ML052140120

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to Calculation E900-04-004, Cv Tunnel Unistrut Survey Design, Appendix B to Final Status Survey Report for Saxton Nuclear Experimental Corporation Saxton Steam Generating Station Structural Surfaces - Cv Steam Tunnel SS22
ML052140120
Person / Time
Site: Saxton File:GPU Nuclear icon.png
Issue date: 04/16/2004
From: Brosey B
FirstEnergy Corp
To:
Office of Nuclear Reactor Regulation
References
E900-04-004, Rev 0
Download: ML052140120 (31)
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Appendix B Unistrut Survey Design

SNEC CALCULATION COVER SHEET CALCULATION DESCRIPTION Calculation Number Revision Number Effective Date Page Number E900-04-004 0 1 of Subject CV TUNNEL UNISTRUT SURVEY DESIGN Question 1 - Is this calculation defined as 'In QA Scope'? Refer to definition 3.5. Yes 0D No El Question 2- Is this calculation defined as a "Design Calculation'? Refer to definitions 3.2 and 3.3. Yes 0 No E Question 3 - Does the calculation have the potential to affect an SSC as described in the USAR? Yes ] No 0 NOTES: If a 'Yes' answer is obtained for Question 1, the calculation must meet the requirements of the SNEC Facility Decommissioning Quality Assurance Plan. If a 'Yes' answer Is obtained for Question 2, the Calculation Originator's immediate supervisor should not review the calculation as the Technical Reviewer. If a "YES' answer is obtained for Question 3. SNEC Management approval is required to implement the calculation. Calculations that do not have the potential to affect SSC's may be Implemented by the TR.

DESCRIPTION OF REVISION

.___-_APPROVAL

__ SIGNATURES Calculation Originator B. Broseyl 3 Date Technical Reviewer P. Donnachie/ Date Additional Review A. Paynterd Date J4 q, Additional Review Date SNEC Management Approval Date

a. . E SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-04-004 0 l Page 2 of.I Subject _

CV TUNNEL & UNISTRUT SURVEY DESIGN 1.0 PURPOSE 1.1 The purpose of this calculation is to develop a survey design for remnants of CV Tunnel unistrut embedded in the SNEC CV Steam Tunnel ceiling and walls. The total length of the remaining unistrut sections is approximately 70.5 feet.

1.2 This survey effort may be performed in conjunction with the CV Tunnel concrete re-survey effort.

2.0

SUMMARY

OF RESULTS The following information should be used to develop a survey request for this survey design. If remediation actions are taken as a result of this survey, this survey design must be revised.

2.1 Nal Survey Work 2.1.1 No scanning of unistrut is required by this survey design.

2.1.2 Static measurements at a fixed distance over segments of unistrut shall be performed using a 2"D by 2"L Nat detector with a Cs-1 37 window setting. The Cs-137 window shall straddle the Cs-137 energy peak at 662 keV IAW the applicable calibration sheet (see example of Attachment 1-1).

2.1.3 The Nal instrument conversion factor/efficiency shall be no less than 176 cpm/uRth.

2.1.4 Static measurements shall be made 2" from unistrut locations (see below).

Whenever possible, each measurement shall be centered in the middle of a one (1) foot section (. Segments less than 1 foot in length should be surveyed separately at an estimated center position. Record the length of these shorter segments. Note when a segment contains concrete estimate how full the channel is..

Typical Nal Positions

/ (Side View) unistrut I I 0' if 2' 3' 4' 2.1.5 A two (2) minute count time shall be employed. An integrated 2 minute count shall be recorded at one (1)foot increments IAW site procedures. Measurements shall be made over the entire length of the unistrut sections.

2.1.6 Background measurements shall be made by covering a segment of unistrut with a 2Wthick lead brick and then placing the probe against the lead at the center of the brick (see following diagram).

2.1.7 A ten (10) minute count time shall be employed for all background measurements.

r-V SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E90040404 0 Page 3 of '?

Subject CV TUNNEL & UNISTRUT SURVEY DESIGN Nal Background Measurement Location Contact With Brick 2"1 (Side View)

(Top View) 2.1.8 At least three background measurements should be made on each wall and ceiling area in the CV Tunnel area. These measurements should be approximately evenly spaced along the Tunnel length (a total of 9 background measurements). Document all results NOTE Background measurements require the handling of lead bricks. Use caution when positioning these objects to ensure a safe work area. It is recommended that a jig, or custom holder be used to position lead for each background measurement.

2.1.9 All survey points shall be clearly marked and sequentially numbered.

2.1.10 Each two minute integrated counting result (at all locations) shall be recorded IAW site procedures.

2.1.11 Other instruments of the type specified in Section 2.1.2 above may be used during the FSS but must demonstrate an efficiency at or above 176 cpm/uRlh for Cs-1 37.

2.1.12 Some starting points may need to be adjusted to accommodate obstructions within the tunnel area. Contact the SR coordinator to report any difficulties encountered when laying out measurement points.

2.1.13 The following are the applicable effective DCGLw values:

Surface DCGLw (dpm/100 cm2) Volumetric DCGLw (pCUg)

GA = 27,479 (20,609 A.L.) Cs-137 = 6.32 (4.74 A.L.)

GA = Gross Activity A.L = Administrative Limit is 75% of the actual DCGLw value.

SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-04-004 0 Page 4 of Subject CV TUNNEL & UNISTRUT SURVEY DESIGN 2.1.14 The MDCstatic Cs-137 surface value is 2215 dpm/100 cM2. The gross activity concentration is as follows: 2215 dpm/1 00 cm Cs-1 37/0.992 (Cs-1 37 fraction) =

2233 dpm1100 cm 2 .

3.0 REFERENCES

3.1 SNEC Calculation No. E900-03-018, "Optimize Window and Threshold Settings for the Detection of Cs-1 37 Using the Ludlum 2350-1 and a 44/10 Nal Detector", 817/03.

