South China Morning Post  2010-06-16

Disquiet over delay in Daya Bay report

By Cheung Chi-fai and Verna Yu

Disquiet builds over time it took to disclose Daya Bay incident

When should we find out about a nuclear accident, even a minor one? That's the question being asked around the city as news of the Daya Bay nuclear incident sank in yesterday.

There were calls for an investigation and greater openness about operations at Daya Bay after the disclosure on Monday of what was termed an "insignificant" increase in radiation probably caused by an improperly sealed fuel rod at the nuclear power station.

The incident, on May 23, was not made public until CLP Power, one of the operators, and the Hong Kong government spoke out to rebut a media report that there had been a major leak. Legislators and nuclear power opponents called yesterday for an independent investigation and asked why, if the incident was so minor, it had been kept secret.

The Civic Party asked the Legislative Council's security panel to follow it up and the Democratic Party and DAB protested outside CLP's Mong Kok office.

There were also questions on whether the rod was made by the usual French supplier or on the mainland.

Only the national nuclear safety body and the cross-border Nuclear Safety Consultative Committee formed by the mainland operator, Daya Bay Nuclear Power Operations and Management, were informed of the incident.

CLP, which has a minority stake in the station, said "imperfect sealing" in a fuel rod in the reactor of unit two was the "likely cause" of an increase in the level of radioactive iodine and gases in the reactor cooling water.

The substances are released from the fission of the nuclear fuel but are supposed to remain largely within the zirconium metal structure of the fuel rod. It was not clear yesterday whether the rod became defective in the production or assembly process. It was the first defect in a fuel rod reported in the 16 years since the station, the mainland's first commercial nuclear plant, started operating in 1994.

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Fung Chi-wood, a former legislator who collected a million signatures against the building of the power plant 50 kilometres from Hong Kong's border, said the lack of transparency had fuelled scepticism and fears among the public. "If it is as minor as they claim, they should not fear fully disclosing it," he said.

Professor Lee Cheuk-fan, a member of the consultative committee for a decade, agreed the role of the Hong Kong government could be stepped up to improve communication. "In the years I have served on the committee, I have never encountered any Hong Kong officials," he said.

CLP said the incident caused no risk to the environment and the radioactivity level had stabilised. A staff member at Daya Bay said she had not heard of any leak and operations were normal.

Fung said all incidents involving a leak of radioactivity should be reported immediately and that the government should strive for such an arrangement. "Sadly, we have not seen any formal channel through which the Hong Kong government can truly participate in the monitoring of the power stations," he said.

"It has failed to keep the promise made in 1986 to closely watch the operation of the plant."

Fung said he was worried that the operator had refused to shut down the reactor for maintenance for fear of losing income from the electricity, 70 per cent of which is supplied to Hong Kong.

Lee, who has worked in a nuclear power plant, said consultative committee members were sent an e-mail about the incident days before they met last week. He believed the problem, probably related to welding defects, was minor and could be fixed next time the rods were replaced.

CLP Power managing director Richard Lancaster said the operators had acted according to established protocol. He said there had been no leak of radioactivity and the incident was so minor it was not rated on the seven-point international nuclear event scale as defined by the International Atomic Energy Agency.

Under Hong Kong's Daya Bay Contingency Plan, notification is only required in emergencies, although past incidents are reported on the operator's website.

Lancaster said it was "an extremely minor incident" that took place "at the heart of the reactor" with three layers of protective containment, including a 200mm steel casing and a 90mm reinforced concrete structure.

He said the likely cause was "imperfect sealing" in one of the 41,000 fuel rods supplied by a French manufacturer. But the power station's designer, Areva, said mainland companies were also supplying fuel rods for the plant. "The Chinese supply their own fuel rods, but the quality is as good as the French ones - that's what I think," said a senior staff member at Areva's China representative office who did not want to be named.

Consultative committee member Wan Shek-lun said there were lots of unanswered questions. "Is the fuel rod really French-made or Chinese-made? What were the radioactivity readings? How many rods or only a rod is involved? Is the situation deteriorating and how is it to be fixed?"

He said the meeting held last week also covered other operational details of the plant, and there was no time for the members to raise more questions about the incident. The defective rod could pose a threat of explosion if it was allowed to continue to operate at very high temperature and pressure, he said.

The Security Bureau, which is in charge of the Daya Bay contingency plan, said it would continue to liaise with CLP on the issue. It said the radiation monitoring network administered by the Hong Kong Observatory had found no abnormal changes to radiation levels since May 23.

The Hong Kong Nuclear Investment Company website says there have been a dozen operational events since 1997, including temporary suspension of cooling water supply and exposure of staff to radiation dosages higher than internal limits.

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