ML19326B739

Requests Verification of Wall Thickness for Listed Valves & Provides Acceptable Techniques.Current Documentation Required within 30 Days;Complete Documentation within Three Yrs

ML19326B739
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/30/1972
From:	Jennifer Davis NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	Phillips J ARKANSAS POWER & LIGHT CO.
Shared Package
ML19326B720	List: ML19326B719 ML19326B727 ML19326B729 ML19326B732 ML19326B734 ML19326B737 ML19326B739
References
NUDOCS 8004170571
Download: ML19326B739 (3)

Text

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' 030 PE ACH1C C IT N E CT. *10RT Hw EST T a r e nc. 44c4: ?264103 ATL A NT A. GEORGI A M 303 DIRECTORATE OF REGULATORY OPERATIONS In Reply. Refer To:

June 30, 1972 RO:II:JGD 50-313 Arkansas Power and Light Company Atta:

Mr. J. D. Phillips-Vice President and Chief Engineer Sixth and Pine Streets Pine Bluff, Arkansas 71601 Gentlemen:

'This letter relates to your reactor Arkansas Nuclear One, Unit 1.

Information obtained during inspections conducted by the Directorate of Regulatory Operations, has disclosed that a number of facilities have been -

equipped with _ valves with wall thicknesses below the minimum requirements specified by the applicable codes, standards and procurement specifications.

In other instances, licensees have not been able to document whether or no,e their valves ' met minimum wall thickness requirements. Our survey of this subject has disclosed that the matter is not limited to any class of licensee or valve supplier.

In light of the above information, you are requested to verify, through manuf acturing records or other suitable means, that valves important to nuclear safety installed or to be installed at your facility meet the minimum wall thickness requirements of the specified codes or standards.

To the extent that verification records are currently available, you are requested - to promptly accumulate those records at the plant site, and to advise this office within thirty (30) days of the date of this letter, of what. records are available and when our inspector may examine them at the plant. site.

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Arkansas Power and Light June 30,1972 Company In the event that records are not currently available, you are requested

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to advise this office within thirty (30) days, of your plans and schedules for demonstrating by suitable alternate means, that valves important to nuclear safety installed or to be installed at your facility are acceptable with respect to wall thickness. Records of conforman'ce shall

be maintained current with inspections performed.

The valves which require demonstration of acceptable wall thickness are the following:

Each valve within the reactor coolant pressure boundary, as defined in subsection 50.55(e) (Codes and Standards) of 10 CFR 50, where the valve is:

(a) over 1-inch nominal pipe size for pressurized water reactors; (b) over 11/4-inch nominal pipe size in water lines for boiling water reactors; (c) over 21/2-inch nominal pipe size in steam lines for boiling water reactors.

The following techniques are considered to be a sufficient demonstration of acceptable wall thickness. Alternate techniques may be offered, but there 4

is no assurance that they will be found acceptable:

i (1) Documented direct physical measurement of actual wall thickness, with comparison to specified minimum wall thickness.

(2) Documented results of ultrasonic measurement of wall thickness, with comparison to specified minimum wall f'

thickness, and documentation that the ultrasonic measure-ment technique is demonstrated to have a maximum error in repeatability and accuracy, of not more than 2% of the wall' thickness.

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f Arkansas Power and Light June 30, 1972 Company (3) Wall thicknesses, verified by either of the above techniques, to be not less than 90% of specified minimum wall thickness will be acceptable, provided that the documented mechanical characteristics of the material exceed the specification-minimum by an amount sufficient to compensate for the measured reduction in wall thickness.

(4) "Specified Minimum Wall Thickness" as used above, means the wall thickness required by the relevant codes and standards (e.g., ASA B31.1 (1955); USAS B31.1.0 (1967);

USAS B16.5; MSS-SP-66) in effect on the date of the purchase order.

(5) Certain of your valves may have, for procurement convenience, been ordered to ratings higher than actually required by service conditions.

In such instances, you may, if you wish, provide for our s,

review, an engineering justification for accepting valves _which do not conform to procurement specifi-cations, but do, in your opinion, satisfy service requirements. Such justification should.be promptly i

transaf *ted to this office, in ten (10) c.opies.

(6) In certain instances, you may wish to repair valves found j

to have wall thickness below the specified minimum. In such instances you are requested to provide to this office for our review, the: proposed repair procedure, including l

a description of techniques to be used to verify the j'

acceptability of the repaired components. Such a proposed 1

procedure should also be submitted in ten (10) copies.

Acceptable documentation of con #ormance with the above requireme-ts must be' completed within three (3) years of the date of this letter.

Very truly yours, cwnal s;p.d ay J. G. Daws John G. Davis

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