Dave Lochbaum

About the author: Mr. Lochbaum received a BS in Nuclear Engineering from the University of Tennessee in 1979 and worked as a nuclear engineer in nuclear power plants for 17 years. In 1992, he and a colleague identified a safety problem in a plant where they were working. When their concerns were ignored by the plant manager, the utility, and the Nuclear Regulatory Commission (NRC), they took the issue to Congress. The problem was eventually corrected at the original plant and at plants across the country. Lochbaum joined UCS in 1996 to work on nuclear power safety. He spent a year in 2009-10 working at the NRC Training Center in Tennessee. Areas of expertise: Nuclear power safety, nuclear technology and plant design, regulatory oversight, plant license renewal and decommissioning

Nuclear Safety Chapeaux

Nuclear Energy Activist Toolkit #60

Hard hats are ubiquitous within nuclear power plants and construction sites. They protect the heads of the wears from failing objects and from bumps against low overhead piping and such. Read More

Bookmark and Share

New, Renewed, and Subsequent Nuclear Reactor Risks

Fission Stories #193

The Nuclear Regulatory Commission (NRC) initially licenses nuclear power reactors for operation up to 40 years. The NRC can renew the operating licenses for up to 20 additional years, as it has already done for about three quarters of the reactors in the United States. And the nuclear industry is discussing “subsequent license renewal” with the NRC for potentially 20 more years. Read More

Bookmark and Share

Nuclear Autopsies

Nuclear Energy Activist Toolkit #59

Medical professionals diagnose the health of their patients using non-destructive techniques (keeping with the Hippocratic Oath to do no harm) like taking temperatures and pulses and, when necessary, peering inside bodies using X-rays and Cat-scans.

Medical coroners, on the other hand, can use destructive techniques on persons when determining the causes of their deaths. Chest cavities and skulls are cut open to enable organs to be assessed. Tissue samples may be cut from bodies for microscopic examinations.

Insights gained during autopsies supplement the information gathered from treatments and examinations of living patients to broaden the knowledge of human health, allowing medical professionals and researchers to make health care advances.

Nuclear autopsies have been undertaken, and more are planned, for similar purposes—to supplement information gathered during tests and inspections conducted during reactor operation and support technological advances.

For example, the NRC outlined “harvesting” (their use, my re-use) several components during the decommissioning of permanently shut down nuclear power reactors.

Samples from the Zorita nuclear plant

Samples from the baffle plate and core barrel were harvested from the José Cabrera Nuclear Power Station (also known as the Zorita nuclear plant) in Spain as part of the Zorita Internals Research Project.

Fig. 1.

Fig. 1. (click to enlarge)  (Source: Nuclear Regulatory Commission)

Zorita was a pressurized water reactor similar to about two-thirds of the reactors currently operating in the United States. The baffle plate and core barrel formed a metal enclosure around the nuclear fuel within the reactor pressure vessel. They function to direct cooling water flow through the reactor core. Metal specimens attached to the core barrel and other internal components are periodically removed during refueling outages over the reactor’s lifetime for laboratory analysis of radiation effects.

The Zorita samples supplement those insights. Among other things, the results from the examinations will factor into the NRC’s decision-making about subsequent license renewal (SLR)—operating reactors beyond 60 years.

Additionally, there are plans to for samples from concrete structures surrounding the reactor pressure vessel at Zorita to be harvested. Previous concrete samples have been harvested from the containment building at Crystal River 3, from the shield building at Davis-Besse, and from the auxiliary building at Seabrook. The  samples at Zorita will come from concrete structures within the containment building and closer to the high temperature and high radiation emitted from the reactor pressure vessel.

Fig.. 2. (click to enlarge)

Fig.. 2. (click to enlarge) (Source: Nuclear Regulatory Commission)

Samples from the Zion nuclear plant

There are plans to harvest neutron absorber materials from the spent fuel pool at the Zion nuclear plant in Illinois, which permanently shut down a decade ago.

Fig. 3. (click to enlarge)

Fig. 3. (click to enlarge) (Source: Nuclear Regulatory Commission)

Spent fuel pools originally relied on geometry to prevent a nuclear chain reaction—the fuel assemblies in the storage racks were far enough apart to preclude a critical mass from being formed. When reprocessing was eliminated and the repository delayed, spent fuel pools were re-racked to store more fuel assemblies. The fuel assemblies within storage racks are typically closer together than when they are in the reactor core.

To guard against nuclear chain reactions, the walls of the storage racks contain neutron absorbing material. The objective of this material is to “soak” up neutrons emitted by the decay of unstable radioactive byproducts in the nuclear fuel and thus prevent them from interacting with uranium and plutonium atoms to cause fissions. But experience with neutron absorbing materials has not been stellar. There were fabrication problems, degradation problems, leaching problems, analytical problems, and expansion problems to list some of the many problems.

The Zion harvests may complement the humongous trial and error database.

Electrical cables will be harvested from both the Zion nuclear plant in Illinois and Crystal River 3 in Florida. Cables consist of metal wires that carry electricity throughout the nuclear plant wrapped in insulating material that guards against the electricity touching things along the way. The focus is on the cable insulation because it tends to age (degrade) faster at higher temperatures.

Fig. 4. (click to enlarge)

Fig. 4. (click to enlarge)  (Source: Nuclear Regulatory Commission)

Bottom Line

Harvesting of materials to enable fuller insights from their destructive examinations (i.e., nuclear autopsies) has not waited until nuclear power reactors have permanently shut down. As parts have worn out and been replaced (e.g., steam generators, reactor vessel heads, eroded pipes, etc.), specimens have been harvested and analyzed.

