Vermont Yankee

Vermont Yankee was a nuclear power plant, located in the town of Vernon, Vermont, in the New England. The plant had begun commercial operations in 1972 and in 2008, the plant provided 71.8% of all electricity generated within Vermont. On December 29, 2014, its owner Entergy ceased the plant's operations.

In March 2011, 600 people gathered for a weekend protest outside the Vermont Yankee plant, in the wake of the Fukushima I nuclear accidents. On March 22, 2011, the day after the NRC issued Vermont Yankee a license extension, Vermont's congressional delegation, Senator Patrick Leahy, Senator Bernie Sanders, and Representative Peter Welch, issued a joint statement decrying the NRC's action and noting the similarity of Vermont Yankee to units at the Fukushima Daiichi power station. 

Despite an extension to plant life, which had been granted 2 years earlier, on August 28, 2013, Entergy announced that due to economic factors, notably the lower cost of electricity provided by competing natural gas-fired power plants, it would cease operations and schedule the plant's decommissioning in the fourth quarter of 2014.

 When Vermont Yankee was set to close, activists such as Bill McKibben claimed that Vermont “is completely capable of replacing (and far more) its power output with renewables, which is why my roof is covered with solar panels.” Vermont Yankee, a 604-megawatt nuclear plant, provided New England with 42 years of reliable, carbon dioxide-free power before its closure at the end of 2014. The plant’s capacity factor exceeded 80 percent over its lifetime—more than double the capacity factor of the most efficient solar or wind plant in the United States, which were expected by some to replace it.

However, that wasn’t what happened. Instead, natural gas generation expanded in New England. As a result, carbon dioxide emissions increased 7 percent in 2015. And now, Pilgrim, a nuclear power plant in Massachusetts, is also set to close in 2019 due to economic factors. Sadly, Pilgrim employs 600 people with an annual payroll of $55 million, pays nearly $10 million in town and state taxes, and provides power for more than 500,000 homes.

I'm graduating?

Today marks the beginning of the end. Today is the last day my radiation protections class will meet.
It almost doesn't feel real. This is my last semester of undergrad and after this I'll be a "real adult" whatever the hell that means.

My last 4 years have been filled with ups and downs but the best part have been the 14 other nuclear engineers that are graduating with me. We've laughed together, studied together, gotten drunk together, celebrated the end of miserable times together, and we've cried (on the inside) in our sleep deprived states together. They're great. They are really the reason I'm able to graduate. Without them I wouldn't have been able to accomplish all that I did. For all you gators graduating with me this year, thank you. I really mean it. You guys, above all, have made college the wonderful experience it turned out to be.

As for this blog, I'm not done. My posts won't be as consistent but I've found that I really enjoy writing and after all that we've talked about advocating for the nuclear industry, I've found that the nuclear industry really does need defending and it really should be some PR person's job but they're clearly not doing it, so in the mean time, I will!

Tokaimura

The moral of today’s criticality accident is “if you don’t learn from the past, you’re doomed to repeat it.”

On September 30, 1999 (yes this was just 17 years ago), the JCO fuel fabrication plant in Tokaimura, Japan. The facility was authorized to use the image below. In a comment on my last post, I made the statement that sometimes the person who designs the system causes the accident by making a system that’s so inconvenient that avoiding the authorized procedure is simpler. 

The authorized design was terrible. The drain for the final tank was 10 cm (~4 in.) from the floor and it was needed to fill 4 L bottles. Just stop reading and think of this, an iPhone 5 is 4.87 inches long. Imagine filling a bottle on the ground with less distance from the spigot than the length of an iPhone. Instead of working within the system, operators used the procedure below.

The original procedure had a lot of controls to ensure that materials didn’t concentrate in areas and become critical. By hand mixing the solution and transferring it using flasks, there was no guarantee that concentrations were safe. On September 30^th, the gamma radiation alarms at the facility sounded in the building and two adjacent buildings. Criticality continued 20 hours until action was authorized. Residents within 350 m of the plant were recommended to evacuate and residents within 10km were recommended to stay indoors due to airborne fission products. (Don’t worry 90% of people in a 350m area received less than 5mSv and contamination to the area resulted in readings from plant life of less than 0.01mSv)

Two workers that were involved in the pouring of the solution were severely exposed. One operator died 82 days later, the other died 210 days later. A third operator that was at a desk a couple of meters away was in the hospital for 3 months.

