Commercial Nuclear Power

You don t need to be reminded of the most recent nuclear accidents, principally Fukushima Daiichi in Japan in 2011. After the Three Mile Island accident in the late 1970s, the U.S. Atomic Energy Commission developed WASH 1400, The Reactor Safety Study. The WASH 1400 report laid the foundation for the use of probabilistic risk assessments (called probabilistic safety assessments in Europe). According to Henley and Kumamoto (1991), probabilistic risk assessment involves studying accident scenarios and numerically rank[ing] them in order of their probability of occurrence, and then assess[ing] their potential consequence to the public. Event trees, fault trees, and other risk-consequence tools are applied in developing and studying these scenarios. These techniques are extremely useful for the engineer but very expensive. The nuclear industry has been the leader in probabilistic safety analyses. 

The nuclear industry could benefit from HAZOP studies. A nuclear power plant is conceptually very similar to a chemical plant. Because HAZOP looks carefully at process deviations, it would help identify hazards that might go unnoticed in a traditional probabilistic risk assessment. 

System Safety Engineering and Risk Assessment A Practical Approach 

Software safety analysis is a very new technique, but it also has promise for nuclear plants. Much of plant processes are computer controlled, yet until recently, little attention has been given to spurious commanding or sneak paths in the commanding. Software safety tools could help identify these problems and offer solutions. 

As this chapter demonstrates, all industries take safety seriously. There is some variety as to which safety tools they use or whether they are more compliance focused or they use system safety engineering and management. However, what is obvious is that all industries are already using many system safety engineering and management tools and many are slowly but surely incorporating more of them every day. 

---

R. A. Knief, Nuc/ear Engineering Theory and Technology of Commercial Nuclear Power, Taylor Erancis, Bristol, Pa., 1992. 

As of 1994 there were 105 operating commercial nuclear power stations in the United States (1) (see Power generation). AH of these faciUties were light, ie, hydrogen—water reactors. Seventy-one were pressurized water reactors (PWRs) the remainder were boiling water reactors (BWRs). 

Spent fuel can be stored or disposed of intact, in a once-through mode of operation, practiced by the U.S. commercial nuclear power industry. Alternatively, spent fuel can be reprocessed, ie, treated to separate the uranium, plutonium, and fission products, for re-use of the fuels (see Nuclear REACTORS, CHEMICAL reprocessing). In the United States reprocessing is carried out only for fuel from naval reactors. In the nuclear programs of some other countries, especially France and Japan, reprocessing is routine. 

The NRC safety goal can be evaluated by comparison to the risks from accidents incurred from other human activities (Eig. 2) (29). The safety goal and the safety record of the nuclear power industry indicate much lower societal risks from commercial nuclear power than from a wide range of other common human activities. 

If possible comparisons are focused on energy systems, nuclear power safety is also estimated to be superior to all electricity generation methods except for natural gas (30). Figure 3 is a plot of that comparison in terms of estimated total deaths to workers and the pubHc and includes deaths associated with secondary processes in the entire fuel cycle. The poorer safety record of the alternatives to nuclear power can be attributed to fataUties in transportation, where comparatively enormous amounts of fossil fuel transport are involved. Continuous or daily refueling of fossil fuel plants is required as compared to refueling a nuclear plant from a few tmckloads only once over a period of one to two years. This disadvantage appHes to solar and wind as well because of the necessary assumption that their backup power in periods of no or Httie wind or sun is from fossil-fuel generation. Now death or serious injury has resulted from radiation exposure from commercial nuclear power plants in the United States (31). 

Reactor Safety Study An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants, Report WASH-1400 (NUREG-75/014), U.S. Nuclear Regulatory Commission, Washington, D.C., Oct. 1975. 

In 1956, the world s first commercial nuclear power plant started operation in England. By the 1960s, many nuclear power plants were built worldwide. At the end of the twentieth century, nuclear generating plants are used widely by U.S. electric utiHties. Since 1984, these plants have provided the second largest share of total U.S. electricity generation, 21% of annual GW-h generated, behind coal-fired power plants (see Nuclearreactors). 

Hazards and Operability (HAZOP) analysis is an accident detection and prevention technique used primarily by the chemical process industry (CPI) (Lees, 1980). Even though the CPI operates in a different regulatory environment from the commercial nuclear power industry, the goals of risk reduction while maintaining productivity are similar. 

The frequency of fire-induced core melt, calculated by averaging the observed frequency of the Browns Ferry type of fire over the experience of U.S. commercial nuclear power plants, was found to be lE-5 per reactor-year, or about 20% of the total core-melt probability e.slimated in the Reactor Safety Study. Kazarians and Apostolakis (1978) performed the same type of calculations under different assumptions and concluded that the frequency of core melt could be higher by a factor of 10. 

