1

WIPP Laboratories Response to EPA Report, “Verification and 

Validation of WIPP Data Packages”

1) EPA Observation

2.0 Verification Summary

A number of exceptions, defined as deviations from stated requirements or expectations, were 

noted. These included:

 Nine pages were missing from the package for SDG 2014-079

 Typographical errors in case narratives

 Discrepancies in sample collection dates/times between chain-of-custody form (COCs), 

case narratives, raw data, etc.

 Inconsistencies in providing spectra and channel by channel printouts

 A few cases where EPA suspects pages should have been marked “VOID” but were not

Response

WIPP Laboratories acknowledges that there were some typographical/transcription errors within 

the data packages. However, these data packages were copied from the WIPP Laboratories 

files. Copies of these documents were delivered to the clients for final Validation which had not 

been completed yet.

2) EPA Observation

3.0 Validation Summary

EPA checked the following elements from DOE’s SOPs:

 DOE’s reagent laboratory control samples and duplicates (RLCS and RLCSD) 

recoveries between 80% and 120% and within ±3σ limits on control charts

 No deficiencies found.

 The RLCS and RLCSD samples in SDG 2014-079 were analyzed without blank 

correction. This seems to represent a deviation from normal practice, but the impact on 

the results is inconsequential.

Response

As noted the effects of blank subtraction on an LCS are extremely small. Standard practice at 

WIPP Laboratories is to not blank subtract RLCS and RLCSDs for uranium samples, as the 
2

matrix blank (in the case of glass fiber filters) contain uranium. As for Pu, and Am, these are 

blank subtracted along with the other samples.

3) EPA Observation

3.0 Validation Summary (cont.)

 RLCS/RLCSD replicate error ratios (RER) less than 1

o In all the packages only one RER exceeded 1, and only by a small amount. It was 

duly noted in the DOE package’s case narrative.

o The SOP and printed forms indicate that the RER should be less than 2, but since 

the WIPP lab reports all uncertainties as 2σ, it actually checks that the RER is less 

than 1. The SOP and forms should be revised to reflect the actual practice.

Response

At the time that these data packages were compiled, The Environmental Monitoring (EM) SOW 

required the RER to be less than 1. All other WIPP clients request RER to be less than 2. The 

EM SOW was changed in June, 2014 to require the RER to be less than 2. All of WIPP 

Laboratories procedures and forms are now current.

4) EPA Observation

3.0 Validation Summary (cont.)

 Tracers and standards not past their expiration dates 

o No deficiencies found.

 Sample tracer recoveries between 30% and 110%

 

The tracer recoveries for several samples in SDG 2014-079 exceeded 110%. Although the lab 

report stated that these samples were “reprocessed,” giving acceptable recoveries, EPA 

concluded that whatever caused the original high recoveries could still have impacted the 

reprocessed results, since in each case the entire sample had been spiked with tracer and 

analyzed, leaving no remaining sample for a second independent analysis. EPA assigned a J 

qualifier (“estimated”) to each of the associated plutonium results. (See Table 1 for a list of the 

sample result qualifiers used by EPA.) Note that all the affected plutonium results were 

undetectable (less than 2σ).

Response

Standard practice at WIPP Laboratories is to re-process the samples when a tracer recovery is 

over 110%. The samples and associated QC samples are stripped from the filter and 

processed through a “clean up” column, generally the same procedure as used during the initial 

separation. The stripped filter is free of most of the initial matrix interferences which may have 
3

been present during the initial separation. This allows for more effective interference removal 

the second time through the column. Applying this logic, WIPP Laboratories does not qualify 

the data as “estimated” if all of the QC parameters are met after the re-processing of the 

samples.

5) EPA Observation

3.0 Validation Summary (cont.)

o The americium analysis on blank sample C7897 also had a high tracer yield, which 

the WIPP laboratory apparently failed to notice during its internal review of the data. 

EPA assigned a J qualifier to the Am-241 result for C7897 only.

Response

This sample should have been assigned a “J” qualifier and will be corrected in the data 

package.

