Conventional Nuclear (AKA Nuclear Fission) a thread for discussion of the pros / cons.

Quote from JedRothwell

That would be nuclear power

Oh, so that is what Carl meant. I can be so naive when it comes in handy.

Quote from JedRothwell

Before Fukushima I was a lukewarm supporter of nuclear energy. I considered it the least bad solution. For now. Better than coal. That was despite the accidents at Three Mile Island, Connecticut Yankee, Davis-Besse, Brown's Ferry and other outrageous accidents. If the public knew about these accidents there would be less support for nuclear power. Did you know, the Browns Ferry accident in 1975 was caused by some guy with a lit candle looking for air leaks in a hallway? And it nearly destroyed all three redundant control systems because they all went down that same hallway? After you read that kind of detail, you will feel less confident in U.S. nuclear plant engineering. It sounds like it was designed and operated by the Three Stooges.

I hear you. All here are green, including moi...we just come in slightly different shades of green. We all mean well and should respect each others opinion as to the best way forward in meeting the worlds energy needs.

IMO, the difference between people like you and the Carl Pages of the world, is that you are confident solar and wind can fill in for the newer, extremely safe, advanced SMR's, but they are not quite so confident. Firmly believing that, it then becomes a decision on their part between watching the potential devastation caused by rising temps, or grudgingly accepting something that may make a difference.

I guess the best way to put it is that they do not want nuclear, but feel there is no other choice. Of course, as you said, and the reason we all are here, the best outcome would be for LENR to be made commercial tomorrow, if not sooner. And I do have some hope it will be be our salvation, and make unnecessary this dispute between the environmentally conscious.

Quote from JedRothwell

I believe so! That's what he has talked about in the past.

Before Fukushima I was a lukewarm supporter of nuclear energy. I considered it the least bad solution. For now. Better than coal. That was despite the accidents at Three Mile Island, Connecticut Yankee, Davis-Besse, Brown's Ferry and other outrageous accidents. If the public knew about these accidents there would be less support for nuclear power. Did you know, the Browns Ferry accident in 1975 was caused by some guy with a lit candle looking for air leaks in a hallway? And it nearly destroyed all three redundant control systems because they all went down that same hallway? After you read that kind of detail, you will feel less confident in U.S. nuclear plant engineering. It sounds like it was designed and operated by the Three Stooges.

I looked up the Brown's Ferry nuclear accident and found this link:

The Fire at the Bown's Ferry Nuclear Power Station

Absolutely fascinating - I highlighted in Bold where many people understand that the foam is flammable, there are multiple minor flammable accidents and still no one stops the use of using a candle to inspect for air leaks, almost unbelievable,

I trimmed out some of the boring parts (about 1/2 of the article) from that link here is the interesting stuff - I put in Bold some of the more outrageous stuff:

======================================

How a Candle Caused a Nuclear Emergency

At noon on March 22, 1975, both Units 1 and 2 at the Brown's Ferry plant in Alabama were operating at full power, delivering 2200 megawatts of electricity to the Tennessee Valley Authority.

Just below the plant's control room, two electricians were trying to seal air leaks in the cable spreading room, where the electrical cables that control the two reactors are separated and routed through different tunnels to the reactor buildings. They were using strips of spongy foam rubber to seal the leaks. They were also using candles to determine whether or not the leaks had been successfully plugged -- by observing how the flame was affected by escaping air.

The electrical engineer put the candle too close to the foam rubber, and it burst into flame.

The resulting fire, which disabled a large number of engineered safety systems at the plant, including the entire emergency core cooling system (ECCS) on Unit 1, and almost resulted in a boiloff/meltdown accident, demonstrates the vulnerability of nuclear plants to "single failure" events and human fallibility.

