ML19317G704
| ML19317G704 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/20/1972 |
| From: | Rich Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| Shared Package | |
| ML19317G639 | List: |
| References | |
| NUDOCS 8003270291 | |
| Download: ML19317G704 (3) | |
Text
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'g UNITED STATES
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l.1 ATOMIC ENERGY COMMISSION i
REGloN V
- 1 h s 21li cANCROFT WAY 4
BERKE!.EY, cal.lFoRNIA 94704 ran
. su. sus En.sse June 20, 1972 Sacramento Municipal Utility District Docket No. 050-0312 P. O. Box 15830 Sacramento, California 95813 Attention:
Mr. John J. Mattimoe Chief Engineer Gentlemen:
Information obtained during inspections conducted by the Directorace of Regulatory Operations has disclosed that a number of facilities have been equipped with valves with wall thicknesses below the mini-p mum requirements specified by the applicable codes, standards and t
procurement specliications. In other instances, licensees have not been able to document whether or not 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 manufacturing records or other suitable means, that valves important to nucient snfety installed or to be installed at your facility (ies) 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 availabic and when our inspector may examine them at the plant site.
In the event that records are not currently available, you are re-quested to.idvise this office within thirty (30) days of your plans and schedules for demonstrating by suitable alternate means that valves important to nucicar safety installed or to be installed at your facility (ics) are acceptable with respect to wall thickness.
Records of conformance shall be maintained current with inspections performed.
The valves which require demonstration of acceptable wall thickness are the following:
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F Sacrtmento Municipal Utility 2
June 20, 1972 District 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 1 1/4-inch nominal pipe size in water lines for boiling water reactors; (c) Over 2 1/2-inch nominal pipe size in steam lines for boiling water reactors.
The following techniques are considered to be a sufficient demon-stration of acceptable wall thickness. Alternate techniques may be offered, but there is no assurance that they will be found acceptable:
)
(1) Documented direct physical measurement of actual wall thickness with comparison to specified minimum wall l
thickness.
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j (2) Documented results of ultrasonic measurement of vall thickness with comparison to specified minimum wall 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.
(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 diickness.
(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; FSS-SP-66) in effect on the date of the
-l purchase order.
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. (5) Certain of your valves may have, for procurement con-venience, been ordered to ratings higher than actually e
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Sa'cramento !!unicipal Utility 3
June 20, 1972
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District required by service conditions. In such instances, you may, if you vish, provide for our review an engineering justification for accepting valves which do not conform to procurement specifications, but do, in your opinion, satisfy service requirements. Such justification should be promptly transmitted to this office in ten (10) copies.
(6)
In certain instances, you may wish to repair valves found 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 a description of techniques to be used to verify the acdeptability of the repaired components. Such a pro-posed procedure should also be submitted in ten (10) copies.
Acceptable documentation of conformance with the above requirements must be completed within three (3) years of the date of this letter.
rN Sincerely,
__ e R. U. Smith Director, Regica V
- Directorate of Regulatory Operations cc:
V. McMahon, SMllD bec: RO Chief, Reac tor Testing & Operations Br RO Office of Operations Evaluation RO AD for Proc edures RO AD for Inspection & Enforcement
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