SERPENTVTT-Finland – Jaakko Leppänen
NJOYLos Alamos National Laboratory - Jeremy Conlin
COMET code/methodology and Real-Time Particle Transport Simulations - MRT Methodology & RAPID code system.Georgia Tech – Farzad Rahnema
Virginia Tech – Alireza Haghighat

Workshops Regulation:

Limit occupancy: no more than 30 and not less than 15 attendees per workshop and they will be accepted in a first come first serve basis, date for first registration will be announced.

Workshop Fee: 100 US$ recovery fee.

Schedule: Sunday April 22, 2018 and time will be announced.

Serpent - A Monte Carlo Reactor Physics Burnup Calculation Workshop
(4 hours)

Serpent is a multi-purpose three-dimensional continuous-energy Monte Carlo particle transport code, developed at VTT Technical Research Centre his workshop covers the recent development and future applications of the Serpent Monte Carlo code. Serpent has been developed at VTT Technical Research Centre of Finland since 2004, mainly for the purpose of reactor physics applications. The code has been used for generating group constants for deterministic transport codes, but also as a high-fidelity neutronics solver in coupled multi-physics simulations.

The development of a new Serpent-based computational framework "Kraken" was started at VTT in 2017. Kraken is essentially a modular platform that provides reduced-order and high-fidelity code sequences for coupled core physics calculations.

Topics to be covered

1. Introduction to Serpent.

2. Group constant generation for reduced-order calculations.

3. Coupled high-fidelity simulations for best-estimate analyses.

4. Case examples.


Serpent website --

NJOY Processing System Workshop
(4 hours)

Topics to be covered

1. Introduction to the ENDF file format.

2. Introduction to modules needed to create a continuous-energy neutron ACE file.

3. How to use the processed data in MCNP.

4. How to plot nuclear data with NJOY.


After enrollment, a week prior to PHYSOR, it will be sent to the participants an email informing them of things they should download before the workshop.

There will be access to wireless internet so that the participants can download various NJOY input decks and such.

Participants should bring their own computer and should have NJOY installed prior to the beginning of the class.

COMET Method /code Workshop
Farzad Rahnema, Georgia Tech,
(1.5 hours)

COMET (COarse-MEsh radiation Transport) is a hybrid continuous energy stochastic deterministic transport code based on the incident flux response expansion method. The COMET method has THE fidelity of stochastic methods and computational speed that is several orders of magnitude faster than both stochastic and deterministic transport methods. The code decomposes a large heterogeneous system such as a reactor core into a set of small local problems (e.g., fuel assemblies) and for each unique local problem in the system, a solution called response function is obtained by a stochastic solver (response function generator). The overall solution to the global (core) problem is then obtained by repeatedly generating local solutions via a linear superposition of responses for the unique local problems.

The neutronic version of COMET solves for the eigenvalue and the detailed fission density distribution (e.g., fuel pins) in the core with Cartesian (e.g., BWR, PWR, CANDU) as well as hexagonal geometries (e.g., HTTR, VHTR, HTR, ABTR). The coupled photon electron version is used for both detector response and radiotherapy calculations.

In this workshop, the methods for all three applications will be described and the code for the core calculations will be demonstrated.

Real-Time Particle Transport Simulations - MRT Methodology, RAPID code system Workshop
Alireza Haghighat -
(2.5 hours)

The goal of this workshop is to introduce the audience to the novel Multi-stage, Response-function Transport (MRT) methodology, a Physics-based computational technique, for real-time simulation of nuclear systems. Further, it elaborates on a number of MRT-based computational tools developed for solving real-world problems in real time. Particularly, the workshop will emphasize on the recently developed RAPID code system by giving real-time demonstration of the use of the code for solving real-world problems, e.g., a cask containing 32 spent fuel assemblies, on a laptop in real time!

The workshop will include two parts:

Part I: Discussion of the MRT methodology and its application for a few real-world problems:

  • AIMS (Active Interrogation for Monitoring of SNM).
  • INSPCT-S tool (INSPCT-S, Inspection of Nuclear Spent fuel-Pool Calculation Tool ver. Spreadsheet).
  • TITAN-IR (TITAN code system for Image Reconstruction).
  • RAPID (Real-time Analysis Particle-transport In-situ Detection).

Part II: Demonstration of the RAPID code system for simulation of spent fuel casks and pools

In a MRT methodology, the problem of interest is partitioned into stages based on its physics, and each stage is represented by a response function or set of coefficients. These stages are combined into a linear system of equations which are solved iteratively using the pre-calculated functions and/or coefficients.


1. Haghighat, K. Royston and W. Walters, “MRT Methodologies for real-time simulation of nonproliferation and safeguards problems, Annals of Nuclear Energy, Volume 87, Part 1, pp 61-67, January 2016.

2. W. Walters, N. Roskoff, and A. Haghighat, “A Fission Matrix Approach to Calculate Pin-wise 3D Fission Density Distribution,” Proc. M&C 2015, Nashville, Tennessee, April 19-23, 2015.

3. V. Mascolino, A. Haghighat, and N. Roskoff, “Evaluation of RAPID for a UNF Cask Benchmark Problem,” Proc. ICRS-13 & RPSD-2016, Paris, France, October 3-6, 2016.


There will be access to wireless internet so that the participants can have remote access to VRS-RAPID. The current version of VRS-RAPID is optimized for a Personal Computer using the Google Chrome browser, but it can be accessed through iPad, Tablet, etc. using any other browser.

To facilitate establishing individual accounts, participants are encouraged to contact Prof. Haghighat prior to the workshop.

Webmaster: Francisco Javier Bucio Valdovinos.