Monte Carlo calculations were conducted to explore the potentials of zirconium hydride (ZrH2) as possible alternative moderator for high density polyethylene (HDPE) and water (H2O) in a simple (100MBq) 252Cf-based Prompt Gamma Neutron Activation Analysis (PGNAA) assembly. The thickness of moderators was optimized against thermal neutron flux (ϕth) as well as the ratio of (thermal/fast) neutron flux (ϕth/ϕfast), calculated at the sample cavity. The capabilities of moderating 252Cf source neutrons and minimizing the γ-background due to 2525Cf fission γ-rays, 1H(nth,γ)2H γ-rays originates in the moderator as well as other (nth,γ) capture reactions from surroundings were investigated. The optimal selected moderator with sufficient (ϕth) at the sample cavity and minimum γ-contamination was selected as ZrH2 for use in a252Cf-PGNAA for detection of nitrogen and chlorine in bulk sample simulants of melamine (C3H6N6) and sodium chloride (NaCl). The prompt γ-rays spectra were analyzed to detect the 10.83 MeV and 6.11 MeV prompt γ-peaks released by 14N(nth,γ)15N and 35Cl(nth,γ)36Cl, respectively. The results showed that the (252Cf-ZrH2)-PGNAA model has positively identified nitrogen with net counts (1.25 × 105 n.cm−2.s−1) and Chlorine with net counts of (4.19 × 106 n.cm−2.s−1), achieving minimum detectable concentrations of about (350 ppm at 10.83 MeV) and (640 ppm at 6.11 MeV), respectively.