Verification of Predicted Powers and Shim Positions for Advanced Test Reactor Cycle 159A-1

Transcription

1 Verification of Predicted Powers and Shim Positions for Advanced Test Reactor Cycle 159A-1 Nathan Manwaring ATR Reactor Engineering 4 May 2017

2 Acronyms and Abbreviations ASUDAS = ATR SUrveillance Data Acquisition System BU = Backup C = Center CPA = Cycle Physics Analysis CSAP = Core Safety Assurance Package ρ = Reactivity Worth EFT = East Flux Trap EPP = Effective Plate Power EPPL = EPP Limit MW = MegaWatt MWd = MegaWatt-day NE = Northeast NW = Northwest OSCC = Outer Shim Control Cylinder PALM = Powered Axial Locator Mechanism P/D = Power Division SE = Southeast SIHA = Standard Irradiation Housing Assembly S/U = StartUp SW = Southwest

3 Outline Problem: Advanced Test Reactor Experiment and Fuel Positions Power Indications Surveillance Cycle 159A-1 Physics Analysis Requested Powers Predicted Powers Actual Powers Unplanned Shutdown Solution: Cycle 159A-1 AsRun Compare Shim Positions Re-created Powers Some Verification of HELIOS modeling code Some Validation of experiment and fuel models

4 Advanced Test Reactor (ATR) Plan View 9 Flux Traps 6 In-pile Tubes Designed for arbitrary chemistry, pressure, temperature 40 Fuel Elements Highly enriched Uranium 8 pairs of Outer Shim Control Cylinders (OSCCs) Hafnium plates rotate in/out in arc motion Control local power 24 Neck Shims 2 used as regulating rods Smaller experiment positions NW N NE W C E SW S SE

5 ATR Cycle 159A-1 Loading 9 Flux Trap Experiments Mostly backups Powered Axial Locator Mechanism (PALM) to simulate transients SW-191 SE Fuel Elements 5 Lobes NW NE C SW SE Smaller experiment positions

6 ATR Power Indications Thermal Power Temperature at inlet 4 outlets NW NE SW SE N-16 System 10 Water Tubes 16 O(n,p) 16 N 10 Detectors 16 N 16 O+β+γ Over-determined matrix 5 lobe powers Constrained to total thermal

7 ATR Power Indications Thermal-to- 16 N Ratio is limited If exceeded, power is limited Normally within ±5% Nuclear Instruments Not used for lobe powers Automatic protective actions Thermal power Nuclear instrument power

8 ATR Surveillance Data Acquisition System (ASUDAS) Hourly data Lobe Powers ( 16 N Power) Quadrant Powers (Thermal Power) Shim positions Lobe Burnup (Megawatt-days (MWd)) Others Other data Online computation of fission products Scram report if scram occurs ASUDAS is only text Plot in spreadsheet

9 Cycle 159A-1 Physics Analysis (CPA) HELIOS Requested lobe powers (MW) P/D 1 P/D 2 5days 2days NW: 10±3 20±3 NE: 10±3 23±1 SW: 10±3 53+6/ 10 SE: 10±3 51+9/ 11 C calculation Based on preliminary CPA results 11+2/ 4 41±7 Request Changed

10 CPA Comparison with Actual Cycle Startup: 10:30PM 16 June 2016 Actual Data Unexpected shutdown 10:30AM 23 June Until 2:30AM 27 June Scale by burnup Sum of corner lobes So far: CPA conservatively shows safety basis is met Not validated model Problem defined

11 W1-2 N3-4 S3-4 S1-2 Cycle 159A-1 AsRun After actual Cycle operation Model actual irradiation On fuel elements On other core internals Experiment sponsors evaluate experiments Actual shim positions Against total core burnup Comparable N1-2 N3-4 Excess Reactivity NW#6 #5 #4 #3 #2 #1 #1 #2 #3 RR-2 #5 SW#6 NE#6 #5 #4 #3 #2 #1 #1 #2 #3 RR-1 #5 SE#6 E1-2 E3-4

12 Verification of HELIOS Validation of AsRun Avg: AsRun: Avg: AsRun: Avg: 94.9 AsRun:

13 Verification of HELIOS Power Comparison 7.1% 14.0% 14.2% 6.7% C Power largest error N-16 system not modeled +15.9% +12.6% +1.8% +17.0% +12.1% +4.0%

14 Validation of Experiment and Fuel Models 7.1% 14.0% 14.2% 6.7% C Power largest error N-16 system not modeled +15.9% +12.6% +1.8% +17.0% +12.1% +4.0%

15 Validation of Experiment and Fuel Models

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