Simulator Validation and Verification - SCS
12
Simulator Validation and Verification
Transcript of Simulator Validation and Verification - SCS
Simulator Validation and Verification
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SWR66309:Unit 1 manual reactor trip: March 7th 2011 @ 13:39 EST
completed
Sub-tasks: SWR66423-S (completed)
Line Of Business: PA
Project/Flag: OM&A/none
Major System: Models
Job Type: Verification Task
Platforms Affected: FS,DT Software Required: y
Urgency: 7 (Improves Product)
Direct exercise impacts: none identified
Raised By: Deljouravesh, Rama Raised: 2011-03-08
Reviewed: Deljouravesh, Rama
Assigned To: Deljouravesh, Rama Effort:70 hrs est ,120 hrs act
Simulator Installation: Q1 2011 Work Started: n/a
Offered By: Deljouravesh, Rama (Date: 2011-04-19)
Accepted/Rejected By: Goodhand, Michael (Date: 2012-12-21)
Rejections: 0
Lesson Plan Reference
File: none
Storepoint Reference
File: none
Document Reference
File: none
Problem Description:
Unit 1 Reactor Tripped Manually on SDSE due to 1-32310-CV105 Failure Closed. Please refer to SCR: P-2011-05282 for details. Perform simulator validation for this plant transient.
Fasttrack - Comment: By: Deljouravesh, Rama on date: 2011-03-23
Awaiting post-transient review for this event. Please see attachment: "Post Transient Meeting Minutes".
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 1) Please refer to worksheet “Comparison” in attachment “U1 RX Trip 03072011” for a comparison of
(the current) simulator response with PI data from Unit 1. Please note that attachment: “rx_trip_03072011” contains the script used to run this scenario. In brief, moderator valve 1-32310-CV105 was failed closed prior to SDSE reactor trip. After reactor trip, the turbine was manually tripped and boiler level setpoints were adjusted. Refer to attachments: “Electronic correspondence #1” for details from plant engineering. Please
note that the previous unit 1 trip (March 6, 2008) referred to in the attachment has not been used
here for the comparison and discussion of results because of PHT pressure instabilities as well as
reactor power (appears to be a startup ~ 44 % power, setback to 40% followed by a reactor trip). Comparison of PHT pressure response can be seen in figures 9a & 8b. Simulator ROH pressure decreased to 4.75 MPa compared to to 4.58 MPa from PI data. It can be seen that simulator PHT pressure remained below 5.8 MPa for approximately 51 seconds as compared to 82 seconds from PI data. PHT pressure recovered in 130 seconds as compared to 155 seconds from PI data. Simulator PHT pressure recovery appears to be 25-30 seconds quicker than plant performance
from unit 1 PI data. This is likely due to the differences in the response of boiler pressure, ROH temperature, and PHT feed flow response, all of which will be discussed in more detail.
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 2) PHT feed and bleed flows can be seen in figures 10a & 10b. With one pressurizing pump running
(as the more restrictive case), feed valves open fully to provide approximately 16 KG/s per loop. This compares well with 15 KG/s per loop from PI data, however, it should be pointed out that this flow was achieved with 2 pressurizing pumps in service (according to the attached electronic
correspondence). Therefore, simulator PHT feed flows appear to be over-sized and need to be investigated and verified. A work request has been raised to address this issue (SWR66430). The larger PHT feed flow in the simulator is one of the reasons behind quicker pressurization of the PHT mentioned earlier. Also, simulator PHT feed flows appear to be more abrupt in comparison with plant response.
