ML20135D789

Forwards Responses to Comments Re Fort St Vrain Final Survey Rept

ML20135D789
Person / Time
Site:	Fort Saint Vrain
Issue date:	02/27/1997
From:	Borst F PUBLIC SERVICE CO. OF COLORADO
To:	Jim Hickey NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
References
P-97008, NUDOCS 9703050509
Download: ML20135D789 (52)

Text

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16805 WCRservice' 191/2; Platteville, Colorado 80651 February 27,1997 Fort St. Vrain P-97008 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 ATrN: Mr. John W. Hickey, Chief Decommissioning and Regulatory Issues Branch Docket No. 50-267

SUBJECT:

Response to Comments Regarding Fort St. Vrain Final Survey Report

REFERENCES:

1. NRC Letter, Pittiglio to Crawford, dated January 14,1997 (G-97002)

2. PSCo Ixtter, Crawford to Weber, dated November 7,1996 (P-96093)

Dear Mr. Hickey:

Attached are Public Service Company of Colorado's (PSCo) responses to the NRC's comments provided in Reference 1, regarding the Fort St. Vrain Final Survey Report.

This report was submitted to the NRC in three phases, in letters dated May 31,1996, August 9,1996, and October 30,1996.

The attached responses provide clarifications, corrections, and additional information that support and enhance information provided in the Final Survey Report. Based on this information, PSCo considers that the Final Survey Report and associated documentation thoroughly demonstrate that the Fort St. Vrain facility and site are suitable for release for unrestricted use. This information is fully supportive of our request to terminate the i 10 CFR Part 50 license for Fort St. Vrain (Reference 2). ,

9703050509 970227 PDR ADOCK 05000267 kb /

W PDR 050128 Is.55Eltpp.E!EM j

l P-97008 February 27,1997 Page 2 If you have any questions regarding this information, please contact Mr. M. H. Holmes at (303) 571-7633.

Sincerely, h/tML Frederic J Borst l W

Decommissioning Program Director i FJB/SWC Attachment cc: w/ attachment l l

Regional Administrator, Region IV Mr. Robert M. Quillin, Director Radiation Control Division l Colorado Department of Public Health and Environment 1 L i l

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1 FORT ST. VRAIN NUCLEAR STATION I FINAL SURVEY REPORT 4

RESPONSE TO NRC COMMENTS PROVIDED IN JANUARY 14,1997 LETTER l FROM C. L. PfITIGLIO 4

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RESPONSE TO NRC COMMENTS DATED JANUARY 14,1997 REGARDING FORT ST. VRAIN FINAL SURVEY REPORT NRC GENERAI. COMMENT No.1:

Volume 1, Attachment 2, provides the results of the i%t quality assurance surveys by GPU Nuclear Corporation (GPU). What was the acceptance criteria for the GPU results? Were significant differences in the GPU and SEG survey results identified and investigated? For example, Volume 1, Revision 0, Attachment 2, Page 40, shows the results of GPU and SEG measurements on Ievel 7 Turbine Deck. The GPU and SEG results for Total Activity appear to be significantly different for a number of measurements in this area. Was an investigation conducted to determine the cause of this difference? Do these results, and any other significantly different results, indicate a significant systematic bias between GPU and SEG survey results?

PSCo Response:

'the acceptance criteria for GPU survey results were the acceptance criteria provided in the FSV Final Survey Plan, i.e., Regulatory Guide 1.86 limits for total surface and removable activity,5 R/hr above background for exposure rate, and 10 mrem per year dose contribution due to residual activity in soil and water.

PSCo retained GPU Nuclear to provide an independent verification that the Fort St. Vrain facility has met the conditions for unconditional release, and to confirm the validity of SEG's final survey.

The differences between SEG and GPU results are not unexpected, largely due to differences ;n the methods used to account for background activity, as follows: I

• As explained in PSCo's letter dated March 7,1996 (P-96014), SEG determined a two-component background contribution, with one part due to beta activity from the materials of construction (material background);

the second part was due to garama activity from other materials not under the detector, to cosmic radiation and to instrument noise (local area background).

• GPU conservatively did not subtract the beta material background component to obtain the net measurement result. Also, instead of collecting local area background measurements within each Survey Unit, GPU determined a background value for each material type to be surveyed and applied this value to all areas of the facility. This background value J

included an area gamma activity component (e.g., from cosmic radiation) for the area where background measurements were taken, not for the area being surveyed. This difference could be an over-adjustment for certain areas in the Reactor Building where gamma backgrounds were observed to decrease (e.g., due to shielding of cosmic gammas).

The example cited by the NRC illustrates the impact of this difference in background determination. In Survey Area C0033, on the Level 7 Turbine Deck, SEG determined a material background (beta) for red floor tiles of 1013 dpm/100 2

cm . GPU conservatively did not determine this background component and did not subtract it from its grost survey measurements. When the matenal background for red floor tiles is subtracted from GPU's results (shown in the summary table below), SEG's and GPU's survey results are not significantly different.

No formal survey investigations were performed as a result of any GPU survey results, because GPU did not identify any areas that exceeded the criteria for unconditional relcase. However, PSCo did perform a comparison evaluation of GPU and SEG measurement results, as shown in the tables below. Overall, the two data sets are in agreement. 'Ihe differences in background determination explain a large part of the differences in survey results. Also, GPU collected fewer measurements (typically around 10% of SEG measurement totals) so some differences are expected. .

The following observations are made about GPU's and SEG's survey results:

• For total surface activity, GPU measurement results were generally higher than SEG measurements, however the difference is not considered significant. In the 37 Survey Areas where GPU collected total surface activity measurements, GPU maximum measurements were higher for about 60 percent of the areas, and GPU mean measurements were higher in about 86 percent of the areas. The differences in maximums can be explained by the differences in sample size, and the differences in means are likely due to the differences in determining background activity, as discussed above.

There were two Survey Areas in Group F, F0091 and F0124, where GPU  !

performed a full survey with about the same number of samples as SEG J collected; in these cases, both GPU's maximum and mean survey results exceeded SEG's by about 300 to 400 dpm/100 cm2 , which is explained by  !

the differences in backgrounds. l

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For removable surface activity measurements, SEG's measurements were  !

j consistently higher than GPU's, although the differences are not j significant.

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• For exposure rate measurements, SEG's measurements were also  !

. consistently higher than GPU's and the differences are not significant.  ;

4 The two efforts used different techniques for determining the contribution  !

! from licensed material in the Reactor Building and several other areas.

Soil and sediment sample measurements compare favorably between GPU i 4

and SEG. The differences in the Goose Quill ditch areas are likely due  !'

i to the fact that the ditch concrete surfaces were aggressively cleaned i before SEG's survey effort, which was after the GPU survey. GPU l

_ essentially collected sediment samples from the Goose Quill ditch, '

l whereas SEG surveyed a dry, clean concrete ditch.

i-PSCo considers that the differences between GPU and SEG measurements are not significant and can be explained by differences in background determination (for i

total surface activity), or by slight differences in measurement location, survey techniques, or instrumentation. They are similar to the differences between

SEG's initial survey measurements and subsequent investigation or QC survey j measurements, as discussed further in response to NRC Comment No. 4 below.

! When measurements are being conducted at such low levels, the vanability in i data is not unexpected and does not affect our conclusions about the a@ility

!' of the facility for unconditional release. Both SEG's and GPU's IWWt

, survey measurements demonstrate that the facility satisfies the criteria for

! unconditional n? lease, and PSCo feels confident that the SGLVs have not been ,

i extvwied at Fort St. Vrain. '

A comparison of SEG's and GPU's measurement results in survey areas surveyed

! by GPU is provided below:

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COMPARISON OF GPU AND SEG SURVEY RESULTS Total Surface Activity Removable Exposure Rate Survey dpnd100 cm2 dpm/100 cm2 R/hr

^" No. Meas. Maximum Maximum Mean Maximum GPU SEG GPU SEG GPU SEG GPU SEG GPU SEG s

Group A 178 3328 1638 2459 194 148 14 72 3.4 7.6 A341 74 763 659 831 110 81 8.3 16.4 1.3 3.7 A342 34 190 211 1003 1I 164 14 11.8 2 4.1 .

A343 14 60 860 985 543 245 < LLD 9.5 3.4 1.1 A350 26 258 1109 783 158 9 < LLD 71.7 1.7 5.0 A346 30 391 1638 2459 476 236 na 11.3 na- 4.9 Group B 97 3776 1461 1427 194 98 11 22 2.8 4.7 B0015 28 534 413 1166 119 56 <LLD 22.4 1.9 4.5 B0016 41 487 1281 1183 97 121 11 12.0 2.3 3.7 B0017 28 943 1461 1112 412 100 < LLD 15.0 2.8 4.4 l Note: SEG Group Statistics include measurements from all other Survey Areas in Group, as i documented in the Final Report.

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COMPARISON OF GPU AND SEG SURVEY RESULTS l

l Total Surface Activity Removable Exposum Rate I

Survey dpm/100 cm2 dpm/100 cm2 pR/hr

^" No. Meas. Maximum Mean Maximum Maximum GPU SEG GPU SEG GPU SEG GPU SEG GPU SEG Group C 55 18,569 1964 3381 939 52 16 212 2.0 5.6 C0030 17 424 1195 1007 555 -26 < LLD 58.5 1.6 .5.7 C0031 17 419 1149 3381 825 116 16 19.2 2.0 4.2 C0033 21 480 1964 790 1341 76 < LLD 79.4 1.6 3.5 i

Group D 43 1315 1210 5220 89 165 30.1 146 1.9 na D3100 5 43 -14 561 -86 86 30.1 9.0 1.9 na D3300 14 35 279 444 10 26 na 9.3 na na D4800 8 57 1210 1268 472 180 < LLD 50.2 na na D5400 16 40 300 649 22 6 na 12.5 na na Note: SEG Group Statistics include measurements from all other Survey Areas in Group, as documented in the Final Report.

