ML19296A431
| ML19296A431 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 03/15/1979 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7903200373 | |
| Download: ML19296A431 (3) | |
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NSIS NORTHERN STATES POWER COMPANY M IN N E A PO LI S, M A N N E ts OTA 55401 March 15, 1979 P'. rector of Nuclear Reactor Regulation L' S Nuclear Regulatory Commission Washington, DC 20355 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket No. 50-282 License No. DPR-42 50-306 DPR-60 Additional Information related to January 10, 1978 License Amendment Request The subject license amendment request changed the functional test interval for the source, intermediate, and power ranges. To provide a quantitative justification for the refueling interval surveillance f requency, additional information is provided in the following areas -
(1) Number of observations (2)
RMS deviation observed (3) Maximum deviation observed for source and intermediate range setpoints (4) Method of measurement (5) Maximum credible value for drift in an 18-month cycle Attachment A addresses each of these areas based on a review of test data through August 25, 1978.
Very truly yours, U
L 0 Mayer,.'E Manager of Nuclear Support Services LOM/ JAG /ak cc: J G Keppler G Charnoff MPCA W Ferman Attn:
a 7903200373
March 15, 1979 8
Attachment A Source Range Trip:
1.
Method of Obs e rva tion - The level adjustment potentiometer is increased, and the level amplifier output vc1tage is measured. The output vo l t age at which the bistable actuates is recorded.
2.
Frequency of Observation - This testing is being done on a refueling outage i nt e rva l. There have been ten (10) tests of source range liigh 1 evel t rip bistables since Decembe r 19 73.
3.
Deviat ions observed - On a scale of 0-10 V, the RMS deviation for th is tes ting is 0.025 V, and the maximum deviation is 0.041 V.
With the bi s tab le setpoint at IES CPS, a nonconse rva tive RMS deviation yields 1.04E5 and a nonconservative maximum deviation yields 1.06 E5 CPS.
The Technical Specification setpoint is 1E6 CPS.
4.
Additional Surveillance - Additional surveillance has occurred (on a prior-to-startup basis) such that this setpoint has been checked l92 times since Decembe r 19 73.
This surveillance is done by testing bistable actuation vs panel meter reading.
It determines whether the setpoint is within 3% of the desired value.
No bistable recalibration has been necessary based on this test.
Intermediate Range Rod Stop:
1.
Method of Observation - The variable level potentiometer is increased, and the log current amplif ier output volt age is measured. The output vo ltage at which the bistable actuates is recorded.
2.
Frequency of Observation - This tes ting is being done on a ref ueling outage i nt e rva l. There have been 8 tests of intermediate range Rod Stop bistable since December 1973.
3.
Deviations Observed - On a scale of 0-10 V, the RMS deviation for this tes ting is 0.032 V, and the maximum deviation is 0.056 V.
This corresponds to bistable setpoint changes of about 0.75% power and 1.6% powe r respect ively.
This setpoint is not a Technical Specification item, but the Westinghouse recommended setpoint is 20%
power.
4.
Additional Surveillance - Additional surveillance has occurred (on a prior-to-startup basis) such that this setpoint has been checked 174 times since December 1973. This surveillance is done by testing bistable actuation vs panel meter reading.
It de te rmines whether the setpoint is within 1.5% of the desired value. No bistable recalibration has been necessary based on this test.
March 15, 1979 e
Attachment A (contd.) Intermediate Rany.e liigh Irvel Trip:
1, 2 Method and Frequency of Observation - These are the same as for the intermediate ra nge Rod Stop.
3.
Deviations observed - On a scale of 0-10 V, the RMS deviation for th is tes ting is 0.041 7, and the maximum deviation is 0.064 V.
This corresponds to bistable setpoint changes of about 1.3% power and 2.1% power respectively. The Technical Specification setpoint recently changed to 40% power, and the Prairie Island setpoint was is being changed to about 30% power.
4.
Additional Surveillance - Additional surveillance identical to that for the in t e rmedi a t e ra nge Rod Stop function has occurred. No bistable reca'ibrations have been necessary based on this test.