ML20078L504

Discusses Inferred Positive Moderator Temp Coefficient for Unit 2 Cycle 5.Special Rept Will Be Submitted within 10 Days

ML20078L504
Person / Time
Site:	Braidwood
Issue date:	11/21/1994
From:	Kofron K COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
BW-94-0174, BW-94-174, NUDOCS 9411300184
Download: ML20078L504 (4)

Text

'N Commenwarlth Edison Braidwood Nucicar Power Station

-s

' f7_. Route #1, Box 84 U

Braceville, Illinois 60407 Telephone 815/458-2801 November

.2, 1994 Bw/94-0174 Office of Nuclear Reactor Regulation i

U.S.

Nuclear Regulatory Commission Washington D.C.

20555 Attentions Document Control Desk

Subject:

Inferred Positive Moderator Temperature Coefficient For Braidwood Unit 2 Cycle 5

References:

1)

NUREG-1276, " Technical Specifications, Braidwood Station Unit Nos. I and 2, Docket Nos. STN 50-456 and STN 50-457" Specification 3.1.1.3a of Reference (1) requires that the Moderator Temperature Coefficient (MTC) shall be less positive than 0 Ak/k/"F for the all rods withdrawn, hot zero Thermal Power condition in Modes 1 and 2 with K,n greater than or equal to 1.

Measurements conducted and analyzed on November 17, 1994, in accordance with Surveillance Requirement 4.1.1.3.a have inferred that an MTC of + 4.6E-6 Ak/k/"F will occur at a core burnup of 4000 Megawatt Days per Metric Ton Uranium (MWD /MTU). This MTC value is the inferred most positive MTC for Braidwood Unit 2 Cycle 5 operations.

The current measured MTC is

-2. 04E-5 Ak/k/F.

Rod withdrawal limits have been established per Action Requirement "a" of Specification 3.1.1.3 to ensure that MTC remains negative.

Curves depicting these rod withdrawal limits are attached. These limits will t amain in effect until Braidwood Unit 2 Cycle 5 core burnup reaches 8000 MWD /MTU. At this burnup, the Hot Zero Power, All Rods out, Xenon free MTC has been calculated to be less than 0 Ak/k/'F. This value represents the most positive /least negative MTC.

This information is being transmitted in accordance with specification 3.1.1.3 Action a.3 which requires that a Special Report be prepared and submitted to the Nuclear Regulatory Commission pursuant to Specification 6.9.2 within 10 days.

This report shall describe the value of the measured MTC, the interim control rod withdrawal limits, and the predicted average burnup necessary to restore the positive MTC to within its limit for the all rods withdrawn condition.

Please direct any questions regarding this submittal to Douglas S.

Huston, Brai~ ad Regulatory Assurance, Licensing Group, (815)458-2801 extension 3104.

Sincerely,

), [

-on -

Kokrh K.

L.

Station Manager Braidwood Station KLK/DSH/cjm Attachment cc:

S.

G.

DuPont, Senior Resident Inspector - Braidwood R.

R.

Assa, Braidwood Project Manager - NRP B.

Clayton, Branch Chief - RIII D.

M.

Saccomando - NLA K.

G.

Bartes, Regulatory Assurance Supervisor L.

Kepley, System Engineering 9411300184 941121 PDR ADOCK 05000457

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