6) EPA Observation

3.0 Validation Summary (cont.)

 Reagent blank results within ±3σ limits on control charts

o No deficiencies found.

o NAREL observed that the reagent blank results were never blank-corrected, even in 

batches where ordinary sample results were blank-corrected. Presumably this 

represents the lab’s standard practice, which allows reagent blank results from 

blank-corrected and non-blank-corrected batches to be control charted together.

Response

The reagent blank results are not blank corrected as noted in the report. The blanks analyzed 

with the batch are a reagent blank and a matrix blank; however, reagent blanks are prepared 

using deionized water as the matrix, whereas matrix blanks are prepared using a clean filter. 

The matrices are not the same so matrix blank correcting a reagent blank would not be 

appropriate. Subtracting a reagent blank from itself would result in a zero activity every time. 

Reporting the results of the reagent blank obtained without blank subtraction provides more 

information as to the amount of activity added from the normal analytical process. The reagent 

blanks for all types of samples are treated the same, and therefore can be charted together.
4

7) EPA Observation

3.0 Validation Summary (cont.)

 No trends on control charts

o No deficiencies found.

o Although the SOP requires the validator to check for trends on control charts, a trend 

on the U-234 reagent blank control chart had not been noted. EPA found no such 

mistakes in the americium or plutonium data.

Response

This trend was noted on the first page of the control chart. It was not noted in the case 

narrative. Standard protocol is to make note of these items in the case narrative and to perform 

a review to determine if the trend affects that data, which in this case, it did not. This will be 

corrected in the case narrative.

8) EPA Observation

3.0 Validation Summary (cont.)

Documentation in the packages was insufficient to perform useful checks of instrument 

calibrations and quality control. Note that the efficiency calibrations for analyses based on 

alpha-particle spectrometry using alpha-emitting tracers affect only the chemical yields, or tracer 

recoveries, not the final results of the analyses. However, instrument background data would 

have been useful information.

Response

Instrument calibration data was not provided because it is not a part of Level III data package. 

The data packages provided to EPA were the Level III data packages requested in the client’s

SOW. Instrument background information can be found however, on the calculation 

spreadsheets for both alpha spectroscopy and gas proportional counting. Calibration data will 

be provided.

9) EPA Observation

3.0 Validation Summary (cont.)

The WIPP Laboratories never assigned a D qualifier (“detected”) to any americium or plutonium 

result, although many of the results exceeded 10 times the standard uncertainty of the 

measurement, making them not only detectable but quantifiable. In two cases (the Pu-238 

results for samples C7911 and C7912 in SDG 2014-080) EPA assigned a D qualifier where the 

WIPP lab had assigned a U qualifier, “undetectable.” Since the D qualifier had not been used, 

NAREL assumed the WIPP lab considered any result without a U qualifier to be detected. In 

cases where the WIPP lab had assigned no explicit qualifier, NAREL assigned a “D,” indicating 

a detectable result.
5

Response

WIPP Laboratories uses a different set of qualifiers than those listed in EPA report. These 

qualifiers are found in WP12-RL3002 Radiochemistry Laboratory Data Validation and 

Verification.

The WIPP Laboratories qualifiers are as follow:

The “=” qualifier is used for results that are considered above 2σTPU and MDC. It indicates 

there are no quality issues with the result and the activity is reported as measured. The above 

table of qualifiers that are used by WIPP Laboratories are clearly spelled out in each data 

package, letting client know exactly what is meant by the laboratories’ definition of a detect and 

non-detect. While the EPA suggests using the DLC as a detection criterion, the DLC is not 

required by the client and is therefore not taken into account by WIPP Labs. The qualifiers used 

by WIPP Laboratories follow the guidance provided in DOELAP and have been audited and 

approved in reporting to DOE and various clients. They are different from the qualifiers used by 

EPA to review this data.

U Nuclide considered not detected above the reported MDC and 2σ counting uncertainty.

J Nuclide identified; the associated numerical value is approximated.

UJ Nuclide not detected above the reported MDC or 2σ counting uncertainty and a quality deficiency 

affects the data making the reported data more uncertain.