Dal im the start of commercial nuclear power to July 1981 from Verna, 1982. 

The external events PSA was based on standard methods used for commercial reactor PSAs, Fire risk was estimated from commercial nuclear power plant data combined with industrial fire information. The seismic hazard was evaluated using a combination of the EPRI and LLNL ( UREG/CR-.3250) databases. Wind hazards were analyzed by EQE, Inc., using NRC-based nicihodulogy. 

Sullivan, W. H. and Poloski, J. P., Data Summaries of Licensee Event Reports of Pumps at (, Commercial Nuclear Power Plants, January 1, 1972-April 30, 1978, Lvj .o,... 

Mattson et al., 1980, Concepts, Problems and Issues in Developing Safety Goals and Objectives for Commercial Nuclear Power, Nuclear Safety 21, pp 703-716, November-December. 

The NPRDS is an industry-wide system for monitoring the performance of selected systems and components at U.S. commercial nuclear power plants. Information in NPRDS is derived from a standardized format input report prepared by U.S. nuclear plant licensees. The plants are as)ced to submit failure reports on catastrophic events and degraded failures within the defined reportable scope reporting of incipient events is optional. Command faults are not reportable unless they malce an entire system unavailable. In addition, the plants are as)ced to file component engineering reports on all components within the selected systems and reportable scope. These reports contain detailed design data, operating characteristics, and performance data on the selected systems and components (over 3000 components, from approximately 30 systems, per unit). The selected systems are primarily safety systems. 

Data Summaries of Licensee Event Reports at U.S. Commercial Nuclear Power Plants (Vanous Components) Nuclear 11209 one-fine event descriptions on specific component types failure rates and error factors Pumps, valves, diesels inverters, relays, circuit breakers (in separate reports) 100. 

EGSG Idaho s Idaho National Engineering Laboratory reviewed Licensee Event Reports (LERs), both qualitatively and quantitatively, to extract reliability information in support of the USNRC s effort to gather and analyze component failure data for U.S. commercial nuclear power plants. LERs describing failures or command faults (failure due to lack of needed input) for selected components have been analyzed in this program. Separate reports have been issued for batteries and battery chargers, control rods and drive mechanisms, diesel generators, ISC, Inverters, primary containment penetrations, protective relays and circuit breakers, pumps, and valves. 

Reactor Safety Study An Assessment of AccidenI Risk in U.S. Commercial Nuclear Power Plants (WASH-1400)... 

Public opposition to commercial nuclear power plants began with the misperception that the plants could explode like nuclear weapons. The nuclear industi-y made progress in dispelling this misperception, but suffered major setbacks when an accident occurred at the Three-Mile Island nuclear power plant in Pennsylvania and at the Chernobyl nuclear power plant in the USSR. 

JamesTape,Los Alamos National Laboratory Commercial Nuclear Power and Proliferation What is Proliferation Resistance ... 

A particular focus of ourjoint efforts in the DOE work with Minatom has been to reduce the amounts of special nuclear material and to increase the security and accountability of the material that remains. Commercial nuclear power plants are key to the program, since that is where the weapons material is ultimately burned. ... 

The tritium that is needed to maintain the nuclear deterrent will be produced in commercial nuclear power plants which is inefficient and a compromise ofimportant and long standing nonproliferation practice plutonium-238 needed for space exploration is being purchased from Russia. 

Mr. Thomas s vision is sound, except that the problem is not inability, but unwillingness to manage and dispose of wastes from commercial nuclear power plants and recycle valuable materials. 

The first of the open-ended problems to be considered is nuclear weapons proliferation, in the context of its relation to commercial nuclear power. There is a connection, because a country with an active nuclear power program has a head start, in terms of equipment and technically trained people, should it decide to embark upon a weapons program. This has been a live issue in the case of han.5... 

Island/Thurrock Area, HMSO, London, 1978. Rasmussen, Reactor Safety Study An Assessment of Accident Risk in U. S. Commercial Nuclear Power Plants, WASH-1400 NUREG 75/014, Washington, D.C., 1975. Rijnmond Public Authority, A Risk Analysis of 6 Potentially Hazardous Industrial Objects in the Rijnmond Area—A Pilot Study, D. Reidel, Boston, 1982. Considine, The Assessment of Individual and Societal Risks, SRD Report R-310, Safety and Reliability Directorate, UKAEA, Warrington, 1984. Baybutt, Uncertainty in Risk Analysis, Conference on Mathematics in Major Accident Risk Assessment, University of Oxford, U.K., 1986. 

The NRC regulates US commercial nuclear power plants and the civilian use of nuclear materials. ... 

---