ML20206S233
| ML20206S233 | |
| Person / Time | |
|---|---|
| Site: | 07000364, 07003085 |
| Issue date: | 01/19/1999 |
| From: | External (Affiliation Not Assigned) |
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| References | |
| NUDOCS 9901280234 | |
| Download: ML20206S233 (11) | |
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B&W SERVICES, INC.
l PARKS FACILITY l
l FINAL SURVEY REPORT l
1996 Remediated Area of Outfall 3 REVISION 0 JANUARY 19,1999 i
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9901280234 990119 ~
PDR ADOCK 07000364.
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9 TABLE OF CONTENTS 1.0 Introduction
2.0 Background
2.1 Outfall 3 description 2.2 Radiological History 2.3 Remediation of Outfall 3 2.4 Isotopic Resolution 3.0 Final Survey Methodology 3.1 Area Preparation 3.2 100% Walkover Survey 3.3 Final Sampling 4.0 Final Survey Data Package and Analysis 5.0 References ATTACHMENTS i
J Table 1 1996 Remediated Area of Outfall 3 - Final Survey Report i
Volumetric Soil Sample Results with Sum-of-the-fraction Calculations Figure 1 Parks Facilities Project Unit Boundaries Figure 2 Pre-remediation Sample Locations & Results Figure 3 Areas Remediated in 1996 at Outfall 3 Figure 4 Final Survey Locations at Outfall 3 Parks Facility FinalSurveyReport Rev.0 1996RemediatedArea ofOutfall3
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B&W SERVICES, INC.
l PARKS FACILITY I
FINAL SURVEY REPORT 1996 Remediated Area of Outfall 3 1.0 Introduction This report provides the final survey information and data to suppon the release of the 1996 l
remediated area of Outfall 3 at the Parks Township Facility under the site special nuclear l
material (SNM) license, SNM-414.
l The scope of this Final Survey Repon is limited to the area remediated in 1996 that requires j
stabilization (backfill) prior to further characterization /remediation efforts. A full Final Survey 1
l Repon for Project Unit D, including the remainder of the Outfall 3 area, will be provided to the Nuclear Regulatory Commission (NRC) upon completion of the work described in the "Outfalls l
2 and 3 Characterization and Remediation Plan", Rev. O, October 15,1998. The release of this l
portion of Outfall 3 for unrestricted use allows B&W Services, Inc. (BWSI) to stabilize the area l
providing:
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- 1. Increased worker safety during the remainder of the characterization and remediation efTorts of Outfall 3.
- 2. Opportunities to remove the present erosion and sedimentation controls currently in place at Outfall 3 (as authorized by our general permit) as schedule and weather conditions allow.
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2.0 Background
l 2.1 Outfall 3 description l
Project Unit D, in which Outfall 3 residn is located at the western edge of the propeny and consists of approximately 2.5 acres (reference Figure 1). Project Unit D is underlain by three Parks Facilities permitted outfalls (National Pollutant Discharge Elimination System stormwater Outfalls 2,3, and 4) discharging to the Kiskiminetas River. BWSI discontinued all non-storm l
water discharges to the outfalls in 1976. The only sources of discharge from 1976 to date are storm water runoff.
l Although the majority of Project Unit D is classified as unaffected, the Outfall 3 area is considered affected based on its radiological history and remediation (reference section 2.2 l
below) and was therefore, sampled and surveyed as such.
Reference sections 2 0 and 3.0 in the " Parks Facilities Characterization Repart" for physical characteristics and detailed history of the Parks Facilities. Reference the " Parks Facilities Decommissioning Project - Outfalls 2 & 3 Characterization and Remediation Plan" for background and site facility description.
Parks Facilnty FmalSurveyReport Page1ofJ Rev.0 1996 RemediatedArea ofOutfall 3
e 2.2 Radi&gical history
, Elevated concentrations of radionuclides were detected in the soils at Outfall 3, based on the data that w'as obtained during the 1995 Characterization Program. Americium and uranium were the primary radionuclides ofinterest. Co" and Cs were also detected in some samples.