The people of the facility felt pressure to produce fuel and with a weak understanding of the factors that could lead to an accident, they did not understand the possible consequences of their actions. Additionally, officials for JCO felt an accident wasn’t even possible. Nuclear material is only “safe” if you treat it like it’s not and not learning from previous accidents meant JCO officials got cocky, didn’t educate their operators, and eventually this resulted in an accident.

FKBN - April 5, 1968

On April 5, 1968, an accident occurred at the Russian Federal Nuclear Center (VNIITF), which is located in the southern Ural Mountains. The FKBN, a Russian acronym for “a physics neutron pile”, was a vertical lift assembly with a natural Uranium reflected core. The FKBN was developed to study radiation tolerance. The configuration of the assembly consisted of a thick natural uranium reflector with a large internal cavity.

            At the time of the accident, the FKBN was being used to research the effects of a polyethylene sphere on a reactor system. The image below shows how the components were configured at the time of the accident.

            The design consisted of three parts: a stationary core, an upper reflector and a lower reflector. The core was made from Uranium with a polyethylene sphere at its center. The upper reflector was a natural uranium piece and the lower reflector was also a natural uranium piece with the same dimensions as the upper reflector.

            The accident occurred on the afternoon of April 5, 1968.

            The operation of lowering the upper reflector could not be carried out under remote control so a senior specialist operated a lift while a junior specialist stood next to the FKBN reflector to guide it in to place. The assembly became critical as the upper half approached the core and was about to make contact with it. The emergency instrument system responded by dropping the lower reflector returning the system to a subcritical level.

            The accident was caused by a series of miscalculations and errors in judgment. The first error that occurred was the lack of realization of the lower reflector’s position before lowering the upper reflector. The lower reflector was placed was in a higher position than the specialists realized. The lower reflector was at a high location due to a failure to reposition the half after a morning test was concluded. The second oversight was the senior specialist’s expectation that the polyethylene sphere in the middle of the core would have a small effect on the system’s reactivity. 

            Several additional violations of procedure were identified as contributing to the accident. These violations include the switching off of the instrument system that alerted the specialists that the system was becoming critical. There were also two operators that were missing, a third specialist who would’ve manned the control room and a health physics specialist.

            Following the accident, the two specialists remained conscious and were able to inform administrative officials and request an ambulance. The junior specialist, who was positioned close to the assembly, died three days after the excursion. The senior specialist, who was farther, received an accumulated dose in the 5-10 Sv range and passed away 54 days after the accident.

           Once again, the moral of the story is to make sure everyone is there. There are additional lessons of make sure you have all of the equipment in the right position and that your safety systems and radiation detectors are on.

The "Demon Core"

For my first criticality accident I’m going to talk about what is lovingly referred to as the “demon core.” This is due to the fact that it’s been a part of two accidents at Los Alamos National Lab.

The demon core consisted of two hemispheres of plutonium coated in nickel. The core, when the hemispheres are put together, was designed to be 5% below a critical mass meaning that by itself it could not become critical. In order to become critical, the demon core would require a reflector, a material that would bounce neutrons back into the core, or additional nuclear material.

The first incident occurred on August 21, 1945. A physicist was conducting an experiment where he was placing reflector bricks made of tungsten carbide in order to gauge how many it would take to reach criticality. The core was on a stack of bricks and each brick placed around the core put it closer and closer to criticality. The physicist was working alone (always a bad idea) and he accidentally dropped a tungsten carbide brick on top of the core. The brick caused the core to become supercritical and the physicist received a lethal dose of radiation. He unfortunately died 25 days later from acute radiation poisoning.

I wish I could say that the world learned more from this poor man’s death but unfortunately you see physicists and engineers bypassing safety systems, working alone, and thinking that they could do things without help all the time. You’ll definitely hear more about those men from me later.

