Canada's Neutron Source, the NRU Reactor, Closes

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Canada's Neutron Source, the NRU reactor, closes

Daniel Banks

To cite this article: Daniel Banks (2018) Canada's Neutron Source, the NRU reactor, closes, Neutron News, 29:2, 25-31, DOI: 10.1080/10448632.2018.1514200 To link to this article: https://doi.org/10.1080/10448632.2018.1514200

Published online: 10 Oct 2018.

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Canada’s Neutron Source, the NRU reactor, closes

anada has been a leader in neu- 500 million patients around the world tron radiograph was taken that cap- tron scattering for 70 years, start- over its lifetime. tured the last neutrons exiting the re- Cing with the National Research Ex- When the NRU reactor at AE- actor as it shut down (Figure 1). The perimental (NRX) reactor completed CL’s Chalk River Laboratories image was taken of a specially made by the National Research Council closed on March 31, 2018, it was the plaque, composed of layers of nickel (NRC) in 1947. Early neutron scat- world’s oldest major research reactor alloy plates and gadolinium lettering tering experiments were conducted (>5 MW) in the world. Since Febru- to create contrast. The neutron im- at NRX and then continued at the ary 2015, when the fi nal shutdown age shows a stylized layout of the six 10 times more powerful National of the NRU reactor was announced, neutron beamlines around the core Research Universal (NRU) reactor, the team at the neutron beam labo- of the NRU reactor, the biological with a fl ux of 3 × 1014 n/cm2/s. The ratory at NRU, known as the Cana- shield that protects personnel, and NRU reactor was completed in 1957 dian Neutron Beam Centre (CNBC), the graphite column (a further ex- by Atomic Energy of Canada Ltd. strived to extract as much value and planation of the image and how this (AECL), which was split off from the impact from the reactor as possible was done is provided at http://cins. NRC in 1952 to promote peaceful use in its fi nal years of operation. In ca/2018/05/30/the-fi nal-neutrons/). of nuclear energy. The NRU reactor other words, the goal was to ‘cross Most of these beamlines still per- was the primary facility for in-reactor the fi nish line running’, and that is formed among the best in the world, testing of nuclear components during what they achieved: all beamlines in terms of the quantity and quality the development of Canada’s fl eet were collecting data until the end, of output in science and engineering. of nuclear power stations. The NRU except one that had completed its fi - Among these high performers were reactor also produced radioisotopes nal measurements just hours before. a powder diffractometer, a polarized such as molybdenum-99, which have During the last minutes of the triple-axis spectrometer, a neutron been used to diagnose an estimated reactor’s operation, a memorial neu- refl ectometer and a stress mapping

Figure 1. A neutron image of the plaque depicting the ﬁ nal neutrons captured in the NRU reactor, overlaid with labels of each neutron beamline’s designation. (Image credit: CNBC).

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supported by Walter ‘Walt’ J. Woy- towich (1949–53) as technical support and Noel K. Pope (1950–53) in the Theoretical Physics Branch. Soon, scientists Dave G. Henshaw (1951–59), Alec Thomson Stew- art (1952–57), and John ‘Warwick’ Knowles (1954–56) were added to the Section. Together, the Section laid foundations for neutron scattering experiments in gases, liquids and solids. Brockhouse took the lead on examining solids and the development of inelastic neutron scattering, which led to his Nobel Prize in 1994, after over 30 years from these pioneering contributions.

