Control rod and/or instrument tree assembly

An improved core servicing apparatus for a nuclear reactor having a vessel, a head for said vessel, a penetration opening in said head and a core within said vessel of the type having an array of elongated assemblies the improvement comprising:

• a. a support column adapted to be supported by and depend from said head in registry with said penetration;
• b. a plurality of core servicing elements supported by said support column;
• and
• c. means for laterally displacing at least some of said elements between retracted and extended positions relative to said support column, whereby to vary said servicing apparatus between a laterally compact and a laterally expanded configuration, said laterally displaceable elements each including an elongated resilient drive cable extending upwardly therefrom and said lateral displacement means including a guide channel means for each of said elements and associated drive cables, said guide channel means being supported by said support column and extending generally vertically and being directed laterally outward at its lower end, said drive cables being longitudinally movable to move said elements between a position in said channel means and a position laterally outward thereof beyond said lower end.