Effect of mix parameters and hydrogen loading on neutron radiation shielding characteristics of latex modified concrete mixes Santhosh M. Malkapur a, * , Harsharaj Satdive a , Mattur C. Narasimhan a , Narayana B. Karkera a , P. Goverdhan b , V. Sathian c a Department of Civil Engineering, NITK Surathkal, Mangalore, Karnataka 575025, India b R.P.D. Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India c R.A.P.D. Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India article info Article history: Received 22 October 2014 Received in revised form 22 February 2015 Accepted 28 February 2015 Available online Keywords: Mix parameters Hydrogen loading Neutron radiation shielding Latex modified concrete Total neutron cross section Dose transmission abstract With the tremendous surge in the usage of radioactive materials in industry, education and research, medicine and other fields, it becomes a concern to protect the working personnel and common people around, from hazardous radiation leakages that may seriously affect their health. Among the different types of radiation, gamma and neutron radiations require adequate shielding. There have been several attempts to develop newer concretes and evaluate their neutron radiation shielding characteristics. In the present study, an attempt has been made to study the effect of varying the mix parameters and hence the resulting total hydrogen content on the neutron radiation shielding characteristics of Latex Modified Concrete (LMC) mixes. The experiments are planned in such a way that the hydrogen content of the mixes is varied by controlling the mix parameters i.e., cement content, water/cement ratio and polymer/ cement ratio of LMC mixes. The results are statistically analyzed. It is found that definite improvements could be achieved in neutron radiation shielding characteristics of LMC mixes as compared to ordinary concrete, with the increase in hydrogen concentration effected by changes in mix parameters. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Several materials serve as a good shield for alpha and beta ra- diations. Concrete serves as a good shield in a mixed field of gamma and neutrons and in large facilities encountering either of these. One route to further enhance its neutron-radiation (n) shielding properties is to increase the amount of lighter materials, read as ‘hydrogen’ within the concrete. Hydrogen with single nucleon, 1 H 1 , is the best candidate for neutron shielding since it can efficiently thermalize (slow down) the fast neutrons through elastic scat- tering. These thermal neutrons with lower energies, have stronger affinity for getting absorbed, due to higher ‘absorption cross-sec- tion’ values of the shielding materials at lower energies. Various research works, evaluating neutron radiation shielding performances by incorporating different hydrogen sources have been reported in the past. Belyakov et al. (1977) reported the shielding characteristics of polymer based concretes such as furfurylidene-acetone polymer-concrete. Gunduz and Usanmaz (1986) studied shielding properties of polymer impregnated con- crete with boron frit as aggregates. Azharul Islam et al. (1993) investigated the shielding properties of polyethylene (PE), lead (Pb), ordinary concrete (OC), heavy concrete (HC), and their multi- layers, PE þ OC, PE þ HC and PE þ Pb. Kharita et al. (2010) studied the effect of water/cement ratio on shielding performance of con- crete. Sahin et al. (2011) studied the effect of water to cement ratio, curing conditions, dosage of cement and air entraining agent on the gamma radiation shielding performance. Other than concrete, several new composites with different additives were developed to enhance the neutron radiation shielding performances. Abdo et al. (2003) reported the radiation shielding properties of a composite, made from recycled agricul- tural fiber, industrial plastic wastes and lead fibers. Okuno (2005) developed a new type of neutron shielding material based on epoxy resin and colemanite. Also, shielding performance of metal hydrides like Zirconium hydride (ZrH 2 ) and Zirconium borohydride Zr(BH 4 ) 4 (Hayashi et al., 2009) and oil loaded paraffin wax (Aygun and Budak, 2012) were evaluated as a class of newer advanced shield materials. All these works have reported improved neutron * Corresponding author. Tel.: þ91 9945417886. E-mail addresses: sm.malkapur@gmail.com (S.M. Malkapur), mattur.cn@gmail. com (M.C. Narasimhan). Contents lists available at ScienceDirect Progress in Nuclear Energy journal homepage: www.elsevier.com/locate/pnucene http://dx.doi.org/10.1016/j.pnucene.2015.02.010 0149-1970/© 2015 Elsevier Ltd. All rights reserved. Progress in Nuclear Energy 83 (2015) 8e12