COMPARISON OF GPU AND SEG SURVEY RESULTS Total Surface Activity Removable Exposure Rate Survey dpm/100 cm 2 dpm/100 cm2 pR/hr

^" No. Meas. Maximum Mean Maximum Maximum '

i GPU SEG GPU SEG GPU SEG GPU SEG GPU SEG Grou? F 1002 57,643 3341 S768 570 198 228 604 3.3 6.7 P 8 57 520 2181 2147 645 298 9.1 103.4 1.3 2.6 F0030 30 303 1126 781 492 140 10.5 82.8 1.3 2.2 F0034 32 241 1345 1213 324 197 4.5 126.1 -1.7 1.9 F0043 19 180 1757 1275 1167 85 8.6 34.7 1.3 3.0 j F0044 27 332 1650 3549 662 373 8.2 74.5 3.3 4.1 F0045 50 532 998 2204 406 248 27.3 206.8 -0.7 3.0  !

F0050 26 260 996 1050 311 179 4.2 37.0 -1.7 1.5 F0051 28 247 2105 725 1355 121 5.9 178.1 1.3 2.6 F0052 28 294 1182 976 564 138 4.3 61.8 2.3 3.7 F0053 20 180 1386 2058 652 102 2.8 38.2 2.3 3.7 i

Note: SEG Group Statistics include measurements from all other Survey Areas in Group, as documented in the Final Report.

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I COMPARISON OF GPU AND SEG SURVEY RESULTS Total Surface Activity Removable Exposure Rate Survey dpm/100 cm2 dpm/100 cm 2 R/hr No. Meas. Maximum Mean Maximum Maximum GPU SEG GPU SEG GPU SEG GPU. SEG GPU SEG F0054 10 86 1123 832 602 225 3.9 74.7 1.3 3.0 F0073 15 171 1131 808 810 142 9.1 89.1 1.3 2.6 F0075 14 156 923 881 650 60 5.9 129.3 1.3 2.2 F0076 17 151 990 1002 541 14 < LLD 61.8 -0.7 1.5 F0083 18 174 1040 644 619 171 4.5 54.1 1.3 3.7 F0091 179 151 1245 984 517 206 13.2 76.1 1.3 4.1 F0098 17 116 1583 1079 %3 169 4.5 115.7 -0.7 1.9 F0101 25 1% 2134 1235 834 352 6.4 139.5 0.3 3.3 F0102 17 180 1093 816 106- 141 11.8 84.7 -2.7 1.9 F0105 15 142 1554 1398 663 210 12.3 211.0 1.3 2.6 F0124 358 361 3341 2936 516 133 228 103.6 -1.7 1.5

COMPARISON OF GPU AND SEG SURVEY RESULTS h

Total Surface Activity Removable Exposure Rate Survey dpm/100 cm2 dpm/100 cm2 R/hr Area No. Meas. Maximum Mean Maximum Maximum GPU SEG GPU SEG GPU SEG GPU SEG GPU SEG Group I 121 7161 1929 3862 966 115 7.3 507 4.3 6.1 10012 121 1057 1929 1684 966 254 7.3 507 4.3 5.2 Note: SEG Group Statistics include measurements from all other Survey Areas in Group, as documented in the Final Report,

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! COMPARISON OF SOIL AND SEDIMENT DATA l TAKEN FROM LIQUID EFFLUENT PATHWAY i

SEG GPU RESULTS (MAX.) SEG j SURVEY AREA RESULTS i (MAX.)

! TEDE FRACTION OF SUIv! OF 10.0 MREM . FRACTIONS OF l

GLV E0001 3.93 0.39 0.02 E0002 .24 0.02 2.94 E0003 3.17 0.32 0.21 E0004 2.0 0.20 0.15 E0006 .20 0.02 0.40 E0008 9.4 0.94 1.10 E0010 2.44 0.02 0.28 E0011 .51 0.05 0.06 E0012 1.0 0.10 0.16 E0013 .26 0.03 0.10 E0014 2.13 0.21 0.51 9_

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l NRC

GENERAL COMMENT

No. 2:

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, The QC results for Total Surface Activity in G2100 appear to be significantly j higher than the initial final survey results. What was the acceptance criteria for

! evaluating the acceptability of these and other SEG QC results?

PSCo Response:

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l The QC acceptance criteria for evaluating the acceptability of final survey results for G2100 and other QC packages is as stated in Section 3.5.1.d of the Fort St.

i Vrain Nuclear Station Decommissioning Project Final Survey Plan for Site-

Release. The requirement is "... QC measurements are collected to verify the -l l

! conclusions regarding radiological status and suitability for release for unrestricted l use. The results of these analyses will be compared to the action levels and

guideline values which were applicable to the initial set of measurements."

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i For the initial final survey measurements collected within Survey Area G2100 l

l (Survey Package G2100), no action levels or guideline values were excaeded.  !

j For the QC Verification Survey measurements (Survey Package G2101), one {

l location in the system (i.e., Survey Location 6) exceeded the individual j i measurement action level and was therefore investigated in accordance with Final 1 Survey Plan and procedural requirements. Both the original survey package j (Survey Package G2100) and the QC Verification survey package (Survey i Package G2101, including investigation measurements) concluded that Survey i Area G2100 was acceptable for r61 ease for unrestricted use.

i l In addition to verifying that both the initial and QC Verification survey results i met the criteria for release for unrestricted use, graphs overlaying the initial and j QC Verification survey results were prepared to allow a qualitative review of the j two sets of data (i.e., to determine if a significant difference between results was

{ apparent). The total surface activity comparison graph is shown on page 30 of l G2101 and the removable surface activity comparison plot is on page 38. For G2100 and G2101, the qualitative comparison did not indicate a significant I

difference.

4 The reason for the difference in the two survey package mean values for total I surface activity is due to the additional investigation measurements collected within Survey Package G2101. One location in Survey Package G2101 (Survey  :

Iacation 6) indicated total surface activity greater than the individual I 2

measurement action level for affected plant systems (i.e., 3,000 dpm/100 cm ).

Therefore, this location was investigated in accordance with Final Survey Plan and procedure requirements. This resulted in 19 additional investigation measurements collected within Survey Package G2101 that were generally higher in value than most measurements collected in the system. Because all i

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measurement results were included in the calculation of mean values, a higher estimate of the mean total surface activity was obtained for Survey Package G2101 (which included investigation measurements) than was obtained for Survey Package G2100. The total surface activity of 586 dpm/100 cm2 (upper confidence limit) for G2101 is well below any action level.

Investigation measurements were not collected within Survey Package G2100 (i.e., the initial final survey for Survey Area G2100) because no action levels:

were exceMM. Survey Location 6, where the individual action level was excaMM during the QC Verification survey of Survey Area G2100, was also the highest result obtained during the initial survey of Survey Area G2100. It is not considered unusual, with activity present near the individual measurement action level at Survey Location 6 during the initial survey, that the measurement did exceed the investigation level during the subsequent QC Verification survey.

In summary, Survey Area G2100 was surveyed by the initial Survey Package G2100 and the QC Verification Survey Package G2101. No action levels were exceeded during the initial final survey (the highest total surface activity result of approximately 2,500 dpm/100 cm2 was at Survey Location 6). During the QC Verification survey, the individual measurement action level of 3,000 dpm/100 cm2was exceeded at Survey location 6, and was investigated in accordance with Final Survey Plan and procedure requirements. The graphical comparison of survey measurement locations surveyed by both the Initial survey and subsequent QC Verification survey did not indicate any significant differences between the two data sets. The higher mean total surface activity calculated from the QC Verification survey measurements is understood in view' of the additional i investigation measurements taken at Survey Location 6. Both survey packages indicated that Survey Area G2100 was well below the acceptance criteria (i.e.,

all individual measurements were well below 12,000 dpm/100 cm2 and total survey activity means at 95% confidence were well below 4,000 dpm/100 cm2),

and that the survey unit is suitable for release for unrestricted use.

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NRC

GENERAL COMMENT

No. 3:  !

The surveys of the various plant systems identified several elevated areas.

However, the investigations for a number of these elevated areas do not appear i to have determined whether the average surface contamination limit was exceeded 2

in the 1 m area surrounding the elevated area. Examples can be found in release records G4600, G7201, and G130. Was the 1 m2 averaging criteria applied to systems? If not, please provide justification.  ;

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The 1 m 2averaging criteria was not applied to plant systems. Instead, the average of all measurements taken for each plant system survey unit was compared to the average guideline values. l This was in accordance with Proposed Change 2 of PSCo letter dated October 12, 1995 (P-95077) " Fort St. Vrain Final Survey Plan for Site Release, Proposed Revision for Survey of Piping Systems and Suspect Affected Survey Units,"

which was approved by NRC letter dated June 18,1996 (G-%103). In the October 12, 1995 letter, PSCo explained that piping system interior surfaces cannot be surveyed using the same techniques or instruments used for walls and floors.

Since no known technology existed for surveying piping system interior surfaces, PSCo and the Westinghouse Team spent considerable resources developing special instrumentation for these surveys; however, the positioning of the measurement devices was not as easily controlled as for flat accessible surfaces. Also,2 to 3 months were required to obtain survey measurement results where TLDs were used. Averaging all survey data collected from a piping system survey unit was considered reasonable when combined with the biased measurement plan.