3.2 SNEC procedure E900-IMP-4520.04, "Survey Methodology to Support SNEC License Termination".

3.3 Plan SNEC Facility License Termination Plan, Rev 3.

3.4 SNEC Procedure E900-IMP-4500.59, "Final Site Survey Planning and DQA".

3.5 SNEC Facility Historical Site Assessment, Rev 0, March, 2000.

3.6 SNEC procedure E900-IMP-4520.06, "Survey Unit Inspection in Support of FSS Design".

3.7 NUREG-1575, 'Multi-Agency Radiation Survey and Site Investigation Manual", August, 2000.

3.8 Microsoft Excel 97, Microsoft Corporation Inc., SR-2, 1985-1997.

3.9 SNEC Calculation No. E900-03-012, Effective DCGL Worksheet Verification.

4.0 ASSUMPTIONS AND BASIC DATA 4.1 Remediation History The below grade CV Pipe Tunnel originally extended around the base of the CV approximately 270 degrees and connected to the old Waste Treatment, C & A and SSGS Footprint areas. The only remaining section still in tact extends from the SSGS footprint East approximately 40 feet toward the CV area. The CV Tunnel diagram is shown on Attachments 2-1 and 2-2.

Piping systems originally installed in the CV Tunnel, were removed from about 1972 to 1974. These early remediation efforts were not specifically documented. In the late 80's an isolation wall was erected at the far eastern end. Since the CV Tunnel collected seasonal rain and ground water seepage, this wall served to isolate water accumulation to only a portion of the remaining structure.

In the spring of 1994, SNEC personnel entered the tunnel through a hole installed in the ceiling to complete characterization surveys for this structure. No evidence of abrasive remediation of the interior surface of the tunnel was noted. A thorough characterization survey was performed in late 1994. Areas indicating elevated activity were core bored to determine the depth of the contamination.

Shonka Research Associates (SRA) initially surveyed the CV Tunnel concrete surface using a large area GFPC detector array. Remediation was performed to reduce the residual volumetric concentration of Cs-137 and lower the general area exposure rate. However, little was done to reduce the contamination present in/on unistrut sections. Since the unistrut did not appear to contain contamination levels above the effective surface DCGLw,

. . .JSNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-04-004 0 Page 5 of C Subject CV TUNNEL & UNISTRUT SURVEY DESIGN it was decided that this component could be surveyed and allowed to remain in the collapsed CV Tunnel structure.

4.2 Inspection of the concrete surface was conducted IAW Reference 3-6. There is approximately 70.5 feet of unistrut remaining which is embedded in the floor and wall areas of this structure (see Attachment 9-1 to 9-3). The majority of this length is not filled with concrete or other materials that would alter the MicroShield modeling effort (see Attachment 3-1 to 3-2).

4.3 MicroShield modeling considers a one foot segment of unistrut as a volume contaminated object. The results are then assumed to be a surface contamination and are averaged over the entire surface area of a one foot section.

4.4 The sample data base used to determine the effective radionuclide mix for the CV Pipe Tunnel area has been drawn from previous samples that were assayed at off-site laboratories. This list is shown as Attachment 4-1 and 4-6, and includes five (5) analysis results that are thought most applicable. Review of the data indicates eight radionuclides have not been positively identified at any concentration. These radionuclides have been removed from the data set and are not be considered further. Radionuclides removed include H-3, Am-241, Pu-238, Pu-239, Pu-241, C-14, Ni-63 and Eu-152.

Inspection of the data also shows that Cs-137 is by far the predominant radioactive contaminant found in this area. Sr-90 on the other hand, was positively identified in only one (1) sample. Co-60 was identified as a positive contaminant in only two (2)samples.

The re-assessment of the radionuclide mix for the CV Tunnel area was transmitted to the US NRC for concurrence. The current applicable volumetric and surface limit DCGLw values were determined to be as follows (from Attachment 4-1 to 4-6):

Surface DCGLw (dpml100 cm2 ) Volumetric DCGLw (pCi/g)

GA = 27,479 (20,609 A.L.) Cs-1 37 = 6.32 (4.74 A. L.)

GA = Gross Activity A.L = Administrative Limit is 75% of the actual DCGLw value.

4.5 The Nal MDCstatic calculation is determined on the basis of a 2 minute sample count time combined with a 10 background count time. The MicroShield modeled unistrut section is assumed to have a homogeneous composition such that the weight per foot of unistrut divided by the volume of the outer profile yields a mean density of -1.77 g/cc. The unistrut diagram is shown on Attachment 5-1.

4.6 The resulting range of general area background values in the survey unit using the 44-10 probe is a 99 to' 175 cpm (see Attachment 6-1 and 6-3). Then mean background value is 132 cpm. The resulting volumetric MDCstatic value is -8.651 pCi/g Cs-137 and the surface MDCstatic value is 2215 dpm/100 cm2 for Cs-137 (see Attachment 7-1 and 7-2). A series of reasonably conservative assumptions must be made to interpret the data - they are:

4.6.1 The contamination is a surface deposit and thus the surface MDCstatic value is the correct MDC to be used for unistrut sections.

CSNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-04-004 0 Page6of 9)

Subject CV TUNNEL & UNISTRUT SURVEY DESIGN 4.6.2 It is assumed that there is no concrete fill or other materials present in the channel of the unistrut.

4.6.3 The actual surface area of a one foot section of unistrut is about 866 cm2. For purposes of this calculation, the activity is assumed to be evenly dispersed over this area and the result will be reported per 100 cm2.

4.6.4 The entire unistrut area is 866 cm2 /ft x 70.5 feet = 61,053 cm2 or -6.1 M2. The CV Tunnel unistrut will be considered one (1)survey unit.

4.6.5 The MDCstatic Cs-137 surface value is 2215 dpm/100 cm2. The gross activity concentration is as follows: 2215 dpm/100 cm2 Cs-137/0.992 (Cs-137 fraction) =

2233 dpm/1 00 cm2. If all the activity is assumed to be present on only the exposed side of the unistrut (the non-embedded side), the MDCstatic value is twice this surface value or 4466 dpm/1 00 cm2 . This is well below the actual administrative limit for this area of 20,609 dpm/100 cm2. Since the total area of unistrut is only 6.8 M2 at the most and one half of this value if only the exposed side is considered, an area factor between 2 and 3.4 could be applied (Co-60). Thus the actual DCGLw limit for unistrut could be as high as 2.62 x 20,609 = -54,000 dpm/100 cm2 (see Attachment 8-1).

4.7 The survey unit described in this survey design was inspected after remediation efforts were shown effective. A copy of portions of the SNEC facility post-remediation inspection report (Reference 3.6), is included as Attachment 9-1 to 9-3.

4.8 No special area characteristics including any additional residual radioactivity (not previously noted during characterization) have been identified in this survey area.

4.9 The applicable SNEC site radionuclides and their individual DCGLw values are listed on Exhibit 1 of this calculation.

4.10 The survey design checklist is listed in Exhibit 2.

5.0 CALCULATIONS 5.1 All calculations are performed internal to applicable computer codes or within an Excel spreadsheet.