How The Fire Got Started

The fire was started by an electrical inspector (referred to in the NRC report as "C"), working with an electrician, "D", who said,

"Because the wall is about 30 inches thick and the opening deep, I could not reach in far enough, so C [the inspector] asked me for the foam and he stuffed it into the hole. The foam is in sheet form, it is a 'plastic' about 2 inches thick, that we use as a backing material."

The inspector, "C", describes what happened next:

"We found a 2 x 4 inch opening in a penetration window in a tray with three or four cables going through it. The candle flame was pulled out horizontal showing a strong draft. D [the electrician] tore off two pieces of foam sheet for packing into the hole. I rechecked the hole with the candle. The draft sucked the flame into the hole and ignited the foam which started to smoulder and glow.

"The material ignited by the candle flame was resilient polyurethane foam. Once the foam was ignited, the flame spread very rapidly. After the first application of the CO2 , the fire had spread through to the reactor building side of the penetration. Once ignited, the resilient polyurethane foam splattered as it burned. After the second extinguisher was applied, there was a roaring sound from the fire and a blowtorch effect due to the airflow through the penetration.

"The airflow through the penetration pulled the material from discharging fire extinguishers through the penetration into the reactor building. Dry chemicals would extinguish the flames, but the flame would start back up."

"I checked and found that the only water supply to the reactor at this time was the control rod drive pump, so I increased its output to maximum."

Meanwhile, a few feet away on the Unit 2 side of the control room, warning lights had also been going off for some time. A shift engineer stated,

"Panel lights were changing color, going on and off. I noticed the annunciators on all four diesel generator control circuits showed ground alarms. I notified the shift engineer of this condition and said I didn't think they would start."

"At about 1:30, I knew that the reactor water level could not be maintained, and I was concerned about uncovering the core."

Had the core become uncovered, a meltdown of the reactor fuel would have begun because of the radioactive decay heat in the fuel.

In order to prevent the reactor water from boiling off, it was necessary to get more water into the core than the single high-pressure control rod drive pump could provide. It was decided that by opening the reactor relief valves, the reactor would be depressurized from 1020 to below 350 pounds per square inch, where a low-pressure pump would be capable of forcing water in to keep the core covered. None of the normal or emergency low-pressure pumps were working, however, so a makeshift arrangement was made, using a condensate booster pump. This was able to provide a temporarily adequate supply of water to the reactor, although the level dropped from its normal 200 inches above the core down to only 48 inches. Using the makeshift system, the Unit 1 reactor was under control for the time being.

"None of these attempts resulted in establishing torus or reactor shutdown cooling. The attempts were severely limited by dense smoke and inadequate breathing apparatus."

Why the Fire Fighting Efforts Stalled

The fire fighting effort was not going well. Soon after the electricians had fled the cable spreader room, a shift engineer had tried to turn on the built-in Cardox system in order to flood the room with carbon dioxide (CO2) and put out the fire. He discovered that the electricians had purposely disabled the electrical system that initiated the Cardox.

"I tried to use the manual crank system and discovered that it had a metal construction plate on, under the glass, and I tried to remove it. This was difficult, without a screwdriver.... The next day, I checked other manual cardox initiators and found that almost all of them had these construction plates attached."

He finally got the power on, but the Cardox system ended up driving smoke up into the control room above the cable spreader room. One person present described the scene in the control room as follows:

"The control room was filling with thick smoke and fumes. The shift engineer and others were choking and coughing on the smoke. It was obvious the control room would have to be evacuated in a very short time unless ventilation was provided."

After the carbon dioxide system was turned off, the smoke stopped pouring into the control room. It had not put out the fire in the spreading room, however. A safety officer fighting the fire pointed out,

"The CO2 in the spreader room may have slowed down the fire but it did not put it out. We opened the doors for air, as the smoke in the whole area had become dense and sickening. Another employee and I each donned a breathing apparatus and went into the spreader room. We used hand lamps for illumination, but they penetrated the smoke only a few inches. The neoprene covers on the cables were burning, giving off dense black smoke and sickening fumes.... It was impossible to not swallow some smoke. I got sick several times."

