Advanced Moderator Material Handbook (FY25)

Technical Report · Wed Oct 22 00:00:00 EDT 2025

DOI:https://doi.org/10.2172/2999897· OSTI ID:2999897

Kohnert, Caitlin Anne ^[1]; Neilson, William Donald ^[1]; Cinbiz, Nedim ^[2]; Shivprasad, Aditya Prahlad ^[1]; Torres, James ^[3]; Cutler, Theresa Elizabeth ^[1]; Wootan, D.W. ^[4]; Jewel, J.K. ^[5]; Mehta, Vedant Kiritkumar ^[1]; Widgeon Paisner, Scarlett ^[1]; Taylor, C.N. ^[5]; Luther, Erik Paul ^[1]; Trellue, Holly Renee ^[1]

---

1. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
3. MST-8
4. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
5. Idaho National Laboratory (INL), Idaho Falls, ID (United States)

High hydrogen density moderators such as metal hydrides are an important research topic within the DOE NE Microreactor Program due to their ability to retain hydrogen to much higher temper atures than other hydrogenous media. This class of moderators, which includes yttrium dihydride (δ-YH₂) and zirconium hydride (δ-ZrH_1.6 or ϵ-ZrH_1.8), thermalizes neutrons in the system such that the overall fuel mass or the required uranium enrichment in the system can be significantly reduced. Knowledge of material properties, both in the as-fabricated and irradiated state, are important to understanding moderator performance during steady-state and transient reactor operation.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: 89233218CNA000001
• OSTI ID: 2999897
• Report Number(s): LA-UR--25-30471
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE