Well, tools better not be exposed to much neutron radiation, or else the person holding the tools will be in trouble. :)
What he may have been talking about is activation of troublesome elements that cause contamination that interferes with access. A prime example of this is the wear resistant alloy Stellite, used in valve seats. It's an alloy of cobalt. Some cobalt does wear off, gets circulated through the reactor, and is transmuted to 60Co, which increases the radiation field around all the piping.
All the materials in your reactor that are exposed to neutrons need to be purged of troublesome trace elements that can cause this sort of activation.
What he may have been talking about is activation of troublesome elements that cause contamination that interferes with access. A prime example of this is the wear resistant alloy Stellite, used in valve seats. It's an alloy of cobalt. Some cobalt does wear off, gets circulated through the reactor, and is transmuted to 60Co, which increases the radiation field around all the piping.
All the materials in your reactor that are exposed to neutrons need to be purged of troublesome trace elements that can cause this sort of activation.