Measurements were taken from those locations most likely to have elevated measurements, and a large number of measurements were taken for piping survey units suspected of containing elevated activity. Averaging these biased measurements was considered to result in a conservatively high average measured value, when compared to the average SGLV.

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GENERAL COMMENT

No. 4:

l Numerous investigation surveys failed to confirm the elevated residual radioactivity that was identified during the initial survey. In many cases, no

explanation of the discrepancy was provided. For example, in C0039, the initial total surface activity was 6,659 dpm/100 cm 2, and the removable activity was 175 2

dpm/100 cm . The investigation section merely stated that the initial activity could not be confirmed and therefore it was not reponed. This was also identified in C0047 and C0043, C0045, D4500, D7300, F0032, F0039, F0041, F0042, F0069, F0077, F0084, F0086, F0099, F0120, F0143 (EZ001), F0173, F0186, and F0188. Please provide additional explanation as to why the elevated activity was not identified during the investigations, and the rationale for not including the initial results in the final survey report.

PSCO Response:

The disposition of this and all similar investigations should have included a statement that the measurement result was considered an anomaly for those instances where the activity could not be confirmed during Investigation surveys.

There are numerous cases where survey results could not be duplicated, such as during investigations and QC measurements. PSCo considers that our survey methods have been validated during the side-by-side measurements with ORISE, and most of the investigation surveys did confirm the initial elevated measurement.' The differences between initial and investigation survey measurements could be due to numerous factors, such as differences in the exact survey location, differences in survey techniques, removal of the activity, or other factors that could affect measurement results at the low levels of final surveys.

The reason why investigation survey results were used in the final survey report  :

in place of the initial measurements is that investigation surveys are comprehensive surveys, specifically focused on identifying elevated areas. The intent of investigations was to identify instances where licensed material was the j cause of final survey measurements in excess of action levels and to provide i additional confidence that licensed material did not exist in excess of the guideline values. If the investigation survey didn't find elevated activity, then it was assumed not to exist and the initial measurement was replaced. The i documentation describing the investigation and disposition of the measurement I results is in compliance with the FSV Final Survey Plan and procedures.  !

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l NRC COMMENT No. 5:

Volume 1, Revision 2, p. 5 There appears to be text missing from the bottom of page 5-13. ,

I PSCo Response:

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The missing text is a typographical error. The last sentence at the bottom of page 5-13 should read:

i "The calculated radioactivity composition of the activated metallic portions of the PCRV and internal components three years after shutdown was: Fe-55, 85%; Co-60,3%; and H-3,12%."

NRC COMMENT No. 6:

Volume 1, Revision 2, p. 5 The first paragraph should briefly elaborate on the magnitude of the " potential hazards" from the activity remaining in the embedded PCRV pipes.

PSCo Response:

The following paragraph should be added to the discussion of embedded piping, at the top of page 5-23 in Volume 1:

"Although potential hazards exist due to the residual contamination remaining in the embedded piping, reasonable exposure scenarios were evaluated and indicated that likely exposures to future personnel would be very low. The hypothetical doses calculated were below 3 mrem /yr. In addition, actual average total surface activity measurements in embedded piping were a small fraction of the 100,000 dpm/100 cm2average level considered in the dose assessments. Actual embedded piping total surface activity averaged only 2,800 dpm/100 cm2 , with a maximum of 86,714 2

dpm/100 cm , indicating that aggressive decontamination efforts were very successful and the actual potential hazards are small."

NRC COMMENT No. 7:

Volume 1, Revision 2, p. 5 The " level 4, (b)" criteria for grouting embedded piping appears to be inconsistent with the " level 4, (a)" criteria. Please clarify. i PSCo Response:

The investigation criteria of Level 4 (a) ensured that any total surface activity 2

measurement result greater than 50,000 dpm/100 cm in affected embedded piping was investigated to determine if greater activity was present in the vicinity of  ;

the elevated activity (i.e., an investigation would be undertaken to bound the elevated activity).  !

The criteria of Level 4 (b) ensured that the survey unit as a whole received appropriate evaluation if a significant number of measurements were obtamed 1 greater than 50,000 dpm/100 cm2, l

l In other words, if greater than 10% of all total surface activity measurements 2

were greater than 50,000 dpm/100 cm , then not only would individual  ;

measurements be investigated (criteria a), but additional pipe sections would be selected for survey because the survey unit as a whole indicated significant elevated activity (criteria b).

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NRC COMMENT No. 8:

G7202, p.3 - Was the estimated activity in the " grout-like" material that filled the 4" diameter line L7222 accounted for in the final survey results?

PSCo Response:

The calculated result was not an actual total surface activity measurement nor an estimate of total surface activity, and was therefore not included in the tables or  !

graphs of total surface activity measurements in the report. The estimated  ;

activity of the " grout-like" material in the 4" ea neter line L7222 was discussed I in the Survey Area Decommissioning and Remedbtion Activities section of the final survey report.

Because the material did contain significant activity, an " equivalent" total surface activity calculation was performed. The " equivalent" total surface activity calculation was performed to show that the pipe segment did not contain more activity per unit length of pipe than piping grouted with total surface activity up to 100,000 dpm/100 cm2 (i.e., the notification level associated with affected embedded piping). This calculation was also discussed in the Survey Area Decommissioning and Remediation Activities section of the final survey report  ;

for Survey Package G7202.

NRC COMMENT No. 9:

G4600, p.6 - What is a coupon sample?

PSCo Response:

A coupon sample is a portion of a plant system that is physically removed from the system (e.g., a section of pipe) ter laboratory analysis. Coupon samples were typically taken where elevated activi'y was detected but was suspected to be due to natural radioactivity.

For example, if elevated activity was found in a section of piping and was believed to be due to natural radioactivity, a portion of the pipe was removed (i.e., a coupon sample) and analyzed in the radiochemistry laboratory to determine the radionuclides present.

NRC COMMENT No.10:

H0201, p.4 - There appears to be 3 pages with repeat data. Please review and

provide missing data if necessary.

PSCo Response:

' Pages 66,67 and 68 of H0201. which contained summaries of TLD String survey results, do contain repeat data 6 e., pages 67 and 68 repeat the information of ,

page 66). These pages summarized TLD string survey results for each pipe segment surveyed (i.e., provided additional summary information of the TLD String survey results presented in f.he preceding pages).

Pages 67 and 68 have been revised to include the missing summary results for pipe segments surveyed with TLDs, and are included at the end of these l responses to NRC comments. All other Release Records containing TLD String I survey data were reviewed and found to contain all relevant information.

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i NRC COMMENT No.11: -  ;

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H0301, p.4 - What is the estimated activity in the crosshead tendon tubes that j were partially grouted prior to general decontamination of the tubes?

PSCo Response:

The final survey measurements taken in crosshead tendon tubes, which included

! measurements in the ungrouted portions of the partially grouted tubes, provides  ;

l a reasonable estimate of the total surface activity in the partially grouted tubes.  ;

l This activity in the crosshead tendon tubes in H0301 was 3735.3 dpm/100 cm 2

(upper confidence level, total surface activity). As a result of the final survey measurements taken in the crosshead tendon tubes, all crosshead tubes were subsequently grouted throughout their length in accordance with the Final Survey ,

Plan for embedded piping. '

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The partial grouting of a few of the crosshead tendon tubes was conducted prior to the general decontamination of the tubes and the development of the specialized piping detectors and procedures. The ends of these tubes were grouted to allow support mounts to be applied on the inside of the PCRV cavity to support other decommissioning activities. However, these tubes wue wiped out prior to ,

grouting in a manner similar to that performed during the general decontamination i of the crosshead tendon tubes. Operational radiation protection coverage was supplied during the panial grouting evolution instead of support from the Final '

Survey Group. The vast majority of the crosshead tendon tubes, including the )

ungrouted portion of the partially grouted tubes, met the established criteria after  ;

one pass of wiping the tube. ]

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l 1 l l NRC COMMENT No.12:

f j H0303, p.8 - Was the cause of the erroneous measurement discussed in '

Investigation #1 determined? Did the problem affect other measurements?

PSCo Response:

l The spurious result for measurement 17-3 discussed in Investigation #1 could not l be reproduced, and therefore the cause was not determined. The function of the i instrument was evaluated and found to be normal. The technician who performed the survey did not detect any elevated activity during the initial scan of the measurement location. After noting the recorded result, the technician repeated .

the scan at the measurement location again but could not identify any elevated l j activity. As discussed in Investigation #1, an Investigation survey was performed

' i which also could not confirm any elevated activity at the location; therefore, the {'

j measurement was considered an anomalous result.

1 It is not expected that other measurements were affected by whatever caused the  !

elevated result for measurement 17-3 in H0303. Any other measurement with a  !

similar elevated result would be readily evident during data review' as either a

very high or highly negative result (if the measurement spike occurred during the l background measurement). Although there were occasions when elevated activity l was identified during the Initial survey, but was not confirmed by subsequent I

! Investigation survey (see response to General Comment #4), measurement 17-3 i in H0303 was the only spurious result of this magnitude.

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NRC COMMENT No.13:-

j C0018 - Approximately 70% of the total surface activity levels in survey unit AZ001CZ are negative. It appears that an improper medium background has been subtracted to bias these measurements low. Other survey units with unexplained negatively biased total surface activity include B0009, B0015, C0002, C0004, C0008, 'C00ll, C0023, C0041 (BZ001), F0032 (WZ001BZ and AZ001CZ), and F0069.