6.0 APPENDICES 6.1 Attachment 1-1, is an example of a typical calibration data from one typical Nal radiation detector that may be used for this survey effort.

6.2 Attachment 2-1 and 2-2, are diagrams that depict and locate this survey area.

6.3 Attachment 3-1 and 3-2, is a MicroShield model of a one foot section of unistrut used to determine the exposure rate from a I pCi/cc Cs-137 source term.

6.4 Attachment 4-1 to 4-6, is the US NRC concurred sample listing for this area.

6.5 Attachment 5-1, is a cross-sectional diagram of unistrut.

6.6 Attachment 6-1 to 6-3, is the SR-1 06 post-remediation survey results for the CV Tunnel.

6.7 Attachment 7-1 to 7-2, is the MDCstatic results for a modeled section of unistrut.

SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-04-004 0 Page7of Subject CV TUNNEL & UNISTRUT SURVEY DESIGN 6.8 Attachment 8-1, is area factor estimate for the Unistrut sections.

6.9 Attachment 9-1 to 9-3, is the site inspection report for this survey unit.

SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-0404 0 Page 8 of 'q Subject CV TUNNEL & UNISTRUT SURVEY DESIGN Exhibit I SNEC Facility Individual Radionuclide DCGL Values (a) 25 mremly Limit 4 mremly Goal 25 mrem/y Limit (All Pathways) (Drinking Water)

Radionuclide Surface Area Open Land Areas Open Land Areas b (dpm/1OOcm 2) (Surface & Subsurface) (Surface & Subsurface)

(pCI/g) (pcilg)

Am-241 2.7E+01 9.9 2.3 C-14 3.7E+06 2 5.4 Co-60 7.1 E+03 3.5 67 Cs-1 37 2.8E+04 6.6 397 Eu-152 1.3E+04 10.1 1440 H-3 1.2E+08 132 31.1 Ni-63 1.8E+06 747 1.9E+04 Pu-238 3.0E+01 1.8 0.41 Pu-239 2.8E+01 1.6 0.37 Pu-241 8.8E+02 86 19.8 Sr-90 8.7E+03 1.2 0.61 NOTES:

(a)While drinking water DCGLs will be used by SNEC to meet the drinking water 4 mremly goal, only the DCGL values that constitute the 25 mrem/y regulatory limit will be controlled under this LTP and the NRC's approving license amendment.

(b) Listed values are from the subsurface model. These values are the most conservative values between the two models (i.e.,

surface & subsurface).

SNEC CALCULATION SHEET Calculation Number Revision Number Page Number E900-04-004 0 Page 9 of4.

Subject CV TUNNEL & UNISTRUT SURVEY DESIGN Exhibit 2 Survey Design Checklist Calculation No. Location Codes E900-04-004 SS22-5 (Unistrut)

Status Reviewer ITEM REVIEW FOCUS (Circle One) InWals & Date 1 Has a survey design calculation number been assigned and is a survey design summary Y A description provided?

2 Are drawings/diagrams adequate for the subject area (drawings should have compass (Y A I

_______headings)?

3 Are boundaries properly identified and is the survey area classification clearly indicated? _Yes,) N/A 4 Has the survey area(s) been properly divided into survey units IAW EXHIBIT 10 Yes, A 5 Are physical characteristics of the area/location or system documented? N/A 6 Is a remediation effectiveness discussion included?

7 Have characterization survey and/or sampling results been converted to units that are comparable to applicable DCGL values? Les/

8 Is survey and/or sampling data that was used for determining survey unit variance included? Xes A ),'V/

Is a description of the background reference areas (or materials) and their survey and/or Ye N/A i sampling results included along with a justification for their selection? e0 10 Are applicable survey and/or sampling data that was used to determine variability included? YesA) 11 Will the condition of the survey area have an impact on the survey design, and has the Yes probable impact been considered In the design? ____________

Has any special area characteristic including any additional residual radioactivity (not 12 previously noted during characterization) been identified along with its impact on survey Yes.

design?

13 Are all necessary supporting calculations and/or site procedures referenced or Included? es N/A 14 Has an effective DCGLw been identified for the survey unit(s)? iA 0/o 15 Was the appropriate DCG-EUC included in the survey design calculation? (Ye) N/A 16 Has the statistical tests that will be used to evaluate the data been identified? Ys A 17 Has an elevated measurement comparison been performed (Class I Area)? YesN/A 18 Has the decision error levels been identified and are the necessary justifications provided? / 0/

19 Has scan instrumentation been identified along with the assigned scanning methodology? ,N/A )/vw 20 Has the scan rate been identified, and Isthe MDCscan adequate for the survey design? es N/A 4/

21 Are special measurements e.g., in-situ gamma-ray spectroscopy required under this design, and is the survey methodology, and evaluation methods described? Yes,______

22 Is survey instrumentation calibration data Included and are detection sensitivities adequate? Y A 23 Have the assigned sample and/or measurement locations been clearly Identified on a diagram r es, UA or CAD drawing of the survey area(s) along with their coordinates? i _________

24 Are investigation levels and administrative limits adequate, and are any associated actions N/A

______clearly Indicated?

25 For sample analysis, have the required MDA values been determined.? Yes 26 Has any special sampling methodology been identified other than provided in Reference 6.3? Yes Q - I / f NOTE: a copy of this completed form or equivalent, shall be included within the survey design calculation.

f ,qr) PL LUDLUM MODEL 44-10 HIGH VOLTAGE PLATEAU DATA SHEET (Detector peaked using Cs137 #019454 5uCi button)

Serial Number: 196021 700 37,380 701 39,576 702 40.089 703 41,493 704 42,325 706 42,859 706 42,758 707 41,336 708 40,700 709 N/A 710 N/A 711 N/A

- '?-. , - " ......

-: -. -ZDijtbd6f,'P IN dier:fbr.'P'66kiii a " :,... I.'

-.,;f. ;! 4;,:.

...7. -.

Parameter Setting Comments Threshold (1OmVll 00) 612 -Peaked for Cs' 37 at Window (On)

High Voltage 100 705 1.662keV I___________

CPM/mR - i - 221,028 j

- JWHMa&udib

~ 16 6d 7hre~s. bldJ .ZardMrndoeK FWHM= 685 -60512%

662 xlOO0%

Detector peaked for Cs'37using Ludlumn peaking procedure and threshold setting of 612 and window setting of 100 as requested by John Duskin. 2350-1 #117566 calibration due 01/22104 used for peaking 44-10 detector.

Performed By:- 65, W7, Z Date: _ _ _ _

Reviewed B ~,Z0,~6- , A Date: '9 / P-'rO.?

ATTACHMENT 2...- I3..

South Wall 68.5" _ 73"1 East Wall i24"1 Floor ED Opening CV Tunnel

-- Opening

- 488" W.

1 1-Opening -- 73" 68.5" V

North Wall ATTACHMER T -

OFFICE TRAILER 1]

ICONCRETE . , \

PAD _

OFFICE TRAILER SUBSTATION l (REMOVED) DATI PERIMETER O. SUBSTATION STR.C.URE

.. /.\ (REMOVED)

  • Remaining 40'Section of CV Tunnel iGS Footprint NTAINMEN]

. i:l (REMOVED) l . ~SSGS DISCHARGE TUNNEL r  ;'.- waA'-;\'-p'jf'.e' wgt<oi_

IWASTE PENELEC CONTROL TREATMENT LINE AUXILIARY SHACK

  • SSGS (REMOVED)

El F

% I BI Aft a: ....

(KtIMUVtDU)

FILLED DRUM STORAGE GATE /- AREA (REMOVED)

I ),kv1r.,1l It I ATTACHMENTl- 2

MicroShield v5.05 (5.05-00121)

GPU Nuclear Page :1 File Ref:

DOS File: UNISTRUTJMS5 Date:

Run Date: March 30, 2004 By:

Run Time: 10:52:05 AM Checked:

Duration : 00:00:20 Case

Title:

Unistrut

Description:

1 Foot Section of Unistrut - 564 uCi of Cs-1 37 per ft.

Geometry: 13 - Rectangular Volume Source Dimensions Length 4.3 cm 1.7 in Width 4.3 cm 1.7 in Height 30.48 cm I ft Dose Points x Y z

  1. 1 11.92022 cm 15.24 cm 2.15011 cm 4.7 in 6.0 in 0.8 in Shields Shield Name Dimension Material ' Density Source 34.395 in3 Iron 1.771 Air Gap Air 0.00122 Source Input Grouping.Method : Actual Photon Energies Nuclide curies becquerels uCi/cm 3 Bq/cm 3 Ba-137m 5.3354e-004 1.9741 e+007 9.4662e-001 3.5025e+004 Cs-137 5.6400e-004 2.0868e+007 1.-007e+000 3.7024e+004 Buildup The material reference is : Source Integration Parameters X Direction 40 Y Direction 40 Z Direction 40 Results Enerav Acbvty Fluence Rate Fluence Rate Exposure Rate Exposure Rate MeV photons/sec MeV/cm 2 /sec MeV/cm 2/sec mR/hr mR/hr No Buildup With Buildup No Buildup With Buildup 0.0318 4.087e+05 1.499e-01 1.540e-01 1.249e-03 1.283e-03 0.0322 7.541e+05 2.895e-01 2.975e-01 2.330e-03 2.394e-03 0.0364 2.744e+05 1.688e-01 1.751e-01 9.588e-04 9.947e-04 ,

0.6616 1.776e+07 4.795e+03 5.886e+03 9.296e+00 1.141e+01 5Q ATTA:CHMENT- - (3 -

Page :2 DOS File: UNISTRUT.MS5 Run Date: March 30, 2004 Run Time: 10:52:05 AM Duration : 00:00:20 Energy .Activity Fluence Rate Fluence Rate Exposure Rate Exposure Rate MeV 6hotons/sec WeAeV/cm 2 1sec MeVlcrM2 sec mR1Whr mR/hr No Buildup With Buildup No Buildup With Buildup TOTAI-6: 1.920e+07 4.796e+03 5.887e+03 9.301 e+00 1.142e+01 AT TACHMNENWI 3 - a.2

DCGL Calculation Logic-CV Steam Tunnel/Seal Chamber Roof Survey Unit: SNEC Containment Vessel (CV) Steam Tunnel & Top of Seal Chamber 1 & 2 Roof

11.

Description:

The purpose of this calculation is to determine a representative isotopic mix for the CV Steam Tunnel and top of the Seal Chamber I & 2 roof from available sample analyses.

The effective surface area and volumetric DCGLWs are then determined from the mean percent of applicable samples.

Ill. Data Selection Logic Tables: The radionuclide selection logic and subsequent DCGL calculations are provided in six (6) tables. These tables were developed using Microsoft Excel. Table explanation is as follows.

Table 1: Data Listing - This table, which has been extracted from a larger database, provides a list of the most representative sample analyses for the CV Steam Tunnel and top of the Seal Chamber I & 2 roof. These results are from scoping, characterization, and pre/post remediation surveys. The samples consist of various sediments, scrapings and concrete cores that were taken in support of the aforementioned surveys. As applicable, a sample number, sample location/description, radionuclide concentration, analysis date are provided for each sample. Positive nuclide concentrations are noted with yellow/shaded background fields while MDAs are noted in the gray shaded fields.

Table 2: Decayed Listing of Positive Nuclides & MDAs Removed - This table provides the best overall representation of data selected from Table 1. Half-life values (days) are listed above each respective nuclide column. Samples are decayed to the date noted above Table 1 (e.g. January 15, 2004). Positive results are denoted in a yellow background while the MDA values, which were listed in Table 1, have been stripped out.

Table 3: Mean Percent of Total for Positive Nuclides - This table provides the calculation methodology for determining the relative fractions of the total activity contributed by each radionuclide. From this information the mean, sigma, and mean % of total are calculated.

The mean % of total values is used to calculate the surface gross activity DCGLW per MARSSIM equation 4-4. See Table 5. Note that the Co-60 mean percent values were averaged using only samples 1 & 5. In addition, the mean percent calculated from sample 1 for Sr-90 was not averaged throughout the spreadsheet, since this sample was the only one where this respective nuclide was positive. This results in higher "mean percent of total" values in the mix, which is conservative.

Table 4: Ratio to Cs-1 37 for Positive Nuclides - This table provides the calculation methodology for determining the surrogate ratio to Cs-137 for each radionuclide. From this information the mean, sigma, and mean % of total are calculated. The mean % of total values is used to calculate the volumetric DCGL, per MARSSIM equation 1-14. See Table 6. Note that the Co-60 ratios were averaged using only samples 1 & 5. In addition, the ratio value calculated from sample 1 for Sr-90 was not averaged throughout the spreadsheet, since this sample was the only one where this respective nuclide was positive. This results in higher "mean percent of total" values in the mix, which are conservative.

Note: From Tables 3 and 4 only the "mean % of total" values are used as input to the "Effective DCGL Calculation Spreadsheet" as Illustrated in Tables 5 and 6.

Table 5: Effective DCGL Calculator for Cs-1 37 (dpm/1 00 cmA2) - This table provides the surface gross activity DCGLW calculation results from data derived from Table 3.

ATTACHMENT {L - l 1

Table 6: Effective DCGL Calculator for Cs-1 37 (in pCig) - This table provides the surrogate volumetric concentration for the Cs-I 37 DCGLW calculation results from data derived from Table 4.

IV. Summary - Since the CV Steam Tunnel is a concrete structure the release limit is primarily based on the surface area DCGLW. However, some CV Tunnel walls contain unistrut, which are treated as volumetric contamination. Therefore, a volumetric DCGLW is also determined.

The Seal Chamber 1 & 2 roof release limit will be based on the surface area DCGLonly.

Using the above data selection logic tables, the calculated gross activity DCGLW for surface area is 27,479 dpmliOO cm2 . The Cs-137 volumetric DCGLW is 6.32 pCilg. These values would be reduced by 25% as part of SNEC's requirement to apply an administrative limit as discussed in the License Termination Plan (LTP).

A17ACHMENT 2..

2

TABLE I Data Listing (pCUg)

Decay Date January15 2004

_- 5EC Sample Ho LocationtOescription H-3 Sr-90 Co-60 Cs-137 Am-241 Pu-235 Pu-239 Pu-241 C-14 11i43 Eu-152 Analysis Date 1 CV -unnel CV%nnel Stoiment Ccmpcsite. OL-1 C 9.4 9.67 1.26 1250 < 0.18 < 0.55 cD.22 c 44.69 <9.34 <c4.02 < 0.13 Februas1420 2 SXS5CE CVSteaM7rranel Vac-Pac abris < 0.808 < 0.0382 <0.0251 9 26 cO.021 c 0.0348 < 0.00279 <2.6 <0.147 <0.322 < 0.0899 December 10 2003 3 SXS 1 2.1 3 CV Stel SbelScropirgs -Extericr Selcv C-raodeiari <8.04  :<0.0331 0.177 < 0.0246 <0.0517 0.0231 < 3.99 October 11 2001 4 SXSl552. 1S' CVSteelShellScrapiros - ExteriorBelov.,Grace sar, _ <' 0<04 < 0D0305 0 297 < 0.0113 < 0.0372 < 0.0131 <2.36 October 11 2001 s Sxs:744 SSGSl'ezzanine. East.PipeIrternals. SR-CC4 < 123 < 0.18 T 226 39 6 < 0.709 < 0.33 c 0.33 < 50 8 <37-9 c 82.6 <1.46 March 21 2001 TABLE 2* Decayed Listng of Positive Nuclides & MDAsRemoved_(pCUg-T112 T1'2 T1,22 TI2 112 TT112 T112 TV2 12 T1,2 T 12

_ 4485 27 10446 15 1925 23275 11019 5925 157861 05 32050.6875 8813847 75 5259.6 2092882 5 36561 525 4967 4 SNEC Sample flo LocationOescription H.3 Sr-90 Co-40 Cs4I37 Am-241 Pu-235 Pu.239 Pu.241 C,14 Ili-63 Eu-152 Total (pCiig)

I CV tunnel CV-unnel Sediment Ccmposte, CLI 9OEE+OO 8 59E-01 1 17E+03 I I 1178 89 2 SXSMMOJ CVSteamunneti Vac-Pac CeDbris 9.24E+ 00 l 9 24 3 SXSD1531.15 2 15!" CVSte S*el Scrapirs - Exterior Belo%, GraeiTare r 1.68E41 017 4 SXSD1552.iSs cv SteelShelScrapirgs -Exterior Oelcw. GradeT.ar 2 82E-01 _ _ 028 s SXSc744 SSGS uezzanine. East.Pipe Internal& SR-CCC4 - 1561E+01 38 68 9 01Et00 8 59E-01 295E+02 304,55 9 O1EeO82 9 1E 2 ii  : 30455 signro Mean%of IOtOO 1 2,96% 1 0.28% j 2 1/ 676 i1 __ __ 1 1____ 100 00%

KEY I Ilellow Shaded Backgrcund = Pcsitive Result I I Gray Shaded Background = I.IDA I 3

TABLE 3 - Mean Percent of Total for Positive Nuclides SiNEC Sample N1o LocationJDescription Sr-90 Co-SO Cs-137 Total 1 CV unnel CV unnel Sediment Composite. OLI 0.76% 007% 9916% 100.00%

2 SXSDlC CV Steam Tunnel. Vac-Pac Debris 100.00% 100.00%

3 SXSGED 1.1 3.2. 15.2 CV Steel Shell Scrapings - Extericr Belcw Grade Jar __ 100 00% 100 00%

4 SXSD1S.52. 1552 CV Steel Shell Scrapings - Exterior Below Grade J7ar. 100.00% 100 00%

5 SXSG7"4 SSGS M*ezzanine. East. Pipe Internals. SR-OC04 4.03% 95.97% 100.00%

_dean* 7.64E-03 7.28E-04 9.98E-01 1.01 Sigmao _____ 0 004185775 .............

tMlean % of Tota* 0.76% 0.07% 99.17% 100.00%

TABLE 4 - Ratio To Cs-I 37 for Positive Nuclides SHEC Sample N1o LocationJDescription Sr-90 Co-SO Cs-137 Total I CV Tunnel CV Tunnel Sediment Compcsite, OLH 0 008 o0ool 1 000 1 008 2 SXSD1 C5 CV Steam Tunnel. Vac-Pac Debris 1.000 1 000 3 SXSD15.1 1532. 1522 CV Steel Shell Scrapings - Exterior Below Grade (Tar) 1.000 1.000 4 SXSD1552. 1552 CV Steel Shell Scrapings - Exterior Below Grade Jar. 1 000 1 0o0 5 SXSD744 SSGS l.lezzanine. East. Pipe Internals. SR-CCC4 0.042 1 000 1.04 lMean=* 7.71E-03 7 35E-04 1.OOE-00 1.01 Sigma=* 0 .O OE +00 _._.".............._._....._._.__