NJ Nuclide present at an estimated quantity.

R Result is not usable for its intended purpose.

= No qualifier is necessary.

Qualifier Codes

Table 1: Sample Result Qualifiers

D Detected

E Exceptions

J Estimated; unusually uncertain

N Negative

R Rejected; unusable

U Undetectable
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10) EPA Observation

4.0 Package-by-Package Notes: EPA’s Findings When Reviewing DOE’s SDGs

SDG 2014-079

8 samples collected February 17 and 18; 10 blanks

Verification

Typo on page 4 – Am-241 detected for samples C7892, C7893, and C7896 instead of C7893, 

C7893, and C7896.

Response

This was missed in the case narrative; however, all positive results were correctly marked in the 

sample results summary, provided by WIPP Labs. The case narrative will be corrected.

11) EPA Observation

Verification (cont.)

Report pages 17 through 25 were missing.

Response

These pages were inadvertently left out from the EPA copy.

12) EPA Observation

Verification (cont.)

On page 4, C7900 is listed in both batches, SP14-03-09 and SP14-03-10.

Response

This is a minor typo and will be corrected by WIPP Labs.

13) EPA Observation

Verification (cont.)

On page 3, C7896 client ID is incorrect and is also incorrect on page 12.

Response

This is a minor typo and will be corrected by WIPP Labs.
7

14) EPA Observation

Verification (cont.)

On page 232, C7909 was omitted from the first block of the table.

Response

The cell on the calculation spreadsheet was hidden. This will be corrected in the data package.

15) EPA Observation

Verification (cont.)

Batch SP14-03-09 did not provide as much alpha spec raw data as SP14-03-10 such as spectra 

and channel by channel printouts.

Response

EM does not require the spectra to be included, although starting in April, 2014; all spectra have 

been included to WIPP Labs’ data packages regardless of clients. The spectra are also 

available for review on the alpha spectroscopy software. The missing spectra will be reprinted 

and added to the data package.

16) EPA Observation

Verification (cont.)

On page 319, the collection date/time for matrix blanks (MBLK) is not the same as listed on 

page 3. It is correct on page 326.

Response

The MBLK date was incorrectly entered. This typo has very minor effect on data. This will be 

corrected in the data package.

17) EPA Observation

Verification (cont.)

Pages 322 and 323 appear to be the same as 324 and 325. There are slight differences in MDC 

and DLC values. The signatures on 322 and 323 have a later date. Data on pages 322 and 323 

were reported, but 324 and 325 were not voided.

Response

Pages 324 and 325 should have been voided as noted, and will be corrected in the data 

package.
8

18) EPA Observation

Verification (cont.)

On page 429, the collection date/time for MBLK is not the same as listed on page 3.

Response

This will be corrected in the data package.

19) EPA Observation

Verification (cont.)

On page 430, C7909 was omitted from the first block of the table.

Response

The cell on the calculation spreadsheet was hidden. This will be corrected in the data package.

20) EPA Observation

Verification (cont.)

Some Am raw data have spectra and channel by channel printouts; and others do not.

Response

The client does not require the spectra to be included, although starting in April, 2014; all 

spectra have been included to WIPP Labs’ data packages regardless of clients. The spectra are 

also available for review on the alpha spectroscopy software. The missing spectra will be 

reprinted and added to the data package.

21) EPA Observation

Validation

Sample result summaries for samples C7901–C7909 were missing from the data package.

Response

These pages were inadvertently left out from the EPA copy. These pages will be provided to 

EPA.

22) EPA Observation

Validation (cont.)

EPA detected Am-241 in 5 samples, although the case narrative by WIPP Laboratories claimed 

only 3. Two of the detections occurred in samples whose result summaries were missing from 

the package.
9

Response

This was missed in the case narrative; however, all positive results were marked in the sample 

results summary, provided by WIPP Labs. The case narrative will be corrected.

23) EPA Observation

Validation (cont.)

Samples C7896—C7900 originally had high Pu-242 yields. It is unclear how they could be 

“reprocessed” to get valid results. EPA assigned a J qualifier to each of the associated 

plutonium results.