Figure 2 shows the locations where elevated concentrations, to depth, were detected. Soil between zero and three foot in dep"th in the general vicinity of Outfall '.:ontained the hi hest F
radionuclide concentrations. Am was detected a't a maximum concentration of 1,532 pCi/g.
Co" and Cs"' were detected at maximum concentrations of 1.51 pCi/g and 216.15 pCi/g, respectively. The maximum total uranium concentration was 35.14 pCi/g.
2.3 Remeciation of Outfall 3 Following the site characterization in 1995, BWSI determined that some limited soil remediation was necessary near Outfal! 3. BWSI obtained authorization from the NRC to perform remediation activities at Outfall 3 prior to the Decommissioning Plan being approved based on th: general public's accessibility to the riverbank and outfall area.
Remediation of the riverbank area in the vicinity of Outfall 3 was p;rformed in August 1996 (reference Figure 3). The immediate vicinity of Outfall 3 was remediated by means of an extended reach backhoe. During the remediation at Outfall 3 area, the backhoe essentially
.emoved al! soil sediment down to bedrock. During the remediation work, additional samples were taken along the drain path of the outfall to verify that all soil that exceeded the site cleanup criteria (as specified in section 3.2 of the Parks Facilities Decommissioning Plan) was removed and to also establish the isotopic composition of the Outfall 3 soils. Reference section 2.4 below for isotopic reso;ution.
In-process, post-remediation characterization data for this area showed that the area was ready for final survey. The results of these in-process samples taken at biased locations in the remediated area (shown in Figure 4) were previously reported in the " Parks Facilities Decommissioning Project-Outfallr 2 & 3 Characterization and Remediation Plan" If the results of these in-process samples were factored into the data from the Final Survey samples, it would not alter the conclusion that the soils from the r: mediated area are less than the guidelines to release the area for unrestricted use.
2.4 Isotopic Resolution BWS7 reviewed several different statistical approaches to determining the isotopic ratio for Outfall 3. These techniques included mean values, weighted mean,90% upper confidence level, and the 95% upper confidence level. Based on the 90% upper confidence level, BWSI requested, in letter dated 9/17/98 to the NRC, that the isotopic ratios of 1.89 and 12.9 for plutonium alpha to americium-241 and plutonium-241 to americiu.n-241, respectively, be approved for use in the survey and release of Outfall 3.
l The NRC staff reviewed the information submitted by BWSI and concluded that using 12.9 as the ra:io of Am-241 to Pu-241 was appropriate. However, the stafTconcluded that the proposed ratio of 1.89 for plutonium alpha to Am-241 ratio was not appropriate. The NRC staff believed Parks Facdoty FmalSurwyReport Page 2 oII Rev. 0 1996 RemedsatedArea ofOutfall3 l
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2 that due to the wide tr3e of observed values, the use of any mean value based on the und:rlying l
l value. does not provide a sufficient level of confidence that the actual concentration of l
plutonium in the sample can be estimated accurately. The staff concluded that using the value
' that c6rresponds to the 90* percentile of the underlying distribution of the ratios is more l
appropriate. The NRC staff recommended the Pu alpha to Am-241 ratio to be 2.82. BWSI accepted this recommendation.
The final survey data calculations (see Table 1) were performed using the ratios approved by the NRC of 12.9 for Am-241 to Pu-241 and 2.82 for Pu alpha to Am-241. Reference the isotopic resolution letters dated September 17,1998 and OctoL.; 20,1998 for additional information.
3.0 Final Survey Methodology 3.1 Area Preparation Project Unit D is gridded in 10 meter by 10 meter grids as part of the site grid system which is based on the United States Geological Survey (USGS) area markers. The Outfall 3 remediated 2
area is a smaller area within a site grid (reference Figure 3), therefore it is less than the 100m required by the Parks Facilities Decommissioning Plan. A standard five point systematic sampling pattern was applied to the remediated area per section 5.1.3 of the Parks Facilities l
Decommissioning Plan.
3.2 100% Walkover survey A 100% walkover survey with a Sodium lodide (Nal) scintillation survey meter was performed on all accessible portions of the remediated area to identify any locations of elevated activity.
