ML20091A957

Revised Procedure 7202, Control Rod Drop Time

ML20091A957
Person / Time
Site:	Neely Research Reactor
Issue date:	04/25/1984
From:	Neely Research Reactor, ATLANTA, GA
To:
Shared Package
ML20091A948	List: ML20091A955 ML20091A957 ML20091A991
References
7202, NUDOCS 8405300140
Download: ML20091A957 (5)

Text

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GEORGIA TECl! RESEARCil REACTOlt l Chapter Procedure 7202  !

9 Approved 7-17-81 l Instrumentation Control Rod Drop Tine Latest Rev. 4-25-84 l

& Surveillance Page 1 of 5 I. - GENERAL REQUIREMENT A. Frequency.

Monthly B. Technical Specification or other reference See 3.2c., and 4.2c.

II. PREREQUISITES A. Reactor shutdown. Core is cold and xenon free.

B. A-licensed reactor operator to perform the rod withdrawals.

C. Containment Integrity exists (see Tech. -Spec. ,,'.

definition 1.26). -

III. PROCEDURAL INSTRUCTIONS A. Roset all control interlocks.

B. Drive the Regulating Rod f rom IN to OUT and record the following times (in seconds) or positions (in inches) on the data card in the Control Room files.

1. DOM 4 limit switch position.

2. Time to drive to the UP limit.

3. UP limit switch position.

4. Time to drive to the DON 4 limit.

r C. Set up initial conditions for the Universal Counter as described on pages 3 and 4 of this procedure.

D .~ Prior to mea'surement of the shim blade drop times, perform the following steps to evaluate the reactor shutdown margin. Note: These steps should be omitted if the core is not cold and xenon free.

1.'. Raise the regulating rod to the full OUT position.

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o GE0fGIA TECH RESEARCH REACTOR

- Chapter Procedure 7202 9 Approved 7-17-81 Instrumentation Control Rod Drop Time Latest Rev. 4-25-84

& Surveillance Page 2 of 5

2. Raise shim' blade No. 3 to the full OUT position.

3. Raise either shim blade 1, 2 or 4 until 0.015 k/k reactivity has been added (refer to the blade worth calibration' curves.)

4. Verify that the reactor is subcritical. Log this verification in the console logbook.

E. Shim Blade Drop Time. Drive a selected blade fr'om D%N limit to UP limit (determine Aux. Switch setting). Reset counter and press MANUAL SCRAM Switch. Record values for.the following positions and times.

1. DOWN limit switch position.

2. - Auxiliary DohN limit. switch position. ..

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3. . UP limit switch position.

4. Drive time to UP limit.

5. Two drop times in milliseco'nds, as determined by the Universal Counter.

F. Repeat E l-5 for the remaining shim blades. . . .

IV. ACCEPTANCE CRITERIA A. Regulating Rod

1. Limit switch positions.

DOWN limit between 0.0 and 0.2 inch.-

UP-limit between 11.8 and 12.0 inch.

2. Drive ti1ne

~Between 45.5 and 48.5 seconds..

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GECICIA TECII RESEARCil REACNR

~ Chapter Procedure 7202 9 Approved 7-17-81 Instrumentation Control Rod Drop Time Latest Rev. 4-25-84

& Surveillance Page 3 of S B. Shim Blades

1. Limit switch position UP limit between 54 and 57 degrees.

2. Drive time Between 30 and 345 seconds

3. Drop time ,

Between~430 and 500 milliseconds and time is not i20 msec different from previous months time.

C. Advise Reactor Supervisor if any acceptance criteria are not met-9 5

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GEORGIA TECH RESEARCil REACTOR Chapter Procedure 7202

, 9 Approved 7-17-81

Instrumentation Control Rod Drop Time Latest Rev. 4-25-84

& Surveillance Page 4 of 5 V. UNIVERSAL COUNTER - PREPARATION These steps outline the set-up required for the Universal Counter instrument necessary to perform the measurements specifled on the previous pages.

A. Initial Set-Up

1. . Remove LCRM input signal to the Universal Counter at rear of chassis.

2. Select "TI A to B" function. .

3. " Fast / Norm /liold" switch to Hold.'

4. " Time Base / Multiplier" switch to 1 millisecond.

5. " Time Base" toggle to X1.

6.. Channel A " Attenuation" to XI. ,

7. Channel A "AC-DC" to DC. .

8. Channel A " Slope" to minus.

9. "SEP-C04" to Separate. -.

10. Channel B " Attenuation" to XI.

11. Channel B "AC-DC" to DC.

12. Channel B " Slope" to positive.

13. Channel B " Level" to 0.

B. Regulating Rod The Universal Counter is not used for any regulating rod measurements.

C. Shim Safety _ Rods

1. When the auxiliary limit switch position is being determined, first trigger the counter CN by moving the Channel A " Level" control f rom -0.5 to +0.5 7

then back to -0.5.- Drive the blade up until the s switch resets and the counter stops. Then change the Channel A slope to positive. Again, turn the

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GEORGIA TECil RESEARCll REACTOR

. Chapter Procedure 7202 9 Approved 7-17-81 Instrumentation Control Rod Drop Time _ Latest Rev. 4-25-84

& Surveillance Page 5 of 5 level control to start the counter. Drive the blade down until the switch actuates and the counter stops. Read the blade position.

2. Drive the blade to the up limit position.

3. Reset the counter and firmly press the SCIW4 button. The counter will display the drop time in milliseconds.

4. Drive the blade from the down limit to the up t

limit and determine the drive time.

5. Repeat step 3 'above to determine the second drop time.

D. Return to Normal Operating Mode.

1. " Fast / Norm /llold" switch to Norm. , .

2. Function switch on STOP. -

3. " Time Base / Multiplier" to 1 second.

4. Connect LCRM signal lead to ' counter.

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