Text

CRD Partial Scram Test Results & Max Daily Temp Rept for Jul 1989
	ML20245L586
Person / Time
Site:	Fort Saint Vrain
Issue date:	07/31/1989
From:	Brundson B, Steve Jones; PUBLIC SERVICE CO. OF COLORADO
To:	;
Shared Package
ML20245L573	List: ML20245L569; ML20245L583; ML20245L586;
References
	NUDOCS 8908220173
	Download: ML20245L586 (6)
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CONTROL ROD ORIVE PARTIAL SCRAM TEST RESULTS AND MAXIMUM DAILY TEMPERATURE REPORT REPORT PERIOD:

July 1, 1989 - July 31, 1989 Prepared by: /wEeaa4 [v[fm Bruce Brunsdon System Enginear Systems Engineering Approved by:

[m.e Steve da6ei Preventive Maintenance Supervisor Systems Engineering Public Service Company of Colorado Fort St. Vrain Unit No. 1 l

8908220173 890815 PDR ADOCK 05000267 R

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Page 1

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I.

1 ABSTRACT:

L This-report; summarizes the partial' scram' test results and the maximum daily temperature of those control rods with motor

1. temperatures above 215 degrees Fahrenheit.

It'is prepared to ysatisfy the Fort St.. Vrain Interim Technical. Specification

. Surveillance Requirement 4.1.1.A.I.'a.

The time period covered by this report is July 1, 1989', through July 31, 1989.

II.

BACKGROUND Because. propee peration.of the Control Rod Drive Mechanism (CRDM) is cri'.iu. for safe operation of the reactor, a series of quali ficat' ion ~ 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 jog 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 windi.ng life expectancy.

In ' order to monitor CRDM temperatures, Resistance 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 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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 found to be greater than 215 degrees Fahrer:heit during the daily surveillance, the motor temperature of all CRDMs-exceeding 215 degrees Fahrenheit is recorded and a partial scram test is performed on the CRDM with the highest motor temperature once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

These surveillance ensure that CRDM motor-temperatures exceeding 215 degrees Fahrenheit do not degrade the CRDM's reliability to perform its design function when required.

III.

SUMMARY

OF RESULTS

F'E Page 2 l'

During the month of July,1989, CRDM shim motor temperatures in five reactor regions exceeded 215 degrees Fahrenheit.

In j,

accordance with Technical Specification 4.1.1.A.1.a, the maximum' daily temperature exceeding 215 degrees for each of these regions is listed in Table 1.

As shown, the temperature in region 30 exceeded that'in all other regions for the entire reporting period, so a partial scram test was performed on this region once every 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Note that all CRDM shim motors remained below the limiting condition of operation temperature of 250 degrees Fahrenheit for the entire raporting period.

The results of the partial scram tests performed on the region with the highest CRDM shim motor temperature are shown in Table 2.

The parameters associated with the back-EMF voltage data include actual scram time, extrapolated scram time, control rod position and starting acceleration.

The extrapolated scram time is an estimate of the amount of time it would take a particular control rod pair to insert from the fully withdrawn position.

It is calculated based on the initial acceleration and steady state velocity of the rods, measured during the partial scram test.

This parameter provides a means to verify CRD0A operability (per the Technical Specification definition) without conducting a full stroke test, and provides a basis to compare data from partially withdrawn rods to data froa fully withdrawn rods.

The starting acceleration parameter is a measure of the free rotation of the CRDM to a steady state velocity under a known applied torque.

The difference between the actual acceleration and the theoretical maximum acceleration serves as an indication of the mechanical drag present in the drive mechanism.

The amount of torque available to initiate a scram varies as a function of control rod withdrawal height, affecting the theoretical maximum acceleration.

For scram tests ' performed on partially withdrawn rods, the projected starting acceleration is the theoretical maximum acceleration of the mechanism under the amount of torque available.

For fully withdrawn rods, the projected starting acceleration is the actual starting acceleration.

IV.

CONCLUSIONS Many of the back-EMF tests performed during the month of July were affected by noise in the data acquisition sy: tem, which was recorded along with the back-EMF voltage. The noise caused erroneous starting acceleration values to be calculated, but did not affect the actual or extrapolated scram time values.

Those tests affected by noise are identified in Table 2.

