ADVANCED NUCLEAR REACTOR RESEARCH GROUP


Msr

 

Develop new nuclear technology in terms of :

  1. Nuclear use for energy
  2. Isotope production and use
  3. Related nuclear technology use

The aspect to be studied including neutronics, nuclear radiation, heat transfer, material transfer, safety, control, related chemical and physical process and environment impact.

 

 

A. RESEARCH IN NUCLEAR USE FOR ENERGY

GENERAL GOAL :

To solve global world problems of energy with more efficient and safer nuclear energy use.

THE GLOBAL WORLD ENERGY PROBLEMS ARE :

  • Increasing Energy Demand
  • Limiting conventional energy resources (oil, coal, natural gas)
  • Environmental impact (mainly global warming)

MORE SPECIFIC GOAL :

To solve global world problems of the recent use of nuclear energy in order to the nuclear energy become more competitive for future energy source.

THE GLOBAL WORLD PROBLEMS THE RECENT NUCLEAR ENERGY ARE :

  • Limiting nuclear energy resources for recent use (i.e. U-235)
  • Accumulation of long life radioactive waste
  • Need for increasing safety aspect
  • Need for increasing economy aspect (reduction of generation cost)
  • Need for diversification of the using of energy output (electricity or mechanical and thermal output (low temperature, medium temperature, high temperature))
  • Non proliferation consideration

>MORE SPECIFIC GOAL :

To develop new concept of nuclear reactor (Advanced Nuclear Reactor) for solving the global nuclear energy problems mentioned above for more competitive future use

 The Advanced Nuclear Reactor must be :

  • have breeding capability,
  • inherently safe (negative power reactivity coefficient, low excess reactivity)
  • all passive characteristic (passive shutdown system, passive post shutdown cooling system, passive cooling for radioactive material)
  • enhanced multiple barrier,
  • secure, fulfill non proliferation requirement
  • design simplification (increasing integrity and modularity)
  • high reliability,
  • higher energy conversion efficiency
  • higher power spectrum, (small, medium or large power output)
  • diversification of energy output , (electricity or mechanical and thermal output (low temperature, medium temperature, high temperature))
  • flexible in operation mode, base load, secondary variable load

 

  • RESEARCH IN MSR (MOLTEN SALT REACTOR)

Among the several types of Advanced Nuclear Reactor mentioned above, MSR (Molten Salt Reactor) type is chosen to be studied more detail. This is due to the benefit of MSR such as

  • Thermal breeder (Th-232 – U-233 fuel cycle)
  • On line fuel reprocessing (simplify the design of related fuel  management process and equipment as well as increasing proliferation resistance)
  • Can be operated at very high temperature (potentially higher then current HTR operation temperature)
  • Inherent safe (very low excess reactivity and negative power reactivity feedback)
  • Totally passive safety system (passive shutdown system, passive post shutdown cooling system)
  • Multiple barrier (fuel system boundary – hot box – containment)
  • High thermal efficiency, high temperature thermal energy output
PASSIVE COMPACT MOLTEN SALT REACTOR

PCMSR

The special design of MSR (called PCMSR or Passive Compact Molten Salt Reactor) will be developed. The PCMSR design has characteristic of :

  • Advanced Proposed Design of MSR
  • Has all good characteristic of MSR
  • Apply the Totally Passive Safety Characteristic by using simple means
  • Increasing compactness and modularity compared than the previously proposed MSR design
  • Design simplification
  • High temperature operation

PCMSR design applies high modularity and integrity to get the benefit of :

  • Simplification (reducing components, land use, cost)
  • Increasing safety aspect,
  • Increasing reliability

PCMSR design consist of three integral module

  • Reactor module
  • Turbine module
  • Fuel management module

 

  • FLUIDIZED BED NUCLEAR REACTOR

The fluidized bed nuclear reactor (FLUBER) is an innovative design of gas-cooled reactor. It consists of a graphite-walled tube partially filled with TRISO-coated fuel particles. In contrast with other HTGRs where the TRISO particles are encased within a graphite pebble or rods, the particles in FLUBER are laid in the bottom part of the cavity of the tube, forming a packed bed. Helium is used as a coolant that flows from bottom to top through the tube, thereby fluidizing the particle bed. During the fluidization process, the bed of solid particles is transformed into something closely resembling a liquid.

When the flow is absent or at a low rate, the bed remains packed. When the flow rate is increased, the bed expands and forms a fluidized state. Only when the coolant flow is large enough does the reactor become critical because of the surrounding graphite that moderates and reflects the neutrons.