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 3) Boiler level response can be seen in figures 3a & 3b. Initially boiler levels were approximately 1.5-1.6 meters (PI data) in comparison with 1.5 meters on the simulator. Following SDSE reactor trip,
boiler levels decreased by 1.5-1.6 meters, resulting in a an SDSA very low boiler level reactor trip. The simulator boiler model has been tuned to allow a shrink of approximately 1.3 meters on a
reactor trip from FPSS, hence just missing the SDSA very low boiler level trip (based on previous PI data from Pickering A and B). The magnitude of this shrink can be increased (if needed) based on input from training. Boiler level setpoints were adjusted, so that following the initial shrink after the reactor trip, levels recover up to the adjusted setpoint value. This level transient takes
approximately 230 seconds, which compares well with approximately 160 seconds from simulator data, when factoring in the steam generator pressure response as well as ROH temperature response. The long-term response of boiler levels in the simulator is worth particular mention. As can be seen in figure 3b boiler levels in quadrants 1 and 2 continued to increase (to approximately 1.5 meters), while levels in quadrants 3 and 4 remained steady at zero power setpoint ( ~1.0 meters). This effect is caused by condensation in boilers in quadrants 1 and 2, accompanied by boiling in quadrants 3 and 4. Condensation and boiling are cause by the uneven distribution of
temperature in the ROH. This can be seen in figure 7b where there exists a difference of as much as 2.8 degrees between the ROH temperature going into boilers in quadrants 1 and 2 as compared to boilers in quadrants 3 and 4. This issue had already been noticed and a simulator work request was raised to correct it (SWR66005).
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 4) Boiler feedwater response can be seen in figures 1a & 1b. It can be seen that following SDSE reactor trip there is approximately 400 seconds of feedwater flow, which with level recovery in the
boilers eventually drops to zero. This is a different response from Pickering B (Unit 5 reactor trip January 18, 2011 – 240 seconds of FW flow). Interestingly, at 500-900 seconds when boiler level setpoints are being decreased to 1.0, there does not appear to be any corresponding decreases in the feedwater flow as recorded in PI data. This does raise a few questions as to the validity of the recorded PI data for boiler feedwater flow.
Boiler steam flows can be seen in figures 4a & 4b. It can be seen that following the reactor trip
steam flows from all quadrants decreased gradually to zero in approximately 400 seconds. Seen in figure 4b, simulator boiler steam flows decreased to zero within a few seconds of the reactor trip. Simulator feedwater and steam flow response both differ from PI data. These differences are thought to be a result of differences in the ROH temperature response which will be discussed later.
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 5) Boiler feedwater temperature response can be seen in figures 2a & 2b. The initial simulator response is in close agreement with PI data; feedwater temperature decreased to approximately 110 degrees (i.e. DA storage tank temperature). There are however differences in the long-term
response. It can be seen from the simulator response (figure 2b) that feedwater temperature decreased to below 100 degrees in 1800 seconds, whereas in figure 2a PI data from unit 1 indicates that feedwater temperature remained above 120 degrees even after 1800 seconds. This
discrepancy in feedwater temperature response was initially more pronounced, due to a non-responsive deaerator storage tank level controller. A work request was raised to deal with this (SWR66423-S) and the issue was resolved. Current simulator DA storage tank level response (seen
in figures 13a & 13b) is in close agreement with PI data from unit 1, although temperature response remains an issue. A work request was raised to investigate and verify DA storage tank temperature with FW pumps in recirculation (SWR66424).
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 6) Also note, that during the initial simulator transient response feedwater flow to boilers was reduced to zero by BLCV's. Once feedwater flow is re-established at approximately 620 seconds, feedwater temperature began to decrease rapidly. This temperature decrease in the simulation results is not in keeping with plant response and based on an investigation of simulator response is thought to
be caused by 2 effects: colder than expected DA storage tank temperature (WR66424), and evaporative cooling of FW flow through HP heater shell-side vents. Vent lines from HP heaters 5A,
5B, 6A, and 6B depressurize the shell-side of these heaters to main steam condenser pressure (purge lines open after reactor trip speeding up the depressurization). Shell-side condensate, removes heat from feedwater tube-side flow through the drain cooler section as it evaporates. In other words, as shell-side pressure decreases, condensate saturation temperature decreases,
hence cooling the tube-side feedwater flow. The sizing of vent and purge lines is reasonable, however tube-side cooling during shell-side depressurization should be further investigated and GHYD library parts should be developed to better simulate HP/LP heaters, with the goal of eventually replacing our aging condensate and feedwater models. In this analysis HP heater purge lines were manually closed from panel 3B after SDSE reactor trip.