Response

The samples and associated QC samples are stripped from the filter and processed through a 

“clean up” column, generally the same procedure as used during the initial separation. The 

stripped filter is free of most of the initial matrix interferences which may have been present 

during the initial separation. This allows for more effective interference removal the second time 

through the column. Applying this logic, WIPP Laboratories does not qualify the data as 

“estimated” if all of the QC parameters are met after the re-processing of the samples.

24) EPA Observation

Validation (cont.)

Blank sample C7897 also had a high Am-243 yield (greater than 110 %), which the lab failed to 

note during its own data review. EPA assigned a J qualifier to the Am-241 result for C7897 only, 

not to the samples in the batch that were blank-corrected using C7897.

Response

This sample should have been assigned a “J” qualifier and will be corrected in the data 

package.

25) EPA Observation

Validation (cont.)

RLCS, RLCSD, and reagent blanks (RBLK) were obviously calculated without blank correction. 

Other samples were blank corrected. In other SDGs it appeared that the RLCS and RLCSD 

were calculated with blank correction, but the effects of blank correction are so small for spiked 

samples that they may not be detectable.

Response

As noted the effects of blank subtraction on an LCS are extremely small. Standard practice at 

WIPP Laboratories is to not blank subtract RLCS and RLCSDs for uranium samples, as the 
10

matrix blank (in the case of glass fiber filters) contain uranium. As for Pu, and Am, these are 

blank subtracted along with the other samples.

26) EPA Observation

SDG 2014-080

10 samples collected February 15 to 19; 1 blank 

Verification

Collection dates/times on page 79 are not the same as those listed on page 3. Page 3 does not 

compare to the COC on page 53. The low-volume airborne particulate sample data sheets were 

not included with this SDG as they were in SDG 2014-079; so collection data cannot be verified.

Response

The client did not provide the low-volume particulate sample data sheets. Page 79 used the 

time from the sample ID. The sample times on page79 are therefore off by ~8 hours and were 

not noted. This will be corrected in the data package.

27) EPA Observation

Verification (cont.)

The uncertainty for the Am-241 result for sample C7916 is presented on page 15 first as 102 

dpm and then as 10.2 dpm. According to the gamma analysis report, the actual uncertainty is 

102 dpm.

Response

The 2 sigma value is 102, as represented in the table. The 10.2 value used to calculate the 1 

sigma, is a typo and will be corrected.

28) EPA Observation

Verification (cont.)

Pages 142, 212, and 265 also have discrepancies in collection date/times.

Response

The discrepancies are 8 hour intervals that are inconsequential to the data. This will be 

corrected in the data package.

29) EPA Observation

Verification (cont.)
11

Page 264 which is the Am Raw Data separation page is in the wrong place in the package. It 

should be page 212 instead which is where the Am raw data begin.

Response

The placing of the page will be corrected in this data package.

30) EPA Observation

Verification (cont.)

On page 68, the Am-243 tracer source ID is recorded as SP2-177 which is an Am-241 standard 

not an Am-243 standard.

Response

This was incorrectly written in the prep log; however it was entered correctly during all 

calculation steps. The prep log will be corrected and additional verification and validation 

training will be provided to the staff.

31) EPA Observation

Verification (cont.)

Am and Pu raw data sheets have the same collection date/time discrepancies as mentioned 

above. Verified

Response

Page 79 used the time from the sample ID. The sample times on page 79 are therefore off by 

~8 hours and were not noted. This will be corrected in the data package.

32) EPA Observation

Verification (cont.)

Inconsistency in providing spectra and channel by channel printouts occurs in this data package 

as in SDG 2014-079.

Response

The client does not require the spectra to be included, although starting in April, 2014, all 

spectra have been included to WIPP Labs’ data packages regardless of clients. The spectra are 

also available for review on the alpha spectroscopy software. All of the missing spectra will be 

added to the data package.

33) EPA Observation

SDG 2014-080

10 samples collected February 15 to 19; 1 blank 
12

Validation

No samples in SDG 2014-080 were blank-corrected. However, Am-241 and Pu-239/240 

activities were significantly elevated in all the non-blank samples, making the blank correction 

essentially irrelevant.

