Poisons additives

Data from case reports indicated that there is usually a 1- to 24-h delay between exposure and onset of signs and symptoms of poisoning. Additionally, hematologic parameters (e.g., hemoglobin, hematocrit levels) appear to be progressively affected for several days after the exposure. Hence although the exposure is acute, the most serious adverse effect may be delayed by several hours or days. 

The current synthesis of ethyl alcohol eliminates sulfuric acid and uses phosphoric acid suspended on zeolite substrates. Zeohtes are porous aluminosilicate crystalline minerals. The use of phosphoric acid as a catalyst allows the direct hydrolysis of ethylene into ethyl alcohol C2H4 + H20 —> C2H5OH. Industrial alcohol is rendered inconsumable by adding a small amount of a poisonous substance such as methanol or acetone to it. Alcohol unfit for consumption because of a poisonous additive is termed denatured alcohol. 

Another cause of concern in the nineteenth century was food adulteration, especially the addition of colouring materials. In 1851 The Lancet set up the Analytical Sanitary Commission, whose main members were Arthur Hassall and Henry Letheby. The reports of the Commission showed that food was indeed being contaminated by poisonous additives. These findings led to the first Food and Drugs Act of 1860, and from the 1870s Local Authorities started to appoint public analysts.349... 

Fig. 9. Dependence of the reacted amount of allene, nP, on the allene concentration, [P], in propylene polymerization nP and [P] are extrapolated to the poison addition time. Conditions as in Fig. 8, curve 1 and Fig. 7 (except for added amount of allene)...

Knowledge of the structure and function of the skin is essential for proper cosmetic formulation (cosmetology). All ingredients must be tested for possible toxic effects, since the skin is an important means of access for poisons. Addition of proteins to cosmetic preparations is of questionable value. 

The formaldehyde, or other redox by-products from the reduction of Cr/silica by ethylene, probably stay in the reactor and act as mild poisons. Addition of a strong adsorbent or Lewis-acidic carrier, such as zeolites or alumina treated with fluoride or sulfate, to the reactor together with the catalyst significantly increases the activity of the Cr/silica catalyst. Presumably, the Lewis-acidic carrier adsorbs and removes the redox by-products from the reaction mixture (Section 17.6). 

For a package containing Chlorine, the word CHLORINE may be used in the place of the word POISON on the POISON label, provided the letter size and color for CHLORINE are the same as those required for POISON. Additionally, a CHLORINE label may be used in place of the NON-FLAMMABLE GAS and POISON labels otherwise required for Chlorine. 

Activated charcoal lavage may be helpful immediately after ingestion of castor beans or ricin, but ricin acts rapidly and irreversibly, which makes treatment very difficult after signs and symptoms appear. Symptomatic care is the only intervention presently available to clinicians treating aerosol ricin poisoning. Additional information on ricin may be found in Franz and Jaax (1997). 

Criterion 27 - Combined reactivity control systems capability. The reactivity control systems shall be designed to have a combined capability, in conjtmction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes to assure that under postulated accident conditions and with appropriate margin for stuck rods the capability to cool the core is maintained. 

In the PHWR 220s two systems, i.e. 14 mechanical shut-off rods which fall freely under gravity into the core and 12 liquid poison stand-pipes into which sodium-penta borate solution is introduced, provide fast acting redundant and diverse shut-down systems. These are reinforced by slow-acting automatic liquid poison addition into the moderator system for prolonged shut-downs. 

The moderator system includes two 100% capacity pumps, two 50% flow capacity heat exchangers cooled by recirculated light water, and a number of control and check valves. Connections are provided for the purification, liquid poison addition, D2O collection, supply, and sampling systems. The series/parallel arrangement of the moderator system lines and valves permits the output from either pump to be cooled by both of the heat exchangers and ensures an acceptable level of moderator cooling when either of the two pumps is isolated for maintenance. Reactor power must be reduced to about 60% if one moderator heat exchanger is isolated. The primary functions of the system are to... 

The liquid reactivity devices consist of the light water zone control units and the liquid poison addition system. 

Addition of a small amount of burnable poison to the central displacer would further reduce void reactivity, increase the plutonium loading per bundle as well as the absolute amount of plutonium destroyed, but would decrease the plutonium destruction efficiency. The plutonium destruction efficiency would be reduced from about 77% to 71%, by poison addition that reduces void reactivity from about 8.6 mk to zero. 

Poison addition to the reactor is the final general factor affecting neutron multiplication. Poisons can be in the form of boron in control rods xenon and samarium fission products or any absorbing nucleus that is introduced into the reactor. Poisons increase the denominator in the thermal utilization factor making the overall value of f decrease. In the case of resonance absorbers, resonance escape probability also decreases. 

In general, each of the phenomena described fuel burnup, moderator temperature increase, fuel temperature increase, and poison addition, result in a decrease in the reactor multiplication factor, Kgff, if means are not taken to compensate. 

Describe the effects of poison additions on neutron multiplication. 

Establish a credible list of fuel composition candidates along with candidate cladding materials. Plutonium-destruction performance and safety can be optimized. Burnable poison additions should be considered as an integral part of this study. 

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