ML20024B111
| ML20024B111 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 06/24/1983 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20024B100 | List: |
| References | |
| PROC-830624-05, NUDOCS 8307050225 | |
| Download: ML20024B111 (5) | |
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T. PROCEDURE
29; ,
RECIRCULI. TION FLOW CON 1ROU SYSTEM ,
- 1. PURPOSE The purposes of this test are:
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A. To demonstrate the core flow system's control. capability over the entire flow control range,Jincluding valve position, core flow, neutron flux, and load following modes of~ operation'.
B. To determine that all electrical compensators and controllers are set for desired system performance and stability.
- 2. CRITERIA Level 1.
A. Position Loop Criteria.
- 1. The position loop response to test inputs shall not diverge.
B. Flow Loop Criteria.
- 1. The flow loop response to test inputs shall not diverge.
C. Flux Loop Criteria.
- 1. The flux loop responce to test inputs shall not diverge.
D. Load Following Loop Criteria,
- 1. The load following loop response to test inputs shall not diverge.
E. Scram Avoidance and General Criteria.
- 1. None.
F. Flow Control Valve Duty Test Criteria.
- 1. None.
Level 2.
A. Position Loop Criteria.
Gains and limiters shall be set to obtain the following response.
- 1. Maximum steady state rate of change of valve position shall be between 9 & 11% per second for a 100% position demand input.
(Initial valve velocity may exceed this limit for a short time.)
B307050225 830624 PDR ADOCK 05000373 R PDR
STP C29
' Page 2
- 2. Gains shall be set to give as fast a response as possible for small position demand input within the overshoot criterion and without additional valve duty cycle. (See FCV duty criterion (6.2.F.1) for valve duty cycle requirement.)
- 3. The decay ratio of any oscillatory controlled variable must be s0.25, when operating above the minimum core flow for Recircula-tion Master Manual mode. Below this minimum core flow, the decay ratio must be 50.50 with the recommendation that each control system be adjusted to meet 50.25 unless there is an identifiable performance loss involved at higher power levels.
B. Flow Loop Criteria.
- 1. The decay ratio of any oscillatory controlled variable must be 50.25, when operating above the minimum core flow for Recircu-lation Master Manual mode. Below this minimum core flow, the
. decay ratio must be 50.50, with the recommendation that each control system be adjusted to meet s0.25 unless there is an identifiable performance loss involved at higher power levels.
- 2. The flow loops provide equal flows in the two loops during steady state operation. Flow loop gains should be set to cor-rect 90% of a flow imbalance in 20 + 5 sec.
C. Flux Loop Criteria.
- 1. The decay ratio of any oscillatory controlled variable must be 50.25, when operating above the minimum core flow for Recircu-lation Master Manual mode (loops A and B receive command from a common point). Below this minimum core flow, the decay ratio must be s0.50, with the recommendation that each control system be adjusted to meet 50.25 unless there is an identifiable per-formance loss involved at higher power levels.
- 2. For small flux command step changes of between 1%-5%, at near rated power, the following apply:
- a. Deadband, percent rated flux demand: 50.5.
- b. Delay time for flux demand steps, sec.: 50.8.
- c. Response time for flux demand steps, sec.: s2.5.
- d. Maximum allowable flux overshoot, for step demand of s20%
of rated is, in percent: 2.
- c. Flux settling time, sec.: s15.
STP #29 Page 3
- 3. Switching between estimated and actual flux should not exceed 5 times /5 minutes at steady state.
- 4. During flux step transient there should be no switching to actual flux or if switching does occur, it should switch back to estimated flux within 20 seconds of the start of the transient.
- 5. The deadband of the flux controller for a flux demand step shall be s.5% of rated flux demand.
D. Load Following Loop Criteria.
- 1. The decay ratio of any oscillatory controlled variable must be 50.25, when operating above the minimum core flow for Recircu-lation Master Manual mode. Below this minimum core flow, the decay ratio must be 50.50, with the recommendation that each control system be adjusted to meet s0.25 unless there is an identifiable performance involved at higher power levels.
- 2. The response to a step input of less than 10% in load demand shall be such that the load demand error is within 10% of the magnitude of the step within 10 seconds.
- 3. When a load demand step of greater than 10% is applied (N%), the load demand error must be within 10% of the magnitude of the step within N seconds.
- 4. For large Auto Load following Recirculation system maneuvers along the 100 percent rod line, 90 percent of the commanded step power change (P) must be completed within (t) seconds:
- a. For 10 percent change, 9 percent within 10 seconds,
- b. For 20 percent change, 18 percent within 20 seconds.
- c. For 35 percent change, 31.5 percent within 35 seconds.
- 5. The Automatic Load following range along the 100 percent (Flow Control) rod line shall be at least 35 percent power (i.e.,
between 65 percent - 100 percent power).
E. Scram Avoidanc.e and General Criteria. For anyone of the above loops' test maneuvers, the trip avoidance margins must be at least the following:
- 1. For APRM 27.5%.
- 2. For simulated heat flux 25.0%.
.' STP #29 Page 4
- 3. The system response in any mode response shall produce steady steam flow limit cycle variations no larger than 0.5% of rated steam flow.
F. Flow Control Valve Duty Test Criteria.
- 1. The flow control valve duty cycle in say operating mode shall not exceed 0.2% -Hz. Flow control valve duty cycle is defined as:
Total valve travel (%) (% - Hz) 2x time span in sec.
Level 3.
A. Position Loop Criteria.
- 1. Position loop deadband shall be <0.25% of full valve stroke (hot only).
- 2. Overshoot after a small position demand input (0.5 to 5%) step shall be <10% of magnitude of input.
- 3. Performance for 0.5 to 5% steps:
Delay: 50.15 seconds Response: 50.45 seconds
- 4. Performance for steps less than 0.5%, delay / response combination must be within the acceptable region of Figure 12.10.
- 5. Time required from peak of first overshoot for output of 0.2 to 5% steps to settle within a range about the final value is s one second. The range will be + 5% of the step change or +
0.05% full stroke, whichever is greater.
- 6. Any limit cycle in the sensed feedback position of the closed position loop must be less than 0.1% (peak to peak) of the full range as observed on the position feedback transmitter.
B. Flow Loop Criteria.
- 1. Incremental gain from flow demand input to sensed drive flow shall not vary by more than 2 to 1 over the entire flow range.
- 2. Deadband from function generator for valve position demand input to flow shall be s0.5%.
- STP #29 Page 5
- 3. The variation in open flow loop response times shall not exceed a factor of 3 to 1. This applies to both the symmetry of posi-tive and negative flow changes and to responses at the low and high ends of the Master Manual mode range.
- 4. The delay time for flow demand step 1 to 5% shall be 50.4 sec.
- 5. The response time for flow demand step 1 to 54 shall s1.1 sec.
- 6. The maximum allowable flow overshoot for step demand of 1 to 5%
l of rated shall be 6% of rated.
- 7. The flow demand step settling time shall be s6 sec.
- 8. Linearization of the open flow control loop, using function generators must be adjusted so that the graphical slope changes do not exceed a factor of 2 to 1 over the entire valve position range.
- 3. RE,SULTS Test Condition 3.
Recirculation system function generator linearization was successfully performed. Other test sections remain at this test condition. These include the performance of a series of small step, small ramp, and large ramp input demands in the local position command, flow command, flux command, and the automatic load following modes of operation.
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