Transcript Современная система внутриреакторного

Valentin Mitin, Yurij Semchenkov, Andrey Kalinushkin
International Nuclear Forum
VARNA 2008
Abstract
The present report covers object, conception,
engineering solution of construction of modern
system of high-powered reactor in-core control,
including VVER-1000 (V-320) reactors.
It is known that ICMS main task is on-line
monitoring distribution of power release field and
its functioning independently of design programs
to avoid common reason error.
It is shown in what way field of power release
recovery has been carrying on; rest on the
signals of in-core neutron and temperature
sensors.
On the base of the obtained and refined information
there have being automatically generated signals of
preventive and emergency protection on local
parameters (linear power to the maximum intensive fuel
elements, reserve to heat exchange crisis, «picking
factor»).
There have represented technology on sensors and
processing methods of SPND and TC signals, ICIS
composition and structure, program hard ware, system
and applied software. Structure, composition and the
taken decisions allow combining class 1E and class B
and C tasks in accordance with international norms of
separation and safety classes’ realization.
At present ICIS-M is a system, providing implementation
of control, safety, information and diagnostic functions,
which allow securing actual increase of quality, reliability
and safety in operation of nuclear fuel and NPP units.
And at the same time it reduces human factor negative
influence to core work thermo technical reliability in the
operational process.
Goals
The goal of creation of In-core Instrumentation system
(ICIS) for high-powered reactors, including VVER-1000
reactors, is increasing of NPP operation safety and
efficiency, due to:
Increasing of response speed, precision, reliability of
operational monitoring of neutron-physical and thermal
hydraulic parameters of the reactor core and primary circuit in
stationary and transitional regimes including situation when fuel
assemblies with individual characteristics are used;
Reduction of human factor negative influence to core work
thermo technical reliability in the operational process;
Information support provision during transient monitoring
modes;
Detection of anomaly in-core function at the first stages of their
occurrence with the purpose of exclusion of undesirable power
liberation surges, including provision of “mild” condition of
nuclear fuel operation.
The system should posses
Widely developed self-diagnostic function,
providing monitoring and timely indication
during malfunction of some equipment
elements (units), and
Software elements, producing difficulties
and reduction of number of system
functions, and
Signalization of unauthorized access to
the system.
Conception
The logic of function and correspondingly,
conception of modern ICIS structure and
architecture construction cause two-level
ICIS structure, every level of which is
realized in the form of dubbed Soft and
Hardware Complex of Lower Level (SHWLL) and Upper Level (SHW-UL).
On the low level (SHW-LL)
On-the-fly (not more than 0.5 sec. delay) in
seven layers on core height, using particular
calibration coefficients, it is determined maximal
linear power of fuel elements of every 163 fuel
assemblies.
This allows detecting in time exceeding of local
parameters permissible limits in case of Control
Rods uncontrolled motion, or in case of
operator’s error. Then it is made comparison
with the set-points and it is given an automatic
protection signal in case if local parameters
(Fuel element linear power or DNBR) exceed
permissible limits.
Following calculations are made on the upper
level with inaccuracy not more than (2  2.5 %):
The current distribution of power release
volume field and its functionals in space
16316;
The calibration coefficients for lower level,
forecasting calculations of core dynamic
behavior for transient modes
management.
Technical decisions
Fig. 1. General structural diagram
In the steady-state basic operation mode of a nuclear
power plant with the VVER-1000 reactors, the total
thermal power NАKZ released in the reactor was
determined by five independent methods
according to the readings of ionization chamber sensors
being a part of the neutron flux monitoring equipment
(NFME), NАКNP,
according to the readings of self-powered neutron
detectors (SPND), NSPND,
according to the readings of the sensors monitoring the
thermal parameters of circuit I, NIк,
according to the readings of the sensors monitoring the
thermal parameters of circuit II, NIIк,
by the flow rate of feeding water in the circuit, NPVD.
Sensors
To monitor core distribution of
volume field of power release,
signals are used
448 (764) rhodium Self-Power Neutron
Detector (SPND);
95 thermocouples (TC) ChrAl;
16 TC (ChrAl) and 8 thermo resistors (TR)
at primary circuit hot and cold legs
Soft and Hardware Complex of
Lower Level
Built on the base of the equipment, meeting RF modern
standard requirements, IEC and IAEA norms and requirements
which cover safety important systems, and acquire improved
metrological, reliable and time characteristics.
Seismic stable. High requirements to internal impact protection
(disturbance proof, seismic stability, climatic influence stability)
allow using the equipment in hard industrial conditions in
various climatic zones.
With doubling of data links and power supply in equipment and
also connection channels.
Meets 1E safety class requirements.
Measuring, processing and information transfer cycle into
SHW-UL is 1 sec.