Fluidized beds have several features that are advantageous for a nuclear reactor, such as a uniform temperature distribution due to rapid particle mixing and a high transfer rate between particles and fluid. The high heat transfer rate between particles and fluid yields a high temperature of fluid without leading to an excessive fuel temperature. This offers the advantages of a high core outlet temperature and the use of a highly efficient direct-cycle gas turbine. The excellent mixing properties guarantee a uniform power distribution and consequently a uniform fuel burnup.

Another possible advantage of using a fluidized bed for nuclear reactors is that the bed height increases when the gas flow increases. The change in geometry of the bed affects the neutronics of the reactor and consequently, the power produced will change as well. In this manner the power generation can be controlled by altering the inlet flow rate, thus reducing dependencies on control rod mechanisms.

 

In reality, particles in fluidized beds are not distributed uniformly and they even move rather chaotically. The hydrodynamics of gas-solid fluidized beds are a complex phenomenon, determined by the combined effects of formation, motion, and interactions of bubbles as well as by the solids behavior. The time-dependent behavior of a fluidized bed is thus important.

 

 

 

 

  • METAHEURISTICS OPTIMIZATION OF LOADING PATTERNS

Nuclear fuel management includes ways and considerations to decide things to do in order to control flux and reactivity of a reactor core and spatial power distribution and burn-up of nuclear fuels. It has purpose primarily to minimize operation cost of a nuclear power plant but fulfilling the operation requirement.

Generally, nuclear fuel management can be divided into two parts, out-of-core and in-core. Out-of-core fuel management focuses on questions “What to buy?” and “What to be reinserted to the core?” and multi-cycles planning. On contrary, in-core fuel management has an objective to decide loading pattern in a core, e.g. fresh fuels, spent fuels and burnable poisons and control rods location.

In-core fuel management is a problem need to be kept attention in the uses of nuclear energy. Practically, it is done by optimizing fuel loading pattern in a reactor core. An optimum condition in the reactor core can be achieved by looking at its cycle length and power distribution

Optimization in the nuclear reactor core can be quantified by its effective multiplication factor (keff) for certain burnup step. Besides, safety factor must also be considered since optimization may affect the power distribution. For safety reason, PPF or power peaking factor must be used as a constraint in optimizing reactor core. The power peaking factor in the nuclear reactor is defined as the ratio of maximum power to average power in the reactor core. The best PPF is unity, means that all power generation perfectly distributed in the core with exact value.

Practically, fuel loading pattern optimization is difficult to be done because of the excessive numbers of fuel assemblies in a nuclear reactor. In a standard PWR, at least there are more than 1025 combinations to try. The combinatorial problem then will be complicated and need a bunch of time if it is done using conventional algorithms. Metaheuristic optimization methods (for example Genetic Algorithm, Simulated Annealing, Quantum-inspired Evolutionary Algorithm, Bat Algorithm) are thus employed to solve the problem.

 

 

  • DEVELOPMENT OF SELF-SUSTAINING SMALL LWR

To ensure the sustainability of nuclear power, the current open fuel cycle is not sufficient. It is important to establish a closed fuel cycle and nuclear recycle system. The generation IV nuclear reactors are expected to play a major role in an open fuel cycle, but they have not been commercialized yet. On the other hand, light water reactor (LWR) is a proven technology and has an outstanding commercial operation record. Thus, the use of LWR to establish a closed fuel cycle is preferable. To achieve a closed fuel cycle, LWR should be designed to be fuel-self-sustaining which can be achieved by having a small pitch-to-diameter ratio (P/D), hexagonal lattice, and an epithermal to fast neutron energy spectrum.

 

  • INVESTIGATION ON THE USE OF ACCIDENT TOLERANT FUEL IN LWR AND ITS SAFETY CHARACTERISTICS

The use of UO2/Zircaloy (Zr) fuel system has been used widely in commercial nuclear power plants due to several beneficial properties such as high melting point, thermal stability, chemical stability, and low swelling under irradiation. After the accident of Fukushima Daichii, it is widely known that in a severe accident, the current UO2/Zr fuel system will fail, which may damage the plant structure further. It is thus necessary to develop a fuel system which has enhanced resistance to severe accident conditions, especially in an exothermic cladding oxidation.

Accident tolerant fuel (ATF) is then proposed as one of the alternative fuel technology options that must be compatible with existing fuel and reactor systems, more resistant to fuel failure and hydrogen production. Examples of materials proposed for ATF are uranium silicide, uranium nitrides, and fully-ceramic microencapsulated fuel, while for cladding some materials such as FeCrAl alloy, SiC as well as coating materials such as Cr, TiAlN, Ti2AlC have been proposed.

