WordNet (r) 3.0 (2006):

meltdown
    n 1: severe overheating of the core of a nuclear reactor
         resulting in the core melting and radiation escaping [syn:
         meltdown, nuclear meltdown]
    2: a disaster comparable to a nuclear meltdown; "there is little
       likelihood of a meltdown comparable to the American banking
       collapse in March 1933"

The Free On-line Dictionary of Computing (30 December 2018):

network meltdown
meltdown

    (By analogy with catastrophic failure of a
   nuclear reactor) An event that causes saturation, or near
   saturation, of a network.  Network meltdown usually results
   from illegal or misrouted packets (see Chernobyl packet)
   and typically lasts only a short time.  It may also be caused
   by a hardware fault.  It is the network equivalent of
   thrashing.

   [Jargon File]

   (2004-02-17)