ML20127J360

Requests Response to Encl Bulletin 74-10, Failures in 4-Inch Bypass Piping at Dresden 2

ML20127J360
Person / Time
Site:	Monticello
Issue date:	09/19/1974
From:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Wachter L NORTHERN STATES POWER CO.
References
IEB-74-10, NUDOCS 9211190309
Download: ML20127J360 (1)

Text

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UNITED STATES j .' e k, ATOMIC ENERGY. COMMISSION : '

' \Y' DIRECTORATE OF REGULATORY OPERATIONS REGION lil' o % rts o' 799 ROOSEVELT ROAD - -

GLEN ELLYN, ILLINOIS ~ 60137 - (Sit) 858-2000 -.

S E P .. 1 9 ' 1974.- ,

Northern States Power coupeny Docket No. 50-M 3'-

ATnft Mr. Lee Usekter Vies President Power Production and .t Systen Operaties 414 Nieellet Mall Minneapolis, Minnesota. 55401' Gentleneet

'he encioned to Bulletia requests actions by you with regard to your-boiling water reactor (BWR) facilities with operatias liseases..

Should~one or more of your BWR faailities not saatain the bypass pipias system described in this Bulletin, ao estion is necessary on year part..

A writtem response to this office is requested withis 10 days, housver,' --

if you determine this Bulletia act to be applicable to your WWR famility.

Should you have questisas regarding thia Ballatia er estimme requested of you. - please oostact this effie.e.

Simeerely, Jeans C. Kappler .

Regional Director Baclosurst RO Bulletin 74-10 bec: SibMhmtral' Files RO Files PDR-Local PDR

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-9211190309'740919

' PDR- ADOCK 05000263 G. PDR .

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September 19, 1974

. DRO Bulletin No. 74 .

FAILURES IN 4-INCH BYPASS PIPING AT DRESDEN 2-The Commonwealth Edison Company notified the Region III Office of the Directorate of Regulatory Operations by telephone on September 13-15, 1974, of the finding of through-wall cracks in each of two 4-inch dia-meter bypass loops around the discharge valves of the recirculation pumps at the Dresden 2 facility. Early warning of reactor coolant leak-age was provided by the plant's drywell sump collection system.

In each instance the cracks were in the heat affected zone of stainless steel velds joining the 4-inch piping to weld-o-lets on. the 28-inch' diameter main coolant recirculation piping. The cracks were circumfer-ential, from 3/4-inch to 3-inches in length on the OD and extending to substantially greater lengths on the ID of the pipes.

In one instance (the "B" loop bypass line), the area containing the crack can be isolated for repair utilizing valves presently in-stalled. In the other instance (the "A" loop bypass line), the area containing the crack cannot be isolated from the reactor pressure vessel with existing valves in the piping system. Procedures for the repair of this portion of the piping system are presently being consid-ered by the licensee.

Metallurgical examinations are being conducted by the licensee's consul-tants to aid in determining the cause and mechanism of failure.

Several days may be required for such determination.

Inspections conducted by the Commonwealth Edison Company at their Quad Cities Unit 2 on September 15, 1974, have revealed a crack in similar piping at that facility.

Action Requested of Licensees

1. For those boiling water reactor (BWR)--facilities _ presently = shutdown, examine (by ultrasonic or other suitable volumetric nondestructive examination technique) all accessible welds in the bypass piping lines around the recirculation valves for evidence of crack indica-tions similar to those discussed above.. Your. written reply to this-Bulletin shou 3d discuss those welds determined to be inaccessible-for examination.

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A R0 Bulletin No. 74-10 September 19, 1974 I

2. For those ERR facilities presently operating, conduct the examina-tions discussed in 1., above, at the earliest of the following l conditions:

a. Next scheduled shutdown. -

b. Such time that (within the sensitivity specified in paragraph  !

C.S. of Regulatory Guide 1.45) any reactor coolant Icakage detection system indicates, within a period of four hours or I less, either an increase in unidentified 1,cakage to twice the determined normal rate of unidentified Icakage or an increase  !

in the rate of unidentified Icakage by two (2) gpm or more. l (In no case, however, shall the rate of Icakage exceed that j specified by the Technical Specifications without those actions required of the Technical Specifications being taken.)

c. Sixty (60) days from the date of this Bulletin.

3. Notify this office by telephone within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> and in writing within 10 days of the measures you have impicmented, or plan to implement, with regard to those actions requested in 1. and/or 2., above.

4. No :ify this of fice by telephone within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (with written ccafirmation within 10 days) of the results of examinations conducted in response to this Bulletin. A copy of the written n-tification of examination results (including all attachments) s'ould be sent to the Assistant Director for Construction and 0;.crations, Directorate of Regulatos, Operations, AI;C Headquartera i t. Washington, D. C.

Actions K. m!csted of Licensees May be Modified The actions requested of licensees, above, may be modified by this office as meaningful results are available from the metallurgical examinations and failure analyses presently in progress.

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