Geothermal Research At Wairakei’s Steam Bore

Press, Volume XCIII, Issue 27861, 9 January 1956, Page 3

Geothermal Research At Wairakei’s Steam Bore

"The Press” Special Service

AUCKLAND, January 8.

A huddle qf huts in a small, wirenetting enclosed compound at Wairakei, where drifts of steam half-con-ceal a fantastic array of pipes and valves, and the scream of Bore 9 has waxed and waned for years in the cause of science, is a keypoint in New Zealand’s geothermal future. It is the field headquarters of a joint research effort between the New Zealand Department of Scientific and Industrial Research and the British Atomic Energy Establishment. Here the output of a 574 ft deep bore —16,0001 b an hour at 1001 b gauge pressure—is run to and fro through pipes, measured, split into components, remixed, remetered, turned on to test materials, plotted on dharts and finally set loose. Work within the compound, extended at times on to other, larger bores, and in some instances pursued in detail in laboratories in Wellington, has already produced some valuable information for geothermal development. How to dry the “wet” steam has been investigated. It has turned out to be simple for the power station—merely a series of outlet pipes from the bottom of the main flow pipes. They will tap off the water, which runs or. the bottom of the flow. For the heavy water plant, if one is built, it will be more complicated. Much greater purity of steam is required, arid special equipment has been

brought out from Harwell for experiments on a new big bore. Metal has been tested to see if it corrodes or cracks. Some metal in the steam flow collects tiny bubbles of hydrogen at tremendous pressures. Much high-tensile steel cracks under strain. Corrosion rates are checked by weighing metal before and after exposure to the steam. Bore casing behaviour is checked by suspending metal “coupons” right down at the bottom in the “new steam.” Radioactive isotopes have been used to measure the steam flow.

Lithium is present in the output of the Wairakei bores—in minute proportions. but worth about £lOO.OOO a year There has been “some success” in extracting it on a laboratory scale, but. a scientist said recently, “we are a long way from knowing if we can do it commercially.” Lithium is a light metal used for making low-temperature greases and with a future in nuclear energy. Plenty of common salt comes up in the bores, but its concentration is only one-tenth that in sea water, so a Wairakei salt industry is unlikely. Scientists are keen to keep the work going—quite apart from the needs of a power station or a heavy water plant. Here is cheap steam, they say, lots of it. never ceasing. It is New Zealand's oonortunity to do fundamental research on steam which has never teen tackled before.