ML19319E178
| ML19319E178 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 07/17/1972 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Rich Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 8003310695 | |
| Download: ML19319E178 (2) | |
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QGNU2 SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S Street, Box 15830, Sacramento, California 95813; (916) 452 3211 July 17, 1972 4
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Mr. R. W. Smith JUL 201972 Director, Region V Directorate of Regulatory Operations EDT I'
United States Atomic Energy Commission 18IMbh 2111 Bancroft Way Berkeley, California 94704 9
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Dear Mr. Smith:
This is in reply to your letter of June 20, 1972, Docket No. 050-0312, in which you requested that we verify that certain valves for the Rancho Seco Nuclear Gener sting Station meet the minimum wall thickness requirements.
As your inspector is aware, an investigation on this same subject, but of smaller scope, was conducted by the District some i
months ago. The actual measurements made on valves at that time are available at the jobsite and have previously been reviewed by your inspec tor. With the exception of those measurements, there are currently no additional records available at the jobsite on this sub-ject.
We have established a program to verify the wall thickness of the valves as required by your letter. This program and the status are as follows:
1.
Establish a list of the valves to be verified. This has been completed. There are approximately one hundred (100) valves involved.
2.
Calculate the minimum wall thickness for each size and type of valve. These calculations have been completed.
3.
Verify that the wall thicknesss of the valves meets the minimum requirement by a record check or by actual me.asure-ment of the wall thickness at the jobsite. This activity has' started the week of July 17, 1972.
It is anticipated that our verification program will be complete and the records available for review within ninety (90) days.
Regarding the repair of valves found to have wall thicknesses i
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. July 17, 1972 below the specified minimum, please be advised that as a result of our previous investigation on this subject, five valves were repaired at the supplier's plant by_ weld build-up. These repairs were performed to approved procedures which included radiographic examination of the repaired greas. The documentation on these repairs is availabe for review at the jobsite. For any repairs to be performed as a result of this current verification program, the proposed repair, procedures will be submitted'for your review.
Please advise us if there are any questions regarding this program.
' Sincerely yours,-
Y. Ju J. J. Mattimoe Assistant General Manager and Chief Engineer 0
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't UNITED STATES L.{
J.L ATOMIC ENERGY COMMISSION REGION V 2111 BANCROFT WAY BERKEl EY, cal.lFoRNIA 94704 in
- c. eu. sus r.xv. es June 20, 1972 Sacramento Municipal Utility District Docket No. 050-0312 P. O. Box 15830 Sacramento, California 95813 Attention:
Mr. John J. Ifattimoe Chief Engineer Gentlemen:
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 mini-mum requirements specified by the applicable codes, standards and procurement specifications.
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 manuf acturing records or other suitable means, that valves important to nuclear safety 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 available.and when our inspector may examine them at the plant site.
In the event that record z.e not currently available, you are re-I quested to advise ~this office within thirty (30) days of your plans and schedules for demonstrating by suitable alternate means that I
valves important to nuclear 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 thicknet.,s are the following:
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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 no.ninal 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 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 thickness.
(2) Documented results of ultrasonic. measurement of wall 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, l
(3) Wall thicknesses, verified by either of the above techniques, tx> 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.
1, (4)
"Specified Minimum Wall-Thickaess," as used above, means the wall thickness required by the relevant codes and
- standards (e.g., ASA B31.1 (195S) ; USAS B31.1.0 (1967);
,USAS B16.5; MSS-SP-66)- in effect on. the date of the purchase or'er.
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-(5)
Certain of your valves may have, for procurement con-venience, been ordered to ratings higher than actually 1
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June 20, 1972 District required by service conditions.. In such instances, you may, if you wish, 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 i
a dese.ription of techniques to be used to verify the acceptability of the repaired components. Such a pro-posed procedure should also be submitted in ten (10)
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ccpies.
Acceptable documentation of conformance with the above requirements must be completed within three (3) years of the date of this letter.
Sincerely,
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R. W. Smith Director, Region V Directorate of Regulatory Operations cc:
V. McMahon, SMUD bec: RO Chief, Raactor Testing & Operations Br RO office of Operations Evaluation RO AD for Procedures R0 AD for Inspection & Enforcement.
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