ML20033D093
| ML20033D093 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/24/1981 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8112070216 | |
| Download: ML20033D093 (3) | |
Text
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D Northern States Power Company e
414 Nicollet Malt Minneapohs, Minnesota 55401 Telephone
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November 24, 1981 Qi DE
-d u.s. C.)1981w y Of fice of Nuclear Reactor Regulat ion
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h coq 8 Director Attn:
Document Control Desk U
US Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Auxiliary Feedwater System Information The purpose of this letter is to provide additional information related to the Prairie Islar.d auxiliary feedwater systems. This supplements information provided to the NRC Staff in our earlier letter dated February 4, 1981.
Our Project Manager in the Division of Licensing has informed us that additional.information is necessary to resolve three remaining open items:
- 1. Additional Short Term Recommendation 1 - AFW Primary Water Supply Indication
- 2. Additional Short Term Recommendation 2 - AFW Pump 48-Hour Test
- 3. Recommendation GL Suction Protection for AFW Pumps Additional information related to each of these items is attached. Please contact us if you have any questions concerning the information we have provided.
L 0 Mayer, PE Manager of Nuclear Support Services LOM/DMM/bd cc: Director, IE.TII, USNRC i
NRR Project Manager, USNRC Resident Inspector, USNRC l
G Charnoff j
f g6 L Attachment 64 \\
8112070216 811124 PDRADGCK05000g P
e Director of NRR Novemer 24, 1981 Attachment Additional Short Term Recommendation 1 - AFW Primary Water Supply In addition to the modificatica described in our letter of February 4, 1981 to provide redundant low level alarms, the following action will be taken to resolve this issoe:
- a. Cables for Unit 1 and Unit 2 condensate storage tank level indication will be rerouted to meet FSAR separation criteria for redundant safeguards instru-mentation.
- b. A Technical Specification change request will be submitted to require cross-tie valves between Unit 1 and Unit 2 condensate storage tanks to be tagged in the open position with all changec in valve position to be under direct administrative control.
We believe these actions will aseure redundant indication of primary water supply to the auxiliary feedwater pumps.
in addition, the contents of all condensate storage tanks will be available to each unit.
The Technic.tl Specification change request will be submitted within 90 daye of receipt of the Staff'e Safety Evaluation Report.
Additional Short Term Recommendation 2 - AFW Pump 48-Hour Test A report of this testing, including graphs of bearing and ambient temperatures, included with our February 4, 1981 letter.
was As noted in our report, humidity instrumentation was not available at the time of the testing. Humidity conditions, observed by personnel during the testing, remained in the normal range for this area.
As noted in our report, ambient temperatures remained below 100 F during all enuurance testing.
Maximum turbine bearing temperature was 206 F.
Maximum motor bearing temperature vas 139 F.
Maximum pump bearing temperatur.
.as 131 F.
As noted in the report, all temperatures remained well within um operational range established for this equipment. Temperatures were inficanced more by the time of year each pump was tested (and the resulting cooling wacer temperature) than by the extended run of the equipment.
Cooling is provided by a safety grade cooling water system which is described in the FSAR.
No special environmental qualification requirements were applied to the auxiliary feedw. ster pumps or drivers when they were purchased. This equipment will not be exposed to a harsh environment (FSAR, Appendix I,Section I.7).
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g-Director of NRR Novemer 24, 1981 Attachment Additional Short Term Recommendation 2 (continued)
The only value specified in instruction manuals for bearing temperature is that the pump return oil temperature should not exceed 160 F.
No vibration limits are specified.
In all cases, values established since the original preoperational tests at Prairie Island have been used to establish operational limits.
Vibration limits used were between two and three mils double amplitude (depending on the individual pump). Pump bearing metal temperature, also monitored during the test, has an upper limit of 180 F.
No problems were observed with these parameters.
In summary, all test data indicates that extended operation of the auxiliary feedwater pumps has a negligable impact on pump parameters and ambient conditions.
Recommendation GL Suction Protection for AFW Pumps A design change to install suction and run-out protection for all four auxiliary feedwater pumps was described in our February 4,1981 letter.
Discharge pressure switches will be used since the layout of the Prairie Island condensate storage tanks and auxiliary feedwater pumps makes usel of suction pressure switches impractical (the pump. suctions are approximately-three feet above the condensate storage tank suctions).
Some difficulty has been experienced in locating seismically qualified pressure switches for this application. We believe, however, that this modification'can be completed within 25 weeks of receipt of the Staff's Safety Evaluation Report.
A procedure has been prepared to address the loss of auxiliary feedwater and to alert the operator oi. the existence of conditions for switching _ the-suction to the cooling water system. This procedure, E5, " Loss of Feedwater Supply," is.available on site for review by the Office of Inspection and Enforcement;f A copy has been made available to our. Project Manager lin the
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Division of Licensing.
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