ML20058Q110
| ML20058Q110 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 08/10/1990 |
| From: | Debarba E CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9008210090 | |
| Download: ML20058Q110 (3) | |
Text
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h-ONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT RR81
- BOX 127E
- EAST HAMPTON, CT 06424-9341 U. S. Nuclear Regulatory Commission August 10,1990 Document Control Desk Washington, D. C.
20555
Reference:
Docket No. 50-213 Iladdam Neck Plant Accidern Monitoring Instrumentatic i IDCmrable Core Exit Thermocouple Gentlemen:
In accordance with the Special Reporting requirements of Technical Specification 3.3.3.5, Table 3.3 7 Accident Monitorine Instrumentation. Item 17 Core Exit Thermocouples, ACTION STATEMENT 38; Connecticut Yankee Atomic Power Company (CYAPCO)is providing the NRC staff with the following informatic a.
The referenced Technical Specification contains operability requirements for the Core Exit Thermocouples based on total channels available in the com as well as total channels available per core quadrant. The portion of the specification that this Special Report applies to is the aquimment to have a total of 4 channels per quadrant operable. A previously submitted figure is attached to this letter which explains the method used to establish which thermocouples are in each quadrant.
On July 27,1990 at 0113 hours0.00131 days <br />0.0314 hours <br />1.868386e-4 weeks <br />4.29965e-5 months <br /> the plant entemd Mode 3 with less than the required 4 channels operable in Quadrant 1. Due to problems with the thermocouple in core location N6, only 31/2 channels were operable in that quadrant. In accordance with the specification, ACTION STATEMENT 38 was entered which requires restoring the inoperable channels within 7 days, or su't mitting this Special Report within the next 10 days.
Trothleshooting efforts were ongoing at the time that the ACTION STATEMENT was entemd.
On Aupst 6,1990, the problem was isolated to a faulty section of QA, EEQ mineral insulated cable that connects two junction boxes one of which is located on the Reactor Vessel Head. The other box is located on the side of the refuelin;; cavity. CYAPCO is workin ; with the vendor, Combustion Engireering, to procure a fully, qualified replacement cable since tie station does not stock this specific cable. Due to its location on top of the reactor vessel, this cable cannot be chan.;ed at power. ALARA and personnel safety issues (primarily heat stress) indicate that thisjob shouid be performed in Cold Shutdown. Accordingly, it is C1 APCO's intention to replace this cable (turing the first Cold Shutdown after the replacement cable is obtained.
No alternate methods are necessary to estimate core exit temperature since the Minimum Channels Operable requirement is met. Additionally, the Total ho, of Channels for the whole core requimment,16/ core, is fully met as 40 com exit thermocouples are operable.
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i Page 2 of 2 The licensee contact for this Special Report is John Chiarella, who may be contacted at (203) 2f 7 3659.
Very truly yours, Connecticut Yankee Atomic Power Company
&D-W E..\\. DeBarba Nuclear Station Dimetor EAD:JJI/ mig cc:
T. T. hiartin. Regional Administrator, Region I A. Wang, NRC Project hianager, liaddam Neck J. T, Shedlosky, Senior Resident inspector, IInddam Neck E. J. hiroczka, Senior Vice Pmsident of Nuclear Engineering and Operations t
R. hi. Kacich, hianager of Generation Facilities Licensing l
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s TICURE 1 CONNECTICUT YANKEE CORE Core Exit Therwocouples
- For each quadrant, credit 1s taken for half.of the CETs on an axis.
- No credit taken for center CET.($D 15 14 13.
12 11 10
'9 8
7.
6.
S 4
3'2 1-
.cmin ums i
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[-
l Quadrant II X
X X
Quadrant I i
b X
X 0
X X
X X
X N.
X X
X X
X X
X b
h h
X X
X X
X X
X b
i f
J X
X X
X X
t Y
Y M
v v
X X'
- a x
h s-I G
X x
F E'
D X
"X C
Quadrant III Quadrant IV 8
I
.A i
x - CtT X - Currently out-of-service 0 - Ussd for RV head Temp I
.