Response

These types of filters are not blank corrected by WIPP Labs as generally the number of blanks 

provided does not match the number of samples in a composite. The decision was made to 

keep results consistent with historical station B filters, i.e. that no blank subtraction should be 

done. In the future, if EPA expects blank corrected results, it should be discussed with the lab’s 

client. The current practice has been audited and accepted by the EPA Region 6 team from 

Dallas on an annual basis.

34) EPA Observation

Validation (cont.)

All samples in the SDG were counted for 60 minutes, although the case narrative states that 

they were counted for 1000 minutes (the routine procedure). Since all of the non-blank samples 

in this group contained elevated levels of Am-241 and Pu-239/240, the rationale for the shorter 

counts was clear.

Response

All calculation sheets and raw data show the correct count time. This will be corrected in the 

data package.

35) EPA Observation

Validation (cont.)

WIPP Laboratories detectable Pu-238 in samples C7910 and C7916 only. EPA also assigned a 

D qualifier to the Pu-238 results for C7911 and C7912 since both those results exceeded 2σ (as 

well as the DLC).

Response

WIPP Labs compares activity to 2 sigma TPU and MDC, as stated in the qualifiers section in the 

case narrative, not DLC. The client uses another definition of what detection is. Reporting of the 

DLC is not required per client. This practice has been audited and approved. Activity was 

detected from the underground release.

36) EPA Observation

Validation (cont.)

WIPP Laboratories Pu-239/240 in all the non-blank samples.
13

Response

This was noted in the case narrative and shown on the results summary by the qualifier. Activity 

was detected from the underground release.

37) EPA Observation

Validation (cont.)

WIPP Laboratories Am-241 in all the non-blank samples.

Response

This was noted in the case narrative and shown on the results summary by the qualifier. 

Activity was detected from the underground release.

38) EPA Observation

SDG 2014-098

1 sample collected February 21; 1 blank

Verification

Client ID incorrect on pages 3 and 8.

Response

Recorded as B13022141600, COC has B130221141600, this will be corrected in the data 

package.

39) EPA Observation

Verification (cont.)

Pages 57 and 58 are voided but not pages 62 through 68.

Response

These will be voided in the data package.

40) EPA Observation

Validation

WIPP Laboratories detected Am-241 and Pu-239/240 in the non-blank sample.
14

Response

This was noted in the case narrative and also shown on the results summary by the qualifier. 

Activity was detected from the underground release.

41) EPA Observation

Validation (cont.)

The sample and blank in SDG 2014-098 were counted for 60 minutes, although the case 

narrative states that they were counted for 100 minutes. One sample was a blank, but Pu239/240 was easily detectable in the other sample and the Am-241 result was quantifiable 

(greater than 10 times its standard uncertainty), implying that the 60-minute count times were 

adequate.

Response

The entry of 60 rather than 100 minutes in the case narrative was a typo and will be corrected. 

However, all calculation sheets and raw data show the correct count time.

42) EPA Observation

SDG 2014-101

11 samples collected March 11; 2 blanks

Verification

There are no Pu-238 counts on page 109, yet counts were entered on page 98.

Response

This is an issue with the instrument alpha spectroscopy software from the vendor (Canberra), 

which Pu-238 region of interest is listed as <not ID’d> at an energy of 5.397 MeV. The Canberra 

software uses a weighted average energy for the nuclide. The count(s) in the region of interest 

fell outside of the 100 keV tolerance set in APEX Alpha. This resulted in the <not ID’d> output. 

The issue could have been resolved in APEX Alpha data review by increasing the tolerance. In 

this case, correct count values were entered for Pu-238. This page will be reprinted with Pu-238 

identified. The data verification and validation procedure will be revised to include instructions 

to verify all ROIs are identified on the instrument printout for the APEX software. 

43) EPA Observation

Validation

No issues
15

44) EPA Observation

SDG 2014-108

11 samples collected March 18; 2 blanks

Verification

On page 7, the 4th table should be for U not Pu since only U was recounted on 3/24/2014.