When Hurst left the Physics Di- vision in 1955, Brockhouse took Figure 2. Bert Brockhouse with the ﬁ rst version of his triple-axis spectrometer for inelastic scat- over as Section Head, and Knowles tering at the NRU reactor (circa 1958–1959). (Image credit: AECL). moved on to do neutron nuclear physics soon after. In 1960, Neu- diffractometer. These beamlines the 1950s. Donald ‘Don’ G. Hurst tron Physics became a separate supported a strong community: over was Head of the Neutron Spectrom- branch of AECL headed by Brock- the last 5 years, about 800 research eters Section of the General Phys- house. In addition to neutron scat- participants from Canada and around ics Branch of NRC’s laboratories tering, the Branch included neutron the world, including students and re- in Chalk River, known in the late nuclear physicists, who used the searchers from universities, govern- ’40s as the Atomic Energy Project. NRX or NRU reactors as a neu- ment labs, and industry. Hurst was the inspiration behind the tron or gamma-ray source for other Over its lifetime, the neutron scat- neutron scattering program, work- methods including neutron-capture tering program at NRU made major ing with experimentalists Gertrude gamma-ray spectroscopy and posi- contributions to materials science ‘Trudi’ H. Goldschmidt (post-doc), tron annihilation. When Brockhouse and to neutron beam instrumenta- Andrew ‘Andy’ J. Pressesky, Philip left Chalk River in September 1962 tion. Innovative neutron instruments R. Tunnicliffe, and Norman Zinkan to become a professor at McMas- and methods developed in Canada Alcock, and theorist John Ashley ter University, Dave Woods took have been replicated at every ma- Spiers, to develop early neutron over the leadership of the Neutron jor neutron beam centre worldwide. spectrometers, take measurements Spectrometers Section. The Neutron These include Brockhouse’s triple- on gases, and solve the structure of Physics Branch was headed by Gil- axis spectrometer from the 1950s deuterated ammonium chloride. bert ‘Gil’ Alfred Bartholomew until (some shielding from the original in- These scientists each left Chalk 1971 (this was the only time the Sec- strument from the 1950s was still in River between 1949 and 1951, leav- tion Head responsible for neutron use on the E3 beamline at NRU) and ing Hurst and Bertram ‘Bert’ Nev- scattering was not also the Branch advances in neutron stress scanning ille Brockhouse (1950–62)1 as ex- Head). in the 1980s. perimentalists to carry forward the Throughout the 1960s, ’70s, and The neutron beam lab grew out development of neutron scattering, ’80s external researchers obtained of the pioneering efforts of scientists access to neutron beams primarily from NRC, and subsequently from 1Years indicate time associated with the by collaborating with Neutron Phys- AECL, from the late 1940s through neutron scattering lab unless otherwise noted. ics Branch scientists: A.D.B. ‘Dave’