The data unaffected by noise indicated that the performance of the CRDM with a shim motor temperature in excess of 215 degrees Fahrenheit did not degrade during the 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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~-TABLE'1.

o MAXIMUM DAILY CRDQ SHIi1 MOTOR TEMPERATURES

~

REG. 09

- REG. 12 REG. 25 REG.f26

' REG.!30 DATEL CRDM 18 CRDM 36-CRDM 21 CRDM 29 CRDM 05 17/1/89:

242.0 235.3

.7/2/89 216.5-238 4 1216.9

.244.7 07/3/89 237.8 216.8:

243.2-

-7/4/89 236 0 216.0 240.2

'7/5/89

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=238.8 215.8' 244.5 215.2 244 3^

-7/6/89 238 3

-7/7/89.

219.1 238.4-216.3 215.3 244 3 7/8/89 216.4;

'239.0 215.1-

-215.6 245.4-7/9/89"

'216.3.

239.1 215 1 215.1 245.1 7/10/89 -

R216.0~

238.8-215.0 244.9 7/11/89' 215.5.

,239.6 215.7 215.0 245.6 7/12/89:

'215 5 239.4-215.6 245.5 L7/13/89~

215.0 239.2 215.4 245.0 238.8 215.2-244.8 17/14/89 47/15/89'

-215 0 238.9-215.4

'246.0 s

7/16/89 216.5 240.7 217.0 215.3 248.0 7/17/89 217.8-242 1-218.2 216.1 249.3 7/18/89 238.6 215.3 215 3 245.2 7/19/89.

238.4 215 2 215.2 245.1 244.8 17/20/89

'238.4 215.3 238.3-215.1 244.7 17/21/89 238 2 215.0 244.7 7/22/89-244.6 7/23/89.

238.2.

215.2 7/24/89-238'.6 215.0 244.5

.7/25/89 238.8-215.2 215 3 244.5

.238.7 215.3 215.0 244.6 7/26/89-241 2 218.0 215.6 247.3

'7/27/89 7/28/89

-241 2 217.9 215.5-247.4 7/29/89 239.2 215 4 215.0 245.7-238.9 215.0 245.1 7/30/89 17/31/89 238.0 244.8 NOTE:

All temperatures reported are in degrees Fahrenheit.

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l LTABLE 2.-

CRDM PERFORMANCE PARAMETERS FROM DAILY PARTIAL SCRAM TESTS SCRAM L TIME:

ACCELERATION' y '~

-(seconds)'

(radians /sec/sec)

DATE_

REGION-'CRDM TEST PROJECTED ACTUAL PROJECTED.

4.

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-7/2/89'*~

. ~ 30

'05 10.0 134 1 114.6-17/1/89 *

' '30 05 -.

10.0'

.134 8 105.0 1

?7/3/89 +

30' 05 10.0 134.7

.81.7 7/4/89 *

'30-05' 10.0 134.7 114.6

-7/5/891*

130 05 10.0 134.8 104.9 i

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7/6/89.*/

30 05 10.0

=134 6 107.4 i

o 7/7/89:*/

'30' 05:

10.0 134.8 111 4' 4

7/8/89

+1 130 05' 10.0 134.8 109.9-1 7/9/89.:*_

~30:

.7/10/89L*.

05 10.0 134.8 119.2 30 05 10.0 139.4 73.3 i

17/11/89 +

30

-05' 10.0 134.9 38 4-i 7/12/89'*<

.30 05 10.0 134.8 139.4 17/13/89 +

30 u05 10.0 134.8 55.0

7/14/89

30.

05 10.0 135.0-118.1 l

7/15/894*.

30 05-10.0 135.1 106.3 7/16/89

30.

05-10.0 134.9 103.7 l

l 7/17/89 +

30i

'05-.

10.0 134.9 75.3 L

7/18/89.*

30-05 10.0 135.0-118.2-6 E7/19/89.

30.

05

.10.0 135 1 117.7 r

'7/20/89;*.

30' 05 10.0 134.9 118.6-

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~7/21/89.

-30 05 10.0 135 2 116.7 7/22/89 iM) 05-

10. 0..

135 1 116.3~

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E 17/23/89.,

30=

05 10.0-135.1 116.5

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'7/24/89' 301 105

~10.0 135.2 116.6-j 7/25/89-

'30

~ 05 :

10.0 135 1 117.4 E7226/89-30 05-

-10.0 135.1 116.7 L7/27/89.

30 05 10.0 135.1 116.1 1

S7/28/89 30' 05 10.0 135 2 116.2 i

~

L7/29/89 30 05 10.0 135 2

-116.2 7/30/89; 30 05 10.0-135 3 116.2 i

7/31/89 30 05 10.0 135 3 116.4

-Notes:1 Back-EMF tests affected by noise in data acquisition system are j

indicated with an asterisk.

No projected starting acceleration values are reported because

.a l l scram testsLuere performed from the fully withdraun position.

l

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ML20245L586

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