At the end of WWII, the Navy wisely collected all the good ideas they could get from anywhere and built them into the “Fast Attack” class of 6 submarines. I was commissioning CO of HARDER in ’52 and had a fascinating time with a faster, deeper diving, snorkeling submarine with novel sonar, fire control, 1,000-volt electrical system, no-bubble torpedo ejection system, powered torpedo and mine handling system, improved environmental controls, hovering system, improved shock protection, better str·eamlined hull, more maneuverability, and compact high speed diesel generator sets.
In the complex geometry or these submarines it is not surprising that the use of full-scale wooden mock-ups allowed hundreds of changes prior to installations. These involved changes in pipe and wire runs and equipment locations to allow operator access for operation and repair. Early arriving commissioning crew members were the ones who identified the changes needed. Perhaps modern computerized design could obviate the need for these expensive mock-ups.
Many of our new systems could be tested only in an operating submarine and we identified hundreds of necessary alterations. For example, the piston driven torpedo ejection system so jolted the torpedoes that batteries were crushed; the system would not work at speeds of over 10 knots because hydraulic pressure on the nose of the torpedo pushed it against the rotating stop bolt preventing operation; the system was also very loud. Electrical transients picked up by the starter control circuits could start the torpedo engine in the tube in port, as happened in TRIGGER. Rapid brush wear in the 5 KVA motor generator set evidently was due to freon leaked from the air conditioning systems. The 400-cycle IC electrical system and the 3,000 psi hydraulic systems were generally successful in providing more compact and faster acting indicators and actuators. Greater care in fabrication was required. In these areas we derived much benefit from experience in aircraft.
The 1,000-volt electrical system produced some puzzling pyrotechnics. The boats preceding HARDER had all made shakedown cruises in calm warm southern waters, so I took HARDER into a monstrous north Atlantic storm. Intuition drove me to invite along the leading electrical engineers from BUSHIPS. As seasick as they were, they were very helpful when we lost all power 13 times with circuit breakers blowing out of sequence and 4foot arcs jumping out of propulsion control cubicles. It turned out that the main problem was that the new type of wedging used between cells in the battery well allo\ofed the cells to work in the heavy seas, loosening the celltop seals and allowing electrolyte to cause complex grounds the effects of which appeared all over the boat. The BUSHIPS people saved me probably hundreds of shipalt requests. In similar fashion, we later made 100 changes in the torpedo ejection system without a single shipalt request.
The Mk 101 Fire Control System was, to me, a very welcome addition in that it provided very rapid rate-control fire control analyses as had the anti-aircraft director computers with which I’d been earlier connected in carriers. Further, the system allowed better use of active sonar in fast moving dog-fight situations. These computers contained large numbers of analog circuit boards. The theory was that we would carry a few spares onboard and ship failed boards back to Arma for repair and return. However, when the MTBF (Mean Time Before Failure) turned out to be about 1 hour, I ordered sets of dentists tools and set up on-board repair.
These weaknesses were later fixed, and even later digital systems were developed.
So far, what I’ve described in the “Fast Attack” class were interesting (if vexing) problems to solve in providing much improved submarines, and leading to systems in future subs. Now I come to the Main Engine Generator sets of the Propulsion and Charging system. Here, there are many lessons to be learned.
In hope of making the submarines of the “Fast Attack” class more compact, GM and FairbanksMorse had been paid to develop engines of about twice the RPM (1500) and power density of the WWII engines of 1500 HP. GM came up with a pancake radial engine with generator suspended underneath. It was very compact, fairly accessible, vulnerable to oil seal leaks into the generator, extremely loud in the engine room (over 120 decibels), and with a MTBF of only a few hours, as unknown vibration effects and high speed tore the engines apart, (4 in each boat). More than once, a submarine lay dead in the water with all engines out, as crews valiantly raced to repair them before the battery went dead.
A similar experience was had with the Fairbanks-Morse slightly larger engine (3 per boat) which were conventionally mounted and not very accessible. Almost every part of the engine was vulnerable and the spare parts flow was incredible. We were fortunate that no fatal accidents occurred though there was one almost tragic incident. TRIGGER (GM engines) was alongside State Pier, New London, next to HARDER one night, conducting a battery charge, when suddenly there was an enormous siren-like roar as an engine went into overspeed in a few seconds. Only the immediate response of a First Class Electricians Mate saved the ship from an explosion. After 48 hours of continuous investigation (we had to assume that all the class were similarly vulnerable) we found that a 10 ampere fuze in the battery compartment had blown. It turned out that this fuze controlled the circuit which controlled the reverse current relay protecting the engine-generator from being motorized by the enormous 1,000-volt battery. I later concluded that the kind of analysis conducted by nuclear reactor safeguard studies would have detected this error in design.
