Not an experiment but similar situation: I talked with a scientist at NIST who told me that their nuclear reactor was shut down once for maintenance, and while the core was out they had the cleaning staff come in and scrub the aluminum panels that lined the walls, since they hadn’t been cleaned in years. When the maintenance was done, the reactor wouldn’t start back up. Eventually they figured out that the cleaning spray used on the walls contained borax. Boron is a potent neutron absorber and the trace amounts left behind were keeping the reactor from going critical. They had to toss out all the panels and replace them.
Not an experiment but similar situation: I talked with a scientist at NIST who told me that their nuclear reactor was shut down once for maintenance, and while the core was out they had the cleaning staff come in and scrub the aluminum panels that lined the walls, since they hadn’t been cleaned in years. When the maintenance was done, the reactor wouldn’t start back up. Eventually they figured out that the cleaning spray used on the walls contained borax. Boron is a potent neutron absorber and the trace amounts left behind were keeping the reactor from going critical. They had to toss out all the panels and replace them.