NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROGRAM OR FUNCTION, SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, CPU, FEATURES, AUXILIARIES, STATUS, REFERENCES, REQUIREMENTS, LANGUAGE, OPERATING SYSTEM, OTHER RESTRICTIONS, ESTABLISHMENT, MATERIAL, CATEGORIES

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Program name | Package id | Status | Status date |
---|---|---|---|

ZZ-BWRSB-FORSMARK | NEA-1551/01 | Arrived | 12-FEB-2002 |

Machines used:

Package ID | Orig. computer | Test computer |
---|---|---|

NEA-1551/01 | Many Computers |

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3. DESCRIPTION OF PROGRAM OR FUNCTION

The purpose of this benchmark is the intercomparison of the different time series analysis methods that can be applied to the study of BWR stability. This is a follow-up benchmark to the Ringhals 1 Stability Benchmark. While the Ringhals 1 Stability Benchmark included both time domain and frequency domain calculation models to predict stability parameters, the new benchmark is focused in the analysis of time series data by means of noise analysis techniques in the time domain.

The first goal is to elucidate if it is possible to determine the main stability parameters from the neutronic signals time series with enough reliability and accuracy. Typically, the main stability parameters are assumed to be the decay ratio (DR) and the frequency of the oscillation. However, there are other parameters that provide valuable information, such us the Lyapunov exponents associated to the time series, or the Haussdorff dimension. In fact, the Lyapunov exponents are also a measure of the stability of the neutronic time series.

The data given in this benchmark were obtained during several stability tests performed at the Swedish BWR reactors Forsmarks 1 and 2, in the period 1989 to 1997.

The database is divided into six cases, the sampling rate of all the time series being 25 Hz, decimated to 12.5 Hz. The data are stored column wise in ASCII format. No filter to the signals and the DC-component has not been subtracted.

CASE 1: This case contains the neutron flux signals measured during several tests. The objective of the case is to study several signals ranging from stable to quasi-unstable conditions. The signals are standard measurements with no distortions. Data contains measured APRM (Average Power Range Monitor) signals from stability tests. The signals are measured at conditions with low Decay-Ratios up to high Decay-Ratios.

CASE 2: This case addresses the importance of the time duration of measured data. Theobjective of this case is to study the variability of the DR and oscillation frequency with the measurement time duration. There are two time series to analyse. Each one has about 14000 points, and will be divided in blocks of approximately 4000 and 2000 points. The results for the short time series will be compared with the original long series results.

CASE 3: APRM data for this case contains more than one natural frequency of the core. The data also contains peaks of other frequencies due to the actuation of the pressure controller. One case has two frequencies close to each other. Cases with more than one natural frequency make the analysis much more difficult. This case contains five measurements contaminated with influences from the plant control systems. In this case, the time series have a bad behaviour, and consequently the standard stability parameters are not clear. It could then be interesting to analyse a set of the dominant poles of the transfer function obtained from the time series.

CASE 4: This case contains a mixture between a global oscillation mode and a regional (half core) oscillation. The case consists of APRM and LPRM (Local PRM) signals coming from one test.

CASE 5: This case is focused on the analysis of two APRM-signals obtained during a small plant transient, that resulted in a bad behaviour of the signals. In this case, it is important to analyse the first dominant poles of the transfer function obtained from the time series. Note that this is a non-stationary case and the autoregressive methods have a limited validity.

CASE 6: This test case shows local (channel) oscillations. The data contains APRM and LPRM signals from two tests that were performed close to each other, both in time and in the operating conditions.

The purpose of this benchmark is the intercomparison of the different time series analysis methods that can be applied to the study of BWR stability. This is a follow-up benchmark to the Ringhals 1 Stability Benchmark. While the Ringhals 1 Stability Benchmark included both time domain and frequency domain calculation models to predict stability parameters, the new benchmark is focused in the analysis of time series data by means of noise analysis techniques in the time domain.

The first goal is to elucidate if it is possible to determine the main stability parameters from the neutronic signals time series with enough reliability and accuracy. Typically, the main stability parameters are assumed to be the decay ratio (DR) and the frequency of the oscillation. However, there are other parameters that provide valuable information, such us the Lyapunov exponents associated to the time series, or the Haussdorff dimension. In fact, the Lyapunov exponents are also a measure of the stability of the neutronic time series.

The data given in this benchmark were obtained during several stability tests performed at the Swedish BWR reactors Forsmarks 1 and 2, in the period 1989 to 1997.

The database is divided into six cases, the sampling rate of all the time series being 25 Hz, decimated to 12.5 Hz. The data are stored column wise in ASCII format. No filter to the signals and the DC-component has not been subtracted.

CASE 1: This case contains the neutron flux signals measured during several tests. The objective of the case is to study several signals ranging from stable to quasi-unstable conditions. The signals are standard measurements with no distortions. Data contains measured APRM (Average Power Range Monitor) signals from stability tests. The signals are measured at conditions with low Decay-Ratios up to high Decay-Ratios.

