ML19338F263
| ML19338F263 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, Zion  |
| Issue date: | 06/29/1972 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8010140660 | |
| Download: ML19338F263 (3) | |
Text
.
s eco
- i UNITED STATES
'e' O
ATOMIC ENERGY COMMISSION l
- ,,,#s
/
g DIRECTORATE OF REGULATORY OPERATIONS
- '11 S' g REG!ON lli 8
799 ROOSEVELT ROAD ymg GLEN ELLYN, ILLINOIS 60137-(312) ess-2sse June 29, 1972 4
Commonwealth Edison Company Docket No. 50-10 ATTN: Mr. Byron Lee, Jr.
Docket No. 50-237 Assistant to the President Docket No. 50-249 P. O. Box 767 Docket No. 50-254 Chicago, Illinois 60690 Docket No. 50-265 Docket No. 50-295 Docket No. 50-304 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 minimum 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 require-ments. 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 nuclear safety installed or to be installed at your facilities 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 records are not currently available, you are requested 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 facilities i
are acceptable with respect to wall thickness. Records of conformance shall be maintained current with inspections performed.
1 J
L~
. ~...
.2 -
~~
Commonwealth Edison Company June 29, 1972 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(a) (Codes and Standards) of 10 CFR 50, where the valve is:
(a) over 1-inch nominal pipe size for pressurized water reactors; (b) over ik-inch nominal pipe size in water lines for boiling water reactors; (c)tover 2h-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 is no assurance that they will be "nund 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.
(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.
I
Comonwealth Edison Cecipany June 29, 1972 (5) Cartain of your valves may have, for procuretient convenience, been ordered to ratings higher than actually required by acrvice conditions. In such inctances, you may, if you wich, provide for our review, an engineering justification for accepting valves rhich do not conform to procurement specifications, but do in ycur opiniot, satiofy cervice requiret:ents. Such justificatier. should be pronptly transnitted to this office, in tea (10) cos.ics.
(6) In certain instances, you nay vich to repair valven found to have vall thickness below the specified cinicu::1. In such instances you are requested to provide this office for our review, the propcced repair procedure, including a descri,tica of teclusiques to be used to verify the t
acceptabilit y of the repaired eceponents. Such a proposed procedure should also be rubmitted in ten (10) copics.
Acceptable docu~.entation of conformance with the above requiretmute cust be ce=pleted within three (3) years of the date of thio Ictter.
Very truly yours, Boyce II. Grier Regional Director bec: RO Files DR Central Files a
-