"Breathing apparatus was in short supply and not all of the Scott air packs were serviceable. Some did not have face masks and others were not fully charged at the time of the start of the fire. The breathing apparatus was recharged from precharged bulk cylinders by pressure equalization. As the pressure in the bulk cylinders decreased, the resulting pressure decrease in the Scott packs limited the length of time that the personnel could remain at the scene of the fire."

The electrical cables continued to burn for another six hours, because the fire fighting was carried out by plant employees, despite the fact that professional firemen from the Athens, Alabama, fire department had been on the scene since about 1:30 pm. As the Athens fire chief pointed out,

"I was aware that my effort was in support of, and under the direction of, Browns Ferry plant personnel, but I did recommend, after I saw the fire in the cable spreading room, to put water on it. The Plant Superintendent was not receptive to my ideas.

"I informed him that this was not an electrical fire and that water could and should be used because CO2 and dry chemical were not proper for this type of fire. The problem was to cool the hot wires to prevent recurring combustion. CO2 and dry chemical were not capable of providing the required cooling. Throughout the afternoon, I continued to recommend the use of water to the Plant Superintendent. He consulted with people over the phone, but apparently was told to continue to use CO2 and dry chemical. Around 6:00 pm, I again suggested the use of water . . . . The Plant Superintendent finally agreed and his men put out the fire in about 20 minutes . . . .

"They were using type B and C extinguishers on a type A fire; the use of water would have immediately put the fire out."

Even when the decision to put the fire out with water had been taken, further difficulties developed. The fire hose had not been completely removed from the hose rack, so that full water pressure did not reach the nozzle. The fire-fighters did not know this, however, and decided that the nozzle was defective. They borrowed a nozzle from the Athens fire department,

"but it had incorrect type threads and would not stay on the hose."

The spare control rod drive pump was inoperative, and although it was later determined that a series of valves could have been turned to allow the Unit 2 control rod drive pump to supply water for the Unit 1 reactor, the reactor operators did not know this at the time.

With the reactor pressure mounting higher and higher, the relief valves were finally brought back into operation at 9:50 pm, and about 10:20 pm the reactor was depressurized to the point that the condensate booster pump could again get water into the reactor.

How the Emergency Planning Worked

Normal shutdown was established on the Unit 1 reactor at 4:00 am the next morning, and the nightmare at Browns Ferry was over.

Had the reactor boiloff continued to the point where a core meltdown took place, however, it is doubtful that the endangered surrounding population could have been evacuated in time; evacuation of the county's residents was the responsibility of the Civil Defense Coordinator for Limestone County, but, as he admitted to NRC inspectors,

"I heard about the fire at Browns Ferry on the morning of Monday, March 24, 1975 (two days later). No one in the Civil Defense System notified me or attempted to do so ... I feel that our county should have been notified since the plant is located in our county."

The sheriff of Limestone County said:

"I heard about the fire at the Browns Ferry plant after it was over ... I have not had any updating of procedures proposed to me since the initial plan was outlined in 1972. I do not have a copy of the emergency plan."

The Sheriff of neighboring Morgan County did hear about the fire four hours after it started, but said,

"I was asked to keep quiet about the incident to avoid any panic."

The NRC noted in its investigative report that,

"No official notification was made to the State of Alabama Highway Patrol by the State of Alabama Department of Public Health or by TVA...

"An attempt was made to notify the Lawrence County Sheriff at 4:08 pm, but no answer was received. Only one attempt was made to locate the sheriff."

Large numbers of plant employees went into the plant control room, adding to the chaotic situation there. Instead of the six persons normally there, one assistant shift engineer reported,

"The maximum number of people in the control room at only one time I guessed to be about 50 to 75."

Although it is perfectly possible to design an inexpensive anemometer to test for air leaks, or even use smoke from a cigarette, these methods were rejected two years ago by the Browns Ferry plant personnel in favor of using candles.