CASE 2: This case addresses the importance of the time duration of measured data. Theobjective of this case is to study the variability of the DR and oscillation frequency with the measurement time duration. There are two time series to analyse. Each one has about 14000 points, and will be divided in blocks of approximately 4000 and 2000 points. The results for the short time series will be compared with the original long series results.

CASE 3: APRM data for this case contains more than one natural frequency of the core. The data also contains peaks of other frequencies due to the actuation of the pressure controller. One case has two frequencies close to each other. Cases with more than one natural frequency make the analysis much more difficult. This case contains five measurements contaminated with influences from the plant control systems. In this case, the time series have a bad behaviour, and consequently the standard stability parameters are not clear. It could then be interesting to analyse a set of the dominant poles of the transfer function obtained from the time series.

CASE 4: This case contains a mixture between a global oscillation mode and a regional (half core) oscillation. The case consists of APRM and LPRM (Local PRM) signals coming from one test.

CASE 5: This case is focused on the analysis of two APRM-signals obtained during a small plant transient, that resulted in a bad behaviour of the signals. In this case, it is important to analyse the first dominant poles of the transfer function obtained from the time series. Note that this is a non-stationary case and the autoregressive methods have a limited validity.

CASE 6: This test case shows local (channel) oscillations. The data contains APRM and LPRM signals from two tests that were performed close to each other, both in time and in the operating conditions.

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10. REFERENCES

- Tomas Lefvert:

Proposed Benchmark for Core Stability Evaluation Methods

presented at the Eighth Nuclear Science Committee Meeting

9-11 June 1997

FTT-A1200/PAK (May 1997)

- Tomas Lefvert:

Proposed Benchmark for Core Stability Evaluation Methods

presented at the Eighth Nuclear Science Committee Meeting

9-11 June 1997

FTT-A1200/PAK (May 1997)

NEA-1551/01, included references:

- G. Verdu, M.J. Palomo, A. Escriva, D. Ginestar:FORSMARKS 1 AND 2 Stability benchmark

Final Problem Specifications.

NEA/NSC/DOC(98)2 (June 1998)

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15. ESTABLISHMENT

G. Verdu, M.J. Palomo, A. Escriva

Department of Chemical & Nuclear Engineering

Polytechnic University of Valencia

P.0. Box 22012

46071 Valencia, Spain

D. Ginestar

Department of Applied Mathematics

Polytechnic University of Valencia

P.0. Box 22012

46071 Valencia, Spain

Data released by:

Per Lansaker

Vattenfall

Forsmarksverket

S-74203 OESTHAMMAR, Sweden

G. Verdu, M.J. Palomo, A. Escriva

Department of Chemical & Nuclear Engineering

Polytechnic University of Valencia

P.0. Box 22012

46071 Valencia, Spain

D. Ginestar

Department of Applied Mathematics

Polytechnic University of Valencia

P.0. Box 22012

46071 Valencia, Spain

Data released by:

