ML19291C911
| ML19291C911 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/04/1971 |
| From: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Minnick L YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 8011140254 | |
| Download: ML19291C911 (2) | |
Text
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DISTRIBUTION g ocket File PDR DR Reading DRL Reading MU IC71 Branch Reading W. Dooly, DR R. Engelken, CO (2)
- H. Shapar, OGC Docket No. 50-29 N. Dube, DRL (2)
J. Buchanan, ORNL R'. Boyd, DRL
<v R. DeYoung, DRL 2
Yankee Atomic Electric Company F. Schroeder, DRL ATTN:
L. E. Minnick, Vice President D. Skovholt, DRL 441 Stuart Street K. Vollraer, DRL Boston, Massachusetts 02116 R. Schemel, DRL A. Burger, DRL Gentlemen:
S. Teets ACd5'l11 h, DRL In a letter dated December 30, 1966, we requested that you evaluate the adequacy and reliability of the Yankee emergency core cooling system and determine the need for additional provisions to limit the release of fissicn products from the core in the event of a major pipe rupture in the primary cooling system. Our records indicate that the follcwing actions have been taken to date in connection with efforts to upgrade the Yankee emergency core cooling system.
By your letter dated March 21, 1969, you provided us the results of your detailed study of the core coeling system in your report, YAEC-1025R,
" Review of the Yankee Safety Injection System".
This report describes several minor modifications which have been made to the safety injection systes, based on your study results, and indicates that additional modifications to the a sfety injection system would be evaluated in con-junction with the planned installation of a zircaloy core in Yankee.
By letter of March 24, 1969, you proposed performance criteria for the planned zircaloy core and modification in the safety injection system and emergency power system needed to meet these criteria. The planned system modifications are summarized in Yankee's report " Conceptual Radesign of the Yankee Safety Injection System" which you submitted with your letter of June 18, 1969. We commented in our letter of August 20, 1969, that your proposed criteria are appropriate for use in the design of a sircaloy core for the Yankee reactor.
In your letter of March 24, 1969, you also informed us that Yankee would contract for two zircaloy reload batches if visual inspection of the sircaloy test assemblies during the August 1969 refueling outage confirms good appearance of these assemblies; further, that the first zircaloy batch would be loaded in the fall of 1970 or spring of 1971. This schedule appeared to allow sufficient lead tLae for Yankee to perform the final redesign and reanalyses of the safety injection system, for our review, and for implementation of system modifications before the first tirealoy reload batch would be installed in the Yankee core.
8011340 N I
Yankee Atomic Electric Company F#- 4 ~ 1971 Yankee's inspection of the aircaloy clad rods from tid test fuel assem-blies, during the August 1969 refueling outage, identified changes in
. t t,pe the lengths of these rods that were greater than anticipated. As a 3 result, Yankee did not recycle the zircaloy test assemblies as planned.
- ,.y"l6 Thereafter, it became apparent that at least until Yankee investigates and resolves the unexpected physical changes in the zirecloy cladding, your plans to install a sircaloy core vould be delayed and your scheduled implementation of the safety injection system modifications would be postponed.
During 1970 Yankee made two significant plant changes that in effect upgraded the safety injection system; namely, the addition of an emergancy core cooling recirculation capability and the installation of three emergency diesel generators to provide redundant sources of emergency power.
We are not aware of your present plans for a more comprehensive upFrading of the Yankee emergency core cooling system, either in conjunction with a contemplated transition to a siccaloy core or with the present stainless stee! core. Please advise us of your planned actions in connection with further ef forts to upgrade the Yankee emergency core cooling system.
Sincerely, p
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, ~;t.u Peter A. Morris, Director Division of Reactor Licensing cc:
C. Duane Blinn, Esquire Day, Berry & Howard Counselors at Law 1 Constitution Plaza Hartford, Connecticut 06103 y
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