Sean O Kelly Chief, Reactor Operations and Engineering. November 29, 2010

Transcription

1 Sean O Kelly Chief, Reactor Operations and Engineering November 29, 2010

2 NIST Center for Neutron Research (NCNR) NCNR Research Reactor (NBSR) Conversion Strategy Performance Penalty for NCNR Reactor Barriers to Conversion Applications Precluded by Performance Penalty

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4 NIST Center for Neutron Research (NCNR) NCNR Research Reactor (NBSR) Conversion Strategy Performance Penalty for NCNR Reactor Barriers to Conversion Impact on Current Program and Lost Opportunities NCNR Performance Penalty Mitigation Strategy

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6 The NCNR Has 25 Operating Beam Instruments Tailored to Specific Needs BT8 Resid. Stress Diff. BT7 3-Axis Spec. NG1 AND/R NG1 Vert. Refl. NG1 Depth Profiling NG2 Backscattering Spec. BT9 3-Axis Spec. NG0 MACS NG3 30 m SANS BT1 Powd. Diff. Thermal Column BT5 USANS NG-5 SPINS NG5 Spin-Echo Spec. NG4 Disk Chopper TOF Spec. BT2 Neutron Imaging Facil. BT4 FANS NG7 Hor. Refl. NG7 Prompt NG6 Neutron Physics Diffraction Instruments Spectrometers NG7 Interferometer Other Neutron Methods NG7 30 m SANS

7 RESEARCH PARTICIPANTS US States = 42 + DC & PR US Universities = 146 US Govt Org + Nat Lab = 32 US Corporations =

8 RESEARCH PARTICIPANTS 2011-Another Upgrade Shutdown US States = 42 + DC & PR US Universities = 146 US Govt Org + Nat Lab = 32 US Corporations =

9 Many sub-projects: 5 new capabilities MACS relocation instrument moves software guides/shields cold source confinement building Blue Instruments relocated Red Instruments are planned for fabrication and installation guide hall addition Major areas of activity: Construction Cold source Guide systems Shield systems Instruments Control room upgrade existing guide hall

10 The NCNR Research Reactor 20 MW heavy water cooled and moderated reactor 30 split-core fuel elements containing HEU Operates on a 7 week cycle (39 days up and 11 days shutdown) Averages >98% reliability with over 260 experimental days a year

11 NCNR will convert to LEU gradually by changing 4 elements per fuel cycle and transition fully in just over one year (8 cycles) Fuel external dimensions will not change but current dispersion fuel will be replaced with monolithic (U10Mo) fuel plates Fuel element loading will increase from 350 grams 235 U to 386 grams to maintain cycle length Power level will remain 20 MW but neutron availability will decrease by 10%

12 Qualified fuel is not yet available Fuel testing not complete NRC review and approval process not clear Chapter 18 of NUREG-1537 is expected to be revised Who will be the independent NRC fuel qualification reviewers? Difficult to prepare NBSR conversion analysis without knowing final details required Fuel has not been manufactured Scale up to production level in progress but years away Production appears to be throughput limited and not costeffective Experience and high quality production has not been developed Fuel costs GTRI estimates ~30% increase in fuel costs based on INEG ROM analysis but final costs are unknown and could be higher NCNR needs to maintain at least a 3 year supply of fuel to support high reliability operations In the long range planning, higher fuel costs prohibit or reduce neutron instrument development without an increase in NCNR budget

13 Back end of fuel cycle has not been defined Reactors have not seen any confirmation that SRS will accept new fuel Long-term disposal or reprocessing methods have not been established for monolithic fuels GTRI says that disposal is not a conversion related issue but NIST considers it to be a barrier Unacceptable loss of performance NIST considers a 10% loss of performance to be unacceptable to user program and requires other improvements to offset conversion penalty

14 NCNR Expansion will increase cold neutron measurement capacity by 30% but loss of intensity will likely prevent some experiments NCNR averages a 2 to 3 oversubscription rate New Guide Hall Old Guide Hall 10% intensity loss is equivalent to losing 3 instruments

15 Increase cold neutron intensity by replacing liquid hydrogen source with liquid deuterium source Requires larger helium refrigerator and source chamber Shift in neutron spectrum will require replacement of neutron guides to exploit cold source gains Recover some intensity loss on thermal neutron instruments by improvements in detection technology

16 NBSR Fuel Spec and SAR Design and Fabricate LD 2 CNS NRC Reviews Fuel Fabricate (88) LEU Conversion Outage Install CNS Design and Fabricate LH 2 CNS Install upgraded instruments Design and Fabricate N-Guides

17 Preliminary design of LD 2 Cold Source indicates intensity gain of approximately 1.5 on average Shift in neutron spectrum would impact one high usage neutron spectrometer so additional LH 2 Cold Source could be installed in single beam tube to maintain spectrometer function Over half of NCNR research is performed using cold neutrons but thermal instruments would also require improvement in detection efficiency to compensate for 10% flux reduction

18 Conversion of the NCNR Reactor is feasible assuming all barriers are addressed Loss of facility performance by conversion is considered significant and unacceptable to the NCNR user program A mitigation strategy exists but it must be implemented in the near-term to remain off the conversion critical path

19 Thank you