ML17252A897

Letter Informing of 07/02/1973 Discovery, During a Periodic Test and Calibration Procedure PT-M12, of the First Stage Turbine Pressure Setting in Excess of the Technical Specification Limit - Indian Point Unit 2

ML17252A897
Person / Time
Site:	Indian Point
Issue date:	07/12/1973
From:	Caldwell W Consolidated Edison Co of New York
To:	O'Leary J US Atomic Energy Commission (AEC)
References
Download: ML17252A897 (2)

Text

., William E. Caldwell.,A Vice President W Consolidated Edison Company of New York. IB **~.

4 Irving Place. New York. N Y 10003 Telephone (212) 460-5181 July 12, 1973 Re Indian Point Unit No. 2 Facility Operating License DPR-26

~c Docket No. 50-247 Mr. John F. O'Leary Directorate of Licensing

u. s. Atomic Energy Corrunission*

Wash-ington, D. C. 20545-Dear Mr. O'Leary The following report*of Abnormal Occurrence No.-J . . . 2-9 is provided pursuant to the requirements of Section 6.6.1.B of the Technical Specifications to FaCiliiy Operating Li6ense No. DPR-26.

On July 2, 1973, during tne performance of periodic test and calibration procedure PT-Ml2, i t was discovered that the first stage turbine pressure setting was in excess of the limit defined by Faciiity Technical Specification 2.3.2.A.2 .. One of the *two*

channels was found to be set at 10.3% of full load first stage turbine pressure, instead .9f the' prescribed 10 % maximum. . Addi.,..

tionally,.the periodic test reveaied that one of* the two safety injection steam flow bi-stables*iri Loop No. 24 was set 0.3% higher

. than !-hat prescribed in Table 3 .1 of the Technical Specifications~

The discrepancy is believed to have resulted from an improper initial cal{bration, or possibly, instrument drift. To correct the situation, the first stage turbine pressure instrument was- .

reset so that the reactor trip would be unblocked by tbis channel at the prescribed 10% of full power* . The safety injectio;n steam flow bi-stable was replac~d with a-spare bi-stable which was properly calibrated.

• During future calibration. checks, particular *attention will be paid to these instr~ments so tnat a definite determination can be~made.as tocwhether or: not ,instrument drift was a causitive f?ctor in tl}is incident.

• In cons:j.dering the safety implicayions of the occurrence, i t should be noted that the. discrepancies* in. these instruments were detected during a_ routine surveillance test which is performed monthly.

Furthermore, ~he*1.)pr0:tect.ive*:ri9g.iJ:d1:wi11~not>.f>l0ck

• the reactor trip*

signal unless both* of. the two.pressure instruments have sensed low turbine' impulse stage pressure. Since the second instrument was calibrated correctly, the trip block would have been initiated at the proper power level..

• 5484

John F. O'Leary*

• July 12~.1973 Re Indian Point .Unit* No. 2 Facility Operating License No. DPR-26 AEC Docket*No. 50-247 The safety injection high steam flow circuitry is provided with.

similar redundancy. *The second high steam flow*bistable in Loop 24was found to be within specification and would have been able to initiate safety injection. Finally, allowances for setpoint drifts of these small magnitudes were made in the original unit safety analysis. For these reasons, there are no safety implications to the occurrence.

Very truly yours md President Copy to James P. 0' Reilly (AEC) *

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