Lungmen: building on experience20 August 1999
Although worldwide the number of nuclear plants under construction has been dwindling, the units that are under construction, notably in Asia, have been benefitting from improved technology to dramatically cut lead times. The Lungmen Advanced BWR, now under construction in Taiwan is a good example. Asian projects such as this are becoming the benchmark for what can be achieved in nuclear plant construction.
Nuclear plants today are constructed very differently from the way they used to be built in the past. The most notable difference is the schedule. A 1350 MWe ABWR (Advanced BWR), for example, can be built in less than four years, from first concrete to the start of commercial operation. This would have been unthinkable 15 years ago.
At Kashiwazaki in Japan it took just 36.5 months to construct unit 6 (from first concrete to fuel load), and 38.3 months for unit 7, which was about 10 months less than the average time for the previous BWRs constructed at the Kashiwazaki site.
Design simplifications, modularization and the use of new construction technologies and techniques make this possible.
Today, the plant owner is spared the worry of schedule delays and cost overruns. Suppliers commit to a fixed schedule and price, largely because the design has been pre-licensed and pre-engineered. Of course there is no substitute for project experience. The Lungmen ABWRs are being supplied by a veteran team of US and Japanese suppliers led by GE that were also involved in the supply of the Japanese ABWRs. This team and the supporting network of equipment subsuppliers is accustomed to working on an international stage and can readily transplant its experience and know-how to a new host country. This is the basis for the "learning curve" effect which reduces capital costs by about 10 per cent with each new unit.
Capital costs are around $1400-1600/kW at which level nuclear is very competitive with other forms of power generation. Recent estimates for an ABWR built in the USA suggest a per-kWh cost of under 4 cents. Capital costs are of course higher than for fossil but fuel prices are lower and more stable and predictable (about 80 per cent of the total cost of nuclear electricity is fixed). Global sourcing is another major contributor to keeping costs down.
The ABWR in Taiwan
An important milestone for Taiwan Power Company's Lungmen ABWR project was passed in March 1999 with the issuing of the construction permit by the Taiwanese Atomic Energy Commission. Preliminary excavation at the site started in January 1998 and first permanent concrete was poured in April 1999. The schedule for unit 2 is one year later than that for unit 1.
Taiwan plans to systematically increase its use of nuclear energy from the current level of 10 per cent to about 20 per cent and Taiwan's Ministry of Economic Affairs recently announced a national energy plan which included the construction of new nuclear plants at the rate of two additional units every five years. The rationale is that the low and predictable costs associated with nuclear power are needed to maintain the health of Taiwan's industries which depend significantly on export markets. A liberalized electricity market is to due to be introduced in March 2008.
Lungmen exemplifies the modern approach to nuclear plant construction. The ABWR nuclear plant has been designed and licensed in its entirety prior to the start of construction and, long before first concrete is poured, all safety and engineering issues are identified and resolved. This precludes construction delays due to re-engineering which plagued so many projects in the past and contributed significantly to the high (and in some cases mind-numbing) capital costs.
The ABWR has been designed to higher levels of safety, including being designed to prevent and mitigate the consequences of a severe accident (eg a core melt). Licensing documents approved by the USNRC indicate that even in the event of a severe accident, there will be no release of radioactive material to the public.
The complete ABWR plant and equipment design has been captured electronically using an information management technology called POWRTRAK (above). The benefits appear not only in construction, where it has been shown over and over again with fossil plants that use of this engineering tool reduces construction time and cost, but also for configuration management during the operation and maintenance of the plant. POWRTRAK is both a 3D model design tool and an extensive database for plant equipment and materials. It provides a single common database which is used by GE, its partners and the customer. All project documentation, correspondence and vendor submittals are maintained in a computer-driven, integrated configuration management system which is the key to maintaining the integrity of the design basis.
Building on experience
As already noted, the ABWRs at Lungmen build on experience in Japan, where the world's first ABWR, Kashiwazaki-Kariwa unit 6, began commercial operation on 7 November 1996. Kashiwazak1 7, the second ABWR, followed shortly thereafter with commercial operation on 2 July, 1997. These are the sixteenth and seventeenth nuclear units operated by The Tokyo Electric Power Company – all BWRs – and are expected to be the first of many ABWRs to be built in Japan over the next 10 to 20 years.
Both these ABWRs are now in cycle 3 of operation. Performance to date has been excellent, with, for example, only one scram (due to a lightning strike) and high load factors. All performance goals, which are indicative of the higher standards set for an advanced plant, have been met, including those for radwaste (60 drums/y) and occupational exposure (20 mrem/y).
Meanwhile in the USA, although there are currently no plans to build any ABWRs (or any other nuclear plants for that matter), the ABWR has been pre-licensed, a process described as the most exhausting review ever undertaken by the US Nuclear Regulatory Commission. The efforts of the NRC and GE came to fruition on 2 May 1997 when the then Chair of the NRC, Shirley Jackson, approved and signed the design certification for the US version of ABWR. This was a significant accomplishment, one that has been envisioned for a long time - pre-approval of a standard design of an advanced nuclear plant.
Also in the USA, the ABWR First-of-a-Kind Engineering (FOAKE) programme was completed in September 1996. This is significant because it represents a major step towards the US industry's other goal – to have a (pre-licensed) design 90 per cent complete prior to the start of construction. At the conclusion of the FOAKE programme, about 65 per cent of the engineering of the US version of the ABWR was complete with the remaining engineering to be completed for the Lungmen units. The FOAKE exercise essentially provided the basis for the Lungmen design.
In Europe the EUR Steering Committee agreed to review the ABWR design against the European Utility Requirements (EURs) with work to begin in 1999. The ABWR review is sponsored by three major European utilities who began working with GE in 1998 on a preliminary review of the EURs. The development of a European ABWR (EABWR) that meets unique European requirements but is also based upon licensed designs and worldwide project experience is an important initiative that may, in a few years, culminate in an ABWR project in Europe.
Also under development is the ESBWR, an advanced design based upon the ABWR but with some additional passive features, namely natural circulation. These European versions of the ABWR trace their history to the ABWRs now being deployed in Asia, but have been adapted to meet unique European requirements.
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