JERUSALEM, 19 March 2004 — Nuclear whistleblower Mordechai Vanunu has no more secrets to spill upon his release next month after serving 18 years in solitary confinement for treason, relatives said yesterday.

Prime Minister Ariel Sharon ordered Vanunu closely monitored when he goes free on April 21, citing concern he will discuss his past work at Dimona atomic reactor — the subject of a 1986 British media interview over which he was convicted of treason.

But his brother Meir Vanunu called such fears unfounded.

“Mordechai has no more secrets to tell,” Meir Vanunu told Reuters. “He has the right to speak out against Israeli policies if he wants, but that is not the same as compromising national security.”

Vanunu’s revelations to the Sunday Times led analysts to conclude Israel has some 200 nuclear warheads, blowing away the Jewish state’s ambiguity over its non-conventional capabilities.

Absent from the expose were the names of Dimona researchers and descriptions of security measures at the site. Israeli security sources say Vanunu could still reveal these, as well as sensitive data about locally developed atomic technologies.

According to security sources, Vanunu will be barred from leaving Israel for a probationary period after his release. His contact with the media will be severely restricted, sources say.

In letters to fans, Vanunu — who embraced Christianity and anti-nuclear activism after being fired from a job as mid-level Dimona technician in 1985 — made clear he feels no remorse.

“The secrets collapsed without any bombs, without killing anyone. That was the great power of a non-violent act,” the US Campaign to Free Mordechai Vanunu website quotes him as saying.

Such remarks infuriate Israeli top brass, who see efforts to expose Dimona’s capabilities as endangering military deterrence needed to fend off Middle East foes.

“Vanunu is a traitor who is on an all-out mission against his nation and religion,” said Uzi Arad, a retired Mossad operative who advises the Sharon government on strategic issues.

He accused Vanunu of mental instability and said any future account he gives on Dimona is as likely to be fantasy as fact.

“The imprimatur of having worked at Dimona makes Vanunu seem completely credible. Who is to say that the combination of his own obsessions and pressure from publishers and anti-Israel lobbies won’t make him invent libels about us?” Arad said.