on the recent problems that have been associated with Alloy 600 when used as mechanical steam generator plugs. Therefore, the use of Alloy 690 is the correct choice of material for steam generator plugging applications to avert potential plug cracking concerns.

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b L-i r .. l NRC Document Control Desk 1 JHT/89-235 November 7, 1989 Page 2 l

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l Should you have any further questionc regarding this matter, we will be' pleased to discuss them with you.

By copy of this letter to Mr. J. E. Richardson, he is requested ,

to advise me promptly as to whether a December 15, 1989 approval is feasible. B&W plans to begin installing 690' plugs in January 1990.

Very truly yours,

s. '

gf -

. Y. Ta or, Manager '

Licensing Services JHT/bcc Attachment cc: L. B. Engle/NRC K. R. Wichman/NRC J. E. Richardson /NRC S. P. Hellman J. R. Bohart R. B. Borsum 1

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Washington. DC 3p398 .

l ATTSim0N: Document control Desk SUBJECTt Calvert Cliffs Nuolear Power Flaat Unit Nee. ! 4 2; Declost Nos. 50-317 4 30-818  ;

L l Revleien of Proposal of Altern4tive to ASMB 5eller and Pressese l

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l Gentisment j The purpose of this letter k to ausend Referesse (a) with the following proposal. la -

assordamos with 10 CFR 80J8e(s)(3), we are propeelas an alternative to the l requhement of 10 CFR 50J8e(s). The oristaal proposal arreeseuely ented that it wee is subseisted la eseosdanse whh Referesse {D), ,

1 l We have determlaed that Alley 690 is esperior to Alley 600 for 'ues se repineament i pressuriser ;ne'er. material due to la prhnary waser stress soriosion creeklas (SCC) feelemass. The ASME Beller and Pressure Vessel (B&PV) Code approves the use of Alloy 090 under Speelfloation 53-163 for Seedon M (Code Casse N-20-3 and N-4?d), J but Spesifisesione $5-166 and 85-107 are not curready leoluded. .We are psopeeles to use, at our opiloa, ' Alloy 690 mesdag Spectriostloa 5B-166 or 88-167 lastead of Alley ,

600 for penseurier penetrettes soplacemean. i 1

i, c o - = = i. N w w.k an A e = r!v. As r_ ,

L The seinshed drawing Identifies all pressoriser penetrations, We plea to use f Ainoy 890 unear spostfloation $5-146 or SB-167 fbr say penetratloa that requlrse replacement. These penetrations were orislaally desisned to ASME BAFV Code secties M. Class 3,1965 Edition through Winter 1967 Addenda.

gg, AaME Rman!  : far WMeh an Airr M!= 1. Prema**d .

We have adopted the alternative allowed by ASME B&PV Code Seetion XI.1986 Edition, paragraph IWA-7210(c). The alternative allows that 'repkan. ente sesy

- most all or portions of the niquiremens of later editions of the Constructica Code . . .

• We have reviewed the ASME B&FY Code Section W and noted that the use of Alloy 690 meeting .*peelflaations $3-166 and 53-167 la not 3aalad*d Reguintory Guide 1.85 list Cooe Case N-20-1 as approved; however, this 0446 h lI'lO I

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, vv T) . iF3 rnoM CCNP M END NEF-lF U. mM N Deemment Control Desk '1

. Celeber 87.1989 pese heat esp!!ss only to Spesificaden 59163 esamless tablas for eendenser or enchanger appilettless with e 40 kai etaisus yloid stroasth. Additionally, we sets est Code Case N to 1 has emphed and has been renewed as N 20-3. Also,  :

Code Case N-47d has recently been approved by the ASME Code Committee (which includes approval by the NRC repressatative Mr. R. J. Bossak) darias its l l

Pobruary 1949 nimestias.. and will appear la the neat ASME B&PV Code Case  ;

publicatloa. Agala, this Code Case applim only to Spesifloation 53-163, but '

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allows the use of a 35 kel minhausa yield strength masselst. l l

i M. Enala rhe pmanamina na Alespinalwa t

During the surrent Unit 2 refuelles estage, na laservios inspectiam of the Unit 2 pressuriser elseovered evidemos of remotor coolant .from a . somber '

pesotrations and one pressuriser pressure penettstion.

of bester Butesquent lavestigations have revealed that a number of those penetrations must be either pepelped or repleted.

The orislani penetrosions are made of Alloy 600 'While tide material is seceptable as repleosment maserial, the current body ' of den ladleness that Alloy 690 pensemos superior SCC resistanos. The laeressed ehromium content i

i of Alloy 490 produces a material that has been demeestrated to be Isanname or at '

i least realetant to degrudation mechannama that are active with Alley 400. For osaapie, om page 2-9, Reference (c) states, ' ell avellable dem for Alley 490 ,

i sagssets this material (' microstructure') is not sueseptible to primary water strose corrorton orookins (PWSCC).. Therefore, even though the other fheters are presset (ettoes and temperature), PWSCC has not been observed la this alloy.' Page 8-1 of Referosse (d) ooncludes, ' Alley 490 was lamene to SCC la pure water under all conditions evaluated' tad "Reaking of the alleys la lerms letruslea environment of their SCC resismase la the simulated resia indicated that . . . Alloy 600 . . . had latertmedisse resistnace, and Alloy 400

. . . had the highest resistemos.* Page y of Reference (e) states, 'ABoy 400 was much more resistaat to stress sorrosien than Alloy 600 and was hamass to Also, cracking la most of the - acidic sul' ate solutions enesdeed.'