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Woods (1958–79, Section Head plishments include an extensive se- ment. Davis Earle and many other 1962–71, Branch Head 1971–79), ries of measurements on the inelastic AECL scientists and technical staff Gerald Dolling (1961–85, Branch neutron scattering from 4He by Dave contributed to the technical develop- Head 1979–85), Roger A. Cow- Woods and Eric Svensson. Woods ment of SNO into the ’90s, and the ley (1961–62, and 1964–70), Brian and Svensson demonstrated the exis- discoveries arising from it led to Mc- M. Powell (1964–98, Branch Head tence of a Bose-Einstein condensate Donald’s 2015 Nobel Prize in Phys- 1991–98), William ‘Bill’ J. L. Buy- in the superfl uid phase of liquid 4He ics as the leader of the SNO project. ers (1965–2007, Branch Head 1985– and measured precisely the associ- In addition, AECL nuclear fuel 91), C. Peter Martel (1965–93), Eric ated condensate fraction as a func- researchers operated a neutron im- C. Svensson (1966-2002), Thomas tion of temperature. Many of their aging beamline at the N1 beam ‘Tom’ M. Holden (1966–98), and measurements stood as the world port of the NRU reactor, as neu- Soo M. Kim (1970–97). There was standard for many years, and their tron imaging is uniquely powerful high turnover in the few technical measurements of the static struc- for non-destructive examination of staff positions that supported the ex- ture factor of liquid 4He remain the hydriding, a common cause of fuel periments in these years. Yet a few most accurate to date. With Robin failures. Under the direction of Alan served for signifi cant periods, includ- Armstrong from the University of Ross and then Glen MacGillivray, ing: Ed A. Glaser (1956–70), Har- Toronto, Bill Buyers experimentally N1 developed into a world-leading old F. Nieman (1964–94), Remick confi rmed the existence of the Hal- radiography facility in the ’80s. In ‘Rem’ S. Campbell (1967–78), Mel- dane Gap in 1985. This confi rmation 1994, AECL spun off this capability vin ‘Mel’ M. Potter (1968–10), Alan overturned the wisdom of the day and as a private business, Nray Services, H. Hewitt (1968–88), Don C. Ten- led to the acceptance of topological which was headed by MacGillivray nant (1971–97), and Jim C. Evans theory, for which Duncan Haldane and served the aerospace industry for (1979–86). shared the Nobel Prize in physics in inspection of turbine blades. Nray By the late ’70s, the Branch op- 2016, thereby opening the fi eld of to- immediately moved its operations erated several beamlines: triple-axis pological materials. The Branch also to the McMaster Nuclear Reactor, neutron spectrometers at the C4, C5, benefi ted from collaborations with where it still operates today. L3, and N5 beam ports, a gamma-ray members of the Theoretical Physics AECL experienced reduced monochromator for Compton scat- Branch, such as K. Bruce Winterbon funding in the mid-’80s, and in re- tering at C1, a fast neutron chopper at (1964–89), Varley F. Sears (1965– sponse, it began cutting deeply its C2, and an external thermal-neutron 97), and Henry R. Glyde (1969–75), fundamental research programs. beam for neutron-capture gamma- on the theories of neutron scattering AECL chose to focus remaining re- ray experiments at N4. In addition, needed to understand experimental sources for fundamental research ef- university researchers also part- results. In particular, Sears published forts on just a few large facilities that nered with AECL to establish two many foundational papers and his it described as “unique in Canada, additional beamlines at NRU: the tables of neutron scattering lengths at the forefront of all such facilities McMaster University double-mono- and cross sections are still in use to- worldwide and available to all quali- chromator triple-axis spectrometer at day [1]. fi ed Canadian scientists.” [2] Thus, E3, used by Professor Brockhouse’s The Branch included prominent losses in personnel in the Neutron students, and the GWELFNEUD II neutron nuclear physicists. Eric and Solid State Physics Branch were diffractometer at D3, built by Profes- ‘Davis’ Earle, M. Aslam Lone, and mainly limited to the sections for sor Peter Egelstaff (Guelph Univer- Warwick Knowles collaborated with neutron nuclear physics and detec- sity) for neutron scattering of liquids Arthur ‘Art’ B. McDonald, then tor development, leaving the section and gases. There was also an ultra- a member of the Nuclear Physics for neutron scattering experiments cold neutron experiment at T3 for Branch, on over 30 papers in the intact. McGill University. ’70s and early ’80s. These were pri- The construction of the DUAL- The Neutron and Solid State marily parity violation studies using SPEC facility (1985–92), which Physics Branch, as it was renamed in accelerator-produced gamma rays included two beamlines, at a capi- 1971, enjoyed a strong international that formed a basis for the Sudbury tal cost of $4M, marked a turning scientifi c reputation. Notable accom- Neutrino Observatory (SNO) experi- point for general user access to neu-