1
01
B
02 The
3
03 section of
08
2
2
5
3
6
4
5
2
6
2
6
5
2
6
4
2
4
3
B
3
1
1
A
1
2
6
row
06
07
6
5
04 the second
05
4
1
5
3
6
1
4
4
5
3
2
6
2
6
1
A
5
09
Cartogram of location
КNI with SPND,
TC, and Control
Rods3
4
4
1
10
The section
of the
12 center of
13 active zone
11
1
HPA with
VIK
3
5
5
2
14
15
1
3
1
4
6
4
6
5
3
2
5
HPA with
thermal couple
17 19 21 23 25 27 29 31 33 35 37 39 41
16 18 20 22 24 26 28 30 32 34 36 38 40 42
Soft and Hardware Complex
of Upper Level (SHW-UL)
Key features of SHW-UL technical platform go as follows
Software and Hardware work in operational environment “Unix”
(SUN “Solaris”, “Linux” etc.);
sample architecture of open systems, which enables creation of
modern and prospective decisions on the base of widely used
standards (standards – POSIX 1, 1.b, 1.c and others);
the most technological industrial constructive (reliability, repair
ability, assembling decision spectrum) – Compact PCI;
high productivity – processor modules with operating speed,
enough for analysis of the reactor unit state, including modeling
of core neutron-physical and thermo hydraulic processes in real
time;
system reliability with application of new structural decisions,
including some components control and monitoring, and also
support of cluster technologies for full use of computing
resources together with automatic resources reconfiguration in
case of components or modules failure.
Flux Distribution of fuel elements. The section through
the center of the core A–A. The Upper level.
Flux Distribution of fuel elements. The section through
the center of the core A–A. The Middle level.
Flux Distribution of fuel elements. The section through
the center of the core B–B. The Upper level.
Flux Distribution of fuel elements. The section through
the center of the core B–B. The Middle level.
Results
Khortitsa-M” application software package in
combination with SHW-UL were tested and
put into operation
the 5th and 6th blocks at the Kozloduy
nuclear power plant and
the newly built 3rd block of the Kalinin
nuclear power plant and
the 1st and 2nd blocks of the nuclear
power plant in China
Determination of the
measurement errors for the total
thermal power
The measurement error for
the total thermal power at
transient regimes
Fig. 7. Reactor unloading, MCP disconnecting, changes in the departure from
nucleate boiling ratio
Fig. 8. Time delay in controlling the core heat power using dc SPND
The monitoring error at the
steady-state basic regime
Results of measurements and statistical weights for calculating power
NAKZ (The 3rd block «Kalininskaya»)
Measuring
values Ni
Calculated
weights wi
Results on 5 measurements
NAKNP
2905,8
0,2383
NDPZ
2871,3
0,2434
N1K
2894,5
0,2428
N2K
2870,8
0,2432
NPVD
2667,9
0,0323
NDPZ
2871,3
0,4157
N1K
2894,5
0,1728
N2K
2870,8
0,4115
NDPZ
2871,3
0,5000
N2K
2870,8
0,5000
Results on 3 measurements
Results on 2 measurements
Results of calculating power NAKZ and indices of error
of measuring (The 3rd block «Kalininskaya»)
Relative
variance
NAKZ
σ
5 measurements
2877,84
106,33
3 measurements
2875,08
2 measurements
2871,05
Relative error of measuring with
level of confidence
95%
99%
99,9%
3,69%
3,24%
4,26%
5,44%
14,31
0,50%
0,56%
0,74%
0,95%
0,35
0,01%
0,02%
0,02%
0,03%
Fig. 9. Operation model of Rhodium detector equipped
with corrective filter and Kalman filter
Fig. 10. Outcomes of processing SPND currents using Kalman filter with
various assigned response rates, and corrective filter with assigned
scanning rate
Fig. 11. Arrangement of ICIS detectors at Kozloduy NPP, Unit 5
KNI
Monitoring KNI
The cell with fallen
cluster
Fig. 12. Position of CR 11-26 during the falling and withdrawal
Fig. 13. Position of CR 11-26 during the falling in the first 11 seconds
Fig. 14. Position of CR 05-26 and other control rods of bank 10
with CR falling in channel 11-26 during 10 min
Fig. 15. SPND currents in NFMC 12-25 without elimination of delay period
at the moment of CR falling in channel 11-26 (10 seconds)
Fig. 16. SPND dc in NFMC 12-25 with eliminated delay period
at the moment of CR falling in channel 11-26 (with Kalman filter) (10 seconds)
Fig. 17. SPND currents without elimination of delay period
at the moment of CR falling in channel 11-26 depicted within expanded time interval
16.11.2005 КНИ
12-25
Без фильтра Калмана
(10