The second incident occurred on May 21, 1946. It’s popularly portrayed in the 1989 movie Fat Man and Little Boy. A group of scientists were conducting an experiment where they placed the demon core within a beryllium sphere that acted as a neutron reflector. The beryllium sphere was also comprised of two hemispheres and as the hemispheres got closer and closer together around the core, the core became more critical. The experiment consisted of changing the gap between the two hemispheres in order to measure the activity of the core. However, a standard screwdriver inserted in the gap between the hemispheres was manipulating the gap width. If this sounds stupid, it’s because it was, and Slotin, the head physicist, was warned that if he continued to do the experiment he would be “dead within a year”. On the day of the accident, the screwdriver slipped out and the two beryllium hemispheres met. The core became supercritical instantly. Slotin knocked the two spheres apart stopping the reaction. Slotin, four other scientists, a technician, an engineer, and one guard received radiation doses. Slotin died 9 days later from acute radiation poisoning. All others were far enough that they did not receive lethal doses.

I guess the moral of the story today is no one is a god and experiments, especially those with radioactive materials, should be conducted with the utmost respect for the lethality of the material.

Criticality Accidents

I've spent a lot of time defending the nuclear industry, now I'm going to tell you about my odd passion within the industry, what happens when things go wrong.

A subcritical configuration refers to nuclear material that is not contributing to a continuing reaction. A critical configuration usually produces as many or more neutrons per "generation" as the last generation had. Criticality accidents are accidents where nuclear material was supposed to be subcritical but error led to nuclear material becoming critical. When nuclear becomes critical, or even supercritical, it becomes dangerous for humans to be around because more and more radiation is being created and human exposure could become lethal very quickly.

Critical or supercritical configurations aren't necessarily bad. Nuclear reactors need to become critical in order to continue producing energy. However, you don't really want to be in the same room when it happens.

Criticality accidents are my personal passion within the nuclear industry because they highlight how important it is to do things by the book and to pay attention. I also sort of enjoy seeing how nuclear research safety rules have changed in order to prevent accidents. Most importantly, it shows that the people that suffer most from radiation are the people working with it and it acts as a reminder to always think through the risk.

 For my next couple of posts I'll be talking about criticality accidents. What went wrong? What went right? What could have been done to prevent it?

Spring Break: NOLA discovered

Today’s post isn’t really about radiation but it is about another topic that isn’t widely known about, the lead poisoning problem in New Orleans. Admittedly, I only found out about it two weeks ago when I was there for spring break but I think it is super important that people find out about the things that affect our country.

New Orleans is one of the older cities in the United States. It was originally founded May of 1718 by the French Mississippi company. It has, since then, passed through Spanish hands before being sold to the US. New Orleans also saw some big changes during the civil war. Most recently, New Orleans was deeply affected by Katrina. Through all that the city has been through, it still contains a large “old world” problem, LEAD PAINT. Lead paints cover a large amount of property in New Orleans and it’s a huge problem, especially in impoverished areas.

What happens is this: Say your door is old and the paint is starting to chip so you want to replace it. What’s the first things you do? Sand off the old paint so you can put a clean coat on top. What you didn’t know is that the old paint was lead based so now you’ve released tons of little lead particles into the air. Now, you, your children, and your neighbors can inhale these particles. This kind of release of lead is very dangerous and it’s an incredibly prevalent problem in poor neighborhoods that either don’t know they have lead paint or don’t know how to prevent releases. Additionally, the lead will also contaminate the topsoil.

Lead is incredibly toxic and lead poisoning can lead to a bunch of problems such as lower IQs, learning disabilities, attention problems, and brain damage. Problems are so prevalent that my cousin, who works in a public school in New Orleans, said that if a child is constantly acting up they recommend that parents have them tested…for lead! In screenings done in 2013, the Louisiana Department of Health and Hospitals reported that nearly a thousand children six years and younger—15 percent—had levels high enough to be deemed lead poisoning.

Awareness of an issue is the first step to fixing it. So now that you know, go do something. Contribute to clean up efforts, inform someone else, or do both. The most important thing is to not let this problem be ignored.