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Abnormal Occurrence Reports AO-21-75, AO-22-75, AO-23-75. Reports Involve Failure of Valve Associated with HPSI System, Safety Injection Tanks Less than 1720 Ppm Boron & Incorrect Release Rates of Liquid Radwaste
	ML18348A628
Person / Time
Site:	Palisades
Issue date:	09/22/1975
From:	Sewell R; Consumers Power Co
To:	; Office of Nuclear Reactor Regulation
References
	AO-21-75, AO-22-75, AO-23-75
	Download: ML18348A628 (10)
	v • d • e

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consumers

Power company General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201

Area Code 517 788-0550 September 22, 1975 Division of Reactor Licensing US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255, LICENSE DPR-20 PALISADES PLANT Attached are reports describi.ng three abnormal occurrences that occurred at the Palisades Plant. These reports involve the failure of a valve associated with the HPSI system, the safety injection tanks less than 1720 ppm boron and incorrect release rates of liquid radwaste.

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Ralph B. Sewell ~

Nuclear Licensing Administrator CC: JGKeppler, USNRC File

ABNORMAL OCCURRENCE REPORT Palisades Nuclear Plant

l. Report No: A0-21-75, Docket 50-255 2a. Report Date: September 22, 1975 2b. Occurrence Date: September l2, 1975 3, Facility: Palisades Nuclear Plant, Covert, Michigan

4. Identification of Occurrence: MOV-3007, high-pressure safety injection valve failed to pass fluid. This incident was identified as an abnormal occurrence by Technical Specifications 3.3.l and 3,3.2. All other valves, piping and interlocks associated with (safety injection pumps) and re-quired to function during accident conditions were operable.

5. Conditions Prior to Occurrence: The plant was operating at 48% power level and escalating power at l0% per day. The monthly safety injection bottle sampling had been in progress.

6. Description of Occurrence: At 2230 hours0.0258 days 0.619 hours 0.00369 weeks 8.48515e-4 months on September 12, 19,75 '.'A" high-pressure safety injection pump was being used to refill the safety injec-tion bottles after sampling. MOV-3007, although indicating open, would not pass borated water.

7. Designation of Apparent Cause of Occurrence: The apparent cause of the incident was a valve stem to valve disc separation. A visual observation of valve stem movement coupled with the inability to achieve flow is the basis of this conclusion.

8. Analysis of Occurrence: MOV-3007 and the associated high-pressure

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safety injection path was classified inoperable under Section 3.3.lg of the plant Technical Specifications. Section 3,3.2 provides up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months for resolution. Within this period, an extensive background search was made and a PRC meeting held to study the possibility of utilizing the redundant HPSI header by opening valves CV-3018 and -3036, and closing valves CV-3037 and -3039. This was considered within system design requirements by PRC and accomplished the next morning. The redundant HPSI header, which is not normally aligned for automatic actuation, provides full HPSI capability.

9. Corrective Action: The immediate corrective action taken was to place in service the redundant valve MOV-3068 and complete the filling operation of the safety injection bottle. Subsequent action taken was to verify the operability of and switch over to the redundant high-pressure safety injec-tion system. Further investigation of the failed valve will be carried out to resolve whether a generic problem exists. Until then, the in-service HPSI valves will be either tested periodically or le~ open during opera-tion.

10. Failure Data:

a. MOV-3007 manufacturer is Velan Engineering Co and the part number is W8-376-13MS.

b. The motor operator is manufactured by Philadelphia Gear Corp and the.

part number is SMB-00-15.

c. A similar HPSI (MOV-3013) failed by disc-stem separation in January 1972 .

2

ABNORMAL OCCURRENCE REPORT Palisades Nuclear Plant

1. Report No: A0-22-75, Docket 50-255 2a. Report Date: September 22, 1975 2b. Occurrence Date: September 12, 1975

3. Facility: Palisades Nuclear Plant, Covert, Michigan

4. Identification of Occurrence: Safety injection tanks less than 1720 ppm boron. This incident was identified as an abnormal occurrence by Technical Specifications 3.3.2(a).

5. Conditions Prior to Occurrence: The plant was operating at approximately 40%, increasing power. The monthly surveillance sampling of the SI tanks had started.