IMean % of 7otai= 0.76% 0.07% j 99.16% 100.00%

4

Table 5 Effective DCGL Calculator for Cs- 137 (dpml100 cmA2) , -Gross' Activity DCGLw;; I Gross Actilvity Admlnlstritive Limit 27479 dpml1OO cmA2 20609 dpml100 cmA2 1l 25.01 nrernty TEDE Limit

.Cs.137. Limit.,.9%,gi; ;,s'., Cs-137 Administrative Limit, .V '

SAM.iPLE 1lO(s)n'ICV Tunnel I

27250 _dpml1OO cm^A2 20438 ldpml100 cmA2 l <!SNEC AL .; 75%

Individual Sample Input Limits Allowed Beta dpmr1OO Alpha dpmiloo Isotope (pCilg, uCi, etc.) le of Total (dpmn100 cm^2) dpm:100 cmA2 mrem,' TEDE cmA2 cm^2 i Ain.241 0.000% 27 0.00 0 00 ° A. 0.00 Am.241 2 C-14 0.000°' o3,700,000 0.00 0.00 0.00  : ,' C 14 31Co.60 7.28E-04 0.072% 7,100 19.88 0.07 19.88 UA. Co-60 4 Cs.137 . . 9.98E.01 -- 99.168% 28,000 27250.22 24.33 27250.2 lA Cs.137 n s Eu-152 0.000% 13,000 0 00 0.00 0.00 0- . Eu-152 6 H.3 0.000% 120,000,000 0 00 0.00 Hiot Detectable } H-3 7 IJi-63 0 000% 1,800,000 0.00 0.00 Hot Detectable ll-A fll 63 8Pu.238 0.000% 30 0.00 0.00 .:.::: 0 00 Pu.238 s Pu.239 0.000% 28 0.00 0.00 . 0.00 Pu.239 10 Pu-241 0.000%O 880 0.00 0 00 Hot Detectable ..-..... !I.. Pu.241 II Sr.90 7.64E.03 0.759% 8,700 208.61 0.60 208&61 ..i....... Sr.90 100. 000% 27479 25.0 27479 0 Maximum Permissible dpmt100 cmA2 5

Table 6

.1.s I.

6

3mm 5

El I' Al 10Omm 1 43mm 7mm 2

UNIS TRUT C,

K LT'- 35 866 cmA2/ft.

564 cmA3 per Foot (vol.)

2.202 Ibs/ft.

127 cmA3/ft.

37

-.--- 4.----.----- 4 I I

43mm

3 4.

-$RVY PQEt YRWEQUEWi;0CONTNUATIl T1 SHE:

T '.<:,-Pl~r

-. til.SR NUMBER :: SR-1 06 -AJLcATION CV Steam Pipe Tunnel

  • _ -. .- SPEC1FEAMPLIN ISURVEY INSTRUCTIONSORCOM.

RESULTS

SUMMARY

FOR SR-406 SR-106 was issued to obtain Nal detector scan measurements of CV Steam Pipe Tunnel surfaces. The data will indicate whether remediation is complete. The SR required the following radiological measurements:

  • Surface Scan Measurements for Gamma Activity Using a Nal Detector - perform a scan survey representative of the entire tunnel to Include approx. 50% of total surface area. Focus on previously known contamination areas. Scan at a rate not exceeding 5 cm per second at a distance not exceeding 2 inches. Established action level is 200 gross cpm.
  • Variability Study Using the LM 2350-1 with a GFPC - obtain at least 20 unbiased measurement pairs using a GFPC. Perform 1-minute counts spaced throughout the entire tunnel and include a combination of floors, walls, and ceiling surfaces. The detector will be held on contact with surface.
  • Variability Study Using the LM 2350-1 Nal Detector - obtain at least 20 unbiased measurements using a Nal Detector. Perform 1-minute counts spaced throughout the entire tunnel and indude a combination of floors, walls, and ceiling surfaces. The detector shafl be within 2 inches of the surface.
  • Loose Surface Contamination (Smear Survey) - obtain at least 20 smears spaced throughout the entire tunnel and include a combination of floors. walls, and ceiling surfaces.
  • Additional sampling/surveying may be performed as requested by the SR Coordinator.
  • QC Repeat Measurements - A minimum of 5% of all measurements and sampling will be re-performed using identical methodology.
1. Summary of Results A. Surface Scan Measurements Using a Nal Detector Approximately 63% of the tunnel surfaces were scanned.

Results: all areas indicated activity <adion level except for 6 areas. Static measurements performed on these areas indicated <action level.

B. Static Measurements Using a GFPC Detector Twenty-two unbiased measurement pairs were obtained.

Results: The range of static measurement pairs' difference was from 8 to 220 ncprn. The highest unshielded reading. taken at F.P #17, was 431 cpm. Unshielded readings ranged from 237 to 431 cpm.

C. Static Measurements Using a Nal Detector Twenty-three unbiased measurements were obtained.

Results: The range of measurement results was from 99 to 175 gross cpm.

Page 1 of 3 TO JewA NV_4_MNn,4q 1TRFqFqV1R R1:V1 VAAZ/OE/EO

R,1.,VY--F,.qPE1T- CO NTIN PATATO~EU.

_ RM- A1REILOCATI.ON lN CV Steam Pipe Tunnel

-.  ;.Fi:C:t:.-.U~e It.:':.~Y~ R i R 'C.MMENTS

>CTms. .  :.::

D. Loose Surface Contamination Survey Twenty-three unbiased smears were obtained.

Results: The smears indicated <MDA (166 dpm. Beta-gamma and 13.5 dpm. Alpha). Theses smears were composited and the gamma analysis indicated <1.6 E-5 uCUsmeargroup Cs-137.

E. Result Summary Table The following table lists the surveylsmear locations with the static measurement and smear results:

Survey Point/ 44,10 Detector Result nshieded Readn Smear Results (ncpm/100 cm-Smear Location (gross cpm) )

.chel ng Alpa fcpm) Eleta-gamma Alpha I 111 304 3 0 2 123 337 -6 0 3 14 313 -2 0 4 132 288 2 0 5 131 338 1 0 6 174 316 -2 1 0 7 157 244 -8 1 0 5 110 362 -4 0 9 125 301 -1 0 10 116 missed 0 0 11 116 318 -3 0 12 115 -298 1 0 13 93 265 3 0 14 157 237 -7 0 15 120 304 1 a 16 1:5 322 -3 0 17 175 431 5 0 15 '1110 323 2 0 19 _ 122 316 1 a 20 133 398 2 0 21 113 391 .2 0 22 155 398 -3 0 23 137 401 -7 0 MEAN 131.74 327.5 2-Sigma Uncertainty 42.9 102.6 AX 175 43212.0 MEDIAN 125 317.0 .~ 2 Page 2 of 3 ZO 39Vd dV3-onNnds 118E9GEp18 E81:V VOOP Z /OE /E0

OR14Am

-13IF TIO0N'ONLY, SUVYRQUEST ~QTNATION S.'qT S SR-A06 1.:.' ARENJLOWKtiAiQPL; CV Steam Pipe Tunnel

= . $PECIFICSAMPLN';Si/VEY INST ioNS ORt.;;. I.

cTiGMSo .. .

