1. MIT NUCLEAR REACTOR LABORATORY AN MIT INTERDEPARTMENTAL CENTER Irradiation and PIE Capabilities at MIT Research Reactor Lin-wen Hu NSUF User’s Meeting, June 22-25, 2015 Associate Director, Research Development and Utilization

2. MIT Research Reactor (MITR-II)  Multi-purpose research reactor owned and operated by MIT.  Constructed in 1958 (MITR-I), upgraded in 1975 (MITR-II)  Up-rate in 2010 to 6 MW th (2 nd largest university reactor in U.S.)  Operates 24/7, 10-week cycles  Tank-type, light water cooled and moderated  D 2 O and graphite reflector  Excellent track record in in-pile irradiation experiments including LWR loop, fuel, high-temperature materials. MITR joined NSUF as first partner facility in July 2008.

3. MIT Nuclear Reactor Laboratory 3 MITR Core  HEU plate-type fuel  3 dedicated in-core experiment positions  Beam ports for neutron experiments  Fission Converter/Medical Beam facility

4. MIT Nuclear Reactor Laboratory 4 MIT Reactor Top View

5. Irradiation Positions FacilitySizeNeutron Flux (n/cm 2 -s) In-core 3 available Max in-core volume ~ 1.8” ID x 24” long Thermal: 3.6x10 13 Fast: up to 1.2x10 14 (E>0.1 MeV) Beam ports Various radial: 4” to 12” ID Thermal: 1x10 10 - 1x10 13 (source) Vertical irradiation position 2 vertical (3GV) 3” ID x 24” long Thermal: 4x10 12 - 1x10 13 Through ports One 4” port (4TH) One 6” port (6TH). Avg thermal: 2.5x10 12 to 5.5x10 12 Pneumatic Tubes One 1” ID tube* (1PH1) Thermal: up to 8x10 12 One 2” ID tube* (2PH1) Thermal: up to 5x10 13 Fission Converter Beam Facility (FCB) Beam aperture ~ 6” ID Epithermal: ~ 5x10 9 Thermal Beam Facility (TNB) Beam aperture ~ 6” ID Thermal: up to 1x10 10 Fast flux is ~ 20% of ATR.

6. Three In-core Experiments Installed 6 Water Loop In-core Sample Assembly Special Purpose Facility

7. In-Core Sample Assembly (ICSA) In-core section Full ICSA ICSA high temperature capsule demonstration (up to 850°C) with NSUF support.

8.  ACI (Water Loop, NSUF) o SiC LWR cladding in PWR conditions  BSiC (Water Loop, NEET) o SiC channel box and guide tubes  WATF (Water Loop, NEET) o Accident-tolerant cladding and coatings  HYFI (Fuel, NSUF) o U-Zr-H LWR fuel rods with liquid metal bonding  AFTR (NEUP) o Internally- and Externally-Cooled Annular Fuel  HTIF (INIE, NSUF for PIE) o Very high-temperature gas irradiation 1000-1400 C.  Drexel (ICSA, NEUP) o MAX-phase materials at 300-700°C in inert gas  LUNA-1 and LUNA-2 (ICSA, SBIR, STTR) o Fiber optics at 700°C in inert gas  FS-1 (ICSA, IRP) o FHR coupons in flibe salt at 700°C  FS-2 (IRP) o FHR coupons in flibe salt at 700°C  ULTRA (ICSA, NSUF) o Ultrasonic transducer and self- powered detector test  ICCGM (Water Loop, INL) o Actively-loaded real-time crack growth monitor Recent In-Core Experiments

9.  Magnetostrictive and Piezoelectric ultrasonic sensors operating in-core o Particularly interested in fast neutron damage o Real-time monitoring throughout irradiation o Two types of magnetostrictive magnets o Three types of piezoelectric crystals  Self-powered detectors included for local power monitoring o Vanadium neutron detector (SPND) o Platinum gamma detector (SPGD) Ultrasonic Sensors (INL & PSU) First lead-out ICSA capsule demonstration!