Per Lansaker

Vattenfall

Forsmarksverket

S-74203 OESTHAMMAR, Sweden

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NEA-1551/01

MISTP: LIST List of filesDATTP: C1_APRM.1 Case 1 APRM test 1

DATTP: C1_APRM.2 Case 1 APRM test 2

DATTP: C1_APRM.3 Case 1 APRM test 3

DATTP: C1_APRM.4 Case 1 APRM test 4

DATTP: C1_APRM.5 Case 1 APRM test 5

DATTP: C1_APRM.6 Case 1 APRM test 6

DATTP: C1_APRM.7 Case 1 APRM test 7

DATTP: C1_APRM.8 Case 1 APRM test 8

DATTP: C1_APRM.9 Case 1 APRM test 9

DATTP: C1_APRM.10 Case 1 APRM test 10

DATTP: C1_APRM.11 Case 1 APRM test 11

DATTP: C1_APRM.12 Case 1 APRM test 12

DATTP: C1_APRM.13 Case 1 APRM test 13

DATTP: C1_APRM.14 Case 1 APRM test 14

DATTP: C2_TEST.L1 Case 2 time series 1 long

DATTP: C2_TEST.L2 Case 2 time series 2 long

DATTP: C2_TEST.S11 Case 2 time series 1 short 1

DATTP: C2_TEST.S12 Case 2 time series 1 short 2

DATTP: C2_TEST.S21 Case 2 time series 1 short 1

DATTP: C2_TEST.S22 Case 2 time series 1 short 2

DATTP: C2_TEST.S31 Case 2 time series 1 short 1

DATTP: C2_TEST.S32 Case 2 time series 1 short 2

DATTP: C2_TEST.S41 Case 2 time series 1 short 1

DATTP: C2_TEST.S42 Case 2 time series 1 short 2

DATTP: C3_TEST.1 Case 3 Test 1

DATTP: C3_TEST.2 Case 3 Test 2

DATTP: C3_TEST.3 Case 3 Test 3

DATTP: C3_TEST.4 Case 3 Test 4

DATTP: C3_TEST.5 Case 3 Test 5

DATTP: C4_APRM Case 4 APRM

DATTP: C4_LPRM.1 Case 4 LPRM Position 01

DATTP: C4_LPRM.2 Case 4 LPRM Position 02

DATTP: C4_LPRM.3 Case 4 LPRM Position 03

DATTP: C4_LPRM.4 Case 4 LPRM Position 04

DATTP: C4_LPRM.5 Case 4 LPRM Position 05

DATTP: C4_LPRM.6 Case 4 LPRM Position 06

DATTP: C4_LPRM.7 Case 4 LPRM Position 07

DATTP: C4_LPRM.8 Case 4 LPRM Position 08

DATTP: C4_LPRM.9 Case 4 LPRM Position 09

DATTP: C4_LPRM.10 Case 4 LPRM Position 10

DATTP: C4_LPRM.11 Case 4 LPRM Position 11

DATTP: C4_LPRM.12 Case 4 LPRM Position 12

DATTP: C4_LPRM.13 Case 4 LPRM Position 13

DATTP: C4_LPRM.14 Case 4 LPRM Position 14

DATTP: C4_LPRM.15 Case 4 LPRM Position 15

DATTP: C4_LPRM.16 Case 4 LPRM Position 16

DATTP: C4_LPRM.17 Case 4 LPRM Position 17

DATTP: C4_LPRM.18 Case 4 LPRM Position 18

DATTP: C4_LPRM.19 Case 4 LPRM Position 19

DATTP: C4_LPRM.20 Case 4 LPRM Position 20

DATTP: C4_LPRM.21 Case 4 LPRM Position 21

DATTP: C4_LPRM.22 Case 4 LPRM Position 22

DATTP: C5_APRM.1 Case 5 APRM test 1

DATTP: C5_APRM.2 Case 5 APRM test 2

DATTP: C6_APRM.1 Case 6 APRM test 1

DATTP: C6_APRM.2 Case 6 APRM test 2

DATTP: C6_LPRM.11 Case 6 LPRM test 1 Position 01

DATTP: C6_LPRM.21 Case 6 LPRM test 1 Position 02

DATTP: C6_LPRM.31 Case 6 LPRM test 1 Position 03

DATTP: C6_LPRM.41 Case 6 LPRM test 1 Position 04

DATTP: C6_LPRM.51 Case 6 LPRM test 1 Position 05

DATTP: C6_LPRM.61 Case 6 LPRM test 1 Position 06

DATTP: C6_LPRM.71 Case 6 LPRM test 1 Position 07

DATTP: C6_LPRM.81 Case 6 LPRM test 1 Position 08

DATTP: C6_LPRM.91 Case 6 LPRM test 1 Position 09

DATTP: C6_LPRM.101 Case 6 LPRM test 1 Position 10

DATTP: C6_LPRM.111 Case 6 LPRM test 1 Position 11

DATTP: C6_LPRM.121 Case 6 LPRM test 1 Position 12

DATTP: C6_LPRM.131 Case 6 LPRM test 1 Position 13

DATTP: C6_LPRM.141 Case 6 LPRM test 1 Position 14

DATTP: C6_LPRM.151 Case 6 LPRM test 1 Position 15

DATTP: C6_LPRM.161 Case 6 LPRM test 1 Position 16

DATTP: C6_LPRM.171 Case 6 LPRM test 1 Position 17

DATTP: C6_LPRM.181 Case 6 LPRM test 1 Position 18

DATTP: C6_LPRM.12 Case 6 LPRM test 2 Position 01

DATTP: C6_LPRM.22 Case 6 LPRM test 2 Position 02

DATTP: C6_LPRM.32 Case 6 LPRM test 2 Position 03

DATTP: C6_LPRM.42 Case 6 LPRM test 2 Position 04

DATTP: C6_LPRM.52 Case 6 LPRM test 2 Position 05

DATTP: C6_LPRM.62 Case 6 LPRM test 2 Position 06

DATTP: C6_LPRM.72 Case 6 LPRM test 2 Position 07

DATTP: C6_LPRM.82 Case 6 LPRM test 2 Position 08

DATTP: C6_LPRM.92 Case 6 LPRM test 2 Position 09

DATTP: C6_LPRM.102 Case 6 LPRM test 2 Position 10

DATTP: C6_LPRM.112 Case 6 LPRM test 2 Position 11

DATTP: C6_LPRM.122 Case 6 LPRM test 2 Position 12

DATTP: C6_LPRM.132 Case 6 LPRM test 2 Position 13

DATTP: C6_LPRM.142 Case 6 LPRM test 2 Position 14

DATTP: C6_LPRM.152 Case 6 LPRM test 2 Position 15

DATTP: C6_LPRM.162 Case 6 LPRM test 2 Position 16

DATTP: C6_LPRM.172 Case 6 LPRM test 2 Position 17

DATTP: C6_LPRM.182 Case 6 LPRM test 2 Position 18

REPTP: Report NEA/NSC/DOC(98)2 (June 1998)

MISTP: Abstract

Original files. See Y98F02.

Keywords: BWR reactors, reactor stability.