ML20234C031

Forwards Response to NRC Bulletin 87-001 Re Pipe Wall Erosion/Corrosion Monitoring Program Currently Being Developed for Plant

ML20234C031
Person / Time
Site:	Seabrook
Issue date:	09/14/1987
From:	George Thomas PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	Russell W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-87-001, IEB-87-1, NYN-87106, NUDOCS 8709210149
Download: ML20234C031 (5)

Text

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U George S. Thomas Vice PresJdent Nuclear Product 6on 4

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Put30c Service'of New Homoshire NG;w Hampshire Yankee Division NYN-87106 September 14, 1987 United States Nuclear Regulatory Commission ,

Region'1 631 Park Avenue King of Prussia, PA '19406 Attention: Mr. William T. Russell Regional Administrator Subj ect : Response to NRC Bulletin No. 87-01

Dear Sir:

As requested by NRC Bulletin No. 87-01, Enclosure 1 provides information pertinent to the pipe wall erosion / corrosion monitoring program currently being developed for Seabrook Station.

Should you require further information regarding this matter, please contact Mr. G. Kann at (603) 474-9574 extension 2503.

.l' Very truly yours, M '

Ceor S. Thomas Enclosure cc: 5 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ,

1 Mr. A. C. Cerne i NRC Senior Resident Inspector l Seabrook Station Seabrook, N.H.- 03874 8709210149 8709143 PDR ADOCK 05000443 Y

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P.O. Box 300 . Seabrook, NH 03874 . Telephone (603) 474-9574 i j

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. STATE OF NEW HAMPSHIRE

' Rockingham,' ss.1 September. 11,'1987

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Then personally appeared before me,: the above-named George S. Thomas- who',-

being duly sworn,' did' state that.he is'.Vice President Nuclear Pioduction of-Public Service Company of New Hampshire,'that he.is duly; authorized'to execute

- and . file the foregoing information in the name and. on behalf of Public- Service l

Company of New' Hampshire. and that the statements therein are true to the.best of his knowledge and belief. /

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'D'oris g./ Patterson, Notary Public My ComMssion Expires : .-October 29, 1991.

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l ENCLOSURE 1 TO NYN-87106 Response to NRC Bulletin No. 87-01 Action Requested:

1. . Identify the codes or standards to which the piping was designed and I l

fabricated.

Response

The piping to be considered for inclusion in the erosion / corrosion monitoring program was designed and fabricated in accordance with either the ASME Boiler and Pressure Vessel Code,Section III (for safety class 1, 2 and 3 piping) or. ANSI B31.1 (for non-nuclear safety class piping).

Action Requested:

2. Describe the scope and extent of your programs for ensuring that pipe wall thickness are not reduced below the minimum allowable thickness.

Include in the description the criteria that you have established for:

a. selecting points at which to make thickness measurements

b. determining how frequently to make thickness measurements

c. selecting the methods used to make thickness measurements

d. making replacement / repair decisions I

Response

The Seabrook Station piping erosion / corrosion monitoring program is currently under development, utilizing for the most part the methodology and technical guidance described in the Final Summary Report of the NUMARC Technical Subcommittee Working Group on Piping Erosion / Corrosion dated June 15, 1987. Specific comments relating to items 2.a through 2.d above follow:

a. The key tool for selecting piping locations for thickness measurements is the Chexal-Horowitz-Erosion-Corrosion (CHEC) personal I computer program now being developed by EPRI. Specific information (e.g., pipe diameter, material and schedule, fluid chemistry, velocity, temperature and pressure) utilized to select piping locations to be monitored will be determined by the input requirements of the CHEC computer program. Selection of specific measurement points within the piping location identified by he CHEC computer program will be made by use of a grid system describeC 2 -

the NUMARC Subcommittee Working Group Report.

b. The f requency of thickness measurements will initially be established based on a predetermined likelihood of erosion / corrosion. The sample lot determined to be most susceptible will be examined prior to the second fuel cycle. Subsequent measurements will be scheduled based  !

on calculated rates of wall thickness reduction such that minimum allowable wall thickness requirements will not be violated. l l

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6.. ; Manual . ultrasonic tanting tsdhniques will normally la used to measure sall thickness. This wl11 be coupled vith a . grid > mrking system to l ensure adequate area coverage and repeatability. .

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d. Replacement / repair decisions ufl1 be made based on calculated tirt.e-( .r' to-failure (violation of minimum allowable wall thickness), outage

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y schedules and planned work on a particular system or portion of a feystem. Areas found to have already violated minimum ellowable thickness, or that will seach min!num allowable. Caickness bef ore the next scheduled outage, will'be insedi.ttely evaluated and l '

replaced / repaired ecgocelingl1y{ A p) Ar, to? cie tihe"to quinimum-wall W"

,thioned to examination cycles will be devcicted prior to l impleme.wation of this program.

Action Req (rested:

3. For lig;.id-phase systems, state specifical.ly whether the foW owing factors have been consf.i' e red in establishing your criteria Tor selecting

'poin'tc at which moni;or pipitig thickness (Item 2a): ,

a. riping material (e.g., chromium content) "

'b. piping configuration (e.g., fittings less than 10 pipe diameters apart)

c. pR of water ie.. ,the system (e.g. , 'pH less than 10)

d. systen temperat.ure (e.g. , between 190 and 300'F) '

e. fluid bulk velocitp (e.g. , greater than 10 f t/s)

t. oxygen content;fo the system (e.g., o.iygen content less than <

50 ppb) -

R i sponse:

s Since the '!UFiARC Wo! king Group methodology and technical guidelines are not fiM11 red and thq EPP.I IHEC computer program has not been released, final deedstoas regardtag the inclusion of the above and other f actors in our progrn.n have not.been made. However, it is expected that each of the abeve f actors will be' Eousidered f n the CHEC program in establishing the

, criteria for piping locations to be monitoreo for thicknese.

Act. ion Requested :

4. C>ronologf cally list and sumnarize the results of all inspections that have been performed, which v are specifically conducted for the purpon cf identifying pipe wall thinning. yhether or not pipe wall thinning. m discovered, and any other inspe:tions where pipe wall *.hinning was discovered even though that usio the purpose of that inspection.

Response

Since Seabrook Station's piping sysum have not yet experienced -

significant durations of fluid flow, no pipe wa.11 thir.atng inspections have bacn performed to date.

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5 .' Describe any plans either for revising the present or for' developing new or' additional programs for monitoring pipe wall' thickness.

Response

The' initial pipe wall thickness monitoring program will be developed for implementation when Seabrook Unit 1 begins commercial. operation. At this time we plan to use the NUMARC Working Group guidelines , including the Chexal-Horowitz-Erosion-Corrosion (CHEC) program, to help establish the scope and content of this monitoring program. j

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