In-Core Experiments (ICE Group)

The In-Core Experiments group performs a variety of corrosion, chemistry, and materials related experiments in both pressurized water reactor and boiling water reactor environments.

Stress Corrosion Cracking (IASCC) -- Three facilities are available to study Irradiation Assisted Stress Corrosion Cracking (IASCC) or related phenomena: the In-Core Constant Load Test Rig, the In-Core Slow Strain Rate Test Rig, and the Double Cantilever Beam (DCB) Crack Growth Sensor Irradiation Rig (Sensor).

In-Core Constant Load Test Rig (UNCLTIC) -- The uniaxial constant load test in core (UNCLTIC) facility is a series of ten mechanical property test specimens that are actively loaded with five in core specimens and five out of core specimens for direct in-flux and ex-flux comparisons under water chemistry conditions simulating BWR conditions. The specimens are loaded to yield and held until failure.

In-Core Slow Strain Rate Test Rig (IASCC-SSRT) -- A mechanical property test specimen was actively loaded in-core with water chemistry and temperatures simulating BWR conditions. The rig was configured for this experiment for slow strain rate testing at strain rates down to about 10-7/s using a ball-screw loading machine. An in-core platinum electrode and out-of-core external reference Ag/AgCl electrodes were used to measure the electrochemical corrosion potential of the specimen. The IASCC-SSRT is available for routine operation.

Double Cantilever Beam (DCB) Crack Growth Sensor Irradiation Facility (Sensor) -- The Sensor project consisted of passively loaded DCB sensors developed to measure crack growth rates in BWRs. The Sensor loop contained ten DCB and seven ECP sensors both in-core and just above. BWR coolant chemistry and temperature conditions were maintained in the irradiation volume. Hydrogen water chemistry effects on crack growth rate was also observed.

PWR Coolant Chemistry Loop (PCCL) -- The PWR Coolant Chemistry Loop (PCCL) is a one-third scale model of a unit flow cell in a PWR. It is carefully designed to simulate those aspects of the PWR water environment which are important to the transport of radioactive corrosion products.

BWR Coolant Chemistry Loop (BCCL) -- The BWR Coolant Chemistry Loop (BCCL) shares many of the technological features of the PCCL but is not intended to simulate the entire BWR primary circuit. Rather, this loop can be used to simulate a range of individual primary loop components with particular emphasis on in-core radiolysis under conditions very similar to commercial BWR cores. back to top

Capabilities for Simulation of Coolant Environments -- The staff and facilities of the In-Core Experiment Group provide unique and wide ranging capabilities for simulation of light water power reactor primary coolant environments. The links above provide some specific examples of experiments which have already been carried out. An even broader range of conditions can be achieved within the guidelines below.

The neutron and gamma fluxes in-core are similar to those in commercial power reactors and the total volume available is about 3cm in diameter by 50 cm long. A range of temperatures and pressures spanning PWR and BWR operating conditions has been achieved and wide latitude is available to alter heat fluxes and flow rates to suit the experimental requirements. Controlled boiling and steam/water separation can be applied. Thermal isolation of the facilities from the MITR-II coolant and the use of electrical heaters allow thermal/hydraulic conditions in the loop facilities to be maintained independent of the reactor operating conditions. An exceptionally wide variety of materials and water chemistry additives can be used. The main constraints are reactivity and induced activity limits. Instrumentation can include standard temperature, pressure and water chemistry parameters in addition to custom chemical, electrochemical and electromechanical measurements. Access to the experimental facilities in the low temperature and pressure MITR-II core tank is unusually flexible. A servo-mechanical test machine is available for controlled loading of mechanical property specimens in-core in high pressure and temperature water environments.