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tron beams at Chalk River. DUAL- berta, which spilled 800,000 liters of W. Montaigne (1985–99), Gerry SPEC’s construction and operations oil. ANDI ran successfully for over A. Sims (1986–95), J.J.-P. ‘Jimmy’ were funded jointly by AECL and 20 years, providing proprietary data Bolduc (1986–2016), Larry E. NSERC (a federal funding agency to enhance safety and reliability or MacEwan (1988–2015), and John for university research). The NSERC optimize processes in energy and Fox (1993–2014). In particular, Ron grant was awarded to Malcolm Col- manufacturing sectors such as air, L. Donaberger (1986–2015), gained lins of McMaster University, which automotive, rail, and marine trans- suffi cient neutron diffraction ex- represented applicants from 10 uni- portation, metal production, oil and pertise to serve as a local expert for versities, to ensure that it would be gas, and defence. many user experiments. operated as a national user facility. In the early 1990s, the future was The hopeful outlook in the The Canadian Institute for Neutron bright at AECL’s newly renamed Branch was validated when Brock- Scattering was formed to represent Neutron and Condensed-Matter Sci- house shared the 1994 Nobel Prize users’ collective interests in the facil- ences Branch, with the success of in Physics with Clifford Shull of Oak ity. A national user model was soon ANDI and the growing user-access Ridge National Lab (USA) for their adopted for the other neutron spec- program through DUALSPEC. The pioneering contributions to neutron trometers that remained, following user community was rallying behind scattering in the 1950s. Their selec- a restructuring of the beam facilities a reactor concept for NRU’s succes- tion for the prize refl ected the versa- in preparation for the installation of sor, the Irradiation Research Facil- tility and irreplaceability of neutron DUALSPEC: three triple-axis spec- ity. New neutron scattering experi- beams as scientifi c tools, providing trometers at E3, L3, and N5, and a mentalists had joined the expanding insights about materials that can- prototype low-angle scattering in- branch, including John H. Root not be obtained by other scientifi c strument at T3. (1986–present), Zin Tun (1989–pres- techniques. Over the 30 years since In parallel to the development ent), Ian P. Swainson (1992–2010), Brockhouse’s pioneering work, his of partnerships with university us- Ron B. Rogge (1993–present), and methods had been replicated and ers, commercial services to indus- John Katsaras (1994–2010). Frank further advanced at major neutron try emerged. In 1983, Tom Holden J. Marsiglio (1990–97) joined the sources around the world, enabling with Brian Powell and Gerald Doll- Theoretical Physics Branch to pro- many areas of research in solid state ing demonstrated stress mapping of vide theoretical support for under- physics. intact components of nuclear power standing superconductivity, the sub- But in spring 1996 when many reactors on the C5 and L3 beam- ject of many neutron experiments. In other government agencies were fac- lines, which led to the Applied Neu- fact, when the Theoretical Physics ing cutbacks, AECL’s budget was tron Diffraction for Industry (ANDI) Branch was disbanded in 1993, four cut 40%, and decisions were made to service. After the Space Shuttle theorists, whose work was relevant eliminate all of its remaining funda- Challenger disaster in January 1986, to materials research, transferred to mental research activities. The Phys- ANDI was selected to examine an the Neutron and Condensed-Mat- ics Division was disbanded, then as-manufactured section of a booster ter Sciences Branch: Varley Sears, composed of primarily accelerator rocket casing provided by the acci- Frank Marsiglio, Michel Couture physics at the Tandem Accelerator dent investigation. Neutron diffrac- (1986–96), and Hoong-Chien ‘Paul’ Superconducting Cyclotron, neutron tion showed that the stress distri- Lee (1968–93). At the same time, scattering at NRU, and support for bution in question was acceptable, Ted Hsu (1992–94) joined as a re- development of SNO. There was a pointing the failure investigation to search associate in theory (Hsu was strong outcry from the neutron user look elsewhere. ANDI became the later the science critic as a Member community, and Bill Buyers lev- go-to service for failure analyses of Parliament, 2011–15). eraged contacts in federal depart- for high-profi le incidents, such as The neutron scattering experiments to advocate for retention of the Point Lepreau Nuclear Generat- ments were also well supported with neutron scattering. Senior offi cials ing Station shutdowns in 1997 and additional technical staff who had at Natural Resources Canada (re- 2001, the Space Shuttle Columbia recently joined the Branch. Those sponsible for nuclear matters) and accident in 2003 and the 2005 train who provided dedicated supported Industry Canada (responsible for derailment at Lake Wabamun in Al- for a decade or more include: Mike science and economic development)