Response

This typo will be corrected.

45) EPA Observation

Verification (cont.)

The collection date/time for the RBLK on page 330 is different than that used on page 360.

Response

The time is off by 2 hours. The 12:00 on page 330 is correct and is the value used for 

calculations. The typo for the time will be corrected on Page 360.

46) EPA Observation

Verification (cont.)

The Pu and Am control chart filter matrix blank activity data sheets and control charts are 

missing for SP14-06-02. Therefore the value used on pages 364 and 431 for the “Blank 

Standard Deviation of the Activity Charts” cannot be verified for the matrix blank values.

Response

SP14-06-02 was the first point on the chart, returning a “Divide by 0” error for the standard 

deviation, so the values were not included until 14-06-01 was charted. The “Blank Standard 

Deviation of the Activity Charts” is therefore the same for 14-06-01 and 14-06-02. The only 

issue was the lack of explanation in the case narrative of how the standard deviation is 

calculated on new control charts. This will be added to the case narrative.

47) EPA Observation

Verification (cont.)

The sample net counts and background counts for Pu-239/240 cannot be verified because Pu239 data are not listed on page 368.
16

Response

This is an issue with the instrument alpha spectroscopy software from the vendor (Canberra). 

The Pu-239 region of interest is listed as <not ID’d> at an energy of 4.971 MeV. The Canberra 

software uses a weighted average energy for the nuclide. The count(s) in the region of interest 

fell outside of the 100 keV tolerance set in APEX Alpha. This resulted in the <not ID’d> output. 

The issue could have been resolved in APEX Alpha data review by increasing the tolerance. In 

this case, correct count values were entered for Pu-239. This page will be reprinted with Pu239 identified. The data verification and validation procedure will be revised to include 

instructions to verify all ROIs are identified on the instrument printout for the APEX software.

48) EPA Observation

Verification (cont.)

Pages 468 and 473 were in the wrong places and should be switched.

Response

The placement of pages will be corrected in the data package.

49) EPA Observation

Validation

There was an apparently unnoticed trend on the U-234 RBLK control chart, but the uranium 

analyses were outside the scope of EPA’s review.

Response

This trend was noted on the chart; however, it was not explained in the case narrative. The case 

narrative will be corrected.

50) EPA Observation

Validation (cont.)

The replicate error ratio (RER) for the Am-241 RLCS/RLCSD pair exceeded 1 by a small 

amount and was duly noted in the case narrative.

Response

This was noted and communicated to the client at the time of data package compilation. Per 

new statement of work issued in June 2014, EM requests RER to be less than 2. The EM SOW 

states that the RER should be <1.

51) EPA Observation
17

5.0 Observations

All of the data are considered usable for decision-making; however, EPA makes the following 

observations that need to be addressed in order to provide the highest quality, most defensible 

data possible at all times:

1. It appears that the calculation spreadsheets perform blank corrections using the 

absolute value of the blank count rate (MBLK). Using a measured blank value, positive 

or negative, for blank correction is common, but converting negative blanks to positive 

introduces a negative bias into the measurement process. When the blank result is 

positive, the sample result is reduced, as expected; but when the blank result happens 

to be negative, the sample result is also reduced by this approach.

Response

The calculations will be revised to stop using the absolute value of the blank count rate. This 

will go into effect once the controlled software is validated and the data reduction procedure is 

revised. The blank subtraction protocol is being evaluated and discussed with WIPP 

Laboratories customers.

52) EPA Observation

5.0 Observations

2. The calculation spreadsheets appear to double-correct for both Am-243 and Pu-242 

“abundances” in the tracer regions of interest. Fortunately, both abundances are close 

to 100%, making the errors small (less than 1%).

Response

The calculations will be revised to remove the abundance correction. This will go into effect 

once the controlled software is validated and the data reduction procedure is revised. 