Development of ATF from fuel design and manufacturing point of view has been in the third phase based on the technology readiness level (TRL) assessment, which reaches the verification of new fuel concept, including fabrication and sample irradiation test. In order to use ATF in a commercially operated LWR to replace the monolithic UO2 fuel with Zircaloy cladding, the ATF should have reached the ninth phase of the TRL assessment. Henceforth, many researches and development should be performed before the ATF technology becomes mature for commercial operation.

From nuclear reactor safety point of view, the TRL phase 3 poses many challenges to answer before the ATF is proven safe for commercial operation at normal condition, transient, DBA and beyond DBA (BDBA). Safety analysis should be performed to understand the influence of using ATF to the performance of reactor at accident situation.

  • INVESTIGATION ON POTENTIAL USE OF FLOATING NUCLEAR POWER PLANTS

Floating nuclear power plant (FNPP) is a nuclear reactor emplaced and operated above water surface and has mobile ability. This reactor design enables nuclear reactor facility mobilization from the electrical grid location at the seashore or mobilized towards the shipyard for maintenance of the ship and the reactor away from electrical generation site. Other characteristics of this SMR design is its small volumetric size and low generated power. This reactor can be used for cogeneration such as desalinating seawater. Another cogeneration application is the district heating function such as room heating.

 

B. RESEARCH IN NUCLEAR USE FOR ISOTOPE PRODUCTION

Safeguard system AHRGENERAL GOAL :

To solve global world problems in term of radioisotope uses in fields of industry, health, agriculture, scientific. Mo Market

THE GLOBAL WORLD ENERGY PROBLEMS ARE :

  • Increasing Demand for Radioisotope
  • Limiting production capacity due to the aging and limiting number and capacity of the recent research reactor and other means (accelerator, etc)
  • Specially Increasing demand in short lifetime radioisotope which needs direct production as demand
  • Some important radioisotopes are fission product

The Advanced Nuclear Radioisotope Production Reactor to be developed has the characteristics of :

  • Producing radioisotope (i.e. Mo, I and Cs) using fission process
  • using liquid fuel (i.e. aqueous salt, the liquid fuel gives benefit of the simplification of fuel and radioisotope separation process as well as the high efficiency in uranium use)
  • inherently safe (negative power reactivity coefficient, low excess reactivity)
  • all passive characteristic (passive shutdown system, passive post-shutdown cooling system, passive cooling for radioactive material)
  • enhanced multiple barriers,
  • secure, fulfill non-proliferation requirements
  • design simplification (increasing integrity and modularity)
  • flexible in an operation mode, base load, secondary variable load
  • The overall design is similar to PCMSR design but operated at a far lower temperature

MORE SPECIFIC GOAL :

To develop a new concept of nuclear reactor dedicated for radioisotope production with high efficiency and competitive for future isotope production

Pu-Mo-AHRThe Advanced Nuclear Radioisotope Production Reactor must be :

  • high radioisotope production capability,
  • inherently safe (negative power reactivity coefficient, low excess reactivity)
  • all passive characteristic (passive shutdown system, passive post-shutdown cooling system, passive cooling for radioactive material)
  • enhanced multiple barriers,
  • secure, fulfill non-proliferation requirement
  • design simplification (increasing integrity and modularity)
  • flexible in an operation mode, base load, secondary variable load

 

 

C. RESEARCH IN NUCLEAR USE FOR RADIOISOTOPE PRODUCTION USING OTHER MEAN THAN NUCLEAR REACTOR

Radioisotope can be produced using other means than a nuclear reactor, i.e. accelerator. The radioisotope production using accelerator has benefit to get special isotope needed, thus eliminating the process for separation and purification. However, the radioisotope production using accelerator consumes more energy than producing radioisotope using a nuclear reactor. The research interest is to produce short live radioisotope using simple accelerator (i.e. cyclotron).

 

 Computational resources

  • Neutronics codes:  SRAC, SCALE, MCNP, Serpent, Donjon-Dragon
  • Thermalhydraulics codes:  RELAP5-3D, SUBCHANFLOW
  • Simulator:  IAEA PC-Based Nuclear Simulators

 

RESEARCHERS

  • Dr. Ir. Andang Widi Harto, M.T.
  • Dr-Ing. Sihana
  • Dr. Alexander Agung, S.T., M.Sc.

 

Contact Person : Dr. Ir. Andang Widi Harto, MT. (andangwh@ugm.ac.id)