Why was Flammable Material Used?

Some senior personnel at the plant thought that the urethane sheet foam used to seal the cable penetrations was fireproof. The leader of the electrical conduit division at the plant said:

"The practice of using RTV-102 and sheet foam to seal air leaks has been the practice for two or three years. We believed that the urethane would not sustain a fire. Urethane samples had been tested several years ago and it needed a flame for 20 minutes to sustain a fire."

They had only tested two of the polyurethane samples, however, using an American Society for Testing Materials (ASTM) test that the Marshall Space Flight Centre later found to be of marginal value. No test had been made of the foam polyurethane, however, and the NRC's consultants, from the Marshall Space Flight Centre, found that,

"A cursory match test on a piece of the foam rubber disclosed almost instantaneous ignition, very rapid burning, and release of molten flaming drippings."

Even though some people at the plant thought the ASTM tests showed the penetration sealant material to be non-flammable, senior management knew it was highly flammable. The plant instrument engineer told NRC inspectors that,

"During the test and startup period of Unit #1 (in 1973), I demonstrated the flammability of the sealing material to the Plant Superintendent. I burned the material in the Plant Superintendent's office. He immediately called someone with Construction and they discussed the situation .... I feel the Plant Superintendent did all that was immediately possible to investigate the situation as it appeared that construction was not going to change the material."

The Plant Superintendent admitted to the NRC inspectors,

"I was aware that polyurethane was flammable, but it never occurred to me that these penetrations were being tested using candles."

Many senior management personnel at the plant denied knowing of the practice of using candles to test cable penetrations.

The rest indicated that they knew candles were being used, but thought the sealant materials were not flammable.

The electricians seemed to be the only group who knew both that the foam rubber was flammable and that candles were being used as the testing method. As one electrician later recounted,

"The electrical engineer called the group (of electricians) together and warned us how hazardous this method was. 'Why just the other day,' the electrical engineer said (in effect), 'I caught some of that foam on fire and put it out with my bare hands, burning them in the process.'"

One of the electricians who started the fire said that candles had been used for more than two years but said,

"I thought that everybody knew that the material we were using to seal our leaks in penetrations would burn....I never did like it."

How the Warnings Were Ignored

The real irony of the Browns Ferry fire was that two days before, a similar fire had started but had been put out successfully. After the fire on Thursday night, the shift engineers and three assistant shift engineers met. According to one of them,

"We discussed among the group the procedure of using lighted candles to check for air leaks. Our conclusion was that the procedure should be stopped."

Yet nothing was done. The fire was noted in the plant log, and briefly discussed the next day at the plant management meeting. No one on the management level seemed to consider it a safety problem worth following up. This was the standard operating procedure; as the NRC investigative report notes,

"Previous fires in the polyurethane foam materials had not always been reported to the appropriate levels of management, and, on the occasions when reported, no action was taken to prevent recurrence."

In the face of these practices, it was probably nor a question of whether the Browns Ferry plant would have a major fire, but when.

Has Anything Been Learned?

What will the fire mean for other nuclear plants? That depends on whether the NRC carries out the recommendation made by the Factory Mutual Engineering Association of Norwood, Massachusetts, the fire underwriters the NRC engaged as consultants:

"Conclusions and Recommendations:

"The original plant design did not adequately evaluate the fire hazards of grouped electrical cables in trays, grouped cable trays and materials of construction (wall sealants) in accordance with recognized industrial 'highly protected risk' criteria....

"It is obvious that vital electrical circuitry controlling critical safe shutdown functions and control of more than one production unit were located in an area where normal and redundant controls were susceptible to a single localized accident .... A re-evaluation should be made of the arrangement of important electrical circuitry and control systems, to establish that safe shutdown controls in the normal and redundant systems are routed in separated and adequately protected areas."