10. ULTRA Design

11. ULTRA Loading

12.  Irradiation carried out February 2014 through May 2015, produced real-time transducer and SPD data  Two piezoelectric and both magnetostrictive sensors transmited good signals throughout duration of irradiation. ULTRA Sensor Data

13.  Unexpected SPD responses to changes in reactor power and capsule temperature  Investigating this with help from INL and CEA ULTRA SPD Data

14. Water Loop Design  Exposing specimens to typical power reactor conditions  Using a loop to achieve 300°C, 10 MPa, typical LWR flux, H 2 overpressure if desired for <5ppb O 2  For SiC, have achieved max exposures >800 EFPD, >3000 MWd

15. Irradiation Campaigns  3 primary irradiations in water loop starting in 2006 and still in progress.  During intermediate shutdowns specimens can be exchanged or re-inserted after non-destructive PIE. 102238 240 46371 90 Initial SiC clad scoping (Days of exposure) SiC monolith SiC triplex Bonded end caps SiC monolith SiC triplex Bonded shear blocks SiC composites Creep specimens ~1 ppm oxygen Next gen triplex Structural

16. Advanced Cladding Irradiation  Facility is extremely flexible in accepting different types of specimens o Primarily testing partial-length LWR cladding tubes for corrosion and mechanical properties studies (hoop strength) o Coupons for corrosion and creep measurement o Bonded parts for measuring bond performance/shear strength

17. ACI Results 17 Measurement error ±0.5%  Monolithic (α and β) SiC corrosion was negligible  Composite is most vulnerable to corrosion, barrier coating provides protection  Weight change rates are generally consistent over time  Estimated surface rescission based on weight loss as low as 0.5 µm/mo against 100 µm thick EBC for F and H (triplex tube) specimens SiC Monoliths

18. Hydride Fuel Irradiation (HYFI)  University of California, Berkeley project selected by the NSUF for irradiation at the MITR.  Investigating the use of U-Zr-H fuel with zircaloy cladding in light-water reactors. o 19.75% enriched fuel is bonded inside cladding with lead-bismuth eutectic o Improved thermal conductivity leads to lower fuel temperature, fission gas release o Good neutronics properties

19. HYFI Rodlets 12/1/2014  Fuel pellets produced at UCB (Kurt Terrani, Don Olander) from TRIGA fuel supplied by INL  Pellets loaded into pre-oxidized zircaloy rods at UCB and back-filled with LBE  Fuel centerline and cladding surface thermocouples installed at MIT Sheath TC Welded to SS Flange SS304 CF Mini Flange Zr CF Mini Flange He Plenum SS302 Spring Pb-Bi Alloy Alumina Spacer Zircaloy-2 Tube U 0.17 ZrH 1.6 Fuel Zircaloy-2 End Cap 1 cm

20. HYFI Rodlet Radiography 12/1/2014 Active Fuel Region Alumina Spacers Zirconium Flange SS 304 Flange 302 SS Spring Rod 1 Rod 2 Rod 3 Rod 4

21. HYFI Capsules  Zircaloy rodlets were sealed into titanium capsules o Space between rodlet and titanium filled with LBE  Thermocouples pass through cover gas tube  Each capsule has independent cover gas volume

22. HYFI Irradiation  Target temperatures ~575°C fuel centerline, 450°C cladding outer  28 kW/m linear heat rate  Local power increases over irradiation

23. HYFI Data  Capsules irradiated between 1400 and 3400 hours  Initial rise in conductivity followed by gradual decline  Capsules 1 (rodlet #1) and 2 (rodlet #3) were removed early due to increased fission gas release from the rodlet into the secondary containment  Cause of release not yet known

24. HYFI PIE 12/1/2014  Capsules removed from core and cooled in SFP  Gas lines cut and capped in hot cell  Shipped to PNNL in individual casks for PIE (ongoing)

25.  Funded by ATR-NSUF as rapid turnaround experiment in 2014 (PI: R. Ballinger, MIT)  Specimens recently extracted in MITR hot cell  TRISOs examined as part of FHR project HTIF PIE

26.  The only university research reactor that operates a LWR loop.  More than 10 years of experience in testing SiC/SiC composites for LWR applications (NSUF, NEET, NEUP, SBIR)  The only university research reactor that can irradiate fuel samples up to 100 gm U-235.  High temperature drop-in capsule experiments demonstrated for up to 850°C. (NSUF, NEUP, SBIR)  Very high temperature irradiation 1000-1400°C (INIE, NSUF).  Successful demonstration of lead-out capsule experiment (NSUF)  First demonstration of fluoride salt (flibe) coolant and materials irradiation at 700°C. (NEUP-IRP) MITR Accomplishments

27.  MIT-NRL staff contributed to fuel/materials/instrumentation irradiation experiments include: o Dr. Gordon Kohse o Dr. David Carpenter o Dr. Michael Ames o Mr. Yakov Ostrovsky o Dr. Kaichao Sun o Mr. Tom Bork o Dr. Tom Newton o MITR Operations and Radiation Protection staff  MIT-NRL acknowledges funding support for fuel, materials irradiation, and instrumentation irradiation experiments from NEUP, NEET, NSUF programs. Acknowledgments