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

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

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

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

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

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

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

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

8. The Problem’s History • 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 • There was no central facility procedure or document containing the Radiochemistry QA elements • The need to test all methods was not captured in any facility procedure or document

9. The Problem Becomes Apparent • Lab personnel begin testing blind QC crosschecks by heated evaporation • Non-volatile nuclides usually in agreement • 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 • During subsequent staff discussions, questions arose as to why the QCs were being prepared differently for I-131 analyses than field samples were prepared

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

11. Significance • Historically, plant I-131 not found in these non-drinking water samples • 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 • Problem potentially dates back to initial development of the method in mid-1970’s

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

13. Corrective Actions • Discontinue heated evaporation • Direct gamma analyses without evaporation, except for drinking water separation onto resin • Review other test methods to ensure all have some QC verification • Develop central QA/QC procedure • Increased resource and priority on QA/QC Program

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

15. Questions, comments?