4 PSCo Response:

1

! The total surface activity measurements were evaluated in accordance with

guidance provided in Fort St. Vrain procedure FSV-SC-FRS-I-110, Revision 3,

Final Surwy Data Analysis. Section 5.4.9.1 states "For instances were the mean

, of the measurement results is significantly negative (e.g., < -250dpm/100cmr )

j review the applied material background value to verify appropriate (not too large) i for the material surveyed." The mean for each of the total surface activity measurements for the survey units identified as being negatively biased were j greater than ' -250 dpm/100cm2 , and therefore met h acceptance criteria.

4 The mean value of -250 dpm/100cm2 was selected as an indicator of possible j

negative bias in consideration of the variability of natural radioactivity in "similar" materials of construction, and the response of the instrument to the high i

and variable exposure rate at Fort St. Vrain. The latter was, in most instances, i the more significant of the two factors.

i f

i The variability of instrument response to natural radioactivity in materials of construction was due primarily to variations in the concentrations of potassium-40 in concrete. Slight changes in potassium-40 concentration could affect the

unshielded measurement result and, to a lesser extent, the local area background r

(shielded) measurement result. The net measurement result could be affected in  !

, either a positive or negative manner depending upon conditions where one or both I

[ were affected.

l The variability of the instrument responce to the local area exposure ate was due l to the magnitude of the exposure rate an<1 varying proximity of the measurement I location to facility components which could afford shielding. The latter factor  !

could affect the net measurement result in ei6er a positive or negative manner, l

depending upon whether or not the local area background (shielded)  !

measurements were also affected in a similar manner. I l

$ The use of the pre-determined material background component compensated, to l

) the extent practical, for the above conditions. Under these conditions, a mean f value greater than -250 dpm/100cm2 (for example, -150 dpm/100 cm2 ) would i

? l j  :

5 1

i d

e . - . . . .,

l have resulted in an unreasonable number ofinvestigations where the cause of the slight bias was due to the above factors.

It is possible that the collection of additional local area background useasurements l

could have provided a more representative value for the contribution from the 1

local area exposure rate, and reduce download-specific bias. However, note that l

the value selected to identify these trends was small relative to the guideline value I (approximately 7% of the guideline value), and was sufficiently restrictive to l

ensure the identification of measurement bias for those instances where the above factors affected the net measurement results. I i

NRC COMMENT No.14:

1 C0026, p.7 - Scans performed during the 10% verification survey did identify an l area of elevated direct radiation - this should be reflected in the Survey Design i section.

PSCo Response:

i The Survey Design section for C0026 should be revised to describe that elevated activity was found during the Beta Scan, in the same manner that it describes additional Total Surface Activity measurements that were collected due to elevated activity identified during a verification survey.  !

}

The purpose, description, and results of the 10% Verification Survey, includmg j a discussion of elevated measurements, were adequately discussed in i Investigations No.3, No.4, and No.5 within the release record for Survey Unit l C0026BZ001BZ.  !

l l

l

.NRC COMMENT No.15:

C0026, p.8 - Investigation #4 is incorrectly dated 07/0 sic (7)/97. l PSCo Response:

This is a typographical error. The Investigation was initiated on July 1,1996 I 2

instead of July 1,1997, and should be revised. j NRC COMMENT No.16:

C0026, p.59 - There appears to be an incorrect calculation; 451.7 cpm / detector area equals 1,628 dpm/100 cm2 - not 1,544 dpm/100 cm2 ,

PSCo Response:

After review of the values and recalculating the reported activity contained in the last paragraph of page 59, PSCo determined that the calculated activity value of 1,544.3 dpm/100 cm2 is correct as indicated in the final report.

The two calculations represented in this paragraph involve two different downloads, with two different detection efficiencies. Downlad 2148-3 used a

, detection efficiency of 0.222, and download 1763-3 used a detection efficiency

of 0.234. The following calculations were used to verify the measurement results

Download 2148-3:

(431.7 epm per detector /0 222 cts per disinteg) x(100cm2 /125cm2 )= 1555.6 dpm/100 cm 2 Download 1763-3:

(451.7 cpm per detector /0.234 cts per disinteg) x(100cm2 /125cm2 ) = 1544.3 dpm/100 cm2 NRC COMMENT No.17:

C0029, p.54 - Results of beta scanning were not included under the Survey Design section.

PSCo Response:

A review of survey package C-0029 verified that no areas of elevated activity were identified during the scan survey.

The Survey Design section of the Release Record should have included the following:

" Scanned I square meter around each total surface activity measurement location.

No areas of elevated activity were identified."

1 l

NRC COMMENT No.18:

1 C0035, p.2 - It was reported that no affected systems resided within this survey i area, yet portions of System 75 within the survey unit required remediation.

Please provide an explanation for this apparent discrepancy. '

PSCo Response:

The statement "There were no affected systems residing within or traversing this area" should be replaced with "This Survey Area included portions of System 75, an affected plant system, that required remediation after completing the Initial Final Survey of Survey Area C0035. Therefore, after the remediation of System l 75, a 10% verification survey was performed which confirmed the radiological status of the Survey Area (see Investigation #1)."

NRC COMMENT No.19:

C0041, p.133 - The removable activity at SML 595 (92.9 dpm/100 cm2) generated during the investigation does not appear to have been plotted.

PSCo Response:

This question apparently concerns C0047, the QC survey for C0041.

SML 595 (92.9 dpm/100 cm 2) should have shown up in the plot on page 133 that provided a comparison between the original activity measurements for C0041 and the QC measurements documented in C0047. SML 595 is recorded in the final survey report for C0047 on page 123, and it is plotted on page 132, the graph of activity versus location number for C0047.

From a review of the C0041 and C0047 measurements on the comparison plot on page 133, it appears that all of the other measurements are included, and that they are all significantly below the 750 dpm/100 cm2 guideline value.

I

NRC COMMENT No. 20:

C0064, p.2 - This survey package appears to be the QC verification of survey package C0042, not of C0064.

PSCo Response:

Survey package C0064 is the survey package designation assigned to the QC verification efforts for survey area C0042 (Level 11 East General Area), as indicated in the Final Survey Area Breakdown Report. The documentation I contained in survey package C0064 is correct and is for the correct survey area.

l Survey package C0042 is the documentation package for survey area C0042. l The survey package number for QC verification survey packages is different than that for the initial final survey for all Survey Groups, with very few exceptions i (e.g., Survey Area D5400, where the QC verification survey was designated  !

D5400 (QC)).

i i

NRC COMMENT No. 21:

D4100, p.5 - Typo: Should be Th-234 and Pb-212, not Th-232. Same typo on pages 7 and 8 of G4600. I PSCO Response:

Typographical errors on page 5 of D4100, and pages 7 and 8 of G4600 should be corrected to read Th-234 not Th-232.

I NRC COMMENT No. 22:

D4500, p.7 - Appears to be a typo: "... therefore, not greater than..."

PSCO Response:

The text is correct on Page 7, Investigation No. 5. The statement "... therefore, greater than ..." is correct because only two smears were taken, and one of them (i.e.,50%) exceeded 250 dpm/100 cm 2; therefore, since 50% exceeded 10%, the required investigation was conducted.

I I

NRC COMMENT No. 23:

D7300 - The beta scan results are not stated in the survey design section.

PSCO Response:

1 The statement "No elevated activity was identified during the scan", should be added to the Survey Design section of the Release Record of D7300. '

NRC COMMENT No. 24:

D7501, p.19 - A scale sample from location 74-1 exhibited 6.25 pCi/g of Co-60, however,the total surface activity result at the same location is -1,337.5 dpm/100 2

cm . Please provide an explanation for this apparent discrepancy.

PSCo Response:

A scale sample result of 6.25 pCi/g of Co-60 activity would correspond to about 14 dpm/g. This would correspond to a very low total surface activity level as very little piping scale is typically removed per 100 cm2 . In other words, this amount of surface activity would not have been detected by the instruments, efficiencies and count times used to survey inside plant systems. The statistical data scatter associated with the sensitivity of plant system survey measurements would mask such low levels.

The total surface activity result of -1,337.5 dpm/100 cm2for measurement 74-1 was not considered beyond the range of possible statistical fluctuations. For measurement 74-1, the MDA was 1,577.0 dpm/100 cm2 and the Critical Level was 771.6 dpm/100 cm2 . Critical Ievel is the level where a false positive result could be detected 5% of the time (i.e., due to background fluctuations).

Similarly, a result more negative than minus Critical Level is expected 5% of the time. In data sets of 30 or more,1.5 or more results are statistically expected to be more negative than Critical Level. A result more negative than minus MDA would occur statistically about 1 in 2000 measurements (which for the large number of measurements taken for the final survey at FSV can be expected to occur a few times). Therefore, measurement 74-1 is within reasonable statistical fluctuations for the sensitivity of the instrument and count time used (the negative value was between minus Critical Level and minus MDA). The 6.25 pCi/g scale result was not enough. activity to overcome statistical fluctuations which dominate at that level.

NRC COMMENT No. 25:

D7502 - The beta scan result was stated as "no areas of significantly elevated activity were identified." Please provide an explanation for "significantly elevated."

PSCo Response:

Elevated activity was considered to exist when a sustained increase in the audible count rate was observed.

In this instance, no ama of elevated activity was identified during scanning for D7502. The beta scan text should be revised to read "no areas of elevated activity were identified" (i.e., delete the word "significant").

