Soarca 2 22-12 post
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1. The document criticizes the conclusions of the State-of-the-Art Reactor Consequence Analyses (SOARCA) report conducted by the Nuclear Regulatory Commission (NRC). 2. It argues that the SOARCA report was limited in scope by only analyzing a select number of severe accident scenarios and did not consider many real-world factors that could alter the outcomes. 3. The criticisms also question the reliability of the MELCOR software used in the analysis and the NRC's history of producing misleading probabilistic risk assessments.
![NRC withdraws a Consequences Report
• Just two months prior to the TMI accident the NRC was
forced to disavow its accreditation of another Reactor
Safety Study (probability risk analysis) know as the
WASH 1400 a/k/a the Rasmussen Report.
• “The Commission withdraws any explicit or implicit past
endorsement of the Executive Summary [of WASH 1400]”
January 18, 1979 NRC Policy Statement
• The report had stated the probability of an accident was
one in a million per reactor per year. Then came TMI.
Point 6](https://image.slidesharecdn.com/soarca2-22-12post-131005175010-phpapp01/85/Soarca-2-22-12-post-19-320.jpg)
Soarca 2 22-12 post
- 1. NRC‟s Public Meeting on the SOARCA Draft Report at Peach Bottom, Delta PA 2/22/2012 Scott D. Portzline Three Mile Island Alert Security Consultant Criticisms of the State of the art Reactor Consequence Analysis
- 2. Summary 1. The conclusions as represented by the NRC Office of Public Relations are misleading. 2. The NRC has not clearly emphasized that SOARCA limited its simulations to a select group of scenarios. 3. SOARCA does not include many aspects of nuclear accidents which would severely alter the outcomes and conclusions.
- 3. Summary 4. The MELCOR software has numerous shortcomings and SOARCA should caution its readers that divergent results can easily be created. 5. The NRC has not attempted to correct these misconceptions in the media. 6. The NRC has a history of questionable or faulty probabilistic risk assessments. 7. There has never been a timely evacuation order at any of the world‟s nuclear accidents.
- 5. Misleading Conclusion • “SOARCA analyzed the potential consequences of severe accidents at the Surry Power Station near Surry, Va. and the Peach Bottom Atomic Power Station near Delta, Pa.” NRC Press Release 2/1/12 • Should have included the phrase “a few select severe accident scenarios.” • No attempts to correct the erroneous headlines as NRC does for articles casting a bad impression.
- 6. RE: Scenarios #10 What if all sequences that survive the screening process are those that result in an intact containment? Nuclear Energy Institute letter to NRC on how SOARCA will handle certain parameters - November 2006 Point 2
- 7. Real-World None of these real-world nuclear accidents, prior to its occurrence, would have been predicted, or simulated by MELCOR. Three Mile Island – Windscale – Chernobyl - Fukushima
- 8. Three Mile Island apparently is the poster child for MELCOR software CD coverMELCOR web page
- 9. • Things don‟t happen the way you‟d think they would!! e.g. -- A lone TMI licensee employee, acting on his own, deliberately caused one of the releases. No evacuation order or shelter in place order was made. • Confusion prolongs - mitigation efforts, exacerbates radioactive releases, delays communications, and fosters a reluctance to order an evacuation, and for some citizens, it actually creates a reluctance to evacuate. • Confusion cannot be accurately modeled by a computer simulation because of its thousands of possibilities. Intelligence may be advanced, but confusion knows no bounds. (bounding is a term used to limit a set of parameters) Operators exacerbated mitigation efforts and interfered with safety equipment at TMI. The people of TMI know that… Point 3
- 10. Examples of unexpected events from TMI not accounted for in this study • Due to the falsification of reactor leak rates, the reactor drain tank was already nearly full at the start of the event – early transport of radioactivity. • Drain lines were already opened to the auxiliary bldg. – early transport of radioactivity. • Evidence suggests a reactor coolant pump on loop A ran backwards for a time. – unexpected transport… • Steam Generator A steam tubes destroyed as the result of the events rather than a triggering event. – alters sequence… • Coolant pump cavitation may contribute to “core hold up” causing the additional and prolonged generation of hydrogen and radioactive steam. – explosive, and source term size • Certain safety systems were disabled prior to the accident. – alters sequence of events and expectations
- 11. Unexpected Early Release • The mitigated and unmitigated accident consequences of SOARCA hasn‟t account for the aforementioned conditions which could lead to an early release – earlier than SOARCA has indicated. • A small opening or pathway can result in a dangerous release.