6. Description of Occurrence: On September 11, 1975, analysis of T-82A safety injection tank showed low boron (approximately 1690 ppm). This analysis was verified by several resamples. It was initially felt that this sample was contaminated with primary coolant boron (approximately 507 ppm) via leakage through SI injection line bleed-off valves. Several hours were spent performing spectral analysis of the primary coolant and SI tank sample. At 2155 hours0.0249 days 0.599 hours 0.00356 weeks 8.199775e-4 months on September 11, 1975, the SIRW tank was sampled with a resulting boron analysis of 1705 ppm. A review of the recent tank history indicated that on September 7, 1975 the tank (SIRW) had been at 1772 ppm boron. The only addition to the SIRW tank between September 7, 1975 and September 11, 1975 was a small volume----of primary coolant (less than 5,000 gallons) at approximately 1000 ppm boron. 27,000 gallons of 1000 ppm borated water would have been required to dilute the SIRW tank from 1772 to 1703 ppm. The SIRW tank was too full (98%) to possibly allow this, and was verified not to have been overfilled. Therefore, an actual change in concentration of the SIRW tank was seriously questioned.

During the next several hours, the procedure reagent chemicals used for the boron analysis were verified. Also, during this time, the boron con-centration of the SIRW tank was increased by an addition of concentrated boric acid to approximately 1763 ppm, in the event sample analysis proved correct.

Following sample/analysis verification, the safety injection tanks were drained one at a time and refilled from the SIRW tank to boron concentra-tions greater than 1720 ppm.

7. Apparent Cause of Occurrence: The apparent cause of the ~ccurrence was low boron concentration in the SIRW tank .

8. Analysis of Occurrence: The low injection tanks was due to their SIRW tank. The cause of the low mixing in that tank possibly due cQncentration of boron in the safety being filled or "topped off" from the boron in the SIRW is felt to be poor to design and/or temperature gradients.

The basis for Technical Specifications 3.3 states that the SIRW is assumed to contain 250,000 gallons of 1720 ppm boron water. At the time of the occurrence, the tank contained 270,000 gallons of 1700 ppm boron. The basis assumes boron requirements for a new core and 5% shutdown margin.

Based on the above and the fact that our core is approximately 2/3 "burned up," we concluded that no safety margins were exceeded.

9. Corrective Action: The following corrective actions were recommended by the Plant.Review Committee to prevent recurrence of this occurrence:

a. Modify the chemistry operating procedure to maintain the boron con-centration in the SIRW tank between 1820 and 2000 ppm.

b. Modify the chemistry operating procedures to maintain SI bottle boron greater than 1750 ppm.

c. Conduct a review of the SIRW tank recirculation system .

10.

As noted above, SIRW tank boron concentration was increased to 1763 ppm and the safety injection tanks were drained and refilled from the SIRW tank.

Failure Data: Not applicable .

2

ABNORMAL OCCURRENCE REPORT Palisades Nuclear Plant

1. Report No: A0-23-75, Docket 50-255 2a. Report Date: September 22, 1975 2b. Occurrence Date: August 28 and 29, 1975 (Identified September 12, 1975)

3. Facility: Palisades Nuclear Plant, Covert, Michigan

4. Identification of Occurrence: Incorrect release rate of liquid radwaste.

This abnormal occurrence is defined by Technical Specifications 3.9.2:

MPC, 10 CFR 20, Appendix B, Table II, Column 2, shall not be exceeded.

5. Conditions Prior to Occurrence: Plant was at 55% to 70% during power escalation.

6. Description of Occurrence: On September 12, 1975, the Plant Health Physicist, who does not routinely authorize radwaste batches, was asked to authorize a radwaste batch. In the course of his review, he discovered the release rate calculation was incorrect. The release rate was recalcu-lated and the batch authorized. A review of past releases where the same technician was involved was instituted. Eighteen batch release rates were found to be incorrectly calculated. Two exceeded allowable release rate limits; one by 34% and the other by 62%.

7. Apparent Cause of Occurrence: The basic cause of the error was the release calculation form had different units for dilution flow than the procedure.

A technician, inexperienced in batch releases, was assigned to replace the regular technician who was on a two-week vacation. Instruction was given the new technician on the first two batch releases he calculated. These were done correctly. The technician proceeded to calculate batches using

.procedure RMC 4(c). The procedure calls for entering information on Form RMC 4(c)2. Among the information entered is identifying the dilution pumps in service and calculating the dilution flow in gpm. The Form RMC 4(c)2, however, has the units of lpm (liters per minute - circled on attached Form RMC 4(c)2). The technician filled in dilution flow in lpm to agree with the form. The procedure then calls for Form RMC 4(c)3 to be calculated.

