Reactor releases

No No Flow Excess ammonia in reactor. Release to work area. 1. Valve A fails closed. 2. Phosphoric acid supply exhausted. 3. Plug in pipe pipe ruptures. Automatic closure of valve B on loss of flow from phosphoric acid supply... 

Part of Normal flow of decreased concentration of phosphoric acid Excess ammonia in reactor. Release to work area, with amount released related to quantitative reduction in supply. 1. Vendor delivers wrong material or concentration. 2. Error in charging phosphoric acid supply tank. Check phosphoric acid supply tank concentration after charging. 

The reactor accident at Chernobyl in April 1986 released radionuclides into the atmosphere, mostly between April 26 and May 6. Estimates of quantities released are based on observations of deposition within 30 km of the reactor. Releases in this area were predominantly highly irradiated fuel particles. It is estimated that the discharge of 241Pu through May 6, 1986 was 5,200 TBq (140 kCi), which amounted to 3% of the reactor content of this radionuclide (Askbrant et al. 1996 Pattenden and McKay 1994). The material was released mainly in the lower troposphere. 

The Seveso and Duphar accidents could have been avoided if proper containment systems had been used to contain the reactor releases. The proper application of fundamental engineering safety principles would have prevented the two accidents. First, by following proper procedures, the initiation steps would not have occurred. Second, by using proper hazard evaluation procedures, the hazards could have been identified and corrected before the accidents occurred. 

On March 28, 1979, a loss of containment incident occurred at the Three Mile Island nuclear power plant near Harrisburg, Pennsylvania. An overheated reactor released radioactive steam and water to the atmosphere resulting in a mass evacuation of the surrounding community. Although no direct injuries were attributed to the incident, environmental effects were later observed and public outcry resulted in a slowdown in the growth of the nuclear power industry. 

Strontium-90 behaves much hke calcium in the biological environment. In birds, °Sr is expected to occur in bone and in the calcium-rich eggshell. In one case, a positive relation was demonstrated between reactor releases of °Sr to the Columbia River and °Sr concentrations in reed canary grass Phalaris arundinacea) and eggshells of the Canada goose (Branta canadensis moffitti) (Rickard and Price 1990). 

Tritium is present naturally in the atmosphere, but the amounts were increased greatly in the late 1950s and 1960s by production and testing of thermonuclear weapons. Tritium is also a fission product and activation product produced in power reactors. Releases occur from reactors and reprocessing plants. Its use will increase greatly if fusion power is developed. 

Explosion and fire in the graphite core of one of four reactors released radioactive material that spread over part of the Soviet Union, Eastern Europe, Scandinavia, and, later. Western Europe. Claimed dead total was 31. Total casualties are unknown. This is the worst such accident to date... 

The destroyed reactor released a very large amount of radioactive material into the environment lO becquerels. Although the discharge included many radioactive chemical elements, just two of them—iodine (in the short term) and caesium (in the long term)—were particularly significant from a radiological point of view. 

A small percentage of the fuel elements in a water-cooled reactor release gaseous fission products to the coolant. The insoluble noble gases are collected and stored for radioactive decay prior to their release to the atmosphere. Calculate the required storage time such that the radioactivity levels of Xe and Kr in the released gas are equal. Assume fissions at constant power only in an average irradiation time of 2 years, and assume that these noble gas radionuclides are released to the coolant in the same proportion as they exist within the fuel. Obtain mass yields from Table 2.9. Twenty-three percent of the fissions at mass 85 produces Ki. 

U.S. Nuclear Regulatory Commission (1976). Estimating Aquatic Dispersion of Effluents from Accidental and Routine Reactor Releases for the Purpose of Implementing, Appendix 1, Regulatory Guide 1.113. USNRC, Washington, DC. 

The major sources contributing to Tc in the environment are fallout from atmospheric nuclear weapons tests and releases from the nuclear fuel cycle, i.e., authorized or accidental releases from nuclear installations (e.g., reprocessing or enrichment plants, nuclear reactors), releases from waste disposal sites, and from dumping of nuclear materials. Contributions from natural processes, i.e., spontaneous fission of in mineral ores such as pitchblende or nuclear reactions in molybdenum ores irradiated with cosmic-ray neutrons are negligible. 

Event. An explosion in a polyethylene reactor was caused when a seal blew out on an ethylene loop reactor, releasing ethylene-isobutane and setting off a series of fires and explosions. 

A practical sodium borohydride system is shown in Figure 8.25. The solution is pumped over the reactor, releasing hydrogen. The motor driving the pump is turned on and off by a simple controller that senses the pressure of the hydrogen, and which turns it on when more is required. The solution is forced through the reactor, and so fresh solution is continually brought in contact with the catalyst. The rate of production is simply controlled by the duty cycle of the pump. The reaction takes place at room temperature, and the... 

Runaway Polymerization Reaction VCM polymerization has the potential to rupture the reactor, releasing the VCM with major damage possible. 

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