Homework on a lesson -- Assignment No 2

Please click here to see my previous entry Homework on a lesson -- Assignment No 1

In Assignment No 2, I discuss a second aspect put forward by Dr M. R. Srinivasan, Member (formerly Chairman) Atomic Energy Commission in his article published in The Hindu, on 11th September 2007 under the title "A lesson in nuclear reactors", in favour of importing LWRs (in the context of the civilian nuclear co-operation agreement with USA, presently being debated vigorously in our country).

Phew!! For this assignment, it took me a long time indeed to gather all relevant information in the public domain almost entirely from the Internet, understand the science behind it and present the same in this blog.

Dr. Srinivasan writes:

"Natural uranium reactors, both Magnox (GCR) and PHWR, require to be fed with fresh fuel regularly (on a daily basis). Some spent fuel has to be taken out when the reactor is operating. The PHWRs, due to their inherent lower reactivity, have a limitation on how quickly they can restart and be loaded, after an interruption due to any fault. The LWRs do not suffer from this disability. [Emphasis mine] They can run for 15-18 months without a fuel change; the latter requires the reactor to be off line for a month or so.

I would be wary of uncritically accepting this soft sell for LWRs.

I believe that the above comparison between PHWR and LWR has been made by Dr. Srinivasan based on his earlier experience with PHWRs in India which were of small capacity (220 MWe) operating in relatively small and unstable grids. In an effort to reduce the total capital cost, the volume and quantity of heavy water in the coolant circuit was kept as low as possible and hence did not have adequate "cushion" to tide over severe load-demand fluctuations from the grid side. This is not the case with modern larger PHWR (540 MWe) as well as CANDU design which have a "pressurizer" incorporated in the primary coolant circuit which greatly enhances the plant's ability to accommodate load changes (though not to as great a degree as in a thermal power plant). In other words, modern PHWRs and CANDU designs have comparable ability as LWRs in terms of load-follow capability.

Keep in mind that fissile material in the core (limited to U-235 for this discussion) provides "positive reactivity" that is necessary for fission chain reactions to take place. On the other hand all other materials in the core, including the moderator, coolant and other structural materials are neutron absorbers to a greater or lesser degree and hence contribute to "negative reactivity". Light Water used in LWR absorbs neutrons to a much greater degree than Heavy Water in PHWR. Hence LWR is considered to be very neutron-wasteful since a significant portion of the neutrons that come out of fission is absorbed in a wasteful manner, instead of being made available to cause the next fission in the chain reaction.

For chain reactions to proceed and for power generation in the core, the positive and negative reactivities need to be carefully balanced.

Theory of Xenon (Xe) poison build-up in brief

Fission products, which are inevitably formed in the core (fuel) -- somewhat like formation of ash when burning coal -- are also neutron absorbers. Xe-135 is one such fission product which introduces transient negative reactivity in the core. Because of its propensity to absorb neutrons, Xe is said to be a "poison" and the negative reactivity induced by Xe is called "Xe poisoning".

Dr. Srinivasan's comment above, I think, pertains to the ability of PHWR or LWR to overcome Xe poisoning effects that manifest when changes in power production levels take place in the reactor core.

As a nuclear reactor operates, Xe is produced in the core (actually in the fuel), due to a variety of nuclear reactions including the fission process itself and also radioactive decay from its precursor nuclei which are also fission products such as Tellurium and Iodine. Xe production continues for some time even after the chain reactions have stopped (that is, when the reactor is shut down). On the other hand, Xe also gets "removed" through neutron absorption, whenever chain reactions take place (that is, when the reactor is operating). The second way in which Xe gets progressively "removed" is through its natural decay. This happens when the reactor remains in the shutdown state for a length of time (of the order of 40 or 50 hours).