NRC COMMENT No. 26:

Group E, Table 3.1 - It appears that the units in the exposure rate and soil columns are incorrect.

PSCo Response:

The units contained in Tables 3.1 and 3.2 are incorrect for the exposure rate and soil sample result columns.

The exposure rate column heading should be revised to include units of R/hr versus dpm/100 cm2 . The concentrations in the soil column heading should be revised to include units expressed as a fraction of the GLV, or Sum of Fractions (SOF of GLV) versus dpm/100 cm2, NRC COMMENT No. 27:

E0001, p.2 - It appears that there is a discrepancy: the text states that the survey unit is suspect affected, while the table box states it is non-suspect affected.

PSCO Response:

This is a typographical error. The text should be revised to identify the Goose Quill Ditch classification as a Non-Suspect, Affected survey unit.

l NRC COMMENT No. 28:

E0003 - What were the guideline values and units for water samples? The comments above each data table state net concentration reported in pCi/g. The appropriate units should be pCi/L or other similar designation.

)

PSCo Response:

1 The concentration guideline values for surface water which could be used as drinking water are listed in the following table, and were derived from the Allowable Levels of Intake in Environmental Protection Agency Report 520 (EPA-520) in order to limit the committed effective dose equivalent (CEDE) to i 10 mrem /yr.

Concentration SGLV in Drinking Water Derived From EPA-520  !

Nuclide Dose Conversion Factor SGLV (mrem /yr/pCi/ml) (pCi/ml/10 mrem)

. l 3

Co-60 7.28E+00 1.37E+00 Cs-134 5.20E+01 1.92E-01 '

Cs-137 3.64E+01 2.75E-01 Eu-152 4.55E+00 2.20E+00 Eu-154 7.28E+00 1.37E+00 Eu-155 9.10E-01 1.10E+01 Fe-55 4.04E-01 2.47E+01 H-3 4.55E-02 2.20E+02 The unit of measure for the data within the table for the Farm Pond water samples is incorrectly stated as pCi/g (pico Curies per gram). The correct unit of measure for the data within each table should be pCi/ml (pico Curies per milliliter). The numerical values for sample results and the conclusions regarding suitability for release for unrestricted use are not affected by this typographical error.

l NRC COMMENT No. 29:

E0010, p.6 - Gamma surface scans were not indicated in the survey design section - were they performed? Similarly, were gamma scans performed in .

E0011 and E00127 '

PSCo Response: '

i Gamma Scan Surveys were not part of the initial survey design for Survey Areas i E0010, E00ll and E0012, since each was initially classified as an Affected Class 3 Opened Land Area, in accordance with guidance provided within Technical '

Basis Document, FSV-FRS-TBD-209, FinalSurwy Requirements For The Liquid Egluent Pathway.

A gamma scan survey was conducted within Survey Area E0010 as described in Investigation No. 2, and in this instance, was included in the Survey Design, Exposure Rate description. Gamma scan surveys were not conducted within Survey Areas E0011 and E0012.

NRC COMMENT No. 30:

F0043 - Although it is recognized that an investigation was performed to address the issue, there remains a negative bias in survey unit WZ002BZ on the order of 88% negative surface activity levels. Please describe the basis for the background selected for this area.

PSCo Response:

In this instance, the negative bias is likely due to an imperfect fit in the background value for the material of construction, or due to the location of the local area background (shielded) measurements. Since the measurements were collected from concrete, which has significant natural radioactivity, it is difficult to determine which was the major factor.

In either case, the negative bias was not significant relative to the guideline value.

The maximum total surface activity measurement in F0043 was 228.2 dpm/100 cm2 , the minimum measurement was -5%.6 dpm/100 cm2 , and the material 2

background value was 767 dpm/100 cm . Even without correction for any component of the background, the maximum individual result would not have approached the action level of 3000 dpm/100cm2, See PSCO Response to Comment No.13 for additional explanation.

l

.l

NRC COMMENT No. 31:

F0191 - The QC survey for F0074 identified an elevated area of approximately l 2

17,000 dpm/100 cm on a scaffolding handrail. Is there any indication as to why I the initial survey in F0074 did not identify this elevated area?

)

i PSC Response: 1 The survey package for FOO74 indicates that a 100% scan was performed of all accessible surfaces less than 2 meters from the floor and a 100% scan of at least I meter around each SML greater than 2 meters above the floor. There is no indication in the survey package that any elevated readings were identified during i the scan or TSA measurements. The initial survey design did not require scan i survey of 100% ofincluded surfaces above 2 meters and, since the handrails were over 2 meters above the floor, this may be the reason why the elevated activity j on the handrail was not identified during the initial survey. l Once the elevated reading was identified during the QC verification survey, an investigation was initiated, the section of handrail was removed and the area resurveyed (100% scan, TSA measurements and RSA) to define the bounds of the elevated activity. The subsequent investigation scan, additional TSA measurements and RSA measurements were consistent with the initial survey results.

NRC COMMENT No. 32:

F0075 - One value for removable acdvity is reported as -108 dpm/100 cm2 ,

Please explain this extremely negative result.

PSC Response:

The removable tritium activity value of -108 dpm/100 cm2 reported for SML #7 of F0075 is within expected statistical scatter associated with the sensitivity for removable tritium analysis. The Critical Level and MDA for this result were 115.7 dpm/100 cm2 and 237.2 dpm/100 cm2, respectively. Measurements can be expected to exceed the Critical Level due to background fluctuations 5% of the time.

Similarly, a value more negative than minus Critical Level can be expected, on average, in 1 out of 20 measurements. The result for SML #7 did not exceed minus Critical Level and is therefore within expected statistical scatter.

Additionalinformation regarding negative results is provided in PSCo's response .

to Comment No. 24.

)

i

NRC COMMENT No. 33:

F0018 - There appears to be a discrepancy in protocol. An initial measurement 2

(17,902 dpm/100 cm ) was remediated without an investigation survey performed.

In most similar situations an investigation survey was performed to confirm the elevated activity, but it does not appear to have been performed in this case. This discrepancy was also identified in F0024, F0062, F0065, F0066.

PSC Response:

For Survey Area F0018, no such discrepancy could be found. Two elevated measurement locations were identified in Investigation No.1, and they were investigated, confirmed, remediated, and documented as complete via remediation surveys. The 17,902 dpm/100 cm 2measurement at SML 462 was described in Investigation No. 2. The elevated activity at SML 462 identified during the Initial survey could not be confirmed by the Investigation survey and no remediation activities were performed. Subsequently, the initial SML 462 TSA and RSA measurements were replaced by the investigation SML 462 TSA and RSA measurements. Note that Investigation No. 2 was prepared specifically for SML 462, which was mistakenly not identified as an area of elevated activity at the time Investigation No. I was prepared.

For Survey Areas F0024, F0062, F0065 and F0066, remediation actions were initiated and performed without an Investigation survey due to the magnitude of the survey results, to knowledge of the radiological LIstory of the Survey Areas, and for the purpose of saving time and cost associated with collecting investigation measurements.

Direct remediation was not typically performed, but was acceptable in accordance with FSV procedurer Fort St. Vrain procedure FSV-SC-FRS-I-110, Revision 3, FinalSurvey Data Analysis, allowed unique conditions to be evaluated on a case by case basis, in accordance with the Note preceding Section 5.7, Investigations.

Section 5.7.3 of this procedure would have required remediation if, during investigation:

(1) a total surface activity (TSA) measurement was verified to exceed the guideline value (GLV) by a factor of three, and/or (2) a removable surface activity (RSA) measurement was verified to exceed the GLV.

For Survey Areas F0062, F0065 and F0066, the initial TSA measurement results  !

were more than three times the GLV and for F0024 and F0066 the initial RSA measurements exceeded the GLV. The measurement verification for F0062, j F0065, and F0066 consisted of steps 1 through 3 of procedure FSV-SC-FRS-I- i 110, Section 5.8.1 for evaluation of the initial TSA measurements, and an I investigation was initiated in accordance with Section 5.8.2 for each case. These

. _ . _ _ _ _ _ . . _ . . _ _ . _ _ . _ ~ _ . . . _ . . __

y i

J steps were also followed. for evaluation of the initial RSA measurements for i j F0024.

+

7 j The areas of elevated TSA and RSA measurements were successfully remediated 1

i as confirmed by the respective Remediation survey results of each Survey Area.  ;

Remediation following the initial final survey, documented with an investigation,  !

I was acceptable in each of these cases.  !

t

!- NRC COMMENT No. 34:  !

l F0019 - It appears that removable surface activity results are provided twice for  !

. survey unit BZ001BZ.  !

l PSC Response: I l The data for removable surface activity contained on pages 28-29 of the final f 4

survey report for survey area F0019 is repetitious of the data contained on pages  !

! 35-36. 1 i s i i Pages 27-29 were superseded by pages 34-40, and should be removed from the l

final report. Pages following these pages should be re-numbered accordingly. i f

NRC COMMENT No. 35:

l F0022 - The results of the remediation survey were not reported in the I investigation section. Typically, the remediation survey results are either i provided or a statement is made that the remediation survey was successful. This I was also identified in F0024, F0148.

PSC Response: l The numerical measurement results of the Investigation and Remediation surveys were not included in the disposition of the investigation.' Although not required by procedure, for clarity and consistency the disposition should have included a reference to the Remediation survey measurements, and a conclusion that the Remediation survey measurements confirmed that the remediation efforts were successful.

Note that the Survey Area Conclusions portion of each survey area Release i Record includes the following: "The results of total and removable surface  ;

activity measurements and exposure rate measurements collected within this  !

