Friday, December 30, 2016

The Gravitational Wave Era in Astrophysics Has Truly Begun!

Thursday, December 29, 2016

First Fully General Relativistic Simulations of Neutron Star Mergers

Tuesday, December 27, 2016

Recent Tweets on Lattice QCD

Monday, October 3, 2016

World Overview of Rare Isotope Beam Facilities

Wednesday, July 27, 2016

AIAA Prop Energy 2016 - Closing Plenary - Pierre Chao, Renaissance Strategic Advisors

Dr Mark Lewis Speaks at MIT AeroAstro Centennial on Hypersonic Flight

Dr. Lewis talks about why the experience with the X-51, despite what would otherwise be considered only a set of partial successes, was actually quite important both from the technology development and the system point of view: first, the X-51 flew on regular hydrocarbon fuel, not an exotic or cryogenic fuel, such as the hydrogen fuel that other scramjet variants used for hypersonic flight have flown on; second, while the X-51 was launched from the underbelly of a B-52, it was actually flight-scale, that is, an actual missile or ISR (intelligence-surveillance-reconaissance) vehicle would be of roughly the same dimensions; third, it was thermally balanced, in other words, was in no danger of melting - and could have flown [and actually did fly] as long as it had fuel; fourth, it was air-launched, and flew on a B-52 that was originally designed more than 50 years ago - pointing to a possible way of modernizing the warfare abilities of a relatively old aircraft; fifth, unlike previous attempts, the scramjet used in this test demonstrated not only net positive thrust, but positive acceleration, with the hypersonic craft being on a final upward trajectory, thus silencing the many skeptics of scramjet propulsion - this variant was actually designed in 1958!

Dr Lewis also noted that this was a first step, and much more remained to be done to make a missile based on the X-51 operational: the ignition system, cooling,  the booster, controls, guidance & navigation, and warhead aspects would need further development. Furthermore, going up the Mach scale in airbreathing propulsion remains of strong interest, and for example, M=6 is a 'sweetspot' for many military applications, and for two-stage-to-orbit systems, M=11 is of particular interest. At a more fundamental level, of course, there is a greater understanding needed of the physics of hypersonic boundary layers. Overall, a better Test & Evaluation process is also needed.

He also pointed out that alternative modes of achieving objectives, also deserve study - for example, a hypersonic glider, which glides down to earth after being boosted up to high Mach speed by a traditional (non-airbreathing) rocket (as opposed to being thrusted up via is also of interest. Or the approach pioneered by Reaction Engines - the brainchild of Alan Bond - in which a cryogenic system liquefies the air sucked (or breathed) in - and burns the liquid oxygen component of it, together with the cryogenic fuel such as hydrogen that it is carrying - rather like in a conventional rocket engine. This solves the fuel-mixing issues that arise in scramjets, however, the liquid oxygen is not carried  along from the ground, as in conventional rockets, and is obtained by condensing air in flight. This was originally considered as part of the technology scoped out for the National Aerospace Plane, but was negatived then, because condensers (for the air) were considered too heavy and inefficient to serve in the capacity desired. However, Reaction Engines might have an approach that merits further study.

Tuesday, July 26, 2016

AIAA Propulsion & Energy Forum 2016 - 26 July 2016


Monday, July 25, 2016

AIAA Propulsion & Energy Forum 2016 - 25 July 2016 - PM Plenary

AIAA Propulsion & Energy Forum 2016 - 25 July 2016 AM Plenary

Sunday, May 29, 2016

NEA2016 Panel on Preparing for New Reactor Development

This was a most interesting panel indeed, and panel chair and moderator Maria Korsnick of the Nuclear Energy Institute does a great job moderating the discussion (as well as making sure the audience applauded the panel even before the discussion begins, to recognize the eminence of the panelists individually and collectively, very appropriately in my opinion.) Below I excerpt some of more interesting comments made by the panelists at various points in the discussion.

Cynthia Pezze (Westinghouse Nuclear) : Last year we (Westinghouse Nuclear) decided to take a long look ahead, and we decided to focus on the Lead Fast Reactor (LFR). It has a number of advantages - containment at atmospheric pressure, a low coolant operating temperature relative to its boiling point, a compact nuclear island in most conceptual designs,  a core with high density which shields against gamma rays, a high burn-up ratio (increased fuel utilization) etc. Pezze wanted the industry as a whole to move the discourse beyond the safety issue and would like the industry to talk more about things like higher burnup and fuel utilization in the advanced nuclear designs.

