Thorium — Kirk Sorensen and the Modern Thorium Revival
Thorium — Kirk Sorensen and the Modern Thorium Revival
Overview
If Alvin Weinberg was the father of the thorium reactor, Kirk Sorensen is the figure most responsible for rescuing it from historical obscurity and building the modern public and scientific interest that has fuelled the current global revival of thorium energy research.
Biography
| Field | Detail |
|---|---|
| Name | Kirk Sorensen |
| Background | Aerospace engineer; former NASA engineer working on lunar base life support systems |
| Education | B.S. in aerospace engineering; M.S. in nuclear engineering (completed after his discovery of MSRE documents) |
| Key discovery | While working on NASA's lunar base concepts in the early 2000s, Sorensen began looking for energy sources for a lunar base; he discovered the declassified Oak Ridge documents about the MSRE and MSBR programs in the National Technical Reports Library |
| Energy From Thorium blog | Founded approximately 2006; the primary online resource for thorium MSR information; assembled thousands of declassified Oak Ridge documents into an accessible online archive |
| Flibe Energy | Founded 2011; Sorensen's private company pursuing LFTR commercial development; based in Huntsville, Alabama |
| US Senate bill | Advocated since 2006 for preservation of the US stockpile of U-233; on May 18, 2022, Senator Tommy Tuberville introduced S.4242 "Thorium Energy Security Act" in response to Sorensen's advocacy; the bill was not adopted |
The Oak Ridge Document Discovery
Sorensen's contribution to the modern thorium revival began with a simple act of research. While working at NASA on lunar base energy systems in the early 2000s, he began reading the declassified technical reports from Oak Ridge's MSRE and MSBR programs. These documents — available in the National Technical Reports Library but largely unknown outside nuclear engineering circles — contained detailed designs, experimental results, and analyses that Weinberg's team had produced between the 1950s and 1976.
What Sorensen found was striking: a complete, well-documented, experimentally validated case for the LFTR as a superior civilian power reactor. He began scanning, transcribing, and uploading these documents to his Energy From Thorium*** blog, making them accessible to a global audience for the first time.
The TED Talk Moment
Sorensen's 2011 TEDX talk on thorium energy became one of the most widely viewed science presentations on the internet, reaching millions of viewers and introducing the thorium story to audiences far outside the nuclear engineering or energy policy communities. The talk's accessible narrative — the energy source they had, the man who developed it, the political decision that killed it, the revival — provided a compelling framework that resonated broadly.
The U-233 Stockpile Campaign
One of Sorensen's most specific advocacy positions has been the campaign to preserve the United States' stockpile of uranium-233. The DOE accumulated approximately 2 tonnes of U-233 at Oak Ridge — primarily from the MSRE and from other programs. Much of this material has been targeted for disposal as waste due to the cost and complexity of its storage and the political sensitivity of maintaining stockpiles of weapons-related material.
Sorensen has argued that this U-233 — the only significant stockpile of LFTR startup fuel in the world — should be preserved for future use rather than disposed of. The 2022 Tuberville Senate bill (not passed) reflected this advocacy.
Flibe Energy
Flibe Energy — named for the FLiBe salt that is fundamental to LFTR technology — is Sorensen's commercial vehicle for LFTR development. As of the mid-2020s, Flibe Energy remains primarily a design and advocacy organisation; it has not yet received the level of government or private investment needed to construct a prototype reactor. However, its detailed technical work has contributed to the broader MSR research community.
