Four faulty valves replaced at Kudankulam n-plant

Mumbai, April 21 (IANS) Four valves of the passive core flooding system at the Kudankulam 1 and 2 Nuclear Power Plant (KKNPP) units, which were showing "occasional variation" in performance, have been replaced, an official said here late Saturday.

The Nuclear Power Corporation of India Ltd. (NPCIL) also set at rest apprehensions of safety at KKNPP, Tamil Nadu, arising after an Atomic Energy Regulatory Board (AERB) statement two days ago suggesting something was wrong with the four valves.

NPCIL executive director (CO & CC) N. Nagaich said the (passive) valves did not require any motive power for their operation.

"These are tested in situ in an integrated manner during commissioning of the system. The valves were initially tested in factory facilities in simulated conditions," Nagaich said.

However, as a normal industry practice, the performance of components is evaluated under the operating conditions to ascertain their performance as per the design intent.

"During such testing by the Kudankulam commissioning team of NPCIL, it was found that these valves showed variation from expected performance. The performance test reports and corrective actions were reported to AERB as a part of laid down procedures. These four valves have since been replaced and the performance reports are under review by the AERB," Nagaich said.

He pointed out that during commissioning, testing of several systems to verify and fine-tune the systems is taken up simultaneously.

Nagaich said the KKNPP's safety is reinforced with a close scrutiny of performance of the components and taking corrective actions, as intended in the commissioning process prior to operation of the plant.

Assuring that further commissioning activities in KKNPP would be in accordance with the AERB clearances and approved procedure, the NPCIL said that as "a responsible safety conscious organisation, (it) will certainly not take any shortcuts to safety."

The AERB statement had said that generally, several thousand components are installed in a nuclear power plant.

As is normal for all complex engineering systems, occasional variation in their performances during commissioning trials is expected.

"The very intent of such commissioning trials is to identify non-conformances, if any, and take corrective actions. The commissioning tests and results, including corrective actions taken are reviewed by AERB".