ML18005A007
| ML18005A007 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/01/1981 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17319A935 | List: |
| References | |
| NUDOCS 8106190096 | |
| Download: ML18005A007 (3) | |
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Implementation of Recomendattons for Auxiliary Feedwater System 1.
Additional Recommendation 1 - "The licensee should provide redundant level indi-cations, and a low level alarm in the con.rol room for the heal system primary water supply to allow the operator to anticipate the need to make up water or transfer to
'h alternate water supply anc! prevent a low pump suction pressure condi"ion from occurring.
The low level alarm setpoint should allow at least 20 minutes for operator action, assuming that the largest capacity ARL pump is operating."
In response to this recommendation, the licensee stated in letters dated December ll, 1979, March 28, 1980, and June 26, 1980, that the existing level monitoring system for the Condensate Storage Tank (primary water source) is provided with redundant level sensors which provide signals for a continuous recorder (a pneumatic system).
Low and low-low alarms which are powered by the same DC power bus, are provided for each level indicator sensor.
The low-low level alarm is set to allow 35 minutes for operator action.
Addi-tionally, in a letter dated September 18, 1980, the licensee comitted to installing an additional indication channel.
The new level monitoring channel, electronic in nature, will be a control room, panel-mounted, indicator through separate circuits and power supplies from the existing level monitoring system.
Me have reviewed the licensee's response and conclude that the existing pneu-matic system utilizing a continuous recorder and the additional electronic level indication provides the required redundant level indication.
The redun-dant low level alarms of the pneumatic system provided the required redundant low level alarms and the low level alarms allow at least 20 minutes for operator
~ action.
- Thus, we conclude that this recomendation is adequately met.
4'.
Recomoendation-
" "The licensee should perform a 48-hour endurance test on all AFM system pumps, if such a test or continuous period of operation has not been accomplished to date.
Following the 48-hour pump run, the pumps should be shut down and cooled down then restarted and run for one hour.
Test acceptance criteria should include demonstrating that the pumps remain within design limits with respect to bearing/bearing oil temperatures and vibration and that pump room ambient conditions (temperature, humidity) do not exceed environmental qualification limits for safety related equipment in the room."
In response to this recommendation, the licensee in a letter dated June 26, 1980, indicated that it would perform the 48-hour endurance test on. all auxiliary feedwater pumps and provide the results within 60 days of the test.
By letter dated February 12, 1981, the licensee provided the results of the 48-hour endurance test for the turbine-driven auxiliary feedwater pumps and the motor-driven auxiliary feedwater pumps.
- 1) A description of how the test was conducted and instrunented included the water source and flow path for the test and method of monitoring the pump and pump driver bearing temperatures.
- 2) All AFM pumps were operated at design rated dis-charge pressure and flow.
The turbine-driven AFM pumps were powered by main steam while the Units were at full power.
- 3) Plots of the bearing tempera-tures versus time were provided for each pump and pump driver bearing and indicated that design limits were. not exceeded.
- 4) Each AFW pump room environ-mental conditions were monitored throughout the test and the environmental conditions remained within their design limits.
5)
Pump and driver bearing vibration readings remained within the acceptable criteria.
We have reviewed the licensee's response and conclude that this recommendation is adequately met.
Basis for Auxiliary Feedwater System'Flow Re uirements - As a result of recent staff revi'ews of operating plant Auxiliary Feedwater System (AFWS), the staff concluded that the design bases and criteria provided by licensees for establishing AFWS requirements for flow to the steam generator(s) to assure adequate removal of reactor decay heat are not well defined or documented.
Me required that the licensee provide AFMS flow design bases information as applicable to the design basis transients and accident conditions for the D. C. Cook Units, Nos.
1 and 2.
By letter dated November 3, 1980, the licensee provided responses to this recommendation.
These responses showed that sufficient AFW flow could be delivered by the AFW system design to meet the minimum heat removal require-ments following any design basis transient or accident and assuming the worst case single active failure.
Me have reviewed the licensee s responses and the results of their analysis which
.tow that the minimum required flow can be met by one 450 gpm motor driven pump.
Based on our review, we conclude that the D. C. Cook Units, Nos.
1 and 2 AFM system design meets the minimum flow requirements and, therefore, the licensee's response to this recommenda-
~tion is acceptable.