ML20006E803

Forwards Request for Relief from Schedule Requirements of NRC Bulletin 89-002, Stress Corrosion Cracking of High Hardness Type 410 Stainless Steel Internal Preloaded Bolting in Anchor/Darling Valves.

ML20006E803
Person / Time
Site:	Prairie Island
Issue date:	02/16/1990
From:	Parker T NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
IEB-89-002, IEB-89-2, NUDOCS 9002260364
Download: ML20006E803 (4)

Text

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414 Nicollet Mall Minneapolis, Minnesota $5401-1927 Telephone (612) 330 5500

- February 16, 1990 NRC Bulletin 89 02 i.

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h Director of Nuclear Reactor Regulation I ,- U S Nuclear Regulatory Commission

" Attn: D6cument Control Desk Vashinr, ton, DC 20555-a, PRAIRIE IS1AND NUCLEAR GENERA 17NG PIANT

" ' Docket Mos. 50-281 License. Nos. DPR-42

$C 306 DPR-60

, Request for Relief fro.e the Schedule Requirements of NRC Bulletin 89 02 h Stren Corrosion Cracking of High Hardness Type 410 Stainless Steel Internal Preloaded holtirg in Anchor Darline Valves Our request for relief from the schedule requirements of NAC Bulletin 89 02 is attached.-

'Please contact'us if you have any questions related to.our request.

. Thomas M Parker-Manager Nuclear Support: Services c: Regional Administrator - Region III, NRC Senior Resident Inspector, NRC NRR Project Manager, NRC y G Charnoff

-Attachments 4

1. Affidavit

-2. Prairie Island Response to Bulletin No. 89-02 1.

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9002260364 900216 PDR ADOCK 05000282 G PNU ,

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I UNITED STATES NUCLEAR REGUIATORY COMMISSION 1

NORTHERN STATES POWER COMPANY y ,

FRA7.RIE lISIAND NUCLEAR GENERATING PLANT DOCKET NO. 50 281 j, 50e306

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..f1'I L STRESS CURROSION CRACKING OF HIGil HARMESS TYPE 410 STAIFLESS STEEL INTERNAL PREILAr2D BOLTING IN ANCHOR DARLING VALVES l! .

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, Ncrtnern States Powey Co:1rt.1y , a Mi inosota corporation, with this .atur is uubmitting informat.fon requested by NRC Bulletip 89-02.

v i This letter contains no restricted or other defense information. l NORTHERN STA ES POW COMPANY By YM12 i

' Thomas M Parker  !

Manager, Nuclear Support Services i onthis/h yo 8 9d before me a notary public in and for.said u County, personally appeared Jrhomas M Parker, Manager, Nuclear Support Services,.

and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof, and ' that to the best of his knowledge, information, and belief the statements made in it are er e and that it is not interposed for delay, V

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m m v:::.v: v:: V:::.v.v:.y v.T MARCIA K LaCORE

NOTARY PURIC-MINNESOTA HENNEPIN COUNTY My Commission Expires Sept 24.1993 w-:: v: v::: v:::.v::: ll v :: :::.

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l mg PRAIRIE ISIAND RESPONSE TO BUf f tTIN No. 89 02 r" .

Prairie Island has reviewed NRC bulletin 89-02, " Stress Corrosion Cracking of i High Hardness Type 410 Stainless Steel Internal Preloaded Bolting in Anchor Darling Model S350V Swing Check Valves or Valves of Similar Design". The j

,_ bulletin requests: .

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'1. disassembly.and inspection of Anchor Darling model S350W swing check  ;

valves and swing check valves of similar design, 4 4 2. summsry of inspection resulta, and f

3. technical justificacion cf alternate schedules to the schedule proposed  :

in the bcIle'in. ,j Thiu 1ctter is written to provide preliminary rusults on Anchor Darling check

,w valve inspectione at Prairie Island and describe an alternate inspection schedule r for similarly, designed check valves in use at Prairie Island.

In response to NRC Information Notice 88 85,-" Broken Retaining Block Studs on Anchor Darling Check Valves", Prairie Island elected to-replace all retaining block studs in' the eight (four per unit) Anchor Darling check valves of subject-in the notice. Replacement material was ASTM A564 TP630-1100. The valves are

- 12"-S350W on the Safety Injection Accumulator Outlets. This work was started Li j

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during the March 1989 outage on Unit 2, and completed during the recent January '

1990 outage 'on Unit 1. None of the 410SS studs removed from the valves had failed. Visual checks did not reveal any degradation. The studs did not receive any further inspections.

Personnel received a dose of 5.3 man rem during the 1989 Unit 2 inspections and 3.2 man rem during the 1990 Unit 1 inspections. For comparison, total dose fo_r  ;

all personnel at Prairie Island during 1989 was less than 47 man rem per unit. ,

Review of other safety related check valves revealed eight valves (four per unit) of.similar design and materials. These valves are Crane 8" 300# swing-check valves (Crane drawing wK-7422-K). The valves are installed in the Residual llont L Removal System on the Residual Heat Removal Pump discharge lines and Residual Heat Removal Pump suction lines from the Reactor Coolant System hot legs, k . The bulletin requests . that, for . the similarly identified check valves, the j

/ inspections be performed at the next refueling outage that begins 180 days af ter i

- receipt of the bulletin. Inspections of the Residual Heat Removal Pump discharge 3 check valves will occur at the next refueling outages for each unit (Fall 1990 for Unit 2 and Spring 1991 for Unit 1). 1 4

However, inspections of the Residual Heat Remaval Pump suction from Reactor i Coolant System hot Icg check valves will be delayed until the next core fuel l 1

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g-reso a or a unload, presently scheduled for the Units' 20-year inspection outages . (Spring

, 1994'for Unit I and Fa1111995 for Unit 2). Isolation for inspection of these

. valves removes both trains of Residual Heat Removal suction from Reactor Coolant.

7 System hot legs from service. Therefore, the inspections;need to be'done when

.n . the fuel t is - removed from the core, Based on the good results of our= Anchor

. Darling check valve inspections, we believe that a. delay in the _ schedule for tho -

suction check valves': inspections will not present a significant' safety , concern.

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