This post covers two potentially useful sources of information. One is a manual titled “Reactor Safety Perspectives” developed by the NRC’s Technical Training Center for its Reactor Safety Course. The other is a manuscript titled “On the History of the Evolution of Light Water Safety in the United States” authored by Dr. David Okrent, a long-time member of the NRC’s Advisory Committee on Reactor Safeguards. The latter weighs in at 1,116 pages while the “shorter” manual has “only” 671 pages. While neither qualifies as a “beach read,” both contain lots of information making them invaluable references.
“Reactor Safety Perspectives”
Revision 2 of the “Reactor Safety Perspectives” manual was issued as NUREG/CR-6042 in March 2002. It’s available online either in the NRC’s ADAMS library or on the NRC’s website.
The manual covers many topics including:
Section 1.1.5 describing the development of defense-in-depth as a safety strategy.
Section 1.2.1 on the Atomic Energy Act of 1954 which allowed for private ownership of nuclear materials and facilities.
Section 1.2.4 on the Price-Anderson Act of 1957 which provide federal liability protection for private owners of nuclear materials and facilities.
Section 1.2.5 on the first intervention against a proposed nuclear plant; the August 31, 1956, filing by the American Federation of Labor–Congress of Industrial Organizations (AFL-CIO) which culminated in a 1960 decision by the U.S. Court of Appeals that the construction permit issued by the Atomic Energy Commission were illegal. This decision was overturned on June 12, 1961, by the U.S. Supreme Court.
Section 1.3.5 on the National Environmental Policy Act which forced most inland nuclear power plants constructed after 1970 to use cooling towers to reduce their consumption of water from and impacts on nearby lakes and rivers.
Section 1.3.7 on the Energy Reorganization Act of 1974 that fissioned the Atomic Energy Commission into the Nuclear Regulatory Commission and what is now called the Department of Energy.
Section 1.4 on design basis perspectives.
Section 1.5 on the Reactor Safety Study and its evaluation of beyond design basis accidents.
Section 1.6 covering the March 1975 fire at the Browns Ferry nuclear plant in Alabama.
Section 2.1 on the March 1979 accident at the Three Mile Island nuclear plant in Pennsylvania.
Section 2.3 on the April 1986 accident at the Chernobyl nuclear plant in the Ukraine.
Section 2.4 on the NRC’s development of safety goals and their application in the station blackout rule and the backfit rule.
Section 2.5 on risk assessments and Section 2.5.7 on the assessment of the station blackout risk.
Appendix 2B.3 on the failure of 76 control rods to fully insert into the reactor core at the Browns Ferry nuclear plant in Alabama following an attempted rapid shut down.
Appendix 2B.4 on an improper maintenance practice at the Salem nuclear plant in New Jersey that disabled the reactor trip safety function.
Section 3 describing how a meltdown progresses within the reactor vessel.
Section 4 describing how the containment systems respond during a meltdown accident.
Section 5 describing the measures planned to protect communities from a meltdown accident.
Section 5.1.4.7 describing how “containment venting to the outside can substantially improve the likelihood of recovery from a loss of decay heat removal and, as a result, reduce the frequency of severe accidents” at boiling water reactors.
On a scale of 1 to 10 with 10 being best, the jargon/acronym index for this manual is around 6.527. Some of the sections are tedious and not user-friendly, but those sections can be skipped. Many sections are fairly easy to follow, at least on a relative scale.
The manual features more user-friendly graphics than the NRC’s typical technical reports. For example, the graphic above is Figure 5.1-2 from the manual striving to put routine releases of radiation in context to the releases estimated to have happened during the Three Mile Island and Chernobyl accidents.
And Figure 3.4-7 from the manual shows the estimated configuration at Three Mile Island Unit 2 224 minutes into its accident showing the upper portion of the reactor core having melted with the molten mix of nuclear fuel, control rods, and infrastructure material slumping towards the bottom of the reactor vessel leaving behind a void.
“On the History of the Evolution of Light Water Safety in the United States”
The “Reactor Safety Perspectives” manual is a good reference for the background on a variety of topics. Dr. Okrent’s manuscript “On the History of the Evolution of Light Water Safety in the United States” supplements this background with a blow-by-blow accounting of various safety issues being debated and resolved
The manuscript was issued in 1978 and thus has a solid excuse for not covering topics like the 1979 accident at Three Mile Island, the 1986 accident at Chernobyl, the 2000 deployment of the Reactor Oversight Process, the 2006 Super Bowl victory by the Pittsburgh Steelers, and the 2011 accident at Fukushima Daiichi.
Chapter 2 covered the evolution of the reactor siting criteria, including the proposal to build a large nuclear plant near the base of the Brooklyn Bridge in downtown New York City. The proposal raised thorny issues – if a nuclear plant is too risky for big city people, how is it acceptable to subject small town and rural people to the risks? And its converse – if a nuclear plant does not subject country folk to undue risk, how could it be too risk for city dwellers?
Chapter 6 covers the evolution of seismic criteria applied to the design and operation of nuclear power plants. The proposed Bodega Bay plant, located less than one-quarter mile from the San Adreas fault, and the Malibu plant proposed for Los Angeles are the focus of this chapter, but other issues at other sites also get mentioned.
A convention used by Dr. Okrent throughout the manuscript is to describe a topic, detail the dialogue (sometimes heated debate) between Advisory Committee on Reactor Safeguards (ACRS) members, regulatory staff, and industry representatives about the topic, and include the formal letter sent by the ACRS to the Commission about it. This approach provides useful insights into how recommendations and decisions were reached, not just the final outcomes.
For example, the manuscript describes why and how the emergency core cooling systems for boiling water reactors grew from the isolation condenser and core spray system in older reactors like Oyster Creek to the array of high-pressure and low-pressure systems featuring a diverse mix of steam-driven and electric-motor driven pumps in latter reactors like Grand Gulf. More than 15 years of my career was spent working at or for boiling water reactors. I knew each had emergency core cooling systems and that the systems varied from plant to plant, but never understood why the changes occurred until reading Okrent’s manuscript.
The online PDF versions of the manual and manuscript can be searched for specific words and phrases. This means one can quickly check them for mentions of “Indian Point,” “containment vent,” or “station blackout” without having to read or even skim each page.
The UCS Nuclear Energy Activist Toolkit (NEAT) is a series of post intended to help citizens understand nuclear technology and the Nuclear Regulatory Commission’s processes for overseeing nuclear plant safety.