The nuclear industry and the NRC seek to expand those insights by harvesting materials from previously un-examined plant areas. These collections permit real data to replace positions established by extrapolating from other real data and/or by computer analyses. Hopefully, the real data reinforces previous positions. Either way, the real data supports better decision-making in the future.

Nuclear autopsies yield insights that cannot be obtained by other means.


The UCS Nuclear Energy Activist Toolkit (NEAT) is a series of post intended to help citizens understand nuclear technology and the Nuclear Regulatory Commission’s processes for overseeing nuclear plant safety.

Bookmark and Share

Palisades 50

Fission Stories #192

Much has been said and written about the Fukushima 50—the workers who remained onsite during the height of the crisis at the Japanese Fukushima nuclear plant after senior managers ordered their co-workers to evacuate because of worsening conditions.

Less has been said and written about the Palisades 50—which involves worsening conditions and workers but not quite in the same way. Palisades 50 refers to the findings by the Nuclear Regulatory Commission (NRC) during a recent inspection at this nuclear plant five miles from South Haven, Michigan. Read More

Bookmark and Share

Enhancing NRC Public Meetings

Nuclear Energy Activist Toolkit #58

By memo dated January 29, 2015, a task group of twenty individuals within the NRC submitted its report to the agency’s Executive Director for Operations on enhancing public meetings. The task group was created in response to written direction dated March 5, 2014, (ADAMS ML14070A070, but not publicly available in ADAMS) from the NRC Chairman. The task group made five recommendations to enhance public meetings conducted by the NRC: Read More

Bookmark and Share

Nuclear Stock Market

Fission Stories #191

News such as last year’s closure of four nuclear power reactors, this year’s closure of another reactor, and Exelon’s claim that many of its reactors cannot break even absent even greater subsidies suggests that now might not be the best time to invest in nuclear technology. But it doesn’t mean that nuclear technology need not be considered when playing the stock market. Read More

Bookmark and Share

Nuclear Columbine

Nuclear Energy Activist Toolkit #57

From Charles Whitman killing 16 people with shots fired from a tower on the University of Texas at Austin campus on August 1, 1966, to two students killing 13 people by gunfire at Columbine High School in Colorado on April 20, 1999, to a gunmen killing 32 people at Virginia Tech on April 16, 2007, to a young man fatally shooting 20 children and 6 staffers at Sandy Hook Elementary School in Newtown, Connecticut, on December 14, 2012, and many other incidents, school shootings have tragically claimed too many innocent lives and given too many families irreplaceable, unforgettable losses.

The United States could have reacted to Whitman’s rampage by closing all public and private schools. That action would have absolutely prevented school shootings and their tragic consequences.

Instead, the United States chose to sustain the benefits from formal education while pursuing measures intended to make schools as safe as possible. While school shootings have continued, I recall the comments made by William J. Bennett, Secretary of Education under President Ronald Reagan, after Columbine. Bennett observed that while you could count the times the safety measures failed, you could not count the times they succeeded in averting tragedies. Rather than suggesting that occasional school shootings were “acceptable losses,” Bennett emphasized the vital role for safety and security in our educational system.

This education situation is similar to our longstanding position on nuclear power. Nuclear power became one of UCS’s focus areas shortly after the organization was formed in May 1969. Nuclear power provides certain benefits by producing large amounts of energy from a relatively small environmental footprint. But the consequences from nuclear mis-steps can be extremely costly. UCS has consistently focused on identifying nuclear power plant safety shortcomings and advocating their solutions. The nuclear plant accidents at Three Mile Island (1979), Chernobyl (1986), and Fukushima (2011) has not altered that focus.

Bottom Line

One of two things would need to happen to move UCS into adopting either a pro-nuclear power or an anti-nuclear power position.

First, we could become unable to find nuclear power plant safety shortcomings if all operating reactors complied with applicable regulations or if all operating reactors were inherently safe. With only benefits to be captured and no costly consequences to be experienced, nuclear power could be embraced by UCS.

Second, we could become unable to find appropriate solutions for nuclear power plant safety shortcomings. With benefits to be derived only at undue risk of costly consequences, nuclear power would likely be opposed by UCS.

Until then, UCS will continue looking for nuclear safety problems and calling for their resolutions.


The UCS Nuclear Energy Activist Toolkit (NEAT) is a series of post intended to help citizens understand nuclear technology and the Nuclear Regulatory Commission’s processes for overseeing nuclear plant safety.

Bookmark and Share

Near Miss at Nuclear Fuel Services

Fission Stories #190

UCS initiated a series of annual reports on the NRC and nuclear plant safety in March 2011. As in this year’s report, these annual reports contain a chapter summarizing the near misses that the NRC investigated during the prior year. We define “near miss” to be any event or discovery at a nuclear plant that prompts the NRC to dispatch a special inspection team to the site to ascertain its cause and verify its correction. Read More

Bookmark and Share

All Over the Nuclear Safety Map

Nuclear Energy Activist Toolkit #56

In 2007, UCS launched the Nuclear Power Information Tracker, an interactive web feature. The default screen showed a map of the continental United States with icons showing the locations of the commercial nuclear power reactors. Running the cursor over an icon prompted a pop-up box with the reactor’s name, some basic information, and a link to a webpage for that reactor with additional details as well as UCS reports about that reactor. Read More

Bookmark and Share

Nuclear Near-Miss at Pilgrim

On January 27, 2015, Winter Storm Juno knocked out both of the 345,000 volt transmission lines connecting the Pilgrim nuclear plant in Plymouth.  Per design, the reactor automatically shut down when the second offsite power line was lost. When equipment problems and operator errors complicated the intended response, the NRC dispatched a special inspection team to the site to investigate what happened (and didn’t happen). Read More

Bookmark and Share