When rate of production is equal to rate of its removal, the Xe concentration in the core reaches an equilibrium level. So when a reactor begins to operate from a "cold clean" condition (when there was no Xe in the core), Xe formation starts and accumulates for some time until the rate of removal through neutron (produced in the fission process) absorption equals the rate of production. It attains an "equilibrium concentration".

In PHWR as well as LWR adequate excess fuel is provided to account for the equilibrium "Xe load" at all operating power levels.

Rates of Xe production and removal are affected whenever there is a change in the power production in the core. This leads to a "Xe transient" whereby the concentration of Xe present in the core may increase or decrease with time.

For purposes of this discussion, we can broadly consider two types of transients. A relatively slower Xe transient occurs when the reactor power in changed due to changes in the turbine output demand, or when operational maneuvers are carried out such as a "reactor step back", "steam dump" and "hot stand by" conditions. In all these case, the chain reactions are not stopped (that is the reactor is not tripped/scrammed). These manoeuvres lead to Xe transients whereby the Xe concentration could temporarily exceed the equilibrium concentration, before settling down to a new equilibrium value. As mentioned earlier, PHWR design incorporates features comparable to that of a LWR in successfully negotiating this transient without needing a plant shutdown.

From the point of view of this discussion on Dr. Srinivasan's comment about a so-called "disability" in the PHWR / CANDU, the more relevant type of Xe transient is one that takes place when the reactor is tripped/scrammed by introducing into the core, a massive amount of negative reactivity in a very short time, usually within about 2 seconds. Such a trip or scram may be automatically initiated by the plant control system or manually initiated by the operator whenever any one of several vital parameters (such as, for example, the coolant pressure) go beyond their (predetermined) safe values.

Figure 1 (below) is a graph depicting the Xe transient. It shows the equilibrium Xe concentration (marked "A") prior to reactor trip. The subsequent curves (in magenta and violet) show how the Xe concentration builds up and reaches a peak (marked "C") following a reactor trip. This happens because one of the two mechanisms of removal of Xe, that is, the neutron absorption process is not present subsequent to a reactor trip. After some time, production of Xe from radioactive decay of I-135 comes down while its own decay continues. So the concentration begins to go down and ultimately a level "D" is reached.

In the figure, it may be noted that the peak Xe concentration ("C") can be several times that of the equilibrium value ("A"). Usually in PHWR as well as in LWR an optimum level of extra positive reactivity is proved in the core so that some Xe poisoning ("B") can be overcome.

If for any reason the fault that caused a reactor trip/scram cannot be rectified within the "override" time, then, reactor restart would have to wait until the Xe concentration comes down to such a level that the positive reactivity that can be made available is adequate to overcome the negative reactivity due to Xe poisoning. Note that removal of negative reactivity is the same as addition of positive reactivity; so withdrawal of control/adjuster rods, or removal of deliberately added soluble poison such a Boron in the moderator has the same effect as adding positive reactivity.

In modern PHWR as well as in LWR reactivity provided to "override" Xe poisoning subsequent to a trip/scram is such that it must be restarted with in about 30 to 45 minutes. In fact, if a land-based power LWR for electricity generation were to be designed to have capability to add positive reactivity as and when required to overcome Xe poisoning to the level of "C", (this is called "full Xe override capability") then it would be even more neutron-wasteful than it already is. Only nuclear submarines which use very highly enriched fuel, have full Xe override capability as otherwise they cannot be "caught napping" while submerged at sea with their nuclear power plant in a tripped/scrammed condition even for a short while, leave alone 60 hours.

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Summary

1. Nuclear reactor, steam turbine, electricity generator and the grid all have to function in a co-ordinated manner for safe and successful generation, distribution and utilisation of electricity.
2. Indian electricity grids, especially during the early days of nuclear power generation, tended to be small and the users often ill-behaved leading to wide fluctuations in voltage and frequency. Such steep variations in operating parameters, usually led the nuclear power plant to trip and separate from the grid as a protective measure to avoid damages to the turbo-machinery.
   
