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trons, holding the shape of the track intact, which permits the three-dimensional reconstruction of the particle track.
According to LBL director David A. Shirley, the TPC, along with other sophisticated detectors, marks a transition from an era when the accelerator was the dominant component in high-energy physics experiments, to an era of colliding beams and events that take place at very high energies, leave very complicated signatures, and are relatively rare in number. The study of such interactions, Shirley says, requires highly sophisticated detectors.
The TPC is the heart of a particle detection system known as PEP-4, which, in addition to the TPC, includes cylindrical drift chambers and related detectors. The PEP-4 detector system cost $25 million and took five years to build. It was funded jointly by the Department of Energy, the National Science Foundation, and the Ministry of Education, Science & Culture of Japan. D
Pipe failure closes New York nuclear plant The failure of a pipe in the steam generator of the Robert E. Ginna nuclear power plant near Rochester, N.Y., last week forced the automatic shutdown of the plant and allowed for the escape of a small amount of steam into the atmosphere. The steam contained total noble gas radioactivity amounting to about 500 curies, according to a preliminary estimate reported by the Nuclear Regulatory Commission.
The full extent of damage to the reactor system and the exact cause of the mishap are still to be determined, according to a spokesman for Rochester Gas & Electric, the utility that runs the plant. Though safety devices put the plant into "cold shutdown," repair crews were not expected to enter and inspect the damaged steam generator until the equipment fully cooled down.
The incident occurred on Monday, and by midweek the details of the incident were still somewhat garbled. For example, sometime during the incident, after the pipe in the primary cooling system of the plant failed, a valve also failed, causing a steam bubble to form transiently. Under normal operating conditions, superheated water is maintained under high pressure and thereby prevented from vaporizing at the
high temperatures it reaches near the reactor core.
The main problem, however, is believed to reside somewhere among the more than 3000 tubes that carry this superheated water through the reactor in the primary cooling system. The incident began when one or more of those tubes burst, allowing that water to intermingle with steam in the secondary cooling system, which drives the turbines of the electric power generator. The burst tubes also caused fluctuations of pressure within the system, and those fluctuations led to venting of steam to relieve high pressure. "As soon as operators recognized a leak in the Β steam generator, they stopped removing steam from it to the turbine,"
says Gary Sanborn of NRC's regional office in Philadelphia.
Radioactively contaminated water, now estimated to be less than 2000 gal, has been removed to a holding tank and will be purified and disposed of in the "approved fashion," according to Rochester Gas & Electric. Equipment in the plant had been judged to have a "moderate amount" of wear and tear by NRC as of mid-1981. About 20 of the tubes in the cooling system had been fitted by then with "sleeves" to provide additional strength. The condition of those and other tubes in the system, particularly the one that failed, may provide a valuable indicator of how this and similar nuclear plants are aging. G
Toxic chemicals use in school labs examined The Consumer Product Safety Commission is reviewing the use of chemicals in secondary school laboratories and is concerned about the school's lack of availability of information on their potential chronic health effects. As a result, CPSC staff will likely recommend that the agency devise some kind of network for informing students and school lab instructors of current toxicity evaluations of the chemicals they use and on the possible use of less hazardous substitutes.
CPSC has tallied 312 stock chemicals used in school labs by asking 22 high schools in 11 states for a list of the chemicals that they ordered at the start of the year. Of these compounds, 33 are listed by the agency as recognized or suspected carcinogens and 11 as suspected teratogens. The primary source for
the toxicity data was "Dangerous Properties of Industrial Chemicals," by N. Irving Sax. Other resources used to evaluate the chemicals were a National Institute for Occupational Safety & Health pocket guide to hazardous chemicals, a commercially available wall chart, and an in-house computer data bank of chemical hazards.
Just how many persons are injured in school lab accidents is not clear. One of the higher figures found by CPSC is from the National Safety Council, which reported about 3000 such accidents during the 1978-79 school year. Most of these accidents involved chemical burns from acids or alkalies. The other incidents apparently were mostly chemical dermatitis reactions and lacerations from broken glassware.
Despite CPSC's obvious concern
Some chemicals are double hazards on list of potential problems Suspected carcinogens Acetamide Isoamyl alcohol Aniline hydrochloride Benzene Benzidine reagent Benzoic acid Cadmium chloride Carbon tetrachloride Chloroform Chromic acetate Chromium trioxide Colchicine Dichloromethane Dichlorophenol Diphenylamine
Ethylene dichloride Ferric oxide Formaldehyde Isobutyl alcohol Kerosine Lead acetate Methylene chloride Nickelous ammonium
sulfate Nickelous chloride Nickelous nitrate Phenol Propanal Pyrogallic acid Sodium chromate Sodium dichromate
CPSC's
Tannic acid Thioacetamide Trichlorotrifluoroethane
Suspected teratogens Cadmium chloride Carbon tetrachloride Colchicine Diphenylamine Ethylene dichloride Lead acetate Lead chloride Lead nitrate Lithium chloride Methyl ethyl ketone Salicylamide
Feb. 1, 1982 C&EN 5
