Three Mile Island’s new steam generator tubes could fail
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The steam generators at Three Mile Island (TMI) are at risk of failure due to unanalyzed design changes, which may lead to catastrophic radioactive releases. Issues include insufficient tube wall thickness and unexpected thermal expansion causing premature wear and vibrations, increasing the likelihood of ruptures under stress. The Nuclear Regulatory Commission (NRC) is criticized for allowing operations without proper analysis, despite failure consequences outlined in safety regulations.
Three Mile Island’s new steam generator tubes could fail
- 1. Three Mile Island’s New Steam Generators Could Fail due to an unanalyzed condition. Scott D. Portzline TMI Alert Jan. 2017
- 2. The French company AREVA falsified records and hid defects in major reactor components it manufactured. Areva manufactured the new Steam Generators for TMI . Scott D. Portzline TMI Alert Jan. 2017
- 3. The Nuclear Regulatory Commission (NRC) is allowing a major safety component (Steam Generators) at TMI to operate with an unanalyzed condition which could result in a catastrophic failure and lead to radioactive releases. The NRC is allowing licensees to swap equipment manufactured with significant design changes, and without extensive testing or analysis, despite a regulation requiring proper analysis for such alterations. Conclusions:
- 4. TMI’s new Steam Generators have significant design changes. The new tube walls are only .0635 inch thick, giving them less margin to failure than the previous design.
- 5. Steam Generator Tubes 15.597 tubes per steam generator
- 6. 15.597 tubes per steam generator These Steam Generator Tubes expand at an unexpected rate and are made from a new metal alloy. This expansion is causing premature wear and thinning of the tube walls. The tubes are vibrating and banging against each other in some places. Under higher temperatures, as in a transient or accident conditions, the tubes might bow even further, and more tubes could experience the vibrations problem to the point of rupture failures.
- 7. Fuel melts when there is insufficient heat removal from reactor. Turbine Building Steam Generators are the primary method to remove heat from the reactor.
- 8. Steam Generator serve critical safety functions. • They are an integral part of the reactor coolant pressure boundary, and thus are essential for maintaining primary system pressure and coolant inventory. • They also isolate the radioactive fission products in the primary coolant from the secondary system. • Some of the unmonitored radiation released from the 1979 TMI accident escaped through the damaged steam generators and out of the unfiltered turbine building.
- 9. The Steam Generator tubes are bowing. • The tubes bowed sufficiently far enough under normal temperatures to cause some tubes to vibrate against each other and cause premature wear of the tube walls. • Some tubes vibrated against metal plates and caused similar wear. • Under higher temperatures, as in a transient or accident conditions, the tubes might bow even further, and more tubes could experience the vibrations problem to the point of rupture failures. • A meltdown and radiological release could result. THE PROBLEM
- 10. I brought this “accident” concern to the NRC’s attention. • Telephone conference with the NRC, TMI, Areva (the manufacturer) - June 17, 2013. • On another occasion the NRC dismissed my concerns stating – a licensee is required to be able to mitigate the loss of a major “steam line.”
- 11. • You wouldn’t want your mechanic to say, “We haven’t analyzed if the new brakes will fail on a hot day, but if they do, you have emergency brakes and can always downshift.” • You want your mechanic to install brakes that have been properly analyzed and won’t fail under stress. WRONG ANSWER
- 12. Backup plans aren’t always what you’d think they are. During the 1979 TMI accident, operators could not use a backup system due to the HIGH PRESSURE. “An auxiliary system which is designed to remove the decay heat from the reactor was available, but it is only operable at lower primary system pressure (<400 psi). These attempts failed.” Oak Ridge National Laboratories
- 13. On another occasion, about half of the NRC staffers present agreed with me. None of them were aware of the high temperatures in the Steam Generators during the 1979 accident. They had believed that was not possible with. • TMI openhouse April 1014. • But nothing was ever done.
- 14. The current testing used for tube integrity does not translate to the potential accident conditions. The tube wear was unexpected. Therefore, one can conclude that the testing was not adequate even for normal conditions. Arnie Gundersen of Fairewinds Associates and David Lochbaum of the Union of Concerned Scientists agree with me that the Steam Generator design at TMI must be properly analyzed. Both men are nuclear engineers.
- 15. The new steam generators at the San Onofre Nuclear Plant had tube failures. San Onofre experienced a different, yet similar problem to TMI’s, caused by a faulty design and the NRC’s failure to regulate. When pushed by legislators and activists, the company chose to close the plant last year and sue the designers of their new steam generators. http://articles.latimes.com/2013/jul/13/local/la- me-07-14-san-onofre-tic-toc-20130714 How San Onofre's new steam generators sealed nuclear plant's fate. LA Times “The generators that were supposed to save San Onofre ended up killing it, and today the atomic behemoth sits idle, never again to produce a watt of power.”
- 16. The NRC must be made to enforce this regulation at TMI: 50.59 Changes, tests and experiments. The Title 10 Code of Federal Regulations, Section 50.59 requirements govern design changes between original and replacement steam generators. http://www.nrc.gov/reading-rm/doc- collections/cfr/part050/part050-0059.html Recommendations:
- 17. A licensee shall obtain a license amendment pursuant to Sec. 50.90 prior to implementing a proposed change, test, or experiment if the change, test, or experiment would: (iii) Result in more than a minimal increase in the consequences of an accident previously evaluated in the final safety analysis report (as updated); (iv) Result in more than a minimal increase in the consequences of a malfunction of an SSC important to safety previously evaluated in the final safety analysis report (as updated); (vi) Create a possibility for a malfunction of an SSC important to safety with a different result than any previously evaluated in the final safety analysis report (as updated); Recommendations: Specific regulatory sections of interest to TMI’s new steam generators:
Editor's Notes
- #5: TMI has new Steam Generators Made a big deal of delivery picture
- #8: We are only looking at 2 components here. This is a diagram showing how a nuclear plant handles ^^the heat generated in the reactor to create electricity. Fuel melting inside the reactor is caused when not enough heat is removed from the reactor core. ^^ The steam generator is the primary source of heat removal. You can think of the steam generator as a heat exchanger.