Survey Area met the criteria for release for unrestricted use." Additionally, the Statistical Summaries for the respective Survey Units provide the measurement results which support the conclusions included in the Survey Area Conclusions section.

l NRC COMMENT No. 36:

F0119, p.7 .It appears that there should be two areas of elevated activity identified by Scans reported in the survey design section.

PSC Response: 4 Yes, two areas of elevated activity were identified by scans. The Survey Design l section does identify that two additional measurements for total and removable surface activity measurements were collected at these locations of elevated activity, and the Survey Design description of Beta Scan measurements should be consistent.  !

' In most instances, all measurements in addition to the initially prescribed measurements that were identified by the initial scan survey am included in the Survey Design section of the Release Record. In this instance, as explained in the Survey Design Description of the Total Surface Activity, one of the two additional measurements was less than the guideline value for a suspect affected Survey Unit and was not included in the Survey Design. This situation was further explained in Investigation No.1, and the specific measurement results were included within the Statistical Summary.

Referencing only the measurement that exceeded the guideline value in the Survey Design Description for the Beta Scan was inconsistent but does not' affect the conclusions regarding suitability for release for unrestricted use.

l NRC COMMENT No. 37:

F0167 - The mean total surface activity level was over 1,000 dpm/100 cm2 in this 1 survey unit. It does not appear that a medium background was used to correct )

the gross measurement data.

PSC Response: j The mean total surface activity result was understood to be due to residual radioactivity. The background code used for calculation of net activity values was BMC01, which has a medium (material) background value of 0.0.

Background code BMC01 is used for generic materials such as wood, drywall, glass, metal, vinyl, carpet, rubber, etc., which have negligible contribution from  ;

natural radioactivity and was appropriate for the material surveyed.

~ _

a NRC COMMENT No. 38:-

i F0171 - It appears that only one area of elevated activity was identified by beta j scans; the other area appears to be located at a systematic location.

PSC Response:

No additional Final Survey Scan was performed of wrvey area F0155, since Characterization Scan Surveys were determined to meet the basic quality j requirements for Final Surveys and are considered the scan survey of record.

The initial survey design prescribed 482 total surface activity measurement locations, with SML 130 being a predetermined location. During the collection

of final survey fixed point measurements, the survey technician identified elevated l activity at SML 130. The survey technician then scanned the area around SML

130 and identified an additional area of elevated activity and designated the location as SML 483. An investigation was subsequently initiated.

1 4

i NRC COMMENT No. 39: l l l j F0178 - Approximately 96% (67 of 70 measurements) of the total surface activity l

levels for download 1100-3 are negative.

L PSC Response:

The protocol followed when evaluating total surface activity (TSA) measurement results for a survey unit was to examine the mean TSA and qualitatively examine I i the distribution for trends (i.e., are there an excessive number of negative or l unexpected positive values). The criteria used to evaluate the mean TSA was i l 1 250 dpm/100 cm2 . For survey unit F0178EZ001BZ of package F0178, the mean i TSA of -242 dpm/100 cm2 was within i 250 dpm/100 cm2 ,

[

As noted by the comment, download 1100-3 considered alone did axhibit a negative bias. After reviewing the background measurements taken for download i 1100-3, it was determined that this was due to higher local area background i measurements relative to the field measurement results (there was no applied

] material background for these measurements). The mean TSA for the

, measurements of download 1100-3 was -242 dpm/100 cm2 , which was within the established criteria. The mean of the remaining 323 measurements of the survey unit was about 110 dpm/100 cm2 . The mean TSA reported for all 393 measurements was 47 dpm/100 cm2, Although there was a bias in the measurements of download 1100-3, this did not affect the conclusion made for this survey unit. If we assume that the local area background in download 1100-3 was closer to the local area background used in the rest of F0178, the mean TSA for this download would be less than 300

i dpm/100 cm 2, and the mean TSA for Survey Area F0178 would be less than 145 dpm/100 cm2 , which is well below any action level for this area.

NRC COMMENT No. 40:

F0180 - It is unclear if a scan was performed during the final status survey; p.3 states that the characterizntion scan was accepted as scan survey of record, however, the report implies that another scan was performed during the final status survey.

PSC Response:

As described in the Survey Design section, and in Investigation No.1, a scan survey over 100% of these surfaces was performed during the final survey.

i A scan survey over 100% of these surfaces was also performed during the l previous Characterization surveys. Since this survey unit was comprised of wall  ;

surfaces to a maximum height of approximately 8 feet that were readily l accessible, and these surfaces posed th:: highest potential for residual l radioactivity, it was determined that the scan survey would be repeated during the final survey.

However, the instruction for repeating the scan survey was inadvertently not originally included in the final survey instructions contained in the survey package. This was identified as missing during the review process, and the scan survey was performed and documented in Investigation No.1.

l

_-_ _ . _ _ - . _ _ _ ~ . _ _ _ _ _ . . _ _ . _ . _ _ . _ . __ _ . _ . .

4 i NRC COMMENT No. 41:

y F0182, p.6 - There appears to be a discrepancy in the number of total surface

activity measurements reported; it appears that the 30 measurements from the 3

remediation survey have not been added to the total. Also, the results of the

remediation survey were not stated in the investigation section. A similar j~ discrepancy was noted in F0183.

PSC Response:

'Ihis is a typographical error. The total No. of Measurements for Total Surface i

Activity and $7 Smeare should be corrected to 313 (each) versus 283 on page 6 of the Release Record for Survey Package ID: F0182.

Also, for F0183, the total No. of Measurements for Total Surface Activity and

$y Smears should be corrected to 416 (each) versus 413 and 415, respectively, on page 7 of the Release Record. Additionally, for Survey Package ID: F0183:

1. The Survey Design description for total surface activity should be revised to reflect that 3 (versus 2) additional measurements were collected at areas of elevated activity identified during the scan, however these additional measurements did not exceed the action levels, and

2. The Survey Design description for the scan survey should be revised to reflect that 3 (versus 2) areas of elevated activity were identified.

The results of investigation and remediation surveys were included in the l statistical summary for their respective survey units for reporting purposes,  !

however the numerical results were not specifically referenced in the disposition of the investigation. Although not required by procedure, for clarity and consistency the disposition should have included a reference to the Remediation survey measurements, and a conclusion that the Remediation survey measurements confirmed that the remediation efforts were successful.

Note that the Sr,rvey Area Conclusions portion of each survey area Release Record included the following: "The results of total and removable surface activity measurements and exposure rate measurements collected within this Survey Area met the criteria for release for unrestricted use." Additionally, the I Statistical Summaries for the respective Survey Units provided measurement results which support the conclusions regarding suitability for release for unrestricted use in the Survey Area Conclusions section.

I

NRC COMMENT No. 42:

F0186 - It is unclear if characterization scans were used as the scan survey r r record; specifically, the report does not swte that the characterization scans meet the quality requirements.

PSC Resporse:

The 100% Beta Scan Survey was prescribed for and performed during final survey acdvities, not during characterization activities.

The Beta Scan description in the Survey Design section on page 6 of the Release l Record for Survey Unit F0186EZ001BZ states " Initially scanned 100% of the 1 accessible surfaces during characterization surveys." This is in error and should ,

be corrected by removing "during characterization surveys" from the Beta Scan  !

description in the Survey Design section on page 6 of the Release Record for j Survey Unit F0186EZ001BZ.

NRC COMMENT No. 43:

H0001 - Page 60 was missing from report. j PSC Response:

Page 60 of the Final Survey Report for survey package H0001 is the Summary of Efficiency Values for Total Surface Activity for investigations performed, and should be included in the final report. A copy of Page 60 is included at the end of these responses to NRC comments.

NRC COMMENT No. 44:

H0003 - Pages were misnumbered; p. 32 follows p. 25. I l

PSC Response: l Page 32 in the Final Survey Report is correctly numbered but is located out of I sequence; these pages should be re-ordered. The final report is complete in l content. l i NRC COMMENT No. 45:

1 H0009, p.49 - The report incorrectly states that there were no investigations .

performed.

PSC Response:

This was a typographical error, and the word "None" should be deleted from this portion of the final report since investigations were performed and documented within Survey Package H0009.

NRC COMMENT No. 46:

H0005, p.6 - The report states that the total surface activity (TSA) levels were biased high. The background levels were reviewed and determined to be appropriate. Is there some other factor that accounts for TSA levels to be biased high or are the TSA levels reported indicative of true residual activity?

Furthermore, TSA levels for H0006 are approximately the same as for H0005, yet there is no note that TSA levels were biased high. I PSC Response:

l Survey Packages H0005 and H0006 both include measurements collected from the i interior surface of the PCRV cavity. The PCRV cavity walls required extensive decontamination using hydrolasers, scabblers and grinders. The TSA levels are considered indicative of true residual activity.

The second paragraph under Survey Area Conclusions on page 6, regarding measurement sets biased high, should be deleted from H0005.

1 NRC COMMENT No. 47:

H0006 - The results of beta scans on p.53 indicate that 11 elevated areas were identified, however, on page 12 the report states that only 4 locations (SML 127 to 130) were identified during the scan survey.

PSCo Response:

Eleven elevated readings were identified during the 100% scan survey. Of the eleven SMLs, 17, 52, 53,111,112,115 and 116 were at predetermined locations. SMLs 127 - 130 were identified as elevated readings during the 100%

Beta scan and were collected in addition to the prescribed 126 measurements.

j NRC COMMENT No. 48:

10004, p.8 - The report states that water activity reported in pCi/g. It appears that the units are incorrect.