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agreed and struck a deal to transfer Fritzsche (2003–present), Lachlan engineers, and students, from uni- the neutron beam lab to the National M.D. Cranswick (2004–10), Zahra versities, industry, and government Research Council (NRC) as the Neu- Yamani (2004–present), Michael A. labs, from Canada and around the tron Program for Materials Research Gharghouri (2004–present), Dimitry world. The ANDI service had gen- (NPMR) on April 1, 1997. The deal G. Sediako (2006–17), and Norbert erated about $6M of fee-for-service provided a smaller budget that could Kučerka (2006–14). New technical revenue for over 200 projects. The accommodate the neutron scattering staff were added during these years CNBC’s $4M/year operations had experimentalists and technicians, but as well, including Tim Whan (2001– achieved a funding balance of 60% not the theorists or neutron nuclear 15), Raymond Sammon (2003–pres- from NRC for baseline operations, physicists. The science staff were ent), Shutao Li (2007–17), and Dave 30% from NSERC to maintain fa- transferred to NRC immediately, Dean (2007–present), each of whom cilities in a state of readiness for user while the technical staff were sec- provided valuable support for over a access, and 10% from commercial onded to NRC for 3 years ending in decade. services and other R&D income. Nu- March 2001, after which some were The NPMR emerged strongly merous beamline upgrades were put transferred to NRC and others were from the crisis of the mid-’90s. An in place, distinguishing the CNBC in redeployed within AECL. international peer review in 2004 stress scanning, powder diffraction, Rebuilding the Program began reported that only three facilities in and polarized triple-axis spectro- under NRC with the strong support the world had more users per beam- scopy. of the neutron scattering community, line, and that the CNBC provided an The fi nal decade of CNBC opera- which attracted funds from govern- extraordinarily high fraction of the tion was characterized by persistence ment granting agencies to boost op- beam time to users (90%), compared through challenges. Federal austerity erations and construct a refl ectom- to 50–66% elsewhere, and to indus- measures following the global 2008 eter at the D3 beamline. Many of try as a commercial service (13%). recession fi rst led to hiring freezes the prominent scientists whose work They concluded that NPMR was a at NRC, and then signifi cant cuts characterized the earlier decades had world-class program run on a shoe- at NRC and NSERC. These cuts, in retired or would retire in the early string budget. Renamed the Cana- parallel to the restructuring of NRC years under NRC. When Brian Pow- dian Neutron Beam Centre (CNBC) led to a decision by NRC in 2012 to ell retired in 1998, John Root became in 2005, the Centre reached a peak eliminate CNBC’s funding. How- Program Leader, and remains so to- around 2008, running at full capacity ever, AECL, which was then under- day. New scientists were attracted, in with six beamlines highly subscribed going its own restructuring, agreed to addition to post-docs and research as- by a community of over 700 frequent take responsibility for funding, gov- sociates, to support the user program: and occasional research participants, ernance and operation of the CNBC, Mu-Ping Nieh (2002–10), Helmut over 5 years, of all types: scientists, effective April 1, 2013. In addition, a

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Figure 3. DUALSPEC at the time of NRU’s closure in March 2018, comprised of the C2 Powder Diffractometer and the C5 Polarized Beam Triple- Axis Spectrometer. Parts of the D3 Reﬂ ectometer and E3 Triple-Axis Spectrometer are visible in the background. (Image credit: CNBC).

heavy water leak led to an unplanned from staff losses in soft materials scientist role, having begun serving shutdown of the NRU reactor begin- expertise or in the ANDI service’s as a local expert for user experiments ning in May 2009 and required a momentum following the 15-month in 2014. challenging repair, thereby creating shutdown. Yet in other areas, the The Canadian Nuclear Safety uncertainty over whether the reactor CNBC bounced back. Research par- Commission required a plan from would be restarted at all. The repair ticipants grew to over 800 over the AECL concerning whether and how job was completed in August 2010 at last 5 years, compared with over it would continue or cease operations a cost of well over $100M. Discus- 700 for the 5 years ending in 2008. of the NRU reactor beyond 2016. sions of replacing the NRU reactor Although proprietary research for After reviewing the business case for were put on hold as government at- industry dropped off, the total pro- extending NRU’s license to 2021, the tention was dominated by questions portion of beam time for industry Government of Canada announced of Chalk River’s role as a national remained the same. Mark Vigder in February 2015 that it would sup- nuclear lab, the structure of AECL, a (2009–present) led a small team in a port an application for license ex- national nuclear policy, global short- successful renewal of the data acqui- tension until March 31, 2018, citing ages of Mo-99 caused by unplanned sition and instrument control systems heavy fi nancial costs and changes in shutdowns of NRU reactor, and a for the beamlines. New scientists the medical isotope market that had $1.6B lawsuit from Nordion over joined, replenishing the professional reduced reliance on NRU. Canadian cancelling the MAPLE reactors in- ranks: Roxana Flacau (2010–14), Nuclear Laboratories (CNL, the suc- tended for Mo-99 production. Julien Lang (2015–present), Hung cessor agency of AECL that has op- All these factors created further ‘Harry’ Ha (2015–present), and Lev- erated the Chalk River Laboratories uncertainty about the continued life- ente Balogh (2016–18). Chad D. since 2014) immediately confi rmed time of the Canadian Neutron Beam Boyer (2009–present), originally a that the government intended this to Centre. The CNBC did not recover technical offi cer, was promoted to a be the fi nal closure date for the re-