Jacob DeWitte (Oklo): Oklo reactor is 2MW in power output; containerized design meant for off-grid or microgrid solutions... The paradigm (for building SMRs) is manufacturing and not construction. The perception that NRC does not have the resources to process a design certification for SMRs is not correct (based on Oklo's own experience). Mass manufacture drives costs down, which translates to lower electricity costs, since capital construction costs drive the price of electricity. But a comparison with the existing cost structure in off-grid is also instructive: the electricity costs in an off-grid location based on diesel generation are much more than in on-grid communities, so the adoption barrier is lower. On safety - physics-based safety should be the term in preference to inherent or passive safety.

Kuzynski (Southern Nuclear): Risk-informed regulation and performance-based (i.e. not prescriptive regulation) are both needed. This would change both the number and character of the regulations - he wanted to let the innovators figure out how to do it (i.e., satisfy a given regulatory requirement). NRC should enable this technology (advanced nuclear reactors) because it improves safety, without worrying about the semantics around whether enabling in this sense also amounts to promoting, which as a technology-neutral regulator it should not be doing. Further, he added that the SMRs and advanced nuclear designs should have no need for accident coverage based on Price-Anderson, as they would be inherently safe and would not lead to core melting in even the worst case scenarios.

Wednesday, May 25, 2016

Senate Hearing on Advanced Nuclear Technologies - 17 May 2016

I am one of those who do pay attention to the making of policy in legislative hearings, and my interest in energy, and nuclear energy policy in particular, is extremely high. While something is always learnt by listening or watching such hearings, this particular session of the US Senate Energy and Natural Resources subcommittee on Advanced Nuclear Technologies was extremely educational indeed. Apart from the details of reactor systems which actually emerged in the prepared testimony and subsequent questioning of the panelists by the Senators, the thorny issue of subsidies and implied subsidies to the nuclear, wind and fossil fuel sectors was openly and frankly discussed, and while that subject will not be much discussed in this blog post, which will restrict itself mainly to the details of some advanced reactors (details that, to the best of my knowledge, have not been in the public domain thus far), it must be noted that I found the open discussion of the subsidies issue - among and between the Senators and the panelists most enlightening indeed.

For someone like myself, who keeps a fairly close eye on developments on the Small and Modular Reactor (SMR) field, it was triply, if not quadruply surprizing to find out about Oklo, an SMR company that takes its name from the uranium mine in Gabon where a water-moderated nuclear reactor ran naturally for billions of years! I had never heard of it before I watched this hearing! Even now, the company has a particularly low profile so much so that the entire first page of Google hits on 'Oklo' refer to the Gabon uranium mine. [In what follows, 'Oklo' refers to the company, and not the mining site; 'Oklo reactor' refers to the reactor the company proposes to design, build and market.]

Oklo: Dr. Jacob Dewitte, CEO of Oklo, said that Oklo formally launched in 2013 though it had been operating for a few years earlier - he said that he saw the economic opportunity for an SMR company - in going small and being off-grid (one notes here that the 'SMR' category can span quite a range in reactor sizes and thermal/electric ratings - and the proposed Oklo reactor appears to be at the really small end of the size/power spectrum. One could even call it a 'micro' reactor, as indeed Committee Chair Senator Murkowski actually did. (Update: At the NEA2016 Panel on Preparing for New Reactor Development on May 24 2016, Dr DeWitte clarified that the Oklo reactor was 2MW). Furthermore, Oklo is focusing on the off-the-grid segment, while many others are specifically designed to be grid-connected). Dr Dewitte explained that Oklo has completed confirmatory verification and validation testing on full-scale heat transport – and hopes to do testing for transients soon. This is  similar to what NuScale did a few years ago. Here Dr. DeWitte explicitly acknowledged the role of NuScale in blazing a regulatory first of a kind path.

Another way of emphasizing the advantage that size confers on Oklo was noted by Dr DeWitte: ‘we’re so small that we can do everything (i.e. all the testing) at the exact scale’, while NuScale had to build smaller scale models for the thermalhydraulic testing, and then use similarity arguments and simulations to understand how the full-scale model might behave. Dr. DeWitte anticipates Oklo submitting a license application to the NRC in the 2018-2019 time frame; and envisions the first deployment of an Oklo reactor in the early 2020s.