Every nuclear plant in the country uses a cable spreader room below its control room. Despite requirements for separation and redundancy of reactor protection and control systems, every reactor has been permitted to go into operation with this sort of configuration which lends itself to a single failure's wiping out all redundant systems.

If every plant currently operating and under construction were required to re-wire so as to achieve true redundancy and eliminate cable trays bunched together, I have made calculations that indicate the cost will range between $7,680,000,000 and $12,343,000,000. It will be interesting to see whether the new commissioners of the Nuclear Regulatory Commission will require such changes.

Except for one news release, written March 27, 1975, NRC headquarters in Washington has remained silent about Browns Ferry. That news release, quoted below, does not make one optimistic that any meaningful lesson has been learned from the Browns Ferry incident.

"The functioning of some in-plant operating and safety systems, including emergency core cooling systems, was impaired due to damage to the cables.

"The two reactors were safely shut down and cooled during the fire. NRC inspectors report that there was redundant cooling equipment available during the reactor cooldown....

"Although some instrumentation was lost, certain critical instrumentation such as reactor water level, temperature and pressure indicators continued to function and both plants were safely shut down....

"On Unit 1, although a loss-of-coolant accident had not occurred, the emergency core cooling system was activated and supplied additional water to the reactor. It was manually shut down to prevent overfilling. Later, during cooldown, when ECCS was called for manually as one of the several alternate means of supply cooling water, it did not activate; the alternate methods had more than sufficient capability to cool the core."

Whether the NRC has sufficient capability to cool the public's reaction, once the facts about Browns Ferry are known, will be interesting to observe.

Quote from j9381

The material ignited by the candle flame was resilient polyurethane foam. Once the foam was ignited, the flame spread very rapidly.

Some people did say that the Three mile island accident was cased by a ignored red emergency light hidden behind the belly of an overly fat operator....

Quote from j9381

The real irony of the Browns Ferry fire was that two days before, a similar fire had started but had been put out successfully. After the fire on Thursday night, the shift engineers and three assistant shift engineers met. According to one of them,

"We discussed among the group the procedure of using lighted candles to check for air leaks. Our conclusion was that the procedure should be stopped."

Yet nothing was done. The fire was noted in the plant log, and briefly discussed the next day at the plant management meeting. No one on the management level seemed to consider it a safety problem worth following up. This was the standard operating procedure; as the NRC investigative report notes,

"Previous fires in the polyurethane foam materials had not always been reported to the appropriate levels of management, and, on the occasions when reported, no action was taken to prevent recurrence."

so basically, this nearly catastrophic meltdown of the reactor was fortuitous in that it has kept us safe since 1975 because we have not (I assume) had any big nuclear plant fires since (not that I have searched the internet for these). That being said, I have never supported nuclear power and this just makes my stance stronger. Technology is better now - but I still have no plans to change my mind. Look at the mistakes made at Fukushima - which had back up diesel generators for cooling in areas where they could get damaged / flooded.

When the Fukushima Daiichi station was constructed, the emergency diesel generators and emergency batteries were installed on the floor inside the plant building to afford protection against earthquakes. Ventilation ducts in the compartments where this equipment was located were not waterproofed. Moving this emergency power equipment to higher ground, safety experts said, would not have increased its vulnerability to seismic shock, provided it was fixed to a platform designed to resist earthquakes.⁶²

The value of taking such action was demonstrated by upgrades that one Japanese utility, Japan Atomic Power Company (JAPC), was in the process of carrying out when the tsunami struck Japan’s east coast. JAPC’s Tokai-2 plant is located about 100 miles south of Fukushima, and the tsunami that ravaged Fukushima also caused flooding at Tokai-2. Prior to the tsunami, JAPC had partially implemented plans to erect a wall to prevent tsunami water from flooding two pits at the plant where seawater pumps were located and to make the pump rooms watertight. The wall was erected before the tsunami occurred. Water entered one of the pits because spaces where pipes penetrated into the pit had not yet been made watertight before the accident. In that pit, a seawater pump that provided cooling for an emergency diesel generator was damaged and unable to function, forcing JAPC to shut down the generator. But no flooding occurred at the other pit where pipe penetrations had been made watertight.⁶³ This saved the cooling pumps for two more diesel generators. Had JAPC not carried out these upgrades, it would almost certainly have lost all three emergency diesel generators, potentially resulting in a much more serious accident.

