ML20002A360
| ML20002A360 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 08/06/1970 |
| From: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Minnick L YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 8011140287 | |
| Download: ML20002A360 (4) | |
Text
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UNITED STATES
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g g ATOMIC ENERGY COMMISSION W ASHINGTON. O C.
20545 August 6, 1970 Docket No. 50-29 Yankee Atomic Electric Company ATTN:
Mr. L. E. Minnick, Vice President 20 Turnpike Road Westboro, Massachusetts 01581 Gentlemen:
In a telephone conversation of March 17, 1970, between Mr. R. J. Schemel of the Division of Reactor Licensing and Mr. C. Andognini of the Yankee Atomic Electric Company, we advised you of a recent in-service difficulty with a furnace-sensitized stainless steel component in a reactor primary solant system and we suggested that you promptly investigate the applica-bility of this information to your facility. The difficulty involved full penetration cracking of a reactor vessel nozzle safe end. The cracked material was furnace-sensitized stainless steel which had experienced overstressing; no conclusive evidence with respect to the effect of corrodents has been established.
We are reviewing the potential applicability of this information to other To assist us in performing this review, we request that power reactors.
you supply the following information (to the extent that it is readily available) relating to the Yankee-Rowe Nuclear Plant within 30 days from rec ipt of this letter and inform us of the dates when the remainder of the nformation will be available. To avoid repetition of material that you may already have filed, you may reply to some questions by a brief summary statement, including specific reference to documents already on file.
1.
Identify all known sensitized stainless steel, components of and within the reactor coolant pressure boundary, including portions of piping.
Include furnace-sensitized components affected by substantial field stress relieving, but not the heat affected zones caused by field welds.
State location, type of material and sensitization process.
A definition of reactor coolent pressure boundary is enclosed.
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8 70 Yaniec Atomic Electric Company 2.
Specify the maximun stress levels (calculated or marr' ired, if knoun) these conpenents receive in service.
Indit-le whether the calculations or measurements of stress level were based on the "an-built" condition, including ef fcets of "as-installed" piping hangers and restraints.
Sunnsrize the results of any field neaaurementn of piping displacement that have been performed, including the system conditions for which the measurements were made.
3.
Specify the normal external operating environnent of the components listed above. Discuss the probability of external surface contact with corrodents.
Indicate the normal water chemistry that has been maintained within the reactor coolant avstem during both operating and shut-down conditions, including the range of values for materials whose concentra'. ions have varied appreciably.
Include measured values of oxyson and halido concentrations.
4.
For each component listed, indicate whether the in;ernal surface is nornally in contact with flowing water, stagnant water, or steam, and indicate whether the configuration and operating con-ditionn are such that a possibility exists of entrapment of gases within the sensitized portion. Also, discuss whether possible corrodents could have come into contact with the internal surfaces during cleaning or other preoperational arposure of these surfaces.
5.
Specify the nondestructive tests that have been performed inter-nally and externally on each component listed since its installation.
Indicate the acceptance criteria established for nach type of test, the sensitivity in terms of flav detection, and the results of these tests.
6.
Indicate whether any destructive metallurgical examinations have been performed on sensitized material removed from the remetor coolant pressure boundary, or samples thereof, and the results of such tests.
7.
Discuan the operating performance of leak detection systems during plant operation to date.
Indicate the current sensitivity of each system.
8.
For each component listed, indicate the dar.ee of accessibility which presently exists for the performance of nondestructive tests and inspectiong %
E Yankee Atenic Electric Coupany if, 6 S,9 9.
Dencribe the plans you have developed for surveillance and non-destructive tents of the sensitized stainless steel connonents of and within the reactor coolant pressure boundary, including a pr< posed timetable.
In this connection, the recent experience with furnace-sensitized stainicas steci couponents indicates that unless a considerable anount of evidence attests to the current integrity of such ecmponents or unless valid technical reasons would preclude performing nondestructive tests, the perfortsance of a progran of nondestructive testing of a sizeable sanple of such conponents may be appropriate at an early date. These exaninations should include dyo penetrant testing and eitlar ultrasonic testing or radiography.
It is requested that forty copies of this infornation be submitted to us.
Sincerely, Peter A. Morris. Director Division of Reactor Licensing
Enclosure:
DISTRIBUTION:
Definition of Reactor Coolant ACRS (3)
Pressure Boundary H. L. Price C. K. Beck cc:
C. Duano Blinn, Esquire M. M. Mann Day, bstry & Howard S. H. Hanauer Counselors at 1.aw P. A. Morris 1 Constitution Plaza E. G. Case Hartford, Connecticut 06103 T. R. Wilson F. Schroeder D. J. Skovholt R. DeYoung R. Boyd W. Dooly, DR R. Engelken, CO (2) pGC (2)
VDocket File PDR HQ DR Reading s % % t b d ' s s
Branch Reading R. H. Vollmer Licensing Assistant
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Definition of Reactor Coolant Pressure Boundary Reactor coolant pressure boundary / means all those pressure containing 1
components of boiling and pressurized water-cooled nuclear power reactors, such as pressure vessels, piping, pumps, and valves, which are:
(1) part of the reactor coolant system or (2) connected to reactor coolant system, up to and including any and all of the following:
(a) the outermost containment isolttion valve in system piping which penetrates primary reactor containment, (b) the second of two valves norr. ally closed during normal reactor operation in system piping which does not penetrate primary reactor etntainment, (c) the reactor coolant system safety and relier selves.
For nuclear power reactors of the direct cycle boiling water Lype, the reactor coolant system extends to and includes the outermost containment isolation valve in the main steam and feedwater piping.
1/ Components which are connected to he reactor coolant system and are part of the reactor coolant pressure boundary may be excluded from these requirements provided:
(a)
For postulated failure of the component during normal reactor operation, the reactor can be shut down and cooled down in an orderly manner assuming makeup is provided by the reactor cool-ant makeup system only.
(b) The component is or can be isolated from the reactor coolant sys-tem by two valves (both closed, both open, or one closed and the other open). Each open valve must be capable of automatic actu-ation and its closure time must be such that for postulated failure of the component during normal reactor operation and assuming the other valve is open, the reactor can be shut down and cooled down in an orderly manner assuming makeup is provided by the reactor coolant makeup system only.
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