minutes)
1.1
1.05
1
0.9
КНИ 12-25-1 (мкА)
КНИ 12-25-4 (мкА)
КНИ 12-25-7 (мкА)
0.85
0.8
0.75
0.7
Время, сек
20:04:57
20:03:59
20:03:01
20:02:03
20:01:05
20:00:07
19:59:09
19:58:11
19:57:13
19:56:15
19:55:17
19:54:19
19:53:21
19:52:23
19:51:25
19:50:27
19:49:29
19:48:31
19:47:33
19:46:35
19:45:37
19:44:39
19:43:41
19:42:43
19:41:45
19:40:47
19:39:49
19:38:51
19:37:53
19:36:55
19:35:57
19:34:59
0.65
19:34:01
Ток, мкА
0.95
Время, сек
20:04:37
20:03:46
20:02:55
20:02:04
20:01:13
20:00:22
19:59:31
19:58:40
19:57:49
19:56:58
19:56:07
19:55:16
19:54:25
19:53:34
19:52:43
19:51:52
19:51:01
19:50:10
19:49:19
19:48:28
19:47:37
19:46:46
19:45:55
19:45:04
19:44:13
19:43:22
19:42:31
19:41:40
19:40:49
19:39:58
19:39:07
19:38:16
19:37:25
19:36:34
19:35:43
19:34:52
19:34:01
Ток, мкА
Fig. 18. SPND currents with eliminated delay period
at the moment of CR falling in channel 11-26 depicted within expanded time interval
16.11.2005(10
КНИ minutes)
12-25 Фильтр Калмана
1.1
1.05
1
0.95
0.9
КНИ 12-25-1 (мкА)
КНИ 12-25-4 (мкА)
0.85
КНИ 12-25-7 (мкА)
0.8
0.75
0.7
0.65
Calculation of errors for the Kalinin nuclear
power plant at different values of Тeff
B
L
O
C
K
1
3
Which cells are included in calculation
Teff
All
With
Kq
Kq
Q
>1 >1.2 <90
Kq>1 Kq>1.2
No
Detect
and
and
detect
ors
Q<90 Q<90
ors
only
8 5.37 4.39
3.99 5.47
4.48
4.18
5.81
5.06
20 3.88 3.32
3.10 3.94
3.36
3.17
4.51
3.41
40 3.62 3.03
3.10 3.65
3.03
3.18
4.32
3.09
2 2.31 2.30
2.23 2.31
2.31
2.23
2.58
2.11
10 2.29 2.28
2.26 2.29
2.29
2.26
2.46
2.17
20 2.32 2.27
2.19 2.33
2.28
2.19
2.45
2.24
The errors in the determination
of the linear power release in
the SPND locations at the
steady-state basic regime
Problems:
the changes in the dimensions of the
emitter in all SPNDs;
the displacements of SPNDs from the
expected design position;
the errors in determining the sensitivity
coefficients;
the correctness in the elimination of delay
in the flexible manner etc.
The uncompensated systematical errors,
which are not revealed by the statistical
analysis, should manifest themselves via the
discrepancy between:
the total thermal power released in the core
determined based on the recovered field and
the total thermal power calculated based on the
thermal and hydraulic parameters of the first and
second circuits.
All systematic and random deviations, which
were not eliminated, contribute to the
resulting value of the statistically estimated
error of the recovered power release field.
The statistical estimate of the error is defined
in terms of the root-mean-square deviation of
the volumetric factor characterizing the
inhomogeneity of the power release field from
its the most reliable value with respect to the
nominal fuel and SPND parameters.
The errors in the determination
of volumetric factor
characterizing the heterogeneity
of power release in the SPNDfree prisms
Dependencies upon time of rhodium SPND indications
Without delay
With delay
About conception of manmachine interface
Minimization of human factor unfavorable
consequences is solved the most efficiently by
reliable automatization of routine control actions to
regulation controls
Human factor favorable influence gain is the most
effectively solved by provision of continuous monitor
screen view of the current information about core
main processes, which are the most advisable for
operations staff attention, and giving a chance to
influence the above mentioned processes. Such
information, presented in friendly, ergonomically
self-possessed form, attracts operations staff
attention to the reactor processes and induces to be
always ready to make an optimal decision.
Efficiently and properly presented information about
the results of previous impacts and core current
status has a mobilized effect on operations staff
The graph SPND signals offsets
The graph of calculated offsets
Position of working group
Conclusions
Modern ICIS system for VVER-1000,
including a number of sensors, cable runs,
corresponding measuring equipment and
computer engineering, software,
accumulated 30 year experience of
intrareactor researches on VVER reactors
and is capable to ensure carrying out of
control, protection, informational, diagnostic
functions and thus to promote real increase
of quality, reliability and safety in nuclear fuel
and NPP power units operation .