53) EPA Observation

5.0 Observations

3. Detection decisions appear to be implemented incorrectly. The case narrative for 2014-

079 states that Am-241 was detected in three samples, while the data show it was 

detected in five. (Two of the detections occurred in samples whose sample result 

summaries were missing from the data package.) Pu-238 was flagged as “U” 

(undetected) in samples C7911 and C7912, apparently because the result was less than 

the minimum detectable concentration (MDC), although it was greater than the 2σ 

uncertainty and greater than the decision level concentration (DLC). EPA flagged Pu238 as “D” (detected) in both of these samples.

Response

WIPP labs had 5 detections as shown in the sample results summaries; there was an oversight 

in the case narrative that did not include 2 of the detections. This will be corrected in the data 

package. 
18

The DLC is not used by the WIPP site EM group. Per WIPP Labs’ qualifiers, an analyte is 

considered undetected when its activity is not above both 2 sigma TPU and MDC.

WIPP Laboratories uses a different set of qualifiers than those listed in EPA report. These 

qualifiers are found in WP12-RL3002 Radiochemistry Laboratory Data Validation and 

Verification.

The WIPP Laboratories qualifiers are as follow:

The “=” qualifier is used for results that are considered above 2σTPU and MDC. It indicates 

there are no quality issues with the result and the activity is reported as measured. The above 

table of qualifiers that are used by WIPP Laboratories are clearly spelled out in each data 

package, letting client know exactly what is meant by the laboratories’ definition of a detect and 

non-detect. While the EPA suggests using the DLC as a detection criterion, the DLC is not 

required by the client and is therefore not taken into account by WIPP Labs. The qualifiers used 

by WIPP Laboratories follow the guidance provided in DOELAP and have been audited in 

reporting to DOE and various clients. They are different from the qualifiers used by EPA to 

review this data.

54) EPA Observation

5.0 Observations

4. According to its SOP for “Data Reduction and Reporting” , the WIPP lab incorrectly 

propagates the uncertainty of the detector efficiency when calculating the uncertainties 

of the final results of americium and plutonium analyses when using an alpha-emitting 

tracer as a yield monitor. The efficiency effectively cancels out of the activity equation, 

so that its uncertainty does not contribute to the total uncertainty of the calculated 

U Nuclide considered not detected above the reported MDC and 2σ counting uncertainty.

J Nuclide identified; the associated numerical value is approximated.

UJ Nuclide not detected above the reported MDC or 2σ counting uncertainty and a quality deficiency 

affects the data making the reported data more uncertain.

NJ Nuclide present at an estimated quantity.

R Result is not usable for its intended purpose.

= No qualifier is necessary.

Qualifier Codes

Table 1: Sample Result Qualifiers

D Detected

E Exceptions

J Estimated; unusually uncertain

N Negative

R Rejected; unusable

U Undetectable
19

activity. Note that the efficiency does affect the calculated value of the yield, or tracer 

recovery, and its uncertainty does contribute to the uncertainty of the yield although it 

does not contribute to the uncertainty of the analyte activity. Note also that the 

uncertainty of the efficiency is relatively small and should make a negligible contribution 

to the total propagated uncertainty even when it is propagated (incorrectly).

Response

The calculations will be revised to propagate the uncertainty of the detector efficiency. This will 

go into effect once the controlled software is validated and the data reduction procedure is 

revised.

55) EPA Observation

5.0 Observations

5. There is no obvious statistical rationale for the expression used for the uncertainty of 

the average background correction, as described in WP 12-RL3003 (the SOP for data 

reduction and reporting 1. The expression appears to be for a single Poisson 

background measurement of duration equal to that of the sample count, not for an 

average of several measurements. If the distribution is truly Poisson, the uncertainty of 

the average should be smaller than calculated; if not, it would seem more logical to 

make use of the experimental standard deviation of the multiple measured 

backgrounds.

Response

We will take another look at how the uncertainty of the average background correction is 

determined and used in the calculations. If it is determined that the suggested approach is 

more suited for WIPP Laboratories use, it will be implemented.

 

1 Nuclear Waste Partnership, LLC. Data Reduction and Reporting, Technical Procedure. WP 12-RL3003, Revision 

12. Carlsbad, NM: Effective date June 19 2013.