The passive heat removal facility (PHRF) and its first phase experiments

The Westinghouse Lead Fast Reactor (LFR) is a 450 MWe class, lead-cooled, fast neutron spectrum, pool-type reactor with passive safety systems. The passive heat removal system (PHRS) is the emergency decay heat removal system of this LFR. A distinctive feature of the PHRS is that it is always on, and does not require any operator intervention, signals of intelligence or moving parts for the actuation and operation, consistent with the IAEA passive safety category B. The system initially removes heat through water boiling and subsequently transitions to (indefinite) air cooling. To assess the performance of the PHRS and provide experimental data for the verification and validation of modeling and simulation tools, the passive heat removal facility (PHRF) has been built at the Ansaldo Nuclear's site in Wolverhampton, UK, with the support from the United Kingdom Government and international partners. The PHRF is a full-height separate effects test facility that follows the power-to-volume scaling rule to maximize its prototypicality. The test matrix of the first phase of testing included both air cooling tests and transition tests from water cooling to air cooling. A significant amount of experimental data were generated in the first phase of testing, confirming the performance of the PHRS both in air cooling mode and during the transition from water cooling to air cooling.