# Neutron Transport Equation
**Entity class:** Mathematical physics model
## Definition
The **neutron transport equation** models the distribution and movement of neutrons through space, direction, energy, time, and interacting materials. High-fidelity discretizations can be computationally large, making model reduction useful for repeated and real-time queries.
## Relationships
- **produces:** [[wiki/Radiation Transport Field|Radiation Transport Field]].
- **DTRA application:** [[wiki/Nuclear Weapon Radiation Effects Modeling|Nuclear Weapon Radiation Effects Modeling]].
- **accelerated by:** [[wiki/Reduced-Order Modeling|Reduced-Order Modeling]] and [[wiki/Scientific Machine Learning|Scientific Machine Learning]].
- **inverse formulation:** [[wiki/PDE-Constrained Inverse Problem|PDE-Constrained Inverse Problem]].
## Sources / Provenance
- [Sheriffdeen et al. — ML-enhanced reduced-order inverse solutions for parametrized neutron transport, 2019](https://arxiv.org/abs/1912.08864)
- [Oden Institute — DTRA project](https://oden.utexas.edu/news-and-events/news/minimizing-uncertainty-in-uncertain-world-of-defense-energy/)