ML19319B853
| ML19319B853 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/20/1976 |
| From: | Roe L TOLEDO EDISON CO. |
| To: | |
| Shared Package | |
| ML19319B847 | List: |
| References | |
| NUDOCS 8001280679 | |
| Download: ML19319B853 (2) | |
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TOLEDO b EDiSDN Docket No. 50-346 LOWELL E. ROE Vice Pres dent April 20, 1976 mss ass-sa4m Dr. Ernst Volgenau, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Coc: mission Washington, D. C.
20555
Dear Dr. Volgenau:
This letter is submitted in accordance with 10 CFR Part 50.55 regarding the apparent deficiency of the Davis-Besse Nuclear Power Station, Unit No. 1, Safety Features Actuation System (SFAS) as previously discussed with Messrs. D. W. Hayes and R. D. Martin, Region III.
I Report of SFAS Analog Amplifier Instruction Manual Deficiency This report is being made pursuant to 10 CFR Part 50.55(c) on Significant T
Deficiencies and documents the evaluation of the possible significant
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de.iciency in the Instruction Manuals for the Analog Anplifiers in the U
SFAS.
Identification of Problem J
The Davis-Besse Nuclear Power Station Unit No. 1 SFAS vas purchased from the Consolidated Controls Corporation (CCC). This system has sixteen Analog Amplifiers that are used to condition the input signals for use with the trip bistables installed in.;he system. The CCC Instruction Manual for the Analog Amplifier Module stated that the module should be calibrated using a -1 to -5 volt input signal. This Instruction Manual was in error as the input signal to the analog amplifiers has a 4 to 20 ma range.
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Analysis Test procedures were prepared using the -1 to -5 volt signal given in the CCC Instruction Manual and the Analog Amplifier Modules were bench tested using these test procedures. After the modules were inserted into the SFAS cabinetry, it was detected during system testing that the process input signal (4 to 20 ma) did not correspond correctly with the trip set points of the trip bistables and the reading on the indicating instruments driven by the analog amplifiers were not correct.
This problem is considered to be a significant deficiency as defined by p) 10 CFR Part 50.55(e), because: (1) There was a significant deficiency in i
V design approval which allowed the error in the Instruction Manual to be released for construction, and (2) it cannot be shown that the bistables l
would have tripped within the tolerances allowed in the FSAR.
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Corrective Action CCC will correct their Instruction Manual for the Analog Amplifier Afodule to show the calibration procedures using a 4 to 2r, input signal. The Applicant's Tes'. Procedures and Maintenance.'rocedures for the Analog A=plifiers Module will then be revised to show that the input signals to these modules will be 4 to 20 ma signals.
The modules will then be recalibraced to the corrected procedures, and te::t.irg performed to assure trip bistable actuation in accordance with FSAR commitments.
Safety Implications Based on the above, we conclude that there were no generic failures of the actual equipment supplied by CCC. While the trip points would not have been exactly as desired, this condition was determined during the thorough and stringent testing of the Applicant on site prior to the time the equipment was turned over for operation. Thus, the safety of the station and the public were not jeopardized.
Yours very truly, Lowell E. Roe, Vice President Facilitics Development D'
wr b/8-9 cc:
J. G. Keppler, Regional Director
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Office of Inspection and Enforcement
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