30 Volume 29 • Number 2 • 2018 Neutron News News and Reports actor, and planning began for how try and the Ontario government, Canada’s best remaining source of to retain staff needed to operate and which owns most of Canada’s nu- neutrons. CINS sees potential to maximize value from NRU’s remain- clear power stations, that it was not upgrade the McMaster Nuclear Re- ing life. Thus, CNL offered positions interested in funding a new research actor’s neutron fl ux and operating to all CNBC personnel. Most of the reactor by itself. It stated that an in- cycle and to add further beamlines, science staff accepted the offers and vestment decision would need to be such as a powder diffractometer were assigned to a Neutron Scatter- based on appropriate sharing of costs and refl ectometer, thereby making ing Branch, created for that purpose. among the many users and benefi cia- it more suitable for a range of high- As a result, the CNBC has been op- ries. Apart from this requirement, the demand capabilities. erated since August 2015 as a team federal government is offi cially neu- Whatever the future may hold for of individuals drawn from both NRC tral. Thus, a prerequisite to such a Canadian neutron beam users, an en- and CNL. decision is alignment of both levels during truth is that neutrons interact Today, the CNBC is in a wind- of government and of stakeholders with materials in unique ways to re- down mode, wrapping up the scien- on a compelling scientifi c and busi- veal knowledge that is often diffi cult tifi c outcomes of the fi nal neutron ness case. As each of the three tra- or impossible to acquire otherwise. beam experiments, and working ditional stakeholder communities, Neutrons will continue to be needed. towards dispositioning the neutron nuclear power, medical isotopes, and beam equipment. Zin Tun and Der- neutron beams, are presently in a Acknowledgements rick West (2012–present, designer) state of reorganization or rebuilding The author thanks John Root, are also completing a project for following the restructuring of AECL Ron Rogge, Tom Holden, Varley McMaster University to design and and the loss of the NRU reactor, only Sears, Bill Buyers, Zahra Yamani, build a small-angle neutron scatter- time will tell if such an alignment Zin Tun, and Helmut Fritzsche for ing (SANS) beamline for the Mc- will occur. input on the manuscript. Ron Rogge Master Nuclear Reactor. CNL’s neu- Since 2015 when the coming led the production of the fi nal neutron scattering scientists now form a closure of NRU was announced, the tron image. Section led by Ron Rogge within the Canadian Institute for Neutron Scat- Materials Sciences Branch of CNL. tering (CINS), which represents the References This section can continue using neu- neutron beam community, has been 1. V.F. Sears, Neutron News 3(3), 26–37 tron scattering, to the extent that the looking to secure funds for a new (1992). doi:10.1080/104486392082 neutron capabilities needed to sup- mode of operation using other neu- 18770 port CNL research projects may be tron sources: CINS aims to secure 2. AECL. Progress Report: Physics and accessible elsewhere. suffi cient beam time at leading for- Health Sciences, Physics Section. PR- Will Canada replace the NRU eign facilities to meet Canadian de- PHS-1 (1986). reactor? The federal government’s mand for experiments that require clearest policy statement about a the brightest sources of neutrons. DANIEL BANKS new research reactor was made in CINS also aims to fully exploit Canadian Neutron Beam Centre, 2010, in which it signaled to indus- the McMaster Nuclear Reactor as Chalk River, Ontario, Canada

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