Additional comment: By: Deljouravesh, Rama on date: 2011-04-19
Comparison and Discussion of Results (part 7) Boiler pressure response may be seen in figures 5a & 5b. The boiler pressurized to approximately 4.4 MPa prior to depressurizing to 4.25 MPa. The impact of this can be seen in RIH temperature
(figure 6a) and also causes BPC to capture down due to the large error signal in the pressure signal (4.4 MPa vs. 4.7 MPa). The simulator response is somewhat different in that the boiler model has been tuned to pressurize to approximately 4.6 MPa prior to depressurizing to approximately 4.4 MPa (based on available Pickering B PI data). This affects RIH temperature as seen in figure 6b, where RIH temperature increased to 260 degrees more quickly than PI data from unit 1. Discussing boiler pressure response in terms of ROH temperature (figures 7a & 7b), unit 1 PI data indicates
that ROH temperatures decreased to approximately 250 degrees in 200 seconds. Simulator response in figure 7b shows that ROH temperature decreased to approximately 259 degrees in 100 seconds, remaining hotter, and responding more quickly, which is also consistent with the observed simulator boiler pressure response.
Main steam condenser pressure can be seen in figures 11a & 11b. It should be noted that the initial
value of main steam condenser pressure is approximately 2.7 KPa which is quite different from 4.3
KPa seen in simulation results. This difference can be caused by differences in ambient conditions, namely condenser cooling water intake temperature. AI1117 and 1118 indicate approximately 5 degrees, which is in good agreement with current simulator FPSS. The simulator main steam condenser pressure corresponding to this lake temperature is therefore too high and should be corrected.
Solution: By: Deljouravesh, Rama on date: 2011-04-19
A comparison of simulator performance against PI data from unit 1 has been carried out. Areas of discrepancy have been included in the discussion of results along with suggestions for areas of improvement.
Attached Documents:
1. Post Transient Meeting Minutes By: Deljouravesh, Rama on date: 2011-03-23
2. Electronic correspondence #1 By: Deljouravesh, Rama on date: 2011-03-23
3. U1 RX Trip 03072011 By: Deljouravesh, Rama on date: 2011-04-19
4. PI Data By: Deljouravesh, Rama on date: 2011-04-14
5. rx_trip_03072011 By: Deljouravesh, Rama on date: 2011-04-19
Software Changes: Work Package:none First Release:none
SDB changes: none initiated
Test Recording System Information:
Recommended tests: none Additional tests: none
Plant Data Simulator Response
Figure 1 a Figure 1 b
Figure 2 a Figure 2 b
0
20
40
60
80
100
120
140
160
180
200
0 300 600 900 1200 1500 1800
Flo
w [
KG
/s]
Time [s]
Boiler FW Flow
0
20
40
60
80
100
120
140
160
180
200
0 300 600 900 1200 1500 1800
Flo
w [
KG
/s]
Time [s]
Boiler FW Flow
90
100
110
120
130
140
150
160
170
180
0 300 600 900 1200 1500 1800
Tem
