One plan to produce energy (PACER) would detonate nuclear weapons ...

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One plan to produce energy (PACER) would detonate nuclear weapons underground. What environmental concerns might a project engineer building the underground cavity need to consider?
 
  What will be an ideal response?

Question 2

How could superconducting magnets be used for short term energy storage?
 
  What will be an ideal response?

[Kjones0604]

Answer to Question 1

If nuclear weapons were to be detonated underground, the cavern in which the
explosions are envisaged to occur would quickly become contaminated with radioactive
products of the explosions. It would be essential to make certain that radioactive materials
not be released to air or water. The latter might be a more difficult to achieve than the
former. Radioactivity can get into groundwater and cause contamination over a large
volume. This groundwater contamination has occurred at Hanford Reservation in
Washington, a Department of Defense site on which no nuclear explosions have occurred,
so a region within which nuclear explosions could be occurring could certainly cause
groundwater contamination problems.

Answer to Question 2

Circulating currents cause magnetic fields. If materials are strong enough,
considerable energy densities can be accommodated. Such systems could be important in
providing backup energy to correct for momentary surges in the grid.