- 12. State of the Art • Means: “pertaining to highest level of development at the time.” – in this case, computer modeling • Humans can recognize the defects of this analytical method (MELCOR) and can list the reasons for its failures and shortcomings. • Computer coding is not a substitute for the understanding of good physics or for good scenario creation. • MELCOR does not meet DOE Quality Assurance Standards for Safety Software Point 4
- 13. The Coming Crisis in Computational Science Los Alamos National Laboratory • New codes are more complex and more ambitious but not as closely coupled to experiments and theory. • Better physics is much more important than better computer science. • Computational science has to develop the same professional integrity as theoretical and experimental science.
- 14. User Dependent • The ability to simulate an accident sequence will be highly dependent on the code user. The user must select the appropriate nodalization and provide the appropriate models for phenomena that are important for the accident sequence to be simulated. MELCOR Analysis of the TMI-2 Accident*
- 15. Many things can be wrong with a computer generated prediction • Experimental and theoretical science are mature methodologies but computational science is not. • Code could have bugs in either the models or the solution methods that result in answers that are incorrect. • Models in the code could be incomplete or not applicable to problem or have wrong data. • User could be inexperienced, not know how to use the code correctly. • Crater analysis of the Columbia Shuttle damage • Sonoluminescence / cold fusion Los Alamos National Laboratory
- 16. • “The ability to use a computer code such as MELCOR for prediction of severe accident progression is best early in the accident and becomes progressively less certain later in the accident. • This is due both to the accumulation of uncertainty in calculation, and through the addition of severe accident phenomena with their associated uncertainty to the calculation.” Uncertainty Analyses Using the MELCOR Severe Accident Analysis Code by Sandia National Laboratories
- 17. • “The TMI-2 analyses provide a good demonstration of this principle. The Phase 1 results were predicted fairly easily, although there is some uncertainty as to what the RCS inventory would be as a function of time. • The phase 2 calculation demonstrates the ability to generate divergent results, due to the addition of highly non-linear processes such as core oxidation and counter-current limited flow in the pressurizer drain line. • Without the known „correct answer‟ of plant data from the accident, it would be easy to generate different consequences ranging from minimal to a highly damaged core.” continued
- 18. NRC promised to correct mis-representations on a previous Reactor Safety Study 1/18/79 Point 5
- 19. NRC withdraws a Consequences Report • Just two months prior to the TMI accident the NRC was forced to disavow its accreditation of another Reactor Safety Study (probability risk analysis) know as the WASH 1400 a/k/a the Rasmussen Report. • “The Commission withdraws any explicit or implicit past endorsement of the Executive Summary [of WASH 1400]” January 18, 1979 NRC Policy Statement • The report had stated the probability of an accident was one in a million per reactor per year. Then came TMI. Point 6
- 20. March 28th 1979 –TMI Accident Tyron PA Daily Herald 3/28/79 RSS author defends the study US aides see risk of meltdown NY Times
- 21. NRC withdrawal statement continued • “The executive summary of the Reactor Safety Study is a poor description of the contents of the report, should not be portrayed as such, and has lent itself to misuse in the discussion of reactor risks. • The executive summary does not adequately indicate the full extent of the consequences of reactor accidents and does not sufficiently emphasize the uncertainties involved in the calculations of their probability. • As a result, the reader may be left with a misplaced confidence in the validity of the risk estimates.”
- 22. “The press release at the time of publication said that the report is „the culmination of the most comprehensive risk assessment of nuclear power plants made to date. The objectives of the study were to make a realistic assessment providing an objective and meaningful estimate of the present risks associated with the operation of present day light water reactors in the United States.‟ " NRC withdrawal statement continued
- 23. All is not well • This study would be analogous to a report on auto crashes coming out of Detroit where scenarios can be written in which all safety systems -- the brakes, the headlights, the electrical systems, the steering and even the air bags are rendered inoperable, yet somehow the car ends up crashing into a mountain of pillows and no one is injured. • The sponsor of such a study can claim that they created scenarios where extremely unlikely failures occur simultaneously, and even then, no one is harmed. That may sound impressive but its completely invalid for real world events.
- 24. No Timely Evacuations • There has never been a timely evacuation or a timely evacuation order issued at any of the world‟s nuclear accidents. • 100% failure rate. • The evacuation projections are purely wishful thinking. • Therefore: SOARCA is not based on reality. Point 7 Three Mile Island – Windscale – Chernobyl - Fukushima
- 25. END