PSCo Response:

The reporting units contained in Final Survey Packages 10004 and 10027 are ,

incorrect for the special samples (well water) isotopic results. The units pCi/ gram should have been pCi/ml.

Also, the Critical Ixvel (Co-60) reported for well water sample location SML 1 for Final Survey Package 10004 is incorrect. The Co-60 Critical Level for SML-1 should have been 2.71 E-2 pCi/mlinstead of 2.71 E-3 pCi/ml.

4 NRC COMMENT No. 49:

I0024, p.3 - The report states that no licensed material was identified by soil analyses. However, soil results for locations 22 and 26 both contained Co-60 concentrations at levels exceeding the minimum detectable activity (MDA).

PSCo Response:

The Survey Area Conclusions on page 3 of the Release Record for Survey Package ID: 10024 of Survey Area ID: 10003 should be corrected to state the following:

"No radioactive isotopes due to licensed material exceeding the nuclide concentration GLV were identified by the analysis."

The balance of the Survey Area Conclusions are unchanged.

I 1

. - - . .~- - . - - _ - _ - - . .- - . .. . - . . ..

4 NRC COMMENT No. 50:

10025, p.3 - The survey area conclusion states that total and removable surface activity levels meet release criteria, however, these measurements were not taken

(this survey unit consisted of soil samples).

i

PSCo Response:

The Survey Area Conclusions on page 3 of the Release Record for Survey j Package ID: 10025 of Survey Area ID: 10003 should be corrected to state the

following:

"No radioactive isotopes due to licensed material exceeding the nuclide concentration GLV were identified by the analysis. The minimum 1 i

detectable activity for each isotope was less than or equal to 25 % of the guideline value for the applicable nuclide.

k i

The results of the surface and sub-surface soil samples and exposure rate j measurements collected within this Survey Area met the criteria for '

release for unrestricted use.

QC sample measurement results within this Survey Unit do not exceed the l Administrative Action 12vels or SGLVs for Unaffected Open Land Areas. l Thez results confirm the conclusions regarding suitability of the Survey i

. Unit for unrestricted use." 1 NRC COMMENT No. 51:

10025, p.6 - The report states that nine elevated areas were identified by the gamma scan. A summary of scU sample results corresponding to these elevated locations was not provided.

PSCo Response:

The measurement results collected from the nine areas of elevated activity identified during the gamma scan, survey measurement locations (SMLs) 31 to 39, were included within the Statistical Summaries for Exposure Rate-Gamma Survey and the Radionuclide Concentrations in Soil for the respective Survey Unit, Release Record pages 11-15 and 16-40, respectively.

A discussion of measurements at the nine locations identified by the survey technician and thought to be elevated was not included in the Release Record because the results of exposure rate measurements and spectral analysis for the concentrations in soil were determined not to be elevated.

.. - - - . - - - . . - - - - - . . . . . . - - . - - . . _.~ . .- ..- . - - .

l 1

NRC COMMENT No. 52: -

Volume 2, A0007, p.72 - The summary section for beta scans states that no areas

} of elevated activity were identified; however, the following statement is made in the survey ~ unit investigations section: " elevated count rates were identified...during the scan portion of the initial final survey." Please clarify this e

apparent discrepancy.

j PSCo Response:

i Areas of elevated activity were identified in portions of the Auditorium during the

performance of the initial final survey as defined in Survey Package A0007 1

(A0346). The Auditorium was subsequently reclassified as Suspect Affected and re-surveyed under Final Survey Package A00ll (A0350).

The Survey Design Description section should be revised to indicate that areas of i elevated activity were found during beta scans.

k j NRC COMMENT No. 53:

Volume 2, A00ll - The survey unit investigation section discusses a small -

. elevated area that was identified in the Visitor's Center. Was this elevated area i due to natural activity from the display case, or was this licensable activity?

, PSCo Response: '

i No isotopic analysis was performed of samples during the performance of Survey i Package A0011 (A0350). Isotopic analysis of carpet samples acquired from this

area during performance of Survey Package A0007 (A0346) indicated the elevated

{ activity was primarily due to uranium (U-238). These samples were further i analyzed, and U-238 was again identified as the primary radionuclide, with a j

~

trace amount of Cobalt-60. The Cobalt-60 was present at a level which could have not been detected by the field measurements (less than 1% of the observed 3 count rate).

i l Rawl on the results of the previous analysis, the elevated activity was attributed to the radionuclides stored in the display cases which were used for instructional and demonstration purposes and not due to licensed activities.

i 1

)

4

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a

NRC COMMENT No. 54:

Volume 3, B0012, p.43 - The statistical summary for tritium removable surface activity measurements states that further investigation is needed because the MDA is not less than 187.5 dpm/100 cm2. Where will this investigation be documented?

PSCo Response:

The note appearing at the bottom of page 43 of the Release Record for Survey Unit B0012FZ001BZ is in error, and the MDA for the measurements was acceptable. The note "FURTHER INVESTIGATION NEEDED" was intended to alert reviewers of an MDA in excess of 25% of the guideline value (GLV) for the specific type survey. The value shown was related to 25% of the SGLV for beta-gamma emitters, rather than 25% of the SGLV for tritium; the SGLV for tritium is 40,000 dpm/100 cm2, The note in the Statistical Summary for Removable Surface Activity - Tritium Survey is in error and should be deleted, and the MDA criteria should be corrected.

)

9 9

I

i j . NRC COMMENT No. 55:

7 Volume 3, B0012, p.74 - The survey design section states that tritium smears are

] collected at approximately 5% of the survey measurement locations for beta-gamma smears; however, only 8 tritium smears (2.5%) were collected. Please explain this discrepancy. Furthermore, what was the rationale for not performing j an Fe-55 assessment in this survey unit - did the smear collected on 4/20/94 from  !

3 the Helium Storage Building indicate the presence of Fe-557 i

4 PSCo Response:

i Although only 8 tritium smears were collected in Survey Unit B0012WZ001BZ,  ;

described on page 74,40 tritium smears were collected over the entire B0012 J Survey Area. With a total of 781 Sy smear samples taken in the five Survey Units in Survey Area B0012, the 5% sample requirement identified on page 2 of  !

the Release Record for Survey Area B0012 was met. I i  ;

1 Iron-55 measurements were not prescribed for this area based on historical use, I the plant systems within the area, and on characterization survey measurement i i results. The source of iron-55 activity in B0012 would have been the interior of i System 24. Backup data included in the Survey Package for B0012 indicates that J 44 smears from the interior surfaces of the helium storage tanks were analyzed  !

for iron-55 in June 1995. Four of the 44 smears had very low amounts of i,ron- l 55: 24.8,14.7,13.5, and 3.7 dpm/100 cm2 . The final survey of the interior of  :

System 24 did not identify significant concentrations of iron-55 (< 15% of the  ;

SGLV). See Release Record G2400 for further details and measurement results.

1 l

! Data from the 4/20/94 smear is not included in the Release Record or supporting 1 l Survey Package; the earliest iron-55 data included in the Survey Package is from )

the 44 smears analyzed in June 1995, as described above.

i l We did consider it prudent to prescribe the collection of measurements for tritium i due to the concentrations of tritium previously identified within System 24, and l 1

due to the presence of some System 24 components within the survey area.  ;

1 It is also noted that the site-specific guideline values included a downward adjustment to the limit for detectable radionuclides, to account for the undetected

, presence of hard-to-detect nuclides, which provided a basis for not collecting measurements for tritium and/or iron-55.

W e

d I

4 4

d NRC COMMENT No. 56:

Volume 4, C0011 - Page 9 and 10 of this Survey Area appear to have exactly the same information.

PSCo Response:

1 Page 10 is a duplication of Page 9, and should be removed from the Final Report.

j Pages following this page should be re-numbered accordingly.

Y l NRC COMMENT No. 57:

i l Volume 4, C0030 and C0052 - Please provide the rationale for deleting data that was identified by a scan suvey and then confirmed by direct measurements of surface activity.

j PSCo Response:

I During the Beta Scan portion of initial final suney of Survey Areas C0030 and

i. C0052, one survey measurement location (SML) was identified as an area of elevated activity within each area, and a total surface activity measurement was j

collected at each location.

! In each case, an investigation was initiated and an Investigation survey was-performed to confirm the initial final survey result and to bound the area of 1 elevated activity. For SML 269 in Survey Area C0030, a 3 x 3 meter 4

investigation area was given a 100% scan and 45 additional total surfree activity  !

measurements were collected. For SML 31 in Survey Area C0052, a 2 x 3 meter investigation area was given a 100% scan and 30 additional total surface activity '

measurements were collected. In each case, the area of elevated activity could

not be confirmed, and was considered to be an anomaly. Subsequently, the measurement results of the Investigation surveys in each case replaced the initial l 2 measurement result for reporting purposes, based on the fact that the Investigation surveys were comprehensive and were performed with the intent of finding the elevated area, and could not detect an elevated measurement.

See PSCo Response to NRC General Comment No. 4 for additional information.

J i

i e -,- - 4

NRC COMMENT No. 58:

r Volume 4, C0031 - The survey design summary states that no areas of elevated 1 activity were detected. This is apparently contradicted by the survey unit  ;

i

' investigation section which states that an elevated area (3381 dpm/100 cm2 ) was r identified by the surface scans. l PSCo Response:

l The Survey Design section should be corrected to add a reference to the area of  !

[ elevated activiv. This error did not affect the conclusions regarding suitability '

for release for unrestricted use.

?