While the Oklo reactor is designed to deal with spent fuel from the current  PWR reactor fleet – he anticipated that the initial fuel will be regular, normal enriched uranium – because Oklo does not want to add to the technological (his emphasis, to stress that it does not add to the safety risk) risk by using spent fuel at the initial stage. He clarified, upon questioning by Senator Heinrich (D – NM.) that the level of enrichment of the initial fuel for Oklo would be on the order of 15% – and further that it will be a relatively small amount of fuel, as the reactor itself is so small (even within the SMR category, and certainly in comparison with a 1GW class reactor) adding further that Oklo is definitely interested in opportunities to help with the plutonium disposition issue, and anticipates that in the future it would operate in a fuel cycle where it is able to fission all the actinides including plutonium by using as its fuel the spent fuel from the PWR fleet. (And here I must acknowledge how impressed I was to hear a technical question such as this from a Senator!)

At the very end of the hearing, Senator Murkowski, Chair, asked about the potential of Oklo as a ‘micro’ reactor in remote areas or islands like Guam or in locations like Bethel in her own state of Alaska, asking how Oklo could deploy at such places. Dr DeWitte said that it (Bethel, AK) was exactly the kind of market Oklo was targeting, and that the proposed Oklo reactor module would be buried 20 foot deep, but could also be 'mounded up' above ground. He further added that it is expected that the Oklo reactor would produce power for 12 years before refueling. Most interestingly (to me), Dr DeWitte explained that many SMR designs, and Oklo's specifically - also 'changes the paradigm' on load-following vs leading, and that Oklo can operate very easily at anywhere from 10% to 100% of rated power, just like gas power plants do. 

TerraPower: Dr. John Gilleland of TerraPower used the occasion to clarify the distinction between ‘spent fuel’ that Oklo plans to use, and ‘depleted uranium’ that TerraPower plans to use - depleted uranium is the uranium left behind at enrichment plants – never having been enriched or seen a reactor, while spent fuel is the formerly enriched fuel which has made its way through a reactor. Dr. Gilleland also clarified that the US State Department has negotiated an agreement with the concerned Chinese authority which allows TerraPower to freely exchange information with China on its Traveling Wave Reactor, the rationale being that, because (eventually) enrichment will not be needed for its fuel and reprocessing will never be needed, there would be no risk of proliferation of sensitive technologies via such exchange. TerraPower's goal, he added, was to come up with a reactor that could be universally and ethically exportable. He anticipated that construction on the first reactor would begin in 2018, and the first prototype would be in operation in 2025-26, and the first commercial units a few years after that. He emphasized that US national labs were playing an important role in materials development for TerraPower, which uses both a metal fuel (the depleted uranium) and a metal coolant (liquid sodium). 

Dr. Mark Peters, Director of the Idaho National Laboratory (INL) mentioned that the Advanced Test Reactor (ATR) at INL carries out a number of activities in support of the Navy's Reactor program – and has a planned operational timeline for the ATR that may have it working till 2050. the ATR will also serve as the main testbed for activities under GAIN (The Gateway for Accelerated Innovation in Nuclear). He clarified also that TransatomicPower (not represented on the testifying panel) proposes an MSR that would need access to the ATR through GAIN, and that, among all US National Labs, Oak Ridge has the strongest expertise on MSR reactors.

(The video embedded above was made available on youtube by Rod Adams (@atomicrod))

Wednesday, April 20, 2016

Brookings Panel on China and the Global Economy - 14 April 2016

Minneapolis Fed Symposium on Ending Too Big To Fail - 4 April 2016

Monday, April 18, 2016

IMF Panel on Fortifying the Global Financial Safety Net - 14 April 2016

"An emerging market is a country that is growing rapidly but whose (financial & regulatory) institutions haven't the credibility (they need) yet", said Raghuram Rajan. "Of course there is a wide variety of emerging markets, e.g. Chile has built up credibility in its fiscal and monetary policies, but many of us are working to build (that) credibility. In this situation, a 'competitive devaluation' does not quite work, but rather brings in inflation, and becomes an investor worry too."... (slight paraphrase).

"Jonathan Ostry and Jeromin Zettelmeyer et al at the IMF put together a proposal 13 years or so ago when I was at the Fund - on what ex-ante facilities would look like. And the idea was we need to create a stigma-free access to liquidity that (countries) would go to early on. And their idea was 'Qualify everybody!' or rather, not everybody would qualify but 'rate everybody'. So even the United States would be rated on their ability to access liquidity, and... its important that it be quick. you could declare an emergency (area) and then any (country) in that area could access the liquidity... then central banks could come and lend into that pool, and the pool would then lend to the country, for a short duration, and if the country could not repay within that short duration, it gets kicked into an IMF backup facility, so central banks are just providing liquidity, they get their money back, because it is backed up by the IMF guarantee." Raghuram Rajan on (emergency) liquidity provision for countries in the context of the Global Financial Safety net theme.

