# Kinetics calculation of fast periodic pulsed reactors using MCNP6

## Abstract

Fast periodic pulsed reactor is a type of reactor in which the fission bursts are formed entirely with external reactivity modulation with a specified time periodicity. This type of reactors could generate much larger intensity of neutron beams for experimental use, compared with the steady state reactors. In the design of fast periodic pulsed reactors, the time dependent simulation of the power pulse is majorly based on a point kinetic model, which is known to have limitations. A more accurate calculation method is desired for the design analyses of fast periodic pulsed reactors. Monte Carlo computer code MCNP6 is used for this task due to its three dimensional transport capability with a continuous energy library. Some new routines were added to simulate the rotation of the movable reflector parts in the time dependent calculation. Fast periodic pulsed reactor IBR-2M was utilized to validate the new routines. This reactor is periodically in prompt supercritical state, which lasts for similar to 400 mu s, during the equilibrium state. This generates long neutron fission chains, which requires tremendously large amount of computation time during Monte Carlo simulations. Russian Roulette was applied for these very long neutron chains in MCNP6 calculation, combined with othermore »

- Authors:

- Publication Date:

- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)

- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA)

- OSTI Identifier:
- 1477457

- DOE Contract Number:
- AC02-06CH11357

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Nuclear Engineering and Technology; Journal Volume: 50; Journal Issue: 7

- Country of Publication:
- United States

- Language:
- English

### Citation Formats

```
Zhong, Z., Gohar, Y., Talamo, A., Cao, Y., Bolshinsky, I., Pepelyshev, Yu N., and Vinogradov, Alexander.
```*Kinetics calculation of fast periodic pulsed reactors using MCNP6*. United States: N. p., 2018.
Web. doi:10.1016/j.net.2018.06.007.

```
Zhong, Z., Gohar, Y., Talamo, A., Cao, Y., Bolshinsky, I., Pepelyshev, Yu N., & Vinogradov, Alexander.
```*Kinetics calculation of fast periodic pulsed reactors using MCNP6*. United States. doi:10.1016/j.net.2018.06.007.

```
Zhong, Z., Gohar, Y., Talamo, A., Cao, Y., Bolshinsky, I., Pepelyshev, Yu N., and Vinogradov, Alexander. Mon .
"Kinetics calculation of fast periodic pulsed reactors using MCNP6". United States. doi:10.1016/j.net.2018.06.007.
```

```
@article{osti_1477457,
```

title = {Kinetics calculation of fast periodic pulsed reactors using MCNP6},

author = {Zhong, Z. and Gohar, Y. and Talamo, A. and Cao, Y. and Bolshinsky, I. and Pepelyshev, Yu N. and Vinogradov, Alexander},

abstractNote = {Fast periodic pulsed reactor is a type of reactor in which the fission bursts are formed entirely with external reactivity modulation with a specified time periodicity. This type of reactors could generate much larger intensity of neutron beams for experimental use, compared with the steady state reactors. In the design of fast periodic pulsed reactors, the time dependent simulation of the power pulse is majorly based on a point kinetic model, which is known to have limitations. A more accurate calculation method is desired for the design analyses of fast periodic pulsed reactors. Monte Carlo computer code MCNP6 is used for this task due to its three dimensional transport capability with a continuous energy library. Some new routines were added to simulate the rotation of the movable reflector parts in the time dependent calculation. Fast periodic pulsed reactor IBR-2M was utilized to validate the new routines. This reactor is periodically in prompt supercritical state, which lasts for similar to 400 mu s, during the equilibrium state. This generates long neutron fission chains, which requires tremendously large amount of computation time during Monte Carlo simulations. Russian Roulette was applied for these very long neutron chains in MCNP6 calculation, combined with other approaches to improve the efficiency of the simulations. In the power pulse of the IBR-2M at equilibrium state, there is some discrepancy between the experimental measurements and the calculated results using the point kinetics model. MCNP6 results matches better the experimental measurements, which shows the merit of using MCNP6 calculation relative to the point kinetics model.},

doi = {10.1016/j.net.2018.06.007},

journal = {Nuclear Engineering and Technology},

number = 7,

volume = 50,

place = {United States},

year = {Mon Oct 01 00:00:00 EDT 2018},

month = {Mon Oct 01 00:00:00 EDT 2018}

}