The International Atomic Energy Agency (IAEA) also found traces of plutonium in so-called hot cells, the diplomat said, reading from a report by the agency.
He noted however that Egypt was cooperating in the investigation and that the incidents were small, with some taking place as long as 40 years ago and could be related to research into the nuclear fuel cycle rather than part of an atomic weapons program.
The Egypt report will be submitted to a meeting that opens in Vienna February 28 of the IAEA's 35-nation board of governors, which decides whether to take nations that violate safeguard before the Security Council.
The diplomat said Egypt's undeclared work was small scale and not comparable to Iran or even to South Korea, a non-atomic-weapons state which has admitted carrying out rogue nuclear experiments.
The experiments the IAEA is looking into involve making uranium metal, which could be used to make weapons-grade plutonium, and carrying out the first steps of uranium enrichment by making uranium tetrafluoride (UF4), the diplomat said.
But Egypt did not do any enrichment, the diplomat said.
Egypt admitted on January 27 to failing to signal a "number of research experiments" to the IAEA, after diplomats said the agency was investigating an Egyptian lab that could be used to make plutonium, a nuclear weapons material.
The reprocessing laboratory is at Egypt's Inshass center, 35 kilometresmiles) northeast of Cairo, where there are two research reactors, and consists of "hot laboratories, procured from France in the early 1980s, which allow for treatment of spent fuel and laboratory-scale plutonium separation," a diplomat said.
But "Egypt is cooperating with the IAEA" and feels the "research experiments and activities ... most of which took place in the distant past are consistent with the NPT," the Egyptian embassy had said in a statement released in Vienna.
The statement said Egypt had been slow to respond to stronger safeguards measures by the IAEA "since the 1990s" and had thus failed from lack of awareness of the new rules to report "to the agency, in an appropriate and timely manner, a number of research experiments and activities."