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[ Note: some areas were not accessible for survey due to being under water). The 100% area surveys confirmed the absence of any elevated locations. In addition, a gamrna measurement, l
using a R-meter was made above the locations where soil samples were to be taken for final l
survey. The gross values taken were between 8.7 pR/hr and 11.2 R/hr with an average of 9.8 pR/hr. Note that with background subtraction (background averaging 9.8 as stated in the Parks Facilities Decommissioning Plan) these walkover surveys are well below the guidelines of 10 R/hr for release for unrestricted use.
3.3 Final Sampling i
l Soil samples were taken based upon a 5-point systematic grid pattern as discussed in section 3.1 above (see Figure 4). This final survey sampling was performed in accordance with section 5 of the Parks Facilities Decommissioning Plan. These samples were forwarded to the BWSI Analytical Laboratory for analysis as discussed below. The NRC Region I inspector was on-site during the final sampling activities.
Parks Facshty RnalSurvey Report Page3of.I Rev.0 1996 Remedsated Area ofOutfaH 3
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4.0 Final curvey dita pack ge cnd cn:ly;is Gamma spectroscopy for the volumetric measurements was performed by BWSI Analytical Laboratory using a Canberra Nuclear Systems Thin Window (beryllium) Intrinsic Germanium (solid state) Detector.
l Analysis of the resulting volumetric sample data was performed using the sum-of-the-fractions methodology as described in our approved Decommissioning Plan. The sum-of-the-fractions (also known as the sum-of-the-ratios) were calculated using either the sample mean, or % the sample mean if the mean was MDA/non-detect. This generates a conservative number. The calculations included contributions from total uranium, Am-241, Pu-alpha and Pu-241. As discussed in section 2.4, the agreed upon isotopic ratios were used to determine plutonium activity from Am-241 gamma spectrometry results. Each isotope value was divided by its respective soil limit and all of these calculated values were added together.
NUREG/CR-5849, Appendix A states that any isotope that is <10% ofits guideline value does l
not need to be included in the sum-of-the-fraction calculations. BWSI has opted to take a more conservative approach. If a radionuclide is less than 10% ofits respective guideline value AND is not detected in a sample, it is considered not to be present; i.e., it is reponed as zero. Non-l detects are considered to be present at % the sample mean. For all results above the detection limit for the sample, the sample mean was used. Reference footnote 1 at the bottom of Table 1.
The resulting sum-of-the-fractions for each individual sample location and the average of the grid are provided in Table 1. These sums meet the guidelines stated in our approved Decommissioning Plan, along with those in NUREG/CR-5849 that states that the affected area sum-of-the-fractions must total less than or equal to one.
Once given authorization to release this section of Outfall 3 for unrestricted use, BWSI proposes to backfill the sampled area at Outfall 3 using riprap (rocks) and return this ponion of the riverbank to its natural environment.
5.0 REFERENCES
- Parks Facilities Decommissioning Plan, Rev. 3.1, September 15,1998 Parks Facilities Characterization Repon, Rev. O, April 30,1996 Parks Facilities Decommissioning Project - Outfalls 2 & 3 Characterization and Remediation Plan, Rev. O, October 15,1998 i
"Outfall 3 isotopic scaling factor resolution" letter, BWS1 to NRC, September 17,1998 Resolution to Isotopic Rations letter, NRC to BWSI, October 20, 1998 NUREG/CR-5849 Manual for Conducting Radiological Suiveys in Suppon of License i
Termination Parks Facolorv FmalSurwyReport Page 4 of 4 Rev.0 1996 RemedsatedArea ofOutfall3
I TABLE 1 1996 Remediated Aree of Outfelt 3 - Final Survey Report Volumetric Soil Sample Results witte Sum-of-he-Fractiors Calculations c
P rt 1: Showing gross values and adjusted values Am-241 Co-40 Co-137 Total Uranium PU(Alpha)
PU-241 Gross Ad> mend Groom Aquated Gross Adjueled Gross A4usend pCWg Sample #
X Y
pcus oues pcus (1) ouel pcvs ousi pcus (1) ousi pcm ousi pcvg(1x2) ouse pcVe ousi (tX2) ound (AM241'2.