- Referentes (f) and (3) eeestado that ersck initiation times for Alley 600 are reduced as the room temperesure yield stroasth and reeldual , streses are lagressed. This same reistleaship would be expected for Alloy 690 material.

Based on the superior stres corrosloa oraeklas reelseaseo properties of Alley 690, we prefer to use It as the rapinoament material for our pressuriner penetradons. The A5MB 34PV Code Section M n!!ews the use of Alloy 690 under Speelfloatlos 88-163: Seamlem Nickel and Nichel Alley Condenser and Heat Bashaager Tubes (up to 7/8-inch 00) whh a 40 kel mishaua yield strenesh per ASME Code Case N-20-3. ASME B&pY Code Case N-474 allows the use c,f 35 ksi niinimum yield strength as speelflod la Speelfloatles52-153 for all i

applicable tubing thlokaanses determlaed la socordamos with N3 3133 using

.- Figure VII-1101 1 la Appendis YH of Sostica III (Refwences h and 1). The ASME B&PY Code, however, does not laolude use of Specifloation 85-146:

i Nickel-Chromium-tron Alloy Red, Bar and Wike or Specifiestlos 88-167:

Nickel-Chromium-tres Alloys amanniana Pipe and Tube.

E~ _ _ __ _ _ _.___________._ ____._________.__.______ . _ _ _ _ _ . _ . . _ , _

Seemment Centrol Desk 1 Ostebet 87,'1909  !

l 7000 $

1 Use of Spoolfloations 88 144 sad 85-14f wiu allow us to repinse the pressurieer penetrations with Auey 690.

!Y. Addistanal mannimmaats .

Timough this proposal, speeltications 85166 and 55.idt will be used tesother with tim applisabes additiesel reduireeman lesend on sowification as. ids la the A8ME B&PY Code Cases N-20 3 and )(.494. Specifissuy, we wiu Whose to the Intent of the A8MB B4FY Code Case N-474 (for 88 ka! minhasa yield ,

strength' sasterial) ftr mechanlaan properties. That lo, we will nuet the minimum yleid OWeagth requirements for Alley 690 as given la 8positleasises l SB-lM or S 167 for Alloy 600, la addiales, we wul establish the sepasste ,

weldlag precedegee sad performance goalifications required for Alloy 690 by the AEME 34pv Cees Cases.

r Your approval of this proposal is scenested by December IS,1949, to nuew the use of ADoy #0 Use of this material wu! provide an aseepteblo level of genuty and safety es described la paragraph m above and further described la Refereness (b), (e) and ,

(d). The esed for thh ' request seuld act reasonably have been entielpand slase ,

f>om peessuriser sleeves or aosales is a rare escursenes. Comp!!sase with the s requiremeses of ASME Code seetloa m wul not result la heniship or unusual dimounty la effeedas repairs. However, the ass of Alloy 600 may be related to the root osuse of the leeksee at the pressuriser poseerations. Thotsfore, the use of Alloy 690 is the oorrest sholes of saaterial for the pressortser sleeve and acule ,

application. Its use wul avert the potential future eensequences (i.e., hardship) -

associated with not uslag the best avelleble material.

Should you have say further questions regardlag this metter, we will be pleased to discuss them with yes.

Very truly yours, V .

OCC/JM0/dian List of Refertases es: D. A. Stuas. Beesiro J. 3. Subers, Esquire ,

L A. Capes.NRC

8. A.McMou,NRC .

W. T. Russou, NRC -

J. R. Strosakler, NRC -

D. F. Lharoth/J. A. Colla, Jr., NRC T. Maestes, DNR l

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,47, 8FTV9M

1. Desseost Control Dee'.

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. . Osteber 87,1989 Sees d ,

IST OF MPERENCES ,

asittmore Oes and Electrie Revisiet of Proposal of Alterestive to ASMB 9ellet and .

Pressure Vessel Code Section m Requirossents l

(a)

Letter from Mr. O. C. Casel (BO&E) to NRC Desumset Control Desk ,

13,19e9, Propetal of Alternatives te ASME Code Seelies M Requirements  !

NAC Staff Onidasse Letter on A$ME Rollef Regesets, dated Jessary 1978 (b)

April 1989, Westisshouse Sesam Generator Tube Plus latesrity Suminary Report.

(o) Electrie C&g:l=, WCAP-12344 Revision 1 .'

L Stress Cemelos Creeking Resistemos of Aueys 600 and 690 and Com

( (d) Metals la BWRs, July 1988. Electric Power Research Instiente, NP-5 rep 8ft (e)

Stress corrosien Crasklas Resisensse ofElectrie AlloysPower 600 Resterth and 690 in Asid Solutions at Blevated Tesapeestur:s, ossober 1983 ,

lastitute, NP 3048 Fleel Report Generseer Tullas. Testing of (f) Intergranular Stress Cerrosion Cracklas la steamAlloy GPO an Materials in Nuclear Power Systems- Water Reactors, TMS.1988 AYT Water, B. F. Mistia and C. E. Shoemaker, C (3) 30,1988 Cases of A5ME Boiler and Pressure Yessel Code Case N 20 3, November -

I (b)

Cases of A8ME Boller and Proesure Vessel code, Case N-474, to be pob!

(1) .

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