Free Hunting Season by P. T. Deutermann Page B

no evidence around the inside penstock area that anyone else had come through the tunnel recently. Besides, Lynn hated confined spaces, so if the kids had come to the arsenal, it wasn’t likely they had come
    through that tunnel. On the other hand, a creek this big probably did not originate within the restricted area, which meant there had to be another water cut through the fence, perhaps over on the higher, western side of the reservation.
    The creek appeared to run east-west.
    His plan was to follow the south bank of the creek all the way across the arsenal and to look for signs of recent human intrusion along the way.
    If that effort turned up nothing, he would follow the north bank back and then cut over into the industrial area, which was north of the creek. He wasn’t even puffing after the exertion of getting through the tunnel and getting set up in the crawl suit, which was a good sign. He was not in the shape he’d been when he was active, but he hadn’t gone entirely soft, either. Except in the head, maybe, he thought. Those two agents had warned him against interfering, and he knew they were right. But since they weren’t actually doing anything, he didn’t feel too bad about it. He also knew that he might not like what he found. He took one last look around the pool area and then started west into the woods.
    Browne McGarand sat in what had been the main control room of the power plant, watching the band of morning sunlight advance across the control room’s wall from the skylights. He was keeping an eye on the pressure gauge of the operating hydrogen generator, which was a five foot-high glass-lined stainless-steel retort into which he had put a sponge of copper metal. Suspended above the retort was a glass container of nitric acid, which was dripping down a glass tube at a controlled rate into the retort. The nitric acid combined with the copper to produce a slag of copper-nitrite and pure hydrogen gas. The reaction was exothermic, which required that the bottom of the retort be encased in a large tub of cold water to draw off heat. When the pressure in the retort rose to five pounds per square inch, a check valve lifted in its discharge line. The physical movement of the check valve activated a pressure switch, which, in turn, closed a contact connecting a small gas-transfer pump to its power supply. The pump drew the hydrogen gas out of the retort and pumped it through the wall into the tank of a propane truck that was parked in the maintenance bay next to the control room. When the pressure in the retort dropped back down to three pounds, the check valve reseated, shutting off the transfer pump, and then the whole process would wait for hydrogen pressure to rebuild in the retort.
    Five pounds of copper took about two hours to produce as much hydrogen
    as it was going to make. Once the reaction began to decay, indicated by a steady drop in temperature, Browne would open valves to bring a second retort on line while he replenished the first one. He would don a respirator, divert the discharge line of the pump into the atmosphere of the control room, and operate the gas-transfer pump with a manual switch until a small vacuum was established on the retort. He would then close all the transfer valves by hand. He would wait, watching the gauge to make sure that it didn’t creep back into the positive pressure range.
    Once certain that the reaction had stopped, he would open a vacuum breaker valve on the retort, and then the main cover. He would remove the slag residue using tongs and rubber gloves, add five more pounds of metal, and close up the retort. He would run a short air purge on the retort, using the transfer pump again, until he had once more established a small vacuum in the retort vessel. Then he would start the nitric-acid drip going again.
    It was slow, painfully slow. But it was a fairly safe way to make hydrogen, and, ultimately, an absolutely untraceable bomb. He had read with great