NRC COMMENT No. 59:

! Volume 5, D2500 - What is the laboratory protocol for analyzing H-3 and Fe-55

] together - or are they analyzed separately and the activities summed? Was the combined H-3 and Fe 55 activity compared to the 40,000 dpm/100 cm2 1 mit for i

removable surface activity to demonstrate compliance? ,

PSCo Response:

i l

)

3 Combined removable H-3 and Fe-55 was' determined by liquid scintillation ,

4 counting and was a H-3 plus Fe-55 activity result. This was maary because

, the distributions of the nuclides were overlapping within the lower channels of the ,

liquid scintillation counter (i.e., H-3 beta energy is from 0 to 18.6 kev with an

, aserage energy of 5.7 kev and Fe-55 emits 5.9 kev X-rays, 5.2 kev Auger i i electrons as well as lower energy X-rays and Auger electrons).

1 i A quench curve was prepared for both Fe-55 and H-3 to determine efficiencies  !

l for each relative to sample quench, which would vary depending on how much dirt had been picked up on the sample smear. For a given smear and its quench level, the data analyses routine would determine the lower efficiency between H-3 l and Fe-55 and apply that efficiency to the background corrected count rate, i Therefore, the total removable H-3 and Fe-55 would be slightly over-estimated

(i.e., conservative).

1 The combined H-3 and Fe-55 removable surface activity was compared to the 40,000 dpm/100 cm2 limit. Typically, the combined H-3 and Fe-55 activity was

~

well below the 40,000 dpm/100 cm2 level. If the combined H-3 and Fe-55

~

, activity was significant relative to the 40,000 dpm/100 cm2 (e.g., apprcximately

10% or more), an explicit unity equation calculation was performed and included in the Release Record (e.g., see Release Record for G2400).

t 9 -

NRC COMMENT No. 60

[ Volume 5, D3300 and D5500 - The data indicates that removable activity was not assayed for Fe-55. If that is the case, then the discussion on page 3 should not include Fe-55.

PSCO Response:

l l

For Survey Packages D3300 and D5500, the sample smears were analyzed for H-3 only. The text on page 3 and Special Samples table on page 9 of each Release Record should indicate that H-3 only was analyzed (i.e., the reference to Fe-55 I should be removed), i l

The general approach for surveying for removable H-3 and Fe-55 in plant

. systems was to obtain a smear and analyze for combined H-3 plus Fe-55 as discussed in response to Comment No. 59 above. In some instances the sample smear would include too much dirt for direct liquid scintillation analysis (i.e.,

sample smear quench would be greater than allowed by established quench curves). Therefore, it was standard practice to take two smears at each specified system location where the second smear would serve as the backup (note - the second smear would be taken over an adjacent area and not over the same 100 cm2as the first smear). When sample quench was too high for combined H-3 and ,

Fe-55 analysis, the backup smear would be distilled and analyzed so at least a H-1 3 only result could be obtained.

(

e ADDITIONAL PAGES INADVERTENTLY OMITTED FROM FINAL REPORT HO2Ol, pages 67, 68 (Comment No.10)

H001, page 60 (Comment No. 43) i

Summary of Results per bxation ID Total Surface Activity (TLD-1) - Beta Survey g W

mom em

$ E.=

Location Code: H020177777HZ 4

Survey Reason: 'IT)1 - Initial Final Release

. C<w=ments: Minimum. -i- mod mean reported in dem/100em2 .

?

A status of ' Passed

• indicates a value less than or equal to 25.000.0 dpmilouem'.

Underhae values (flagged) exceed 25.000.0 dpm/100cm2 .

Bold values (failed) exceed 100,000.0 dpm/100cm2 ,

Inention Number of Minimum Maximum Mean Status ID Measurunents 00116 6 -593.4 464.8 43.2 Passed 00117 3 5.6 251.2 115.8 Passed i 00118 4 -451.4 4%.6 188.1 Passed j 00122 4 180.4 663.7 503.7 Passed i 00123 4 0.0 448.9 152.0 Passed 1 00124 4 415.9 6,036.8 1,993.7 Passed 00125 5 144.3 752.6 365.5 Passed

00126 5 -753.3 315.6 20.5 Passed 00127 6 537.0 1,878.0 1,247.1 Passed l 00128 5 -218.0 258.2 96.5 Passed 00129 3 373.3 930.7 670.4 Passed i 00130 5 -143.8 1,778.5 586.0 Passed 1 00131 4 150.2 420.6 476.2 Passed 00132 6 71.0 1,731.1 461.9 Passed 00133 5 603.7 470.5 174.7 Passed 00134 4 74.3 300.6 189.7 Passed 00135 5 -8.8 462.8 164.7 Passed 4

00136 6 82.4 1,121.3 526.0 Passed i 00137 4 425.5 830.3 624.2 Passed 1 00138 6 -284.4 587.4 207.9 Passed 00139 6 19.8 627.0 290.3 Passed

' i 00140 6 -42.8 393.7 160.3 Passed

00141 4 155.7 504.5 327.9 Passed

! 00142 5 -278.6 78.9 -94.6 Passed 00143 6 261.7 3,121.5 898.1 Passed

. 00144 4 25.3 511.1 229.2 Passed 00145 4 62.6 334.9 216.3 Passed i 00146 5 164.8 746.9 447.5 Passed 00147 4 -375.7 1,119.2 362.4 Passed 00148 4 45.0 417.3 177.1 Passed 00149 5 -174.6 373.8 125.9 Passed

, 00150 5 -174.6 450.8 122.7 Passed 00151 6 -366.3 365.2 106.7 Passed

00152 8 -415.1 534.8 36.6 Passed 00153 5 -130.8 1,343.5 427.5 Passed 00154 7 -686.7 1,113.3 89.9 Passed 00155 6 -316.7 1,434.4 468.7 Passed 00156 5 48.9 726.5 400.8 Passed

00157 6 5.6 373.9 174.3 Passed j

00158 5 61.1 658.6 320.0 Passed Page 19:TSATLD1BS:2.21.97 Page 67 5

• Summary of Results per Location ID Toct1 Surface Activity (TLD 1) - Beta Survey gk g

Location Code: H0201ZZZZZHZ l Survey Reason: 101 - Initial Final Release Cosaments: Minimum, maximum and mean reported in dpm/100cm2 .

A status of " Passed

• indicates a value less than or equal to 25,000 dpm/100cm2 .

Underline values (flagged) exceed 25,000 dpm/lW cm 2.

Bold values (failod) exceed 100,000.0 dpm/100cm2 .  ;

! 14 cation Number of Minimum Maximum Mean Status ID Measurements '

00159 6 728.3 2,931.1 1356.8 Passed 00160 4 237.7 625.3 467.7 Passed 00161 5 66.4 2,472.3 935 6 Passed l 00162 7 307.3 1,079.2 632.6 Passed 00163 3 185.1 411.8 263.1 Passed 00164 5 165.8 846.0 462.3 Passed 00165 5 -36.4 964.8 508.5 Passed 00166 8 229.6 1,545.3 575.8 Passed 00167 7 -339.1 1,743.0 234.6 Passed 00168 5 596.1 3,106.3 1,399.6 Passed 00169 6 637.1 2,006.7 1,391.7 Passed 00171 6 -17.3 651.6 206.4 Passed 00172 5 -183.5 515.7 57.3 Passed

, 00173 7 -169.8 417.8 152.6 Passed 00174 3 277.0 424.1 331.8 Passed 00175 6 1,076.4 7,059.7 2,882.1 Passed  !

00176 5 -184.8 693.5 283.1 Passed 00177 5 58.5 968.9 538.0 Passed 00178 7 113.4 565.5 91.1 Passed 00179 6 -428.4 943.0 93.1 Passed 00180 5 774.5 1,867.5 1,336.9 Passed 00181 4 602.6 2,266.5 1,306.1 Passed 00183 4 909.2 1,688.8 353.7 Passed 00184 6 87.9 499.9 1,295.7 Passed 00185 9 170.2 533.7 324.2 Passed 00186 10 -116.5 423.2 211.8 Passed 00187 1 62.7 62.7 62.7 Passed

' 00188 9 -199.1 497.2 210.6 Passed l 00189 5 245.3 695.1 539.8 Passed

00190 5 729.9 1,627.4 1,100.9 Passed 00192 9 -124.1 728.0 161.9 Passed 00193 4 803.6 1,417.4 1,074.1 Passed 00194 6 70.1 1,122.2 546.4 Passed 00195 9 370.0 2,814.9 1,053.0 Passed 001 % 5 99.5 800.0 434.6 Passed 00197 10 104.0 1,521.6 672.3 Passed 00198 6 464.5 7,447.2 2,299.1 Passed 00199 9 104.0 647.6 434.6 Passed 00200 10 36.9 1 845.6 Passed 00201 6 551.7 2'946.5 664.5 1,276.1 Passed 4

Page 20:TSATLDIBS:2.21.97 Page 68

Summary of Efficiency Values j Total Surface Activity - Beta Survey t E2@Id

,yg.2._;. .,

Location Code: H0001WZ002BZ

, Survey Reasons: T01 - Initial Final Release, R01 - Remediation Comments:

A Detector Detector Download # Efficiency '

Model Serial Number -Station #

i LMI 44-408225 PR119456 1489-3 0.077 LMI 44-408225 PR095107 1495-3 0.082 4

LMI 44-40B225 PR119456 1502-3 0.088 J

LMI 44-408225 PR075065 1504-3 0.090 LMI 44-408225 PR119456 1524-3 0.080 '

LMI 44-408225 PR092621 1614 3 0.082 I f I

4 1

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Page 60 s .