Three Catholic University physicists have invented a new kind of glass "sponge" they say is strong enough and impermeable enough to contain radioactive wastes safely for thousands of years.

Such a container could allow use of the radiation from nuclear wastes for bacteria-killing or other purposes without any danger that the material itself might escape into the environment, the three scientists told a news conference Tuesday.

Drs. Theodore A. Litovitz, Pedro B. Macedo and Joseph H. Simmons have applied for a patent on their procedure for encasulating the wastes, which are piling up nationwide at nuclear power reactor sites and as the result of Defense Department weapons work.

Although other experimental procedures have encapsulated solidified nuclear wastes in molten glass, most weapons-work waste is liquid that has been difficult to solidify. There is an estimated 230 million gallons of such waste now, accumulating at the rate of 7.5 million gallons each year.

In addition, the glass capsules have so far not been considered chemically and physically sturdy enough to resist the ravages of water corrosion, heat, accident and earth movement that would be likely to occur over the 100,000 years or so that the wastes will be dangerous.

The new procedure creates a porous glass that can absorb the liquid and then be sealed permanently into a capsule that is stronger and 1,000 times as leak-proof as existing glasses, the scientists said.

The three and the organization that has funded their research, the National Patent Development Corporation, have launched an effort to convince the Department of Energy "that this is the best possible solution to the waste problem," as Macedo put it. He and a consultant, former Atomic Energy Commission official George Quinn, plan to visit the Battelle Northwest research organization in Richland, Wash., soon, to promote their glass in connection with studies on it being done there.

"We want them to be the ones to say it's durable, rather than us," Macedo explained.

Macedo demonstrated that four kilo gram of weight (8.8 lbs.) would break a conventional windowglass pane, while a pane of glass made with the new process supported 11 kilos (24.2 lbs.) and bent nearly double without breaking.

In the form of rods, the new glass looks milky and feels sticky to the touch of a wet finger as it sucks the moisture in. Once full of liquid, the glass can be heated so that water evaporates while any solids remain behind.

Several soakings and heatings can fill up the pores in the galss with essentially solid waste, now at a level of 15 per cent of the glass weight and soon at 30 per cent, Macedo said. After washing to remove the waste from thin surface layer, the glass can heated a final time tto seal the waste inside.

It can then be handled like any radioactive material, with the difference that nothing else becomes radioactive from contact with it. This would allow nuclear wastes perhaps to be used in place of chemical poisons now used to sterilize fruit, purify water or treat sewage, Macedo said.

"If you can safely encapsulate nuclear waste you can convert it from a hazard to a benefit," he said.

Equipment to encapsulate all existing wastes with the process could technically be in place and operating in two years, "except that that is a political decision," Litovitz said. The cost of such an undertaking would depend on the kind and degree of shielding, the extend of safety precautions and the size of capsules deemed to be necessary, he added.