F. Quality Control (QC) Measurements and Comparisons Scan, Static measurements and smears were obtained. This percentage meets the 5% requirement and the OC static measurements meet the applicable acceptance critena (20%) established In Section 4.6 of E900-IMP-4520.04.

2. Discrepancies and Exceptions The technician performing the 23-688 survey inadvertently missed the unshielded static measurement of survey point #I0.
3. Final Summary:

Based on the results of the surveys performed under this SR. the CV Steam Tunnel indicates residual activity below the acceptable release limits.

M' Na-n.:.e Date _a_____

___C__s_

ujavcU Jargtj n vo-j Page 3 of 3 1T8ESE9VT8 81 :rI POOZ/OE/Eg CO 7=1"A NV3-WNnd9

Nal Static Measurement MDC Calculation Use when Backizround Count Time

  • Sample Count Time B := 1320 TSB :=2 TB:= 10 MSO:= 1.141 - I0 CF:= 176080 Ci:= 5.64 1O-4 K:= CF- MSO B(Cf.2.22. 1I012) K = 1.605 -103 Mass := 998.83 Area := 866 RB:= B Backgroundcounting rate TB L C := 2.33-B Calculationof criticallevel (page 6-34 ofMARSSIMO L C= 84.7 Criticallevel L + B = 1.4103 Any count above this value shouldbe regardedat being greaterthan background (page 6-37 of MA RSSIM).

L D := 3 + 4.65 -4 L D = 171.943 Detection limit

[3 + 3.29 -IR B SB I B ]

MDC:=- ---

K-TSB MDC 100 =2.215-103 dpm 2 MDC= 1.918-10 dpm cm Area 100 AMC 3

= 8.641-10 Results in pCi (MDC\

2.22 POi

\2222- =8651 g Mass ATACHMENT 7 - I

where:

Area = area in square centimeters B = background count in time TB (counts)

CF = conversion factor for instrument calibration (cpm/mR/h)

K = instrument efficiency and other correction factors used to convert to appropriate units Lc = critical level (counts)

LD = detection limit (counts)

Mass = modeled volume in grams MDC = minimum detectable concentration (dpm or pCi)

MSO = MicroShield output in mR/h per uCicc or uCilcm2 RB = background count rate (cpm)

TSB = sample count time (in minutes)

TB = background count time (in minutes)

ATTACHMENT -l -

-r IfZiTan Q AF INTERPOLATOR s3,,sMfw-vA*Area Factors For Structural Surfaces 7 Area factor vs Area (mA2)

I. - Y Square Meters - -

NuclIde 36 25 16 9 4 1 1jAM.241 1 1 . 2 4.1 9.2 36.2 2 C-14 -_1 r 1.4 2.2 4 8.9 35.9 y = 0.0896x' - 0.994x 3 + 3.9035x 2 - 5.9701x + 3.9833

____.___ R = 0.9994 3 co-6 12 1.5 _ 2 3.4 10.1 12 4 Cs.137 1 1.2 1.5 2.2 3.7 11.2 5 Eu.152 1 1.2 1.5 2.1 3.5 10.7 6 H3 1 1.4 2.2 4 8.9 35.8 10 10.1 7 NI-63 1 1.4 2.2 4 9 35.3 8 Pu.238 1 1.4 2.3 4 9.1 36.9 8 9 Pu-239 1 1.4 2.2 4 9 35.4 0 10 Pu-241 1 1.4 2.2 4 9 34.8 11 Sr-90 1 1.4 2.2 3.9 8.8 34.7 U<. 6 NOTE: Used where DCGL Is In dpml100 cmA2 jf1Aree faMR4 i1~12m 1 1~Is 2?'V;I,1,3 o.1 4 j*A0~tM-39*080*2 9.. 1 3.

2 I

I 9 I 4 1 6.8 2.62 0 36 25 16 9 4 1 IIIoint f f I t 6 AFM tA.aaeor 2 3.4 2.62 6.79 AREA (mA2)

ATTACHMENT 5-- l

Exhibit I Survey Unit Inspection Check Sheet ORIGINAL

-SECTION I -SURVEY UNIT INSPECTION DESCRIPTION -

Survey Unit # SS22-1, 2, 3 Survey Unit Location CV Steam Pipe Tunnel - floor, walls, and ceiling Date l 4/8/04 lTime I 100 I Inspection Team Members I D.Sarge, G. Houtz, B. Stoner, G. Woomer, D 4 T I T M. McConahy SECTION 2 -SURVEY UNIT INSPECTION SCOPE Inspection Requirements (Check the appropriate Yes/No answer.) Yes No N/A

1. Have sufficient surveys (i.e.. post remediation. characterization, etc.) been obtained for the survey unit? X
2. Do the surveys (from Question 1)demonstrate that the survey unit will most likely pass the FSS? X
3. Is the physical work (i.e., remediation & housekeeping) in or around the survey unit complete? X
4. Have all tools, non-permanent equipment, and material not needed to perform the FSS been removed? X S. Are the survey surfaces relatively free of loose debris (i.e., dirt, concrete dust, metal filings, etc.)? X
6. Are the survey surfaces relatively free of liquids (i.e., water, moisture, oil, etc.)? X
7. Are the survey surfaces free of all paint, which has the potential to shield radiation? X
8. Have the Surface Measurement Test Areas (SMTA) been established? (Refer to Exhibit 2 for instructions.) X
9. Have the Surface Measurement Test Areas (SMTA) data been collected? (Refer to Exhibit 2 for instructions.) X
10. Are the survey surfaces easily accessible? (No scaffolding, high reach, etc. is needed to perform the FSS) X
11. Is lighting adequate to perform the FSS? X
12. Is the area industrially safe to perform the FSS? (Evaluate potential fall & trip hazards, confined spaces, etc.) X I-Lb
13. Have photographs been taken showing the overall condition of the area? X e

I,-

14. Have all unsatisfactory conditions been resolved? X I NOTE: If a 'No' answer is obtained above, the Inspector should immediately correct the problem or initiate corrective actions through the responsible site department, as applicable. Document actions taken andlor justifications in the 'Comments' section below. Attach additional I sheets as necessary.

