The International Criticality Safety Benchmark Evaluation Project (ICSBEP) Handbook contains criticality safety benchmark specifications that have been derived from experiments that were performed at various critical facilities around the world. The benchmark specifications are intended for use by criticality safety engineers to validate calculation techniques used to establish minimum subcritical margins for operations with fissile material and to determine criticality alarm requirements and placement. Many of the specifications are also useful for nuclear data testing. The handbook is produced by the ICSBEP technical review group, under the aegis of the OECD Nuclear Energy Agency (NEA). While co-ordination and administration of the ICSBEP is undertaken by the NEA, each participating country is responsible for the administration, technical direction, and priorities of the project within their respective countries. 

The evaluated criticality safety benchmark data in the 2025 edition are presented in nine volumes. These volumes span over 84 000 pages and contain 627 evaluations with benchmark specifications for 5 184 critical, near-critical or subcritical configurations, 53 criticality alarm placement/shielding configurations with multiple dose points for each, and 250 configurations which have been categorised as fundamental physics measurements that are relevant to criticality safety applications.

There are eight new evaluations included in the 2025 handbook: one benchmark for fundamental physics, FUND-LLNL-DT-H2O-PNDA-001; two new alarm placement/shielding benchmarks, ALARM-CF-AL-SHIELD-001 and ALARM-CF-PTFE-SHIELD-001; and five critical benchmarks, HEU-MET-FAST-106, HEU-MET-THERM-038, LEU-COMP-THERM-112, PU-MET-FAST-047, and PU-MET-FAST-050.