ML20090E167

Ro:On 741001,during Containment Spray Raw Water Pump Testing,Flow Measurement Was Not Adequate to Determine Specified Performance.Caused by Design Error.Flowthrough Pumps Will Be Adjusted

ML20090E167
Person / Time
Site:	Nine Mile Point
Issue date:	10/31/1974
From:	Schneider R NIAGARA MOHAWK POWER CORP.
To:	Skovholt D US ATOMIC ENERGY COMMISSION (AEC)
References
11261, NUDOCS 8303110625
Download: ML20090E167 (4)

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NIAGARA MOHAWK POWER CO.RPORATION i

NlAGARA MOHAWK j 300, ERIE BOULf v ARD. WEST

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October 31, 1974 'M l- .

l Mr. Donald J. SkovFolt l Aceistant Director for Reactor Operations Division of Reactor Licensing United States Atomic Energy Conniscion Washington, D.C. 20545

Dear Mr. Skovhott:

l In accordance uith Technical Specifications for.

Nine Mile Point Unit 1, the enclosed Unusual svent Report I .

is submitted. This report'is in accordance with the format cet forth in Rcgulatory Guidelina 1.1G.

l Very truly yours, l

R.R. Schneider Vice President -

Electric Operations hJD/t#1 l Enc.

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l PDR ADOCK 0500022

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n O o UNUSUAL EVENT REPORT

1. Report No. Unusual Event 2a. Date October 30, 1974 2b. Occurrence Date October 1, 1974

3. Facility Nine Mile Point Unit #1

4. . Identification of Occurrence Variance from performance specifications contained in the Technical Specifications.

5. Condition Prior to Occurrence Unit steady state 97%-98% pbwer. ,

6, Description of Occurrence _

During testing on the containment spray raw water pumps, it was revealed that the installed, as built design, for flow measurement was not adequate to determine performance as established in the Technical Specifications.

'The exiscing flow instrumentation ranges from 0 to 150,000 lb's/hr (0-3000 gpm). During surveillance testing the indicated flow has generally indicated greater than the 150,000 lb/hr upper point, or off scale. Testing was then conducted, over and above surveillance requirements, to establish a reasonable range for the instrumentation in which the indicated flow would not exceed the upper readable point. During this testing, it was discovered that the precision required for system performance as established in the Technical Specifications could not be obtained on the flow measurements.

This is-due to the piping design of the system which does not per-mit the flow orifice to determine, within required accuracy,- the raw flow parameter. Thus correlation to the certified pump curve cannot be made with both the Total Developed Head (TDH) and pump flow.

The acceptable performance of the system as documented by the Final Safety Analysis Report (FSAR), requires a system flow oi~

3000 gpm and a minimum pressure on the raw water side cf the heat exchanger _ of 160 psig. A varianco, therefore, exists 7 between the Technical Specifications and the FSAR. This is an

- Unusual Event as ' defined in Technical Specification 6.6.b(2)b.

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G' 7 D;signetion of Appar:nt Cause of the Occurrenca ,,

Inability to adequctely determir.e L:iboratory pump curve flow at design TDit in the Station.

8. Analysis of Occurrence Inspection of the vertical pump shows no unusual or unexpected condition. The shutoff head as measured compares favorably with the pump curve. The containment spray raw water system is a 400% redundant system designed to maintain containment spray water temperature no greater than 140 F under the most limiting operating conditions. A flow rate of 3000 gpm is used in the supporting safety analysis (FSAR) to maintain this temperature. A requirement to obtain a greater pressure on the raw water side of the heat exchanger is provided to maintain any leakage flow into the con-tainment system. As indicated in the Safety Analysis (FSAR Vol. I VII-22),

the containment side of the heat exchangers will operate at 123 psig, including containment pres:ure, under accident conditions. The design raw water side operating pressure is 160 psig. Presently, the raw water side operates at 180-185 psig with a pump total dis-charge head of 540 feet of water. This is considerably morc than required.

9. Corrective Action Each of the four (4) pumps were tested in accordance with the klydraulic Institute Standard requirements before shipment from the factory in July 1969 and met or exceeded the specified design

. performance. During the course of the in-plant investigaticn it was wecided to open up one of the pump., for inspection. This inspection revealed that littic if any wear could be observed, or in other words the pump appeared to be in near new condition.

This-fact is further substantiated by operating reports that indicate total operating time on each pump since their original installation is less than 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />.

Because of the fact that these pumps did meet or exceed their design performance at the factory, have tots' operating time of less than 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> and recent inspection indicated like new con-dition, it is concluded that were the pumps subjected to a new test conducted in accord with the liydraulic Institute Standards that they would meet their specified, design performance.

Therefore, based on the above conclusion, the flow through each of the pumps will be adjusted such that the corrected TD11 is 540 ft.

of water. When operating at this TDil, the flow meter indication will be adjusted to read 3000 gpm. This activity will in effect calibrate the orifice plate and give a very accurate flow indication for that range of flows.

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Continued In addition, the performance specification as defined in the bases of the Technical Specification will be rewritten reflecting the '

I safety analysis as presented in the FSAR. This change will rectify the existing variance. This change will be reviewed by the Safety

• . Review and Audit Board at their next regular meeting and submitted in accordance with Section 6 of the Techneial Specifications.

The change will reflect a requirement to measure.the pressure on the raw water side of the heat exchanger (minimum 160 psig) at an indicated flow of at least 3000 gpm on the flow meter. With this clarification of performance determination, the system flow and heat exchanger pressure will correlate directly to the required Safety Analysis and not a design point on a pump curve.

10. Conclusion The investigative actions, results and conclusions meet with full approval of the SORC and that committee concludes that this event does not present a haza:d to the health and safety to the general public, o

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