   
   
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3. As shown in Figure 2, modern nuclear power plants (both PHWRs and LWRs) have the ability to succesfully decouple the turbo generator from the grid and also the reactor from the turbogenerator so that in most cases a grid fault or certain malfunctions in the turbogenerator systems do not require a reactor trip/scram. In these conditions the reactor can be “islanded” and continued operation at a lower power output is made possible by supplying “house loads” and/or by steam discharge; the reactor stays critical (that is, it is not tripped/scrammed).
4. Reactor design takes into account the above situation and as long as the reactor is not tripped/scrammed, enough excess reactivity can be made available to overcome the build up of Xe “poisoning” that might temporaily result from the reduction in the output.
5. This is true for both LWRs as well as PHWRs.
6. On the other hand, should a fault occur in any of the systems associated with the nuclear reactor plant itself (or in the turbogenerator system) that requires a reactor trip/scram, then, it must be cleared within about 30 to 45 minutes to be able to restart the reactor before Xe poison build up takes place to such an extent that it cannot be overcome. If this window of opportunity is lost (that is if the fault causing the reactor trip could not be rectified within 30 to 45 minutes), then plant operators must wait until the Xe poison dies down sufficiently (about 60 hours) before the reactor can be made critical once again.
7. Again (6) above is true for LWRs as well as PHWRs although plant-specific information on the exact time duration available to the operator to “beat the Xe poison” could not be readily obtained in the public domain from the Internet. Only submarine reactors which use highly enriched U235 have full Xe override capability and can be restarted at any time after a reactor trip. In a land-based electricity generating nuclear power plant, to provide for full Xe override capability by building a large amount of excess reactivity in the core would lead to a significant reduction in neutron economy.
8. Modern large capacity PHWR / CANDU is more neutron-economical than a LWR and has similar operational capabilities. To me it seems that imported LWRs do not enjoy a significant advantage over PHWRs (such as India-built Tarapur 3&4) with regard to Xe override capability as indicated by Dr. Srinivasan.
9. What is more important is the overall availability/capacity factor of the nuclear power plant. According to NPCIL's Annual Report for 2006-07 weighted availability factor for its power plants was 85%. Figure 3 below demonstrates that performance of Indian PHWRs (indicated in the figure as NPCIL PHWRs) are comparable to foreign plants.
   
   
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10. It is not just the quality of the design that governs successful operation of a power plant. Good operations and management culture combined with sufficient understanding of know-why is more important than just having imported systems/equipment. Over the last few decades India has acquired much of the all important know-why, the hard way. It is essential this is not lost by resorting to imported equipment/systems. On the contrary, it must be enhanced by providing all the appropriate financial, governmental, managerial and consistent policy support.
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Homework on a lesson -- Assignment No 1

Dr. M. R Srinivasan, Member (formerly Chairman) Atomic Energy Commission has treated us, in his own inimitable and lucid style, to a primer, published in The Hindu, on 11/09/2007 under the title "A lesson in nuclear reactors", on various types of nuclear reactors and India's preferences between them. In the article, he has made a comparison between the PHWR line that has been highly evolved by India (from the original CANDU) and the new designs of LWRs that have been evolved mainly by Russia, France, US, and Japan. As of now, in India, further evolution of PHWRs is a continuing and ongoing process. The Canadians are working on advanced CANDUs as well.

He has made the article into a very persuasive wrapper for his own preference, namely, import the LWRs.

After imbibing the main issues in the lesson, I thought I might do a bit of homework, particularly with respect to some of the points he has made. I present below Assignment No 1 of my homework. I hope to present the others in subsequent posts in this blog.

Dr Srinivasan says:

"Electric power utilities find it simpler and more convenient to operate LWRs [than PHWRs] as they have features flowing out of conventional coal-fired steam power technology."

