April 11, 2012

Chinese Submarine Reactors


China's Type 093 SSN. Does this sub boast the advanced high temperature gas-cooled reactor (HTGR)?

Several days ago Sujith expressed interest in any information about Chinese nuclear submarine reactors. The US appears to have collected most of the available overt information on this subject. Further information might be available to any Indian students of the US Naval War College or Indian naval intelligence talking to US opposite numbers.

From Undersea Warfare (2006) Official Magazine of US Submarine Force.

Background

"The development of Chinese naval nuclear power followed a slow and painful process. The lack of trained technical personnel, a weak industrial base, and the political upheavals of the late 1950s and 1960s restricted the pace at which China’s first indigenous submarine and its propulsion plant were developed. The final product was marginal by international standards, being noisy and apparently plagued with significant technical problems. It is nevertheless impressive that a country that was so politically chaotic and economically backwards could produce one of the most complex

Chinese naval nuclear power program started in July 1958 when Mao Tse-Tung and the Central Military Commission gave approval to start the 09 submarine project.1 The Institute of Atomic Energy (IAE) started the 09 project by looking at information on the U.S. and Soviet submarine programs. Available information convinced them that a pressurized water reactor (PWR) based on the Russian icebreaker Lenin’s propulsion plant would be the best choice. It was also decided early on that a land-based prototype would be built first for testing and training. The IAE created the Reactor Research Section (RRS) and within a few months had recruited over 200 engineers and technicians to start designing the plant.2

RRS personnel scrutinized foreign textbooks, reports and any other resources available to determine the specifications for the plant. The design was completed and approved by mid-1960. The Second Ministry of Machine Building was given control of dozens of factories that were capable of producing the specialized instruments, controls and major components required for a nuclear propulsion plant.

The project was severely affected by the Great Leap Forward (1958-1961), the Cultural Revolution (1965-1975), and the Third Line movement – government-run economic and social transformation programs. These three movements resulted in major program delays, funding cuts, and the loss of talented engineers due to political issues. Despite these delays, the land-based prototype design was completed by 1967 and construction started in March 1968. The People’s Liberation Army (PLA) was required to participate in the construction effort in July 1968 to compensate for the disruptions caused by the Cultural Revolution, and the plant was completed in April 1970. The plant conducted full power operations in July 1970. The prototype was a success, and the basic design of the plant proved adequate.3 The infrastructure built up around Jiajiang, named the Southwest Reactor Engineering Research and Design Academy, or, First Academy, became China’s largest nuclear power industrial complex.

At the same time, the submarine design progressed along with the development of the reactor plant. The layout of the submarine and its subsystems was determined by the use of a full-size wood and steel model used to test fit all the components. This slowed construction but avoided costly rework to the actual hull, and the reactor was in place by early 1971. The submarine was able to get underway for the first time on August 23, 1971. Not surprisingly, many technical abnormalities occurred during sea trials, and it was not until 1974 that the submarine was deemed ready to join the fleet.

Overall, the story behind the building of the Chinese nuclear submarine is also the story of building the Chinese nuclear industry, and in some ways was the basis for building the entire Chinese industrial system. The technology that was developed by Chinese scientists and engineers on the 09 submarine project and other strategic weapons systems helped to build the confidence of a nation that had never had a significant industrial base. Overcoming a vast number of technical challenges amidst the political chaos of the 1960s showed the extraordinary determination of the Chinese to complete the submarine project, and the potential they had to accomplish other high technology projects.

The Organization of China’s Nuclear Industry - The Chinese nuclear industry traces its roots back to January 15, 1955, when Chairman Mao and the Central Secretariat decided to develop atomic weapons. This decision made it imperative to develop the technical and scientific knowledge required to build bombs, which also developed the technology base for building nuclear-powered submarines and eventually a robust civilian nuclear power industry.

The China Institute of Atomic Energy (CIAE) is the main research and devel and 092opment organization of CNNC. It was created in the early 1950s and directly supervised the development of the first submarine nuclear power plant as part of the 09 submarine project. [The first Chief Designer of China's 091 and 092 nuclear submarines was an engineer and scientist of nuclear propulsion engineering Mr. Peng Shilu.] The CIAE created the Reactor Engineering Research Section in 1958 and this became the Reactor Engineering Institute in 1964. The Reactor Engineering Institute (Code 194) did the initial design studies for the 09 submarine project and today is still the primary design institute for submarine propulsion plants.

...China’s Prospective Nuclear Submarine fleet

[Following Chinese development of its first nuclear submarines - the  Type 091 SSBN and 092 SSN] - "The development of China’s type 093 [SSN] submarine started sometime in the 1980s or before. Construction of the first unit began in 1994, but it was not launched until 2002. It is speculated to be similar to a Russian Victor III using two Pressurized Water Reactors (PWR) and other Russian technologies. However, various sources state that the 093 has an advanced high temperature high efficiency reactor plant. Whatever the case, the use of the technology gained by the civilian nuclear industry has the potential to greatly improve submarines designed and built in China.

The transfer of technology has most likely played a part in providing the 093 and future submarines with advanced I & C equipment, a better-designed reactor fuel cell, and higher quality construction of the reactor plant. This is the minimum that the Chinese would be able to get from the technology that they had obtained by the mid-1990s when the 093 was started. The delays on the ship could very well have been caused by continuous attempts to update the design as construction progressed. The 093 was laid down in 1994, but construction began on the Qinshan 2 nuclear power plant in 1996 (with French assistance), Qinshan 3 in 1998 (Canadian), and Ling Ao in 1995 (French). The Yinbin Fuel Plant was upgraded by the French in 1994 and from 1994 to 1996, Westinghouse made the plans for the AP600 (its most advanced civilian nuclear power plant) available for the Chinese to study. Thus, the nuclear technology flowing into China during the period from 1994 to 2002 was – by any measure – very substantial. The Chinese may have made the decision early on to delay the 093 in order to incorporate the maximum amount of foreign nuclear technology possible.

