Generation IV International Forum hosts MSR webinar

Holcomb

The presenter: The webinar will feature David Holcomb, a member of the Reactors and Nuclear Systems Division at Oak Ridge National Laboratory and the U.S. representative on the Generation IV International Forum on Molten Salt Reactors (MSRs), where he serves as a vice chair of the provisional system steering committee. He also chairs the American Nuclear Society’s working group developing a design safety standard for liquid-fueled MSRs (ANS-20.2) and provides technical oversight of the Department of Energy’s university projects on MSRs. Holcomb has in the past served as the ORNL team lead for space reactor instrumentation as part of the Jupiter Icy Moons Orbiter program.

What it’s about: During the webinar, Holcomb will describe the current status and comparative advantages of the three alternative MSR safety adequacy demonstration pathways, as described below.

The GIF’s informational material for the webinar notes that reactor safety is evaluated to demonstrate that a plant’s operation does not present significant additional risk to the life and health of the public. Reactor safety evaluation historically focused on maintaining adequate containment of radionuclides during the maximum credible accident. As progressively larger light-water reactors (LWRs) were developed in the 1960s, however, the increased potential for catastrophic accidents necessitated expanding the safety adequacy from the containment of radionuclides under all conditions to the prevention of accidents and the mitigation of their consequences.

Either a deterministic or probabilistic pathway could be taken to demonstrate the safety adequacy for U.S. MSRs. The deterministic pathway relies on adapting accepted minimum design criteria for LWRs to MSRs, whereas the probabilistic pathway relies on adequately modeling the risks of MSR accidents to discern what can occur, how likely it is to occur, and the consequences of its occurrence.

MSR designs as envisioned have a readily apparent high degree of passive safety. Their combination of low pressure, low stored energy within containment, negative reactivity feedback, and effective passive decay heat removal substantially reduces the potential for cascading and escalating events.

This MSR resiliency opens a third demonstration pathway that refocuses safety adequacy on containment of credible accidents, precluding the need for complete probability information. This approach would be especially useful for early prototype plants that lack sufficient performance data to take advantage of higher-fidelity, data-driven risk modeling.

Upcoming webinars: The GIF has a series of webinars coming up on the next generation of nuclear energy systems and other cross-cutting subjects, as follows:

• September 22, 2020: “Maximizing Clean Energy Integration: The Role of Nuclear and Renewable Technologies in Integrated Energy Systems,” Shannon Bragg-Sitton, Idaho National Laboratory
• October 28, 2020: “Global Potential for Small and Micro Reactor Systems to Provide Electricity Access,” Amy Schweikert, Colorado School of Mines
• November 19, 2020: “Neutrino and Gen IV Reactor Systems,” Jonathan Link, Virginia Institute of Technology

For more information, contact Patricia Paviet by email or visit the GIF website.