The government cannot guarantee Britain will have enough nuclear inspectors when it leaves the EU, MPs on the business committee were told.
The Office of Nuclear Regulation has recruited four new safeguards inspectors but says it needs more time to fill the specialised roles.
Nuclear minister Richard Harrington said there was “plenty of time” to recruit the staff needed.
But he stopped short of offering a firm guarantee.
The government has stressed that nuclear safeguards – the processes by which the UK shows its civil nuclear material is not diverted into weapons programmes – are different from nuclear safety – the prevention of nuclear accidents.