Forsmark 12. S3K Applications. Thomas Smed US User Group Meeting Arizona, October 2008

Transcription

1 Forsmark 12 S3K Applications Thomas Smed US User Group Meeting Arizona, October 2008

2 Introduction It is well-known that we have vast experience in providing S3R (and RAMONA) to training simulators It may be less known that we also have experience from plant applications on transients I will try to exemplify that in this presentation

3 What does a core-designer actually work with? Fuel cycle economics Constraints based on 10 CFR 50, Appendix A, General Design Criterion 10 (GDC 10) Criterion 10 Reactor design The reactor core and associated coolant, control, and protection systems shall be designed with appropriate margin to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation including the effects of anticipated operational occurrences. Simple interpretation: No systematic fuel failures during normal operation or AOOs

4 How is this interpreted? Standard Review Plan Transient and Accident Analyses Analysis Acceptance Criteria for AOOs Fuel cladding integrity shall be maintained by ensuring that the minimum departure from nucleate boiling ratio (DNBR) remains above 95/95 DNBR limit for PWRs and that the critical power ratio (CPR) remains above the minimum critical power ratio (MCPR) safety limits for BWRs. Definition MCPR safety limit: The limit ensures that during normal operation and during AOOs, at least 99.9 percent of the fuel rods in the core do not experience transition boiling.

5 Transient CPR definition 1,6 Calculated Minimum CPR Increased bundle power S3K ,5 1,4 S3K-perturbed SLMCPR 1.24 ICPRmin (=OLMCPR) CPR (-) 1,3 1,2 OLMCPR SLMCPR (=CPRmin) 1,1 1, Time (Sec.) SLMCPR S3K Capabilities for Transient 3D CPR EUGM Budapest Hungary

6 Background Scandinavia Licensing based on 10 CFR 50 Somewhat less formal focus than in the US But Strong emphasis on validation vs. real data Lots of measurements and recorded transients available Improves code quality

7 Why do we get dry-out in the pump trip? System 649 Component protection

8 Event in Forsmark 2 on June 13, bundles below SLMCPR 16 bundles below 1.0 Validation with S3K in progress

9 Stability 10 CFR 50, Appendix A, GDC 12 Criterion 12 Suppression of reactor power oscillations. The reactor core and associated coolant control, and protection systems shall be designed to assure that power oscillations which can result in conditions exceeding specified acceptable fuel design limits are not possible or can be reliably and readily detected and suppressed. Different acceptable strategies to deal with this is discussed in SRP 15.9, one acceptable criterion is A. The calculated decay ratio (DR) for all three common stability modes (corewide, regional and channel) satisfies the relationship DR<(1-σ), where σ is the uncertainty of the calculation. However, everything is not about rules and regulations

10 An operational department that has experienced this will DEMAND that they will not experience it ever again:

11 BWR Stability S3K used routinely to evaluate stability every cycle Measured 1-2 times/cycle in all Scandinavian plants Total of >200 measurements Extended Power Uprates put more focus on stability

12 Stability Increasingly Important with Extended Power Uprates Forsmark 1 och 2. Effekthöjning 120 % 140% 135% 130% 126% 120% Termisk effekt [%] HC flöde [kg/s]

13 S3K Stability Validation vs. Measurements Calculated decay ratio Measured decay ratio Ringhals-1 Cycle Oskarshamn-3 Cycle 7-17 Olikuoto-2 Cycle Leibstadt Cycle 19

14 S3K Stability Validation vs. Measurements Calculated frequency Measured Frequency Ringhals-1 Cycles Oskarahsmn-3 Cycles 7-17 Leibstadt Cycle 19

15 Sometimes the Measurement is Easy to Interpret...

16 But Sometimes my Favourite Quote is Applicable Nobody believes a calculation except the guy who made the calculation. Everybody believes a measurement except the guy who made the measurement Sture Andersson, a swedish senior nuclear engineer and manager, who has been in charge of both a lab as well as computational groups.

17 Stability Measurement ARMA analysis: dr = 0.74 freq = 0.56 Hz

18 More Applications Widely used for RIA (BWR and PWR) New requirements demand Automated Boron in the event of ATWS First Licensing Application based on S3K/RELAP S3K used in Reload Safety Evaluation (RSE) evaluation for Ringhals PWR (3 units) Effort to replace 1-D based licensed method for transient CPR with is S3K on-going

19 Anticipated Operational Occurrences Registrations (measurements) from real incidents Turbine trip Pump trip Pancake core (Inadvertent slow insertion of control rods w/o scram, beyond AOO) Inadvertent closure of MSIV Some validated with standalone S3K, some vs. S3K/RELAP

20 S3K Validation Turbine trip in Olkiluoto-2 Total power measurement s3k 80 % Time Main recirculation flow measurement s3k 70,5 70,0 69,5 211K102 S3K measurement ,0 kg/s 6000 barg 68, , , , Time 66, Time

21 Transient CPR Methodology Initiative Validation examples: Steam dome pressure Pressurization (%) MSIV closure APRM 0 211K301 Bundle Flow time (s) K301 Bundle Flow (KG/S) S3K Bundle flow validation Bundle Flow (KG/S) S3K Measurement Time (sec) LPRM( % ) Pressure (Mpa) Pressure (Mpa) S3K-Pressure 0,0 1,0 2,0 3,0 4,0 5,0 6,0 70,5 Time (Sec.) 531K821 LPRM K821 LPRM 061 (%) S3K - LPRM Time (Sec.) barg 70,0 69,5 69,0 68,5 68,0 67,5 67,0 66,5 Pressure controller Steam dome pressure - 211K102 S3K measurement Time 3D power

22 Some transients can be quite dramatic Load Rejection without Bypass 2,5 APRM as a function of time LPRM (level 2) as a function of time 2 3 2,5 2 APRM (-) 1,5 1 APRM (-) APRM-1 Power (%) 1,5 LPRM (-) LPRM17-2 0, ,5 2 2,5 3 3,5 4 0,5 Time (sec.) 0 1 1,5 2 2,5 3 3,5 4 Time (sec.) APRM is saturated

23 Conclusion We have the experience It is implemented in S3K We can provide the service

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