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:

 N ine pages were missing from the package for SDG 2014

- 079

 T ypographical errors in case narratives

 D iscrepancies in sample collection dates/times between chain

- of

- custody form (COCs),
case narratives, raw data, etc.

 I nconsistencies in providing spectra and channel by channel printouts

 A few cases where EPA suspects pages should have been marked “VOID” but were no t

Response

WIPP Laboratories acknowledges that there were some typographical/transcription errors within the data packages. However, these data pa ckages 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 the2

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) S OW 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 im pacted 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 resul ts. (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 interfe rences which may have3

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 par ameters 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

app ropriate. 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 analy tical 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 pro vided 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 a lpha 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 ass igned 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,” indic ating

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 e ach 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 a ccount 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. 

### Table 1: Sample Result Qualifiers

D Detected

E Exceptions

J Estimated; unusually uncertain

N Negative

R Rejected; unusable

U Undetectable6

1 0 ) 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.

1 1 ) EPA Observation

Verificatio n (cont.)

Report pages 17 through 25 were missing.

Response

These pages were inadvertently left out from the EPA copy

.

1 2 ) EPA Observation

Verificatio n (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.

1 3 ) EPA Observation

Verificatio n (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

1 4 ) EPA Observation

Verific ation (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.

1 5 ) EPA Observation

Verificat ion (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.

1 6 ) EPA Observation

Verificatio n (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.

1 7 ) EPA Observation

Verificatio n (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 n ot voided.

Response

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

.8

1 8 ) EPA Observation

Verific ation (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.

2 0 ) 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.

2 1 ) EPA Observation

Validat ion

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.

2 2 ) 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 re sults were marked in the sample results summary, provided by WIPP Labs. The case narrative will be corrected.

2 3 ) 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. App lying 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.

2 4 ) EPA Observation

Validation (cont.)

Blank sample C7897 also had a high Am

- 243 yield (greater tha n 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.

2 5 ) 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 pra ctice at WIPP Laboratories is to not blank subtract RLCS and RLCSDs for uranium samples, as the10

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.

2 6 ) EPA Obser vation

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.

2 7 ) 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.

2 8 ) EPA Obs ervation

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.

3 0 ) 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.

3 1 ) 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.

3 2 ) 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.

3 3 ) EPA Observation

SDG 2014

- 080

10 samples collected February 15 to 19; 1 blank12

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 bl ank 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 ba sis.

3 4 ) 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 containe d 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.

3 5 ) 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 fr om the underground release.

3 6 ) 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.

3 7 ) 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.

3 8 ) 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.

4 0 ) 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.

4 1 ) 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 Pu

239/240 was easily detectable in the other sample and the Am

- 241 result was quantifiable (greater than 10 times its standard u ncertainty), 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.

4 2 ) 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 issues15

4 4 ) 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
calculation s. 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 a nd 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 incl uded 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 co ntrol 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 Pu

239 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 Alp ha data review by increasing the tolerance. In this case, correct count values were entered for Pu

- 239. This page will be reprinted with Pu

239 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.

4 8 ) 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

V alidation

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.

5 0 ) EPA Observation

V alidation (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.

5 1 ) EPA Observation17

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 t he 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 custo mers.

5 2 ) 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.

5 3 ) 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 mi

ssing 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 de cision level concentration (DLC). EPA flagged Pu

238 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 dete ctions. 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 th e 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. Whil e 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

re view this data.

5 4 ) 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 a mericium 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



### Table 1: Sample Result Qualifiers

D Detected

E Exceptions

J Estimated; unusually uncertain

N Negative

R Rejected; unusable

U Undetectable19

activity. Note t

hat 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

uncerta inty 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 ef ficiency. This will go into effect once the controlled software is validated and the data reduction procedure is
revised.

5 5 ) 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 SO P for data reduction and report

ing 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 sever

al 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.