Following could be some important differences between a coal-fired (thermal) power plant and a nuclear power plant, particularly of the PHWR and LWR types:

As a rule, thermal power plants supply superheated steam (higher pressure and temperature) at the turbine inlet. But LWRs and PHWRs, due to inherent properties of various materials used in the reactor core, and other design requirements, cannot supply the turbine with superheated steam. Turbines in these nuclear power plants operate with saturated steam (lower pressure and temperature, but larger mass flow of steam). For the same power generated (usually specified as Megawatts electrical - MWe), a turbine designed to use superheated steam is smaller than one running based on saturated steam. The larger turbine needs more careful handling when it comes to dealing with fluctuations in important parameters (e.g. frequency, voltage) in the grid system into which they are feeding the electricity generated. In a lighter vein one may say that both the turbine and its operators of a nuclear power plant are more stressed-out than in the case of a thermal power plant.

Particularly in the genaration-starved electricity grids in India, large variations in vital parameters (such as voltage and frequency), taking place over both short as well as long duration, are common. Thermal power plants are capable of quickly adapting to and "survive" rapid variations in the electricity grid as a result of mismatch between electric power generation and the demand load. On the other hand, LWR and PHWRs are best suited to "base load" operation.

A second "property" of a nuclear reactor is that even after the chain reactions are stopped following a "trip" (a very fast action, usually in less than 2 seconds, to quench the chain reactions in the core) or a normal shutdown (a somewhat slower process), heat -- called 'decay heat' -- continues to be produced in the fuel and in some of the structural material inside the core. This heat needs to be effectively removed. Ensuring that adequate decay heat removal is taking place is an area of major importance for a nuclear plant operator, unlike in the case of a thermal power plant operator.

The operator of a nuclear power plant, due to both economic and safety reasons, needs to continually monitor and ensure that adequate system integrity exists at all times (that is, there are no unwanted leaks of any of the fluids from the system into the surrounding atmosphere). This may not be as strict an issue in a thermal power plant.

A third important factor in a nuclear power plant is the likely presence of nuclear radiation in the operating areas and the equipment there in. This is not the case in a thermal power plant. All nuclear plant operations and maintenance (O&M) personnel go through rigourous training and certification processes and are well equipped to deal with the environmental conditions in the areas in which they work. Extensive use of special protective clothing and remote tools is a routine feature of in a nuclear power plant.

However, there is a difference between a PHWR and a LWR when we talk about O&M-related considerations. A PHWR plant operator needs to be aware of the possible presence and radiological effects of Tritium [an isotope of Hydrogen, generated through nuclear reactions, from the Heavy Water present in the reactor] in the environment of the areas in the reactor, which he may access for maintenance or operation. He needs to properly utilise techniques and equipment provided for safely carrying out O&M activities according to well laid out procedures. PHWR plant operators undergo appropriate training for this. Tritium is not a major issue in the case of LWRs since Heavy Water is not used in these reactors (although it could be produced, in small quantities, from the Light Water present in the reactor core). Of course, Tritium is not a concern in a thermal power plant.

In summary, from an O&M point of view, an LWR-based nuclear power plant is not much different from a PHWR-based one. Both require high level of operator skills. [This is not to say that a thermal power plant operator does not need to exhibit a high level of skill in his area of work.]

Glossary:

PHWR - - Pressurised Heavy Water Reactor

LWR - - Light Water Reactor

CANDU - - CANada Deuterium Uranium (The original PHWR type reactor developed in Canada)

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India and the Bush doctrine

Yea, though we walk through the valley of the technology control regime, we need fear no failure: for courage of conviction resideth in our hearts and mind; lessons learnt from our past failures and successes achieved so far in our quest for technology indpendence comfort us.

-- Nuclear Pilgrim's Progress

Dogma and the Doctrine

Main dogma of the Bush doctrine seeks to bequeath a bonanza for the nuclear power plant [npp] industry - which is extinct in the US and in deep stupor in many of the NSG countries - by selling nuclear technology to India, while adopting a superior seller's position, relegating India to a lowly buyer begging for the supplies.

