b'C H A P T E R 8T H E R EA CT O R Z O O G O E S C R I T I C A LGetting to the MTR operating floorrequired passing several safety andsecurity barriers. The MTR complexwas enclosed behind a chain-link fencestudded with night lights and furtherdefended by a ten-foot-wide patrolroad. The bus dropped him at the MTRgatehouse, where a guard checked hissecurity badge each day. If anyonecared to notice, they could see that the250-foot MTR exhaust stack stood onthe downwind side of the complex and,for security reasons, showed no aircraftwarning lights. To get to the reactor,Byrom passed into the exclusion areathat contained the MTR building withits laboratory wing and fuel storagecanal, along with other special labsand storage buildings. The building wasabout 130-feet square and made of pre- INEEL 55-432fabricated concrete slabs. 6 Above. The thickest wrapping around the MTR is thebiological shield. Right. The MTR hot cells. BehindInside, the enriched uranium core of the viewing windows three feet thick, operators examinereactor was like a small jewel wrapped test samples. Note shield plugs above and belowin successively thicker layers of wrap- windows for electrical leads, instrument air, oxygen,ping. Surrounding the fuel was a steel or other requirements.tank thirty-feet deep and six feet indiameter. A steel lid fit over the top.Pumps forced cooling water through each hole, made up of the samethe tank under pressure to keep it from sequence of materials as those adjacentboiling. Two types of reflectors sur- to it in the reactor cabinet. While therounded the tank to bounce neutrons reactor was shut down, operatorsback toward the core. The closest to the removed a plug and inserted a test sam- INEEL 61-4707fuel was made of beryllium metal. Just ple toward the core. Overhead, a thirty- photographic darkroom, one of severalbeyond was an outer zone of graphite, ton crane helped maneuver the heavy labs in the MTR laboratory wing, hecooled by forced air. Then came ten plugs into and out of shielded containers loaded each sheet into a light-tightfeet of dense concrete and gravelthe called coffins. The plugs were sup- holder containing a thin lead foil back-main biological shield. A casing of steel posed to prevent neutrons from straying ing. He matched the film to grid marksenclosed the whole contraption, which to the outer edge of the plug openings. on the cabinet and numbered each gridlooked like an oversized cube thirty- But would they? cell. When the reactor operators startedtwo feet to the side. 7 noodling the control rods, movingByrom used X-ray film to check for them up and down to get familiar withIt was the one hundred holes piercing leaks, the same 14x17 inch size that the MTR as they advanced toward fullthe reactor that were Byroms special physicians used for chest X-rays. He power, Byrom was ready.concern. Acomplicated plug stoppered ordered dozens of boxes. In the MTRs6 7'