ML20211P721
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G A Technologies Inc.
PO. BOX 85608 SAN DIEGO. CAUFORNIA 92138 (619) 455-3000 February 23, 1987 Director, Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
This written report is provided in compliance with Part 21 and is a followup to a telephone call made to Region V on February 18, 1987.
The information below is provided as requested by 10CFR21.21.
(i)
Person informing the Commission:
Richard A. Dean Senior Vice President GA Technologies Inc.
P. O. Box 85608 San Diego, CA 92138-5608 (ii)
Description of the defect:
Sorrento Electronics manufactures a digital and analog version of Reg. Guide 1.97 post-LOCA High Range Radiation Monitor (HRRM).
Both versions use an RD-23 ion chamber detector as the in-containment radiation detector.
The detector is interconnected to an RM-80 Microprocessor (Digital) or an RP-2C Readout Module (Analog) with two coaxial cables.
The defective part of this system is the in-containment portion of the ion chamber's signal coaxial cable.
The cable is manufactured by the Rockbestos Co.
(iii) Identification of the firm:
Sorrento Electronics a subsidiary of GA Technologies Inc.
8703020421 870223 PDR ADOCK 05000010 S
PDR A
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10955 JOHN JAY HOPKINS DR.. SAN DIEGO. CAUFORNIA 92121
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.( v)
The nature of the defect:
Several LOCA and other high temperature tests i
conducted on Rockbestos coaxial cable indicate that the insulation resistance at high temperature is not high enough for the ion chamber and its associated electronics to operate properly.
When the insulation resistance was measured at low voltage (the test that most closely approximate's SE's actual installation condition), the measured insulation resistance was 2.66 E 06 ohms per.1000 feet of cable.
This measurement was made at 344 degrees F.
In order for the SE HRRM's to operate within the factor of two accuracy required by Reg. Guide 1.97, the minimum acceptable cable insulation resistance is 5.0 E 08 ohms.
The cable's leakage resistance in conjunction with the input logarithmic amplifier's offset voltage result in one of two conditions at the amplifier output.
4 1.
The amplifier output signal remains positive, but the error current produced by the amplifier's offset voltage divided by the cable's insulation resistance exceeds the factor of two accuracy limit.
2.
The low cable insulation resistance drives the amplifier output negative which is an abnormal condition for the circuit.
Preliminary tests indicate that condition number two is the predominant failure mode.
(v)
The date on which information was obtained:
February 18, 1987 (vi)
The number and location of the components:
(See Attachment 1.)
(vii)
Corrective action:
At this time, a corrective action has not been i
i identified.
The most probable corrective action will involve either a redesign of the electronics to measure the cable's insulation resistance and correct for its effects or to replace the cable with a different type.
(viii) Advice to Purchasers:
None until corrective action identified.
Purchasers are being informed as to problem.
Sorrento Electronics will work with individual purchasers to evaluate their specific problem.
C
. If you have any questions concerning this report, call me at-(619) 455-2120.
Address technical questions to:
Dennis Nau at (619) 457-8905; or Leonard Karpenko at (619) 457-8807 Yours truly, Richard A. Dean M
Senior Vice President Reactor Programs cc:
C.
R.
Fisher D.
C. Nau Regional Director U.S.
Nuclear Regulatory Commission 1450 Maria Lane Walnut Creek, CA 94596
-Attachment 1 (vi)
The number and location of the components:
Site Digital Analoc
' Arkansas P&L/ Nuclear I X
X Beaver Valley X
Byron X
Braidwood X
Comanche Peak X
Duke Power /McGuire X
X Indian Point III X
X Limerick X
Maanshan X
EG&G Idaho / FAST X
Millstone X
X River Bend X
Songs 1 X
Songs 2 & 3 X
Seabrook X
Shearon Harris X
SMUD/ Rancho Seco X
i St. Lucie X
X Wolf Creek X
South Texas X
TVA/Bellefonte X
Waterford X
- Callaway X
Hope Creek X
Applied Phys ~. Tech.
X Beznau X
BG&E/ Cal. Cliffs X
Dresden X
Quad Cities X
Zion X
LaSalle X
Conn. Yankee X
James Fitzpatrick X
Northern States /Prarie Island X
Monticello X
Pt. Beach X
- Maine Yankee X
- Peach Bottom X
' Dairyland Power /LaCross X
Wisconsin /Kewaunee X
- Niagara Mohawk X
Catawba X
. Toledo Edison / Davis Bessie X
Fermi II X
Florida Power Corp./ Crystal River X
Susquehanna X
Aptec/ Ontario Hydro X
Turkey Point X
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