ML20148G980
| ML20148G980 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 03/21/1988 |
| From: | Novachek F, Spiker D PUBLIC SERVICE CO. OF COLORADO |
| To: | |
| Shared Package | |
| ML20148G976 | List: |
| References | |
| NUDOCS 8803290283 | |
| Download: ML20148G980 (6) | |
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P-88106 1
CONTROL R00 DRIVE PARTIAL SCRAM TEST RESULTS AND MAXIMUM DAILY TEMPERATURE REPORT REPORT PERIOD:
FEBRUARY 1, 1988 - FEBRUARY 29, 1988 Prepared
- /
M tuane L. Spiker '
Senior Technical Services Engineering Technician N'[f Approved by:
s F. J/NovachP Technical / Administrative Services Manager Public Service Company of Colorado Fort St. Vrain Unit No. 1 G
SC'3290283 880321 PDR ADOCK 05000267 P
P-88106 Page 1 1.
ABSTRACT
-s This report summarizes the partial scram test results and the maximum daily temperature of those control rods with motor temperatures above 215 degrees Fahrenheit.
It is prepared to satisfy the Fort St. Vrain Interim Technical Specification Surveillance Requirement 4.1.1.A.1.a.
The tin'e period covered by this report is February 1,1988 through February 29, 1988.
II.
BACKGROUND Because proper operation of the Control Rod Drive Mechanism (CRDM) is critical for safe operation of the reactor, a series of -qualification tests were conducted over a one year time span to demonstrate its capability.
The motor temperature during these tests varied between 200 degrees Fahrenheit and 230 degrees Fahrenheit, and averaged 215 degrees Fahrenheit.
A total of 130,000 job cycles plus 1600 scrams was logged during the final design testing, which is many times that expected over the normal life of a CRDM. The operating temperature of the CRDM is limited by the motor's Class H insulation which is de-rated to 272 degrees Fahrenheit to account for motor temperature
- rise, frictional torque increase, and winding life expectancy.
In order to monitor CRDM temperatures, Resistarce Temperature Devices (RTD's) are mounted on the closure plate, orifice valve motor plate, and CRDM motor as shown on Figure 1.
All CRDM's installed in the Reactor are equipped with RTD's.
Three recorders located in the control room record each of these temperatures for all 37 CRDM's. CRDM motor temperatures are alarmed at 212 degrees Fahrenheit and 247 degrees Fahrenheit.
CRDM motor temperatures are monitored at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to verify that they are less than 250 degrees Fahrenheit, which is a limiting condition for operation.
If one or more CRDM motor temperature (s) is 'ound to be greater than 215 degrees Fahrenheit during the daily surveillance, the motor temperature of all CRDM's exceeding 215 degrees Fahrenheit is recorded and a partial scram test is performed j
on the CRDM with the highest motor temperature once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
These surveillances ensure that CRDM motor temperatures exceeding 215 degrees Fahrenheit do not degrade l
the CRDM's reliability to perform ,s design function when required.
P-88106 Page 2 III.
SUMMARY
OF RESULTS CROM motor temperatures exceeded 215 degrees Fahrenheit for three intervals during this report period. The first interval was from February 1, 1988 through February 3, 1988.
The second interval was from February 9, 1988 through February 10, 1988.
The third interval was from February 26, 1988 through February 29, 1988. Since the daily scram surveillance is performed only when CRDM motor temperatures exceed 215 degrees Fahrenheit, data is presented for these three intervals only.
The partial scram test results and maximum daily temperature of those CRDM's with motor temperatures above 215 degrees Fahrenheit are presented on Table 1.
The pertinent parameter =
are: reactor region involved, control rod position, maximur, daily motor temperature, extrapolated scram times (surveillance value and Back EMF calculated value) and starting acceleration. The control rod position is presented because of its relationship to available starting torque which affects the starting acceleration and extrapolated scram time calculated by surveillance.
The surveillance extrapolated scram time is affected by control rod position because it is calculated using distance travelled versus time.
Since the acceleration is slower at lower control rod positions, a longer period of time is required to reach steady state speed.
This longer acceleration period results in a decrease in distance travelled over a given period of time, and thereby indicating a longer extrapolated scram time, and thereby indicating a longer extrapolated scram time. The extrapolated scram time calculated by the Back EMF program applies a correction factor to provide a projected full length scraft time.
Therefore, the surveillance scram times can only be ccmpared for trends if the control rod position is approximately the same. The Back EMF calculated scram time is more readily trended.ince the value should be independent of control rod position.
o.
P-88106 Page 3 The starting acceleration values preserted represent those calculated by the Back EMF program. These' values reflect the CRDM's freedon of rotation to accelerate to steady state speed and therefore are considered to be valuable performance indicators.
Two values.
are presented: The. actual acceleration nieasured during a scram from the indicated control rod position, and the projected acceleration if the control rods were at the full out position (greater than 188 inches).
If the control rod position is greater than 188 inches, no data is presented for a projected starting acceleration since the actual and projected are the same. As indicated with scram
- times, the projected starting acceleration is more readily trended since the value should be independent of control rod position.
IV.
CONCLUSIONS This performance of CROM's with motor temperatures in excess of 215 degrees Fahrenheit did not show any significant trends or degradation during this report period. Therefore, it is concluded that CRDM motor temperatures exceeding 215 degrees Fahrenheit did not degrade the CRDM's capability to perform its design function when required.
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9 P-88106- -
TABLE 1 Extrapolated Scram Starting Acceleration Maximum Daily *F)
Motor Temp. (
Time (Sec)**
(Rad /Sec/Sec)
Date Regiong Position (In.)
l Surv.
Back EMF Actual Projected 2-01-88 12 189.8 224.6 150.8 143.9 116.1 116.1 i
2-02-88 12 Note 1 222.8 i
2-03-88 12 189.9 224.O 150.8 143.8
'116.9 116.9 2-04-88 through 2-8-88 No Data Presented. All CRDM Temperatures cess than 215'F.
2-09-88 12 Note 1 227.4 2-10-88 12 175.0 226.6 150.8 2-11-88 through 2-25-88 No Data Presenteu. AlI CRDM Temperatures Less than 215 F.
2-26-88 12 Note 1 224.8 2-27-88 12 179.0 227.2 138.3 143.7 116.1 116.1 30
.<227.2 2-28-88 12 177.3 227.0 136.8 144.0 116.0 116.0 s
30
<227.0 2-29-88 12 176.8 225.8 150.8 144.0 114.2 114.2 30
<225.8 l
l Only Region with Highest CRDM Motor Temperature -is Tested Limiting Condition for Operation:
<152 seconds-Acceptance Criteria Applied During Freventive Maintenance:
- Back EMF Data Not Available for Date Indicated
->98.83 Rad /Sec/Sec Note 1 CRDM MOTOR TEMPERATURE WAS BELOW 215 F DURING THAT TIME OF THE DAY WHEN TEMPERATURES WERE CHECKED BY OPERATIONS, THEREFORE NO TESTING WAS CONDUCTED.
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