Comments:

t Response to Question #3 - Vacuuming is required prior to FSS. (especially in troughs and core boreholes).

Response to Question #4 - Items to be removed - 2 scabble guns, air hose, and misc. equipment/liquids.

Response to Question #6 - Standing water located in troughs (west end).

Response to Question #7 - Spray paint used on walls to mark survey grids.

Response to Question #10 - Some areas of ceiling and walls (West end) are inaccessible due to temporary ceiling supports and (East end) are inaccessible due to steel wall comp~osents.

Survey Unit Inspector (print/sign) G. Houtz l Date l /12/o0t Survey Designer (print/sign) I Date

C [8;N 12 EXHIBIT 3 Surface Measurement Test Area (SMTA) Data Sheet SECTION 1 - DESCRIPTION SMTA Number SMTA-SS-22-1 Survey Unit Number SS22-1 SMTA Location CV Steam Pipe Tunnel Survey Unit Inspector I G. Houtz Date 4/8/04 Time 1120 SECTION 2 - CALIPER INFORMATION & PERSONNEL INVOLVED Caliper Manufacturer Mitotoyo I Caliper Model Number (D-6 C CS Caliper Serial Number 763893 Calibration Due Date (as applicable) N/A Rad Con Technician IG. Houtz Date 4/8/04 Time l 1120 Survey Unit Inspector Approval I G. Houtz I Date 1120 SECTION 3 ESUREMENT RESULTS SMTA Grid Map & Measurement Results in Units of mm Comments (Insert Results in White Blocks Below) Comments 1 7 13 19 25 31

  • Entire floor has been scabbled (1 - 2" depth) 021 144 2.97 2.28 1.05 2.5

. . - - -.-

  • East end has steel plate installed with bracing 2 8 14 20 26 32 anchored into floor. Brace obstructs floor access 18 1. 1.44 09 0.9 135 (5' length x 8 width). Plate installed within the 8 . i4 21. 0 135 plane of the floor, therefore obstructs survey.

3 9 15 21 27 33 10 23 1.42 1.03 1.47 1.25 .32

  • Troughs scabbled into floor at wall seams 4 10 16 22 28 34 require special survey considerations

- 2.94 4.82 1.18 2.31 1.48 1.32 8 11 17 23 29 36

  • Core bore holes pose same survey considerations 1.99 9.11 1.91 1.62 044 1.94 6 12 .18 24 30 36
  • Drain trench has been chiseled/scabbled into a L 0.74 1.71 1.4 1.37 263 1.46 'V" shaped configuration. Poses same survey

- - considerations Average Measurement - 1.86 mm Additional Measurements Required

  • 3 (three) 6" core boreholes spaced evenly along length of floor. Depths between 1'-4" to 2'-6.
  • 1 (one) trough along South wall. 8" wide x 24'-2" length. Depth between 1.5 to 2".
  • 1 (one) trough along North wall (west end). 5" wide x 7'-2'. Depth between 1-1.5".

. 1 (one) trough along North wall (east end). 4" wide x 12' length. Depth between 1-1.5".

. Drain trenching (west end). 10" wide x 5'-6* length x 8" depth and 10" wide x 4' length x 8" depth.

  • 4 (four) 3" core boreholes. 3" depth.

EXHIBIT3 Surface Measurement I -st Area (SMTA) Data Sheet 0 tIGJUINAL SECTION 1 -DESCRIPTION SMTA Number SMTA-SS-22-2 and 3 Survey Unit Number SS22-2 and 3 SMTA Location CV Steam Pipe Tunnel (Walls and Ceiling)

Survey Unit Inspector G.Houtz Date 4/8/04 Time 1100 SECTION 2 - CALIPER INFORMATION & PERSONNEL INVOLVED Caliper Manufacturer Mitotoyo I Caliper Model Number CD-6 CS Caliper Serial Number 763893 Calibration DueDate (as applicable) N/A Rad Con Technician lG. Houtz Date 4/8/04 Time l 1120 Survey Unit InspectorApproval I G. Houtz / Date 1100 SECTION -3 Al RESULTS SMTA Grid Map & Measurement Results in Units of mm Comments (Insert Results in White Blocks Below) 1 7 13 19 25 31

  • Wall surfaces are smooth except for areas o o 0 0 0 0 disturbed by scabbling, core boring, and the removal of uni-strut.

2 8 14 20 26 32 o o 0. East end has steel plate installed with bracing anchored into floor. Plate installed within the 3 9 15 21 27 33 plane of the walls, therefore obstructs survey. fryI

- - - - - -

  • Some wall areas are not accessible currently. CD_

'>V 4 10 16 22 28 34 Steel plate blocks access.

o o 0 0 0 0 . Uni-strut at far west end has concrete filler in 5 11 17 23 29 26 three locations. Length is 3', depths between 1.5 to 2-. Total length of uni-strut in tunnel is i-% o o 0 0 0 0 70'-6'. Uni-strut depth is 2".

6 12 I.. . is 18 24 2 30 30Ceiling 36 surfaces are smooth except for form o o 0 0 0 0 separation crack roughly mid-point of tunnel length. Depth is 0.5.

Average Measurement - 1.86 mm Additional Measurements Required NORTH WALL

. 7 (seven) vertically installed uni-struts 1' length spaced 6' on center along ceiling line.

. 7 (seven) vertically installed uni-struts 1' length spaced 6' on center along floor line.

  • 2 (two) 3- core boreholes. Depth is 2".
  • 1 (one) steel plate installed at east end. Poses special survey considerations.

SOUTH WALL

. 7 (seven) vertically installed uni-struts 5' length spaced 6' on center (top at ceiling line).

. 1 (one) trough 7' length x 8- high x 3- depth (middle of wall at floor line).

  • 1 (one) trough 4' length x 16- high x 3- depth (west end at floor line).
  • 1 (one) trough 16- length x 10- high x 2- depth (west end at floor line).
  • 1 (one) chiseled hole 30' high x 1' wide (far west end at uni-strut removal location)

CEILING

  • Form separation crack located mid-point. Depth is 0.5'
  • 5 (five) north-south oriented Uni-struts 4' length spaced 6' on center.
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