This will take approximately one hour to calculate. The procedure then calls for the activity release rate to be calculated in gpm by dividing the dilution flow rate by the sum of the MPC fractions. Due to the error on the form, the dilution flow was in liters per minute so the calculations were incorrect by a factor of +3.785 (the liters to gallons conversion).

The Radiological Materials Control Supervisor reviewed and authorized the releases without catching the error. The RMC Supervisor reviewed the batches extensively because of the new technician for what he considered significant items, such as proper calculations, efficiencies, MPC frac-tions, etc. *

8. Analysis of' Occurrence: The increase* in release did not cause any saf'ety hazards to the environment. Releases over the entire period of' concern were only 2.7% of' 10 CFR 20 limits. on an average basis.

9. Corrective Action: Radwaste Procedure 4(c) will be extensively reviewed to correct ambiguities and to be read easier. Corrected procedure will then be reviewed with all appropriate Health Physics personnel.

In addition to the immediate correction of' this problem, an extensive re-view of' remaining RMC procedures will be initiated. Emphasis will be placed on early completion consistent with the present plant administrative workload.

10. Failure Data: Not applicable *

2

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NRC BHDA CONSUMERS POWER COMPANY 1945 WEST ?ARNALL RD JACKSON, MI TWX 517-787~1987 9-16~75 3-25 PM ATT- DIVISION OF REACTOR LICENSING USNRC - BETHESDA, MD*

TO- J G KEPPLER, USNRC 799 ROOSEVELT RD GLEN 'ELLYN, IL 60137 RE- DOCKET 50-255 LICENSE DPR-20 THIS IS TO CONFIRM OUR TELEPHONE NOTIFICATION TO K R BAKER OF AN EVENT WE HAVE CLASSil'IED AS AN ABNORMAL OCCURRENCE*

DURING THE PERIOD OF 8/16175 TO 9/12/75, EIGHTEEN RADWASTE BATCH RELEASE RATES .. WERE INCORRE:CTLY CALCULATED* -REVIEW OF THE REbEASES INDlCATE THAT TWO BArCHES WERE.OVER MPC LIMITS. BATCHES 75-052-R, 8/28175, AT 1*34 MPC AND 75-054-R, 8/29/75, AT. 1*62 MPG VIOLATED TECH SPEC 3.9.2.

RELEASE RATE ERRORS WERE MADE BY FOLLOWING_PR6CEDURE RMC 4.c, STEP 2*4*1* THIS STEP DIVIDES THE* DILUTION FLOW IN L)TERS BY tHE SUM Or THE MPG FRACTIONS. THE ANSWER IS ENTERED AS THE ACTIVITY RELEASE RATE WHiqH HAS NO UNITS SPECIFIED ON THE CALCULATION FORM.

THE PERSONNEL INVOLVED DID NOT CONVERT LITERS TO GALLONS.-*THE RMC SUPERVISOR REVIEWED AND AUTHORIZED' ALL RELEASES WITHOUT NOTING THE ERROR. THE ERROR WAS DISCOVERED BY PALISADES PERSONNEL DURING. A ROUTINE REVIEW. . . ..

' * ~ I THE ACTIVITY RELEASED DURING THE PERIOD WAS ONLY 26*9 PERCENT OF THE.SPECIAL TECHNICAL SPECIFICATIONS LIMITS AND ONLY 2*69 PERCENT OF l'EDERAL LIMiTS /MPC/. ON AN AVERAGE BASIS. THE MPG LIMITS WERE EXCEEDED ONLY FOR TWO SHORT PERIODS OF' TIME .B.ETWEEN 8/16 AND 9/12/75 AS THE MPC LIMITS DEFINE ACCEPTABLE CONTINUOUS DRINKING '

WATER CONCENTRATIONS AND APPLY TO WATER PRIOR TO DISCHARGE TO AN~

~ILUTION IN LAKE MICHIGAN, IT IS CONCLUDED THAT THESE DISCHA~GES

~AD NO ADVERSE AFFECT ON THE PUBLIC HEALTH.AND SAFETY. . .

'I RALPH B SEWELL I NUCLEAR LICENSING ADMINISTRATOR CC- DIVISION OF REACTOR LICENSING USNRC - BETHESDA, MD .I J G LEW IS, PAL I SADES PL,ANT END -

W~J NRG BHDA

ML18348A628

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