ML20148F411
| ML20148F411 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 10/30/1972 |
| From: | Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Minnick L YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 8011050621 | |
| Download: ML20148F411 (2) | |
Text
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OCT 3 01972 hl Yankee Atomic Electric Comptuy t.TT.h
!.r. L. E. :danick fp Vice President 20 Turapike Road
' ! k' Westboro. Massacausetts 01581 4 hf Change ;o 103 I
Gcatlemen:
License No. DPR-3
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By letter dated October 12, 1972, and supplenental information contained 1 f, in your teletype dated October 27, 1972, you requested authorization
'of certain channes in the Technical Specifications appended to License g
.io. DPR-3.
The proposed changes would allow sealing off the in-core 4
flux wire thinbles in the north instrumentation port and to operate d
the reactor with the reduced number of locations at which flux wires J g Y
can be inserted.
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Tae in-core instrumentation in the Yankee reactor includes twenty-seven k
tuercocouples for conitoring core outlet water temi>cratures and a flux vire system..Laviag nineteen. pathways for inserting activation wires into selected core locations.
This instrumentation provides the infor-i mation that is used to determine the actual power distribution and to confirr. the cargins in the hot channel f actors predicted analytien11y V
for the operating core.
W Tr.o flux wire thinbles terminate in the east and north instruneutation I
ports that penetrate tne reactor vessel head.
Deterioration has occurred
' E Inalde several thinbles in the.iortu port that has readered then uausable 3;
for insertion of flux wires.
As a prudent recasure to preclude potential 6
adverse effecta on the integrity of tne prittary coolins system pressurc boundary, you propose to seal off the entire north instrtcaentation port.
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l We have reviewed the information you have submitted on the modifications f"
to the nortn instrumentation port, including proposed inspection and
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testing. All fabrication, installation and testing will be carried EEi out in accordance with approved written procedures. We have concluded that the proposed method of scaling t.he north instrumentation port is it:
i acceptable, f;%
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3 Yankee Atomic Electric Company OCT 3 01972 2
q Scaling the north instrumentation port will reduce the number of locations at which flux wires can be inserted from nineteen to eight.
75-Data obtained during operation with previous cores have confirmed that k
the analytical predictions of core power distribution include signifi-L*
f cant margins compared with actual operating conditions. The thermal performance variables predicted previously for operating the reactor M,4 6
with Core X at full power are much lower than the design values that were used in establishing the Core I control rod insertion limits that R
are included in the Technical, Specifications. This adds to the safety margins in the hot channel factors. Therefore, reactor operation for
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the remaining life of Core I with the operable core thermocouples and 8
the eight available flux vira locatio'as does not involve enfety consi-E[
derations not previonaly evaluated. We have noted your plans to install f
a new in-core instrumentation package, new reactor vessel head cono-h seals, and a new moveable in-core fission detector monitoring system h
during the 1973 fall refueling outege.
Y
.h.s On the basis of the information you have submitted, we have concluded t$
that the proposed changes do not involve significant hazards considerations not described or implicit in the Final Safety Analysis Report and that 5
the health and safety of the public will not be endangered. Accordingly, pursuant to Section 50.59 of 10 CFR Part 50, Change No.103 is hereby y
authorized.
M4i Sincerely, m
l i$i Donald J. Skovholt Assistant Director for W.
Operating Reactors
'[
Directorate of Licensing
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