Bush's strategy to 'operationalise' this doctrine is to use a provision of the US Atomic Energy Act of 1954 (AEA 54) with regard to Presidential waivers. Towards this objective, he has offered India a bait: "Even though you have not signed the NPT with its full-scope safeguards and hence are not eligible, by our laws, to 'receive' our npp related products / technology, we will make an exception in your case (because we love you). If you agree to place a majority of your nuclear facilities under IAEA safeguards and agree to abide by some other conditions of good behaviour, then we will kindly sell to you nuclear technology, allow you to import uranium from other supplier countries, . .. etc."

Policy-makers-in-charge in India, are falling hook, line and sinker for this subterfuge, and are about to swallow the bait in a single mouthful.

To be able to overcome the non-proliferation requirements of the AEA 54 and sell nuclear products to India (which so far, rightly, has neither signed the NPT nor agreed to the full scope IAEA safeguards) the US Administration needs to use the mechanism of 'exemption and waivers' available in the Act. For this, the US President needs to make a determination that selling nuclear technology to India will not prejudice achieving nonproliferation objectives of US. The Bush Administration has advanced an argument that sale of nuclear technology to India, as per their proposal, will not weaken but actually strengthen the US aims.

NSG countries have, in theory, followed the US lead in taking the position that as India is not a signatory to the NPT and full scope safeguards, they will not sell npp related products to it.

From around 1974, essentially, there have been no large-value npp related exports to India from the US. This has turned out to be mostly to the detriment of the US in terms of lost opportunities to sell their products. It is this policy-related disadvantage that they now are seeking to overcome. However, up to now, a few of the NSG countries have been selling npp related items to India, by selectively applying their non-proliferation rules. When it suited their commercial interests or in the cases where the specifications were not too hi-fi, they supplied the items. In other cases they refused to supply. They may also have maintained a good degree of coordination among themselves on who should supply what to India, and probably also had an understanding of the price to be charged (the extent to which India can be fleeced). It is my conjecture that they may have, at times, even employed tactics to delay India's nuclear power projects. They would quote a low enough price such that the offer cannot be rejected. After the order is placed and the delivery time is well past, the 'supplier' organisation would 'regretfully' say that it can no longer supply the item because the mandatory export licence has not been granted by (its) Government! It would be quite impractical to take, every time, recourse to legal action against the 'non-supplier' particularly if the cost of the item involved is not very large.

One must note that the above strategy adopted by the US / NSG had a very beneficial impact on indigenous development of such items. Indian managers and policy makers were forced to support their engineers and scientists in their quest for development of hi-tech within the country against all odds. It is not mere chance that much progress in development of technology in the past decade or so has coincided with the implementation of nuclear technology control regime on India by the US / NSG. It is interesting to note that US -India Joint Statement was made on July 18, 2005, soon after the India-built 540 MWe PHWR (Tarapur 4) attained first criticality at on March 6, 2005. Again, this seems to be too good to be just a coincidence.

India's efforts in self-help are working reasonably well as can be seen by achievements in setting up or embarking on India-designed PHWRs and PFBRs. Mainly due to inconsistent, non-uniform support of the policy makers who matter in the Indian way of administering technology within the Government sector, the process has been a bit slow, but very steady. (In a later paragraph in this article, I will attempt to show that such hi-tech development efforts cannot be speeded up to a much greater level).

How might India respond to the new US policy?

US has realised that the policy of 'selective sabotage' adopted so far has not worked [see box]. So they have now decided to adopt a modified approach by offering to sell much of the nuclear technology and dual-purpose items for civilian nuclear use.