pe
ratu
re[C
]
Time [s]
FW Temperature
90
100
110
120
130
140
150
160
170
180
0 300 600 900 1200 1500 1800
Tem
pe
ratu
re [C
]
Time [s]
FW Temperature
Figure 3 a Figure 3 b
Figure 4 a Figure 4 b
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
0 300 600 900 1200 1500 1800
Leve
l [M
]
Time [s]
Boiler Narrow Range Level
0
50
100
150
200
250
0 300 600 900 1200 1500 1800
Flo
w [
KG
/s]
Time [s]
Boiler Steam Flow
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 300 600 900 1200 1500 1800
Leve
l [M
]
Time [s]
Boiler Narrow Range Level
0
50
100
150
200
250
0 300 600 900 1200 1500 1800
Flo
w [
KG
/s]
Time [s]
Boiler Steam Flow
Figure 5 a Figure 5 b
Figure 6 a Figure 6 b
3800
4000
4200
4400
4600
4800
5000
0 300 600 900 1200 1500 1800
Pre
ssu
re[M
PaG
]
Time [s]
Boiler Pressure
240
245
250
255
260
265
270
275
280
0 300 600 900 1200 1500 1800
Tem
pe
ratu
re [C
]
Time [s]
RIH Temperature
3.8
4
4.2
4.4
4.6
4.8
5
0 300 600 900 1200 1500 1800
Pre
ssu
re[M
PaG
]
Time [s]
Boiler Pressure
240
245
250
255
260
265
270
275
280
0 300 600 900 1200 1500 1800
Tem
pe
ratu
re [C
]
Time [s]
RIH Temperature
Figure 7 a Figure 7 b
Figure 8 a Figure 8 b
0
10
20
30
40
50
60
70
80
90
100
0 300 600 900 1200 1500 1800
Po
we
r [%
]
Time [s]
RX Power
0
10
20
30
40
50
60
70
80
90
100
0 300 600 900 1200 1500 1800
Po
we
r [%
]
Time [s]
RX Power
240
250
260
270
280
290
300
0 300 600 900 1200 1500 1800
Tem
pe
ratu
re [C
]
Time [s]
ROH Temperature
240
250
260
270
280
290
300
0 300 600 900 1200 1500 1800
Tem
pe
ratu
re [C
]
Time [s]
ROH Temperature
Figure 9 a Figure 9 b
Figure 10 a Figure 10 b
4000
5000
6000
7000
8000
9000
10000
0 300 600 900 1200 1500 1800
Pre
ssu
re [M
PaA
]
Time [s]
ROH/RIH Pressure
0
2
4
6
8
10
12
14
16
18
20
0 300 600 900 1200 1500 1800
Flo
w [
KG
/s]
Time [s]
PHT Feed & Bleed
4
5
6
7
8
9
10
0 300 600 900 1200 1500 1800
Pre
ssu
re [M
PaA
]
Time [s]
ROH/RIH Pressure
0
2
4
6
8
10
12
14
16
18
20
0 300 600 900 1200 1500 1800
Flo
w [
KG
/s]
Time [s]
PHT Feed & Bleed
Figure 11 a Figure 11 b
Figure 12 a Figure 12 b
0
1
2
3
4
5
0 300 600 900 1200 1500 1800
Pre
ssu
re[K
PaA
]
Time [s]
Condenser Pressure
0
1
2
3
4
5
0 300 600 900 1200 1500 1800
Pre
ssu
re [K
PaA
]
Time [s]
Condenser Pressure
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 300 600 900 1200 1500 1800
Leve
l[M
]
Time [s]
Hotwell Level
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 300 600 900 1200 1500 1800
Leve
l[M
]
Time [s]
Hotwell Level
Figure 13 a Figure 13 b
Figure 14 a Figure 14 b
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
0 300 600 900 1200 1500 1800
Leve
l[M
]
Time [s]
Deaerator Level
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3
0 300 600 900 1200 1500 1800
Leve
l[M
]
Time [s]
Deaerator Level
0
10
20
30
40
50
60
70
80
90
100
0 300 600 900 1200 1500 1800
Leve
l [%
]
Time [s]
Liquid Zone Level
0
10
20
30
40
50
60
70
80
90
100
0 300 600 900 1200 1500 1800
Leve
l [%
]
Time [s]
Liquid Zone Level
