Repeat counting for samples 2 and 3 as in Step (5), making sure that each sample is counted exactly 3 min apart, or exactly the time between each sample is taken.
On the basis of gross gamma counts, if all three sample counts are within ±5%, the last sample is selected for further detailed gamma-ray spectrometric analysis (see Section 9).
If all the sample count rates are within ±10%, the highest activity sample is chosen for detailed analysis. If all the sample count rates are not within ±10%, a new set of samples should be taken for analysis.
If the sample vial is not properly evacuated, or the sample vial after filling is still under partial vacuum, the activity concentration in the final analysis should be corrected for the actual sample gas volume (at 760 mm).
(1) C.A.Bergmann and J.Roesmer, “Coolant Chemistry Effects on Radioactivity at Two Pressurized Water Reactor Plants,” EPRI NP-3463 (March 1984).
(2) N.R.Large, et al., “Studies of Problems of Corrosion Product Sampling from PWR Primary Coolant,” Water Chemistry of Nuclear Reactor System 5, Vol. 1, p. 63, BNES, London (1984).
(3) M.V.Polley and P.O.Andersson, “Study of the Integrity of Radioisotope Sampling From the Primary Coolant of Ringhals 3 PWR,” ibid, p. 71, (1989).
(4) PWR Primary Water Chemistry Guidelines Committee, “PWR Primary Water Chemistry Guidelines: Revision 2,” EPRI NP-7077, Final Report (November 1990).