Given the technology transfer described above, it is at least possible that China has developed a submarine-compatible high temperature gas-cooled reactor (HTGR). This possibility is worth considering for several reasons. The first is that, if successful, a HTGR would allow for a much lighter power plant. A HTGR is twice as efficient as a PWR so it would require a substantially smaller core for the same power output. It is also cooled by helium at a relatively low pressure instead of by high-pressure water. This reduces the weight not only of the coolant but also of the piping. The reduced weight would potentially allow the submarine to be faster and smaller.

The second reason is that the Chinese have stated that their goal in designing weapons is to use the latest technology to leap ahead. Developing a unique reactor system would be a dramatic example of this policy. The research on HTGR in China started in the 1970s, before a substantial amount of development in the civilian nuclear power industry began; this tends to indicate that some type of military use was envisioned. This would also help to explain why it has taken so long to build the 093. The conventional theory that the 093 is similar to a Victor III design, and that the Russians assisted in its construction, by contrast, would predict rather rapid development. This, however, has not occurred, suggesting at least the possibility that there is something significantly different about this submarine.

The technical difficulties that would have to be overcome with the blowers (i.e. the need for magnetic bearings) and the fuel loading system to make a HTGR compatible with a submarine are formidable. This makes the probability of the 093 being equipped with a HTGR small. Nevertheless, it should be taken into consideration that if not the 093, then a future Chinese submarine could have a reactor of this type. Such a vessel could take a form that would represent a significant departure from current nuclear submarines that are designed for open ocean long endurance operations.

Chinese strategy for the near and medium term appears to be focused on pushing its defenses out to the first island chain, which includes Japan, Taiwan, and the Philippines. This will require more shallow water access denial platforms, instead of long-range open ocean submarines. A small submarine, similar to a diesel electric submarine but equipped with a small HTGR to recharge the batteries, would be an ideal sea denial platform. It could stay submerged for extended periods of time while lying in wait for a passing ship. This submarine could have technology currently available from the recently purchased Kilo-class submarines for the batteries and propulsion while using a reactor on the scale of the HTR 10 (2500 KW generator). The reactor would have to be quiet, but a HTGR equipped with an integral gas turbine/blower outfitted with magnetic bearings could – in fact – be designed to be very quiet.

Conclusion

We would be foolish to dismiss China’s ability to develop complex weaponry. The 091 submarine is often cited as an example of Chinese engineering incompetence, since the submarine is viewed as one of the worst in the world. But when considered in the context of when it was built and the state of the Chinese economy and political system at that time, it is actually impressive that the submarine was ever finished. No one denies that the Chinese economy and industrial base have made extraordinary strides since that time and that the level of technical expertise in China has risen dramatically. Combine this with the advanced technology currently available to China, and it seems evident that the 093 submarine is unlikely to be a simple copy of a 1970s vintage Russian design, but rather something significantly more advanced."

Another US source is:

Andrew Erickson and Lyle Goldstein, "China's Future Nuclear Submarine Force: Insights from Chinese Writings," Naval War College Review, Vol. 60, No. 1 (Winter 2007), pp. 54-79 http://www.usnwc.edu/getattachment/Research---Gaming/China-Maritime-Studies-Institute/Published-Articles/Erickson-Goldstein_China-s-Future-Nuclear-Submarine-Force_NWCR_2007-01.pdf

Here are fragments - best to read the original PDF article.

"...China will field a total of six 094 SSBNs, divided into patrolling, deploying, and refitting groups.
source suggests that these groups will comprise two SSBNs each.

Chinese sources universally recognize that noise reduction is one of the greatest challenges in building an effective nuclear submarine. For instance, experts at China Ship Scientifi c Research Center
developed a relatively advanced guide-vane propeller by the late 1990s.  China already has advanced seven-blade propellers with cruciform vortex dissipaters on its indigenous Song-class and imported Kilo-class
diesel submarines, suggests that the 093 and 094 will have signifi cantly improved propellers.

A researcher in Qingdao’s 4808 Factory also demonstrates Chinese attention to the need to use sound-isolation couplings to prevent transmission of vibrations to the ocean from major fresh-water circulating pumps in the steam. One Chinese researcher states that the 093 is not as quiet as the [latest US subs] .
analyst estimates that the 093’s noise level has been reduced to that of the Russian Akula-class submarine at 110 decibels [acoustic signature has been reduced to 120 decibels.

It is conceivable, if unlikely, that the PRC has achieved a major scientific feat concerning the propulsion system for nuclear submarines. A wide variety of Chinese sources claim that China has succeeded in developing a high-temperature gas-cooled reactor (HTGR) This development is described as a “revolutionary breakthrough” [its] volume is small, [its] power is great, [its] noise is low—it is the most ideal propulsion system for a new generation of nuclear submarines. The United States and Russia have both not achieved a breakthrough in this regard.


This same analyst suggests that the need to incorporate the new HTGR explains why 093 development has stretched out over a number of years. Despite the above speculation, there are substantial reasons to doubt that China would be willing or able to put such an immature technology in its second generation of nuclear submarines, as this would constitute a substantial risk on the investment. Moreover, as Shawn Cappellano-Sarver points out, “The technical diffi culties that would have to be overcome with the blowers (the need for magnetic bearings) and the fuel loading system to make an HTGR compatible with a submarine are formidable. This makes the probability of the 093 being equipped with an HTGR small.”
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Pete