Worthy as these efforts at engine development had been, the cost in operations and repair and in eventual re-engining all the boats was very high. It would have been much better to spend the effort in development and testing in a shore based prototype, before installation in the boats.
A characteristic of these power plants worth considering is that they were not unitized like an aircraft engine. Each was in a room surrounded by a maze of pipes, tubes, wirebanks, valves, gauges, and levers with accessories spread about the room. Men watched gauges and reached for valves and levers and switches. Accessibility was needed all around for maintenance, not to mention repair. There was no computerized data recording or diagnostic analysis. Men recorded reams of readings every 15 minutes — these useful only in case of failure analysis. There was no automatic sequencing of start-up or shut-d .own through remotely operated valves and switches from computerized central control.
Many, but not all, of these lessons were applied to the development of the nuclear propulsion plants for surface ships and submarines.
Now to some lessons from nuclear power development. In those days, and now, there operated the theory that a high command, established “Requirements” on the basis of which “Feasibility” was established by funded study. But how could a requirement for an advanced system be established until a feasibility had been shown? This leads to a paralyzing logical circularity which has repeatedly hurt the U.S. in ita hi-tech efforts. An arbitrary input is required either between feasibility and requirement or between requirement and feasibility. One of the main useful functions of Admiral Rickover was to provide this arbitrary input. It may be that DARPA can provide this for fuel-cell submarines.
He collected a staff of very bright, tough, dedicated officers and civilians and ran a very centralized operation. With all this centralization, however, he delegated enormous initiatives to a large number of naval and contractor personnel.
He didn’t have to go on the cheap. He insisted on full sized land-based prototypes, extensive testing, realistic training, rigorous safety· analysis, and rigid quality control. He used the safety issue to maintain control. Communications were frequent, dense, and tightly reviewed with dedicated sources at each activity.
There was a black Thursday emergency at the STR prototype in Idaho early in its history, when the reactor was slowed by an unexpected build-up or a neutron absorbing fission product. There was another when “crud” was found to be built up in the primary loop. In each case the reaction was swift and massive and solutions soon found. When a steam pipe failed it was found to be seamed tubing instead of seamless as specified. Then it was found that inspection was an unreliable indicator and that quality control was a problem throughout u.s. industry. Admiral Rickover seized control of all the output of a steel mill and changed all tubing in all his plants.
In the SEAWOLF liquid metal cooled plant it was round that with the 347 stainless steel tubes used in the primary system, there was not only the threat posed by chloride stress corrosion producing rapid cracking found in the water plants and requiring rigid water purity specs, but also the threat of similar cracking produced by the high ph which might be produced by a leak of water into the liquid metal. One effort to avoid this was to substitute mercury for NAK (liquid sodium) in the heat exchanger third fluid systems. For our one plant, we used the annual U.S. production of the sodium which proved impossibly toxic and dangerous to steel.
The liquid sodium cooled reactor plant was in competition with the high pressure water cooled plant. The sodium plant had many potential advantages including greater potential for unitizing and the fact, as it turned out, that the sodium is much less reactive than water at the temperatures and pressures used in the water plants. In the total operation of the SEAWOLF plant, nothing had to be added to or removed from the primary fluid whereas water chemistry in the water plants is of concern every watch. A disadvantage of sodium is the higher level of radiation around the primary loop for some days after shutdown. Separation of primary and secondary fluids was much more important and freezing in the wrong places had to be guarded against. The sodium plant bad the further advantage that higher temperature steam could be produced and that the pressures in the primary loop were much lower.
A further advantage of sodium was that the intermediate spectrum of neutron energies was much more favorable to breeding fuel. Progress in the system might have helped the civil development of breeders.
Good engineering and quality control could have kept the sodium plant competitive, but there was one very basic difficulty; the 347 stainless steel tubes which had to be used had a high coefficient of thermal expansion and relatively low thermal conductivity with the result that temperature waves in the excellent thermal conductor sodium, thermally stressed the steel and tended to crack it unless closely controlled. Water plants won the competition.
I won’t go into the arduous task of developments of the special welding required and its inspection, the metallurgy of zirconium, beryllium, hafnium, and boron; and many others.
When a study of Korean War jet failures showed that most were caused by failure of fasteners which then went through the engines, ADM Rickover decided that all fasteners had to be captive in the primary loops and in many other places. The ingenuity of engineers here was remarkable and important, and probably will be important for fuel cell plants.
The early nuclear plants were heavily instrumented and automated in coolant flow/power level, rate of reactivity change, various scrams, and emergency cooling. Cumbersome magnetic amplifiers preceded digital computers, and the steam sides of the plants were conventional. The steam systems were distributed around an engine room and not unified as in jet engines. With individual pumps etc., separately sound and shock mounted, self noise was still excessive and rafting had later to be used. Large crews are required for operation, data recording, routine maintenance, and repair.