"In other words, contingent automatic credit lines",said Pierre Olivier Gourinchas.... "Some market developments have moved in that direction, for example, growth warrants... (but they haven't gone too far)."

"I am obliged to play the role of skunk at the garden party", said David Lipton (in respect of these different liquidity proposals).

"Rating is not a bad word... Article IV consultations are essentially a rating program, because they authorize country-specific lending in terms of multiples of their quota... " said Raghuram Rajan in response (slight paraphrase). "And how do liquidity crises arise anyway - they arise because the private sector becomes unwilling to lend... because it worries about its ability to access the (state-guaranteed) contingent liquidity provisions... now some of this could be irrational, or it could be perfectly rational (in the limited-information sense), because it does not have access to the same resources as the public sector (like the Fund).... and the point about this access to liquidity is that it is made available when the (country) is solvent but illiquid, a determination that Central Banks have to make all the time." said Raghuram Rajan.

"Liquidity problems don't just arise because of corruption",said Raghuram Rajan, "they arise because of a mismatch between the duration of the investment that has been made (for example, in infrastructure) and the financing that might have been available, which might have been short-term, or a mix (of short-and long-term). But if you do think infrastructure investments are useful to encourage, then in fact the provision of liquidity might be useful." "And with respect to India's role in the Global Financial Safety Net - we are participating in some of these regional arrangements, there is in fact a SAARC Facility (which India has contributed to) and which has been drawn down. Going forward our engagement with the Global Financial Safety Net will increase, and if in fact we decide on a Reserve Pooling Arrangement, India will be part of it....BRICS Bank is in existence, but is called the New Development Bank, and it is getting ready to make its first loan." said Raghuram Rajan.

Update April 28 2016 The IMF has also made available a podcast of an interview with Raghuram Rajan on the Global Financial Safety Net, on soundcloud here.

IMF Panel on The Political Economy of Structural Reforms - 14 April 2016

"The biggest challenge, and the biggest enemy of structural reform is populism", said panelist and Spanish Minister of Economy and Competitiveness since 2011, Luis de Guindos Jurado, "and populism is pervasive now." (at 16:25 in the clip).
"The most corrosive aspect of the populism....(is the public perception that) whenever regulators engage with industry to arrive at a justifiable cost-benefit tradeoff on regulations versus social benefit, that they (the regulators) have become ipso facto co-opted, and that they are no longer independent regulators! The result is that the final regulations become crippling for the industry." (slight paraphrase of Diana Farrell).
"Structural reform is a continuous, ongoing process, but the one indispensable prerequisite is leadership", Mauricio Cárdenas, Minister of Finance and Public Credit of Colombia since September 2012.
"Leadership is important, but process is also important. Where you do reforms and where you are is very important. Low-income countries should focus on agriculture, tariff issues, price-liberalization and market-enabling reforms; and emerging market countries should focus on labor market, regulatory, banking, and telecommunication & transportation sector reforms; while advanced economies should focus on innovation, supporting research & development and on pushing productivity up and the production possibility frontier forward." Min Zhu, Deputy Managing Director, IMF said.
"Informal sector size is determined in part by the regulatory environment and the tax code, e.g., hiring more than 5 and certainly more than 50 workers subjects a company to extremely burdensome regulations." Min Zhu

Wednesday, February 17, 2016

Minneapolis Fed President Neel Kashkari at the Brookings Institution: Lessons From the Financial Crisis

Neel Kashkari mentions the 'Nuclear Reactor Meltdown' analogy for the damage caused by the failure of a 'Too Big to Fail' financial institution at 29:50 in the video.

3/4/2016 Update: Neel Kashkari on the Charlie Rose Show (aired 25 Feb 2016)

Tuesday, January 26, 2016

Raghuram Rajan on Shekhar Gupta's Walk the Talk from Davos 2016

At 22:20 Shekhar Gupta asks Governor Rajan whether he had attended the 'India session' at Davos, i.e. this, and notes Nouriel Roubini's remarkable beginning phrase: India is in a sweet spot, also noted right there! Turns out the Governor of the Reserve Bank of India did not attend the India session at Davos....but agrees largely with Nouriel's assessment.

Thursday, January 21, 2016

World Economic Forum Davos 2016: India and the World

Vikram Chandra asks Nouriel Roubini what advice he would give Finance Minister Arun Jaitley (prefacing his question by observing that 'India has the strengths...'). Nouriel begins answering at 38:45 - "India is in a sweet spot...."