"The Administration has characterized civil nuclear cooperation with India as a 'win' for nonproliferation because it would bring India into the nonproliferation 'mainstream'. In short, the Administration is proposing that India should be courted as an ally in U.S. (not global) nonproliferation policy, rather than continue as a target of U.S. (and global) nonproliferation policy. India should become an ally for three reasons: past policies have not worked; India has a relatively good nonproliferation record anyway, and India could be a useful ally in the nonproliferation regime." [Emphasis added]--- Sharon Squassoni, U.S. Nuclear Cooperation With India: Issues for Congress, Updated March 28, 2006, CRS Report for Congress

How does US hope to achieve its objectives of bringing down India's development efforts?

Hitherto, since civilian and nuclear facilities had not been separated in India, the technology control was being implemented by US / NSG across the board, in a diffused manner, on a selective and case-by-case basis. With India now designating specific facilities as civilian, the US and NSG will be able to apply their technology control methods much more rigorously. They hope to simply dry up all sales to anything that is not designated civilian and hence not subject to safeguards. For each and every item of purchase, India would be required to furnish an end-use certificate with GoI affirming that it is to be used only in the safeguarded nuclear facility as specified in the certificate.

In spite of rhetoric to the contrary, for its electric-power generation nuclear reactors, India still needs to import some items. When the modified technology control regime comes into force, India could follow one of two strategies

Strategy (a): Develop the required items and manufacture them in India,

or

Strategy (b): Import. I foresee that India may end up designating one by one, all its npp-s to be built in future, as 'civilian' and place them under IAEA safeguards. If US / NSG adopt this strategy, then India-made power reactors under the non-civilian category may henceforth cease to come up.

Policy makers in India repeatedly aver that (a) and (b) can and will be implemented simultaneously.

I disagree with this promise with all the strength of expression at my command. Top-level managers responsible for large projects, tend to view indigenous technology development under the present level of industrialisation in India, to be prone to initial technical failures, as well as time and cost overruns. This near term likely disadvantage is usually given very great emphasis, and hence almost always, importing is the preferred alternative. Strategy (b) will almost always win over strategy (a).

There is a danger that adoption of strategy (b) will inevitably destroy whatever we have achieved so far --- it takes only a trice to destroy what the potter has painstakingly created over a full working day.

Mr. Bush and other strategists in the US expect that India will take their bait and go the way of alternative (b) above, which is why they have predicted that 90% or more of India's npp-s will be eventually covered by IAEA safeguards. I agree with this particular 'presidential determination' because, for Indian managers of large-value projects in which cost of money in the form of interest-during-construction is high, (b) affords a softer and safer option. The ultimate result of strategy (b) would be the erosion of Indian ability to innovate along with loss of technological independence - just like a language that is not 'living' falls into disuse. Those hitherto involved in npp design, manufacture, construction and operation as well as many Private and Public Sector agencies who had accepted and overcome technical challenges in spite of possible economic risks and supported the programme in India, are likely to eventually get 'dumbed-down', to use a phrase common amongst software persons in GUI design and implementation.

Technology development in India - how should we go about it?

I place before the reader following propositions:

Are projections of future growth based on 'conventional' methods of forecast valid for India?

According to me, inter-country comparisons of various developmental parameters (such as, for example, 'consumption of electricity') based on a 'per-capita' criterion, are not appropriate when the number in the denominator tends to infinity. The population of our country at the moment is so large that it is tending to infinity. So, parameters based on per-capita usage of anything will tend to become zero and thus enter the realm of 'singularity'. Many physical laws are said to be inapplicable at points of singularity. I postulate that laws of growth projection would also fail at zones near one or more singularities. Also, such comparisons must take into account factors such as type of governance a country has adopted for itself (democracy vs authoritarian rule), civilisational ethos (the 'we-are-like-that-onlee!!' factor), etc.

Imagine our economy and industrial development to be like a large flywheel made of an assembly of parts including the hub, spokes and the rim, designed for and running at 1500 RPM. Now, there are inherent dangers in trying to give this flywheel a step-input of energy to make it run at 3000 RPM. For one, because of its heavy mass (large inertia), the energy required to accelerate it in a short time would be a large quantity indeed. Also there is a danger that the flywheel may tend to disintegrate when run at the higher speeds, the failures emanating from the increased stresses in the various parts and inherent material defects present (however well-made the flywheel may be). It is better to make a 1500 RPM flywheel run safely at 3000 RPM, by applying the input energy gradually while at the same time taking adequate measures to strengthen its various parts suitably.

