N.J. Admin. Code § 7:18-6.3

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:18-6.3 - Requirements for radiochemistry laboratory equipment and instruments

(a) The supervisor shall have control over the equipment and instruments used in radiochemical testing and radon/radon progeny-in-air testing. The laboratory shall have equipment and instruments that satisfy the applicable requirements listed in (a)1 and 2 below, in (b) and (c) below, in N.J.A.C. 7:18-3, and in the applicable DSAM.

1. The laboratory shall have a muffle furnace that:

i. Is automatically controlled;

ii. Has a chamber capacity of at least 2,200 cubic centimeters (cc), and measures at least 10 centimeters (cm) by 9.5 cm by 23 cm; and

iii. Has a maximum operating temperature of 1,000 degrees Celsius continuous and 1,100 degrees Celsius intermittent; and

2. The laboratory shall have a general purpose table-top centrifuge that has a maximum speed of at least 3,000 revolutions per minute (rpm) and a loading option of 4 x 50 mL.

(b) A laboratory performing measurements involving radiation counting (as set forth in 40 CFR 141 and required by the Federal Safe Drinking Water Act) shall have the instruments meeting the requirements in (b)1 through 6 below and the requirements of the applicable DSAM:

1. The laboratory shall have a liquid scintillation system to measure tritium in drinking water samples or radon in drinking water or wastewater samples. The system shall meet or exceed the sensitivity requirements of 40 CFR 141.25;

2. The laboratory shall have a gas-flow proportional counting system (as described in the reference cited in 40 CFR 141.25(a) ) to measure gross alpha and gross beta activities, radium-226, radium-228, strontium-89, strontium-90, cesium-l34, and iodine-l3l. The detector shall be either a "windowless" (internal proportional counter) or a "thin window" type. A combination of shielding and a cosmic (guard) detector operated in anticoincidence with the main detector shall be used to achieve low background beta counting capability. The alpha and beta background count of the system shall be such that the sensitivity of the radiochemical analysis of the water sample will meet or exceed the requirements of 40 CFR 141.25 with a reasonable counting time of not more that 1,000 minutes (16.6 hrs);

3. Instead of the gas-flow proportional counter described in (b)2 above, a laboratory may use a scintillation system designed for alpha counting to measure gross alpha activities and radium-226. When the laboratory uses a scintillation system for counting, it shall follow the sample setup for measurement described in EPA 600-4-80-032, Appendix D, item 2;

4. The laboratory shall have a scintillation cell system designed to accept scintillation flasks ("Lucas cells") to specifically measure radium-226 by the radon emanation method. The system consists of a light-tight enclosure capable of accepting the scintillation flasks, a detector (phototube), a high voltage supply, an amplifier, timers, and scalers. The laboratory shall either purchase the flasks (cells) required for this measurement from commercial suppliers, or construct the flasks (cells) in accordance with the specifications set forth in Lucas, H.F., "Improved Low-Level Alpha Scintillation Counter for Radon". Rev. Sci. Instrum., 28:680, l967;

5. The laboratory shall have a gamma spectrometer system equipped with one of the following to analyze manmade photon emitters:

i. A sodium iodide NaI(Tl) crystal detector that:

(1) Uses a NaI(Tl) crystal measuring at least 7.5 cm x 7.5 cm (though the Department recommends using a crystal measuring 10 cm x 10 cm);

(2) Is shielded with at least 10 cm of iron or the equivalent thereof;

(3) Has sufficient distance from the center of the detector to other part of the shield (the Department recommends a distance of at least 30 cm); and

(4) Has a multichannel analyzer with a memory of not less than 200 channels and at least one readout device for each system;

ii. A solid state lithium drifted germanium detector that meets the requirements of (b)5ii(1) and (2) below, or a gamma-X photon detector that meets the requirements of (b)5ii(1), (2) and (3) below:

(1) The detector shall be sufficiently efficient to make the gamma spectrometry system sensitive enough to meet the minimum detectable activity requirements cited in 40 CFR l41.25;

(2) The detector shall be shielded with at least 10 cm of iron or the equivalent thereof; and

(3) The gamma-X photon detector shall be connected to a multichannel analyzer that has a memory of at least 2,000 channels and at least one readout device for each system; and

6. The laboratory shall have a fluorometer capable of detecting 0.5 nanogram (ng) of uranium for the analysis of uranium by the fluorometric method.

(c) A laboratory certified to perform measurements involving radiation counting (as set forth in the Radon Act) shall meet the following requirements when performing radon/radon progeny-in-air analyses:

1. If required by the authorized measurement protocols, the laboratory shall use a microscope or automated counting system capable of detecting and counting alpha tracks. A laboratory performing an analysis with a radon progeny-in-air integrating sampling unit (RPISU) shall use a thermoluminescent dosimeter (TDL) reader; and

2. To analyze manmade photon emitters, the laboratory shall use a gamma spectrometer system equipped as described under (b)5 above.

N.J. Admin. Code § 7:18-6.3