Water (as coolant) as source of life was source of death in the case of TMI , Tchernobyl and Fukushima.

This way of engineering imposed by US engineers lobbying almost everywhere have been the origin of the nuclear worldwide counter publicity.

My weak country of followers tried a while salt melted solution however came back to the water solution with our f.. EPR.

Then UK used gases for a while, or currently Russia is using lead for example... because are more open mind countries..

Quote from JedRothwell

Incidents like this are why I think fission reactors cannot be made safe.

Quote from JedRothwell

If we made hundreds more fission reactors, all in a standard design, similar to the way we make hundreds of airplanes, perhaps they could be made safe.

there seem to be concepts just around the corner - IMO it sounds promising.

Dual Fluid Inc. - Canadian / German company

here you have a more detailed explanation on DFR dual fluid reactor by the inventor, but only in German.

In fact,

I worked there in the past (I really went into steam generators during maintenance operations) and recently I took part in a think tank with all the real French big names of the nuclear field in the context of the current presidential elections.

Water has many disadvantages, the first the obligation to operate under pressure requiring enormous additional engineering costs compared to all technologies with heat transfer fluids working at ambient pressure.

I like the recent lead-cooled Russian reactor:https://en.wikipedia.org/wiki/…a%20closed%20fuel%20cycle.

Quote from JedRothwell

Do you mean molten sodium? Or molten salt?

https://www.energy.gov/ne/arti…actor-systems-watch-2030#

There have been at least two large reactors cooled with liquid sodium. One in the U.S. I do not recall the name. The other was the Japanese Monju breeder reactor. Both failed disastrously, in dangerous accidents caused by leaking sodium, which ignites in air. Monju was finally closed down completely after only short periods of operation. I cannot judge, but it seems like a terrible technology. It seems inherently dangerous to me.

It may be possible to develop safe fission reactors. I cannot judge. Some experts say pebble bed reactors might be safe. However, we know for a fact that solar panels are safe, and they can produce electricity much more cheaply than fission. Probably cheaper than pebble bed reactors. So why spend a ton of money inventing safe fission reactors now? We don't need them anymore. If they had been invented before solar PV fell in price, we could have used them. No doubt they would have some advantages, such as being more compact, with less overall material needed.

Any technology has advantages and disadvantages. Years after integrated transistors were invented, Ken Shoulders and Charles Spindt invented special purpose chip with microscopic vacuum tubes on it. Spindt told me it was better for some purposes than transistors. If they had come up with that in 1955, perhaps we would not have needed integrated transistor chips. Not for a while, anyway.

Suppose Toyota had come up with the Mirai hydrogen fuel cell car in 1990. It might be cheap and widespread by now, and we might have hydrogen gas stations everywhere. It has a better range than today's electric cars. Hydrogen made by some processes is renewable and not polluting. Hydrogen fuel cell cars might have progressed faster than electric cars, eliminating the need for electric cars. That's one of history's might-have-beens. It didn't happen, and now it is too late for the Mirai hydrogen fuel cell approach. Electric cars may not have been inherently better in 1990. They might have lost the competition. But they won, and you cannot undo that. A winning technology develops economic and technical momentum. It becomes a standard, as more and more people buy it, and mechanics learn to deal with it. Mechanics and automobile companies can only afford to support one or two technical standards -- gasoline and electric. They cannot afford to manufacture, sell and service another standard such as hydrogen fuel cells.

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