By analogy, I am convinced that much of the projections of future energy requirements for our country are not sufficiently realistic and hence are unachievable. Industrial Revolution in Europe took place over centuries. India at 60 is still very young, particularly when its previous history of centuries of subjugation by all and sundry is taken into account. We have done well in the last few decades in countering the effects of nuclear technology control regime. If continued (realistically strict) support and good, enlightened oversight is provided by policy planners and implementers, Indian engineers and scientists in both government and private sectors will definitely rise to the challenge. Nehru - Bhabha combination was able to achieve the correct mix of checks and positive encouragement. We must try to replicate this.

Proposal to import number of big npp-s must be preceded by site approvals

Those who argue in favour of the US-India nuclear cooperation as spelt out in the present 123 Agreement text, highlight the possibility that India will be able to import many nuclear power plants of more than 1000 MWe capacity each. This claim must be verified very carefully.

Siting conditions for an npp are very tough indeed. There are stringent requirements imposed by criteria such as degree of proneness to earthquakes, availability of cooling water in large quantities, non-agricultural land and other environmental issues such as the quantum of 'burden' from plant emissions during normal operation and postulated emergencies that can be safely tolerated by the surroundings, etc. For example, high population density at or near a given site is a major negative factor. Likewise proximity of coal mines (anything less than about 700 Kms) is another factor to be counted in the disadvantage column. Similarly, if the npp has to be near a seashore, then tsunami / storm prone areas are a no-no (e.g. many places in coastal Andhra / Orissa / Tamil Nadu may fall in this category. India's western coast too has its share of demerits.) If the npp site is located at a remote area [load centres far away], then problems associated with construction of new high-capacity power-transmission systems and acquisition of land for the same could also arise. There are many more similar technical issues. Last but not the least is the requirement of enforcing what is (probably unfortunately and inappropriately) called a 'sterilised zone' law/rule -- authorities will not permit, without their prior approval, civilisational or industrial growth over an area of 5 km radius around the npp. This requirement is prevalent only in India. Such restrictions on land-use could cause much heartburn for the affected persons. Value of their property would plummet when an npp comes up nearby, leading to agitations, which in turn lead to project delay (may be even cancellation of the project).

Thus, there are not many sites available in India where large capacity npp-s as are presently projected could be located.

Therefore it is imperative that before accepting the conditions in the 123 Agreement which would place India at a disadvantage in many ways and then sinking so much money, we must insist that the authorities identify and get clean 'prior consent' from the Regulatory agencies (AERB, Environmental clearances, etc.) for all the proposed sites.

Paradigm shift

This probably is an opportune moment for me to 'propound' another idea. In npp project formulations, the conventional view favours economics of scale. So, we are seeing bigger and bigger capacity npps. While this may be true in countries with less population density, and may also be true in some cases in India, I propose that we must also take a look at the possibility of optimisation through economics of quantity.

For example, say 8 x 1000 MWe LWRs are proposed to be imported as 'additionality' under this 123 Agreement. Would 160 numbers of India-made 50 MWe [thermal] reactors each of which could have a very small foot-print, be equally attractive as the 8 big imported LWRs, which are well out of India's range of manufacture?

There could be many advantages in this proposal. I list a few. These small reactors would be designed to be essentially located underground requiring only very little area of exclusion for the public. This means we could have these plants located near many medium sized-town and also cities. Of course appropriate Regulatory approvals as usual would have to be obtained; but this might be easier than in the case of large npp sites. Power from these plants could be used to provide energy not only for the nearby industries but also for railway traction saving valuable hydrocarbon consumption. In the river-linking scheme, appropriately located small-npps could provide the required energy for pumping water up the gradients where required. Such distributed power generation could lead to reduced transmission losses too. Small cores have small inventories of fission products and hence can be designed to be adequately safe. The plants can be designed to have long intervals (say 1 to 2 years) between refuelling and fully automated for minimal operating / maintenance staff.

