Deficient Analysis Method for I-131 in Environmental Water Samples: The Importance of Rigorous Quality Control Greg Barley-Progress Energy

Success does not consist in never making mistakes, but in never making the same one a second time. George Bernard Shaw

NUREG 1301, 1302 I-131 LLDs l 1 pCi/L drinking water l 15 pCi/L if no drinking water pathway l Originally published in 1979 Branch Technical Position (BTP) for Regulatory Guide 4.8

Progress Energy Corporate Radiochemistry Laboratory l Part 50 Composite Analyses for HTDs w Entire fleet l REMP w Sample collection for Shearon Harris Plant w Analyses and REOR preparation for Progress Energy Carolina plants

REMP I-131 Test Methods l Drinking Water Pathway w I-131 separation onto resin, then analyze resin by gamma spectroscopy l Non-Drinking Water Pathway (previous method) w Concentrate gamma emitters by heated evaporation w 1 liter to 500 mL for brackish water w 1 liter to 50 mL for non-brackish water

History of Evaporation Method l Developed as a means to minimize counting time circa 1976 l Developed “in-house” by technically respected personnel l Emphasis was on achieving low levels for I-131 in drinking water l Evaporation method not evaluated when BTP and subsequent NUREGs published.

Back to Basics l What happens to iodine when it is heated? l How does one ensure that an analytical method produces precise, reproducible results?

The Problem’s History l Past quality control blind crosscheck analyses had not tested the evaporation method for non-drinking water samples; only the drinking water separation method had been tested l There was no central facility procedure or document containing the Radiochemistry QA elements l The need to test all methods was not captured in any facility procedure or document

The Problem Becomes Apparent l Lab personnel begin testing blind QC crosschecks by heated evaporation l Non-volatile nuclides usually in agreement l Initially the idea that I-131 could volatilize was recognized, so QCs were analyzed for I-131 prior to heated evaporation, but missed the connection to field sample analyses l During subsequent staff discussions, questions arose as to why the QCs were being prepared differently for I-131 analyses than field samples were prepared

The Problem Unveiled l Examined the I-131 in QC samples that had been subjected to heated evaporation w Where gentle heating was applied, losses were low (0-10%) w Where heating was more aggressive, losses were substantial (0-50%)

Significance l Historically, plant I-131 not found in these non-drinking water samples l However, the requirement to meet the LLD of 15 pCi/L was not met for some number of samples that were subjected to aggressive heating l Problem potentially dates back to initial development of the method in mid-1970’s

Causes l No central QA/QC document or procedure that set forth the required programmatic elements l QA/QC Program failed to change to meet changing regulatory requirements (BTP, NUREGs) l Insufficient priority assigned to QA/QC Program by supervision l No analytical standard for method l Overconfidence in the method

Corrective Actions lDlDiscontinue heated evaporation wDwDirect gamma analyses without evaporation, except for drinking water separation onto resin lRlReview other test methods to ensure all have some QC verification lDlDevelop central QA/QC procedure lIlIncreased resource and priority on QA/QC Program

Summary l Ensure that all analytical methods are tested by some quality control measure l Always exercise questioning attitude w Just because a method was developed by respected individuals and has been in use for a long time does not necessarily make it correct w When there are questions, keep going until they are answered acceptably

Questions, comments?