Manapouri submarine check not urgent

Press, 17 January 1979, Page 6

Manapouri submarine check not urgent

There is no plan to brinj a midget submarine specially to New Zealand to inspect the Manapouri power station’s tail-race tunnel, contrary to a television news report on Monday. When and if a suitable submarine was brought to New Zealand the Electricity Division of the Ministry of Energy would like to use it to make an inspection of the tunnel, said the principal generation engineer of the division (Mr G. R. McKenzie). “It would not justify the expense of a special venture to bring one out ourselves,” he said. The submarine would be used to check the condition of the tail-race tunnel’s concrete lining. There had been no indication in the water flow through Manapouri to suggest damage to the lining but a chance to check it for the first time since the sta-

g tion opened would be useful,! yisaid Mr McKenzie. :tl Gradual movement in the; i- Southern Alps might have' j-iaffected the concrete lining! si of the tunnel, he said. Last year a midget submachine was supposed to pass o through New Zealand in' yj transit to an overseas oil-; if field and the Electricity Di-j it [vision was asked if it would j if'like to make use of it while; ill it was in New Zealand. The! e division agreed but in the I. end the submarine did not arrive. e Most of the small submae rines are used by oil com- ” ■ panies for maintenance work 'on off-shore oil wells. They ie usually carry two divers and n work is carried out by re-i-1 mote control grabs attached n'to the outside of the craft, ri Repairs to rubber gate; □ 'seals between the Manapouri g station's turbines and the r tail-race tunnel had been -'planned for sometime. The

[Stoppage this week was not [an emergency one. ; The repairs had been •scheduled in the summer be- ! cause of the low demand for I electricity at that time, said >Mr McKenzie. Fourteen million units of | electricity are being lost (each day during the close--down which is expected to lend on Saturday. ; The lost generating capacity is being made up by.re- ; leasing extra water from Lake Hawea and Lake Pukaki so that the stations they supply can generate extra power. There has also been a reduction of four to five million units in the amount of power sent to the North Island. The North Island reduction has been compensated for by increasing the output of both North Island hydrostations and the coal-fired station at Meremere.