There might be a negative aspect too. Reactor designers say that a larger core means better neutron economy; that is, better utilisation of the inventory of all the fissile atoms available in our country. We would have to take this into due account at the time of evaluating the overall merits and demerits.

Lest I am misunderstood, let me hasten to indicate here that IAEA have done considerable work and published several reports on 'Small and Medium' npp concepts. I understand that BARC have evolved a design of a 'compact nuclear power pack' using highly enriched fuel for being located in remote areas supplying heat and electricity. What I have proposed here is not so compact an unit, but one that would not require highly enriched fuel or exotic coolants..

For me, the important plus point is that we should be able to make within India, most of the components (including the turbine, generator and other equipment) in the 'conventional' as well as the 'nuclear' side of the small-npp which is not the case with the large sized plants proposed to be imported.

It is better to spend resources in consistently supporting continued development of indigenous nuclear technology rather than importing

A better strategy would be to avoid splurging our newfound wealth in importing foreign nuclear technology. Instead we must utilise it with appropriate realistic managerial controls in developing the still-needed technologies in India. As and when we successfully develop indigenous high technology, others countries are likely to purchase from us, on account of our superior product quality and its economics. At this juncture, we can trade with them, on an equal footing just as the advanced countries do amongst themselves. We can import hi-tech items we find costlier to make in India and sell those hi-tech items which others find costlier to make in their own country.

Spare a thought for spare parts

In their preoccupation to ensure uninterrupted supply of fuel, India's negotiators seem to have forgotten about the equally important need for spare parts. The present 123 Agreement is silent on the required uninterrupted supply of spares, should at any point in future US decide to walk away from the agreement even as it did in the case of the Tarapur. It may neither be feasible nor economical to procure, along with the initial order itself, lifetime stock of many of the spare parts. (Life of a modern npp could be as much as 60 years or more). In the case of Tarapur 1&2, India was obliged to develop its own technology for many of the items that needed replacement although some safety related spare parts might have been imported from the US / NSG even after US stopped normal supplies under the contract.

Indigenisation of a spare part, in the last minute (after its failure has been detected), may prove to be costly. Unlike Tarapur 1&2, npp-s proposed to be imported now are of very large capacity. Loss in electricity generation of these large capacity plants, while efforts are underway to manufacture the spare parts locally, could be prohibitive. In addition IPR issues could arise for these localisation efforts.

Walk away from the deal; resolve the problem of Tarapur 1&2 spent fuel first.

We have travelled far along the road to winning technology freedom for our country. We have done reasonably well in our efforts. There is no need to deviate from the path we have successfully followed thus far and go seeking non-existant short cuts via dangerous crooked alleys and cul-de-sacs. Let us resolve to do better what we have done so far.Therefore, we must walk away from the present 123 Agreement; and also not implement the proposed separation plan. Instead, we should 'verify' US's new-found love for India before 'trust'-ing them by first negotiating an honourable agreement for the disposal of the spent fuel from Tarapur 1&2. I list below some possibilities:

(a) US to allow India to reprocess the Tarapur 1&2 spent fuel in an existing Indian facility under campaign mode safeguards or in a 'new national facility' to be built by India, with pre-agreed methodologies for safeguards verification by IAEA. The economics of building a new facility and the deployment of the recovered fissile and fertile isotopes may have to be justified by some 'forward looking' thinking.

(b) US to take back the spent fuel with a reasonable compensation to India for the energy content in it (fissile, fertile and probably other usable isotopes).

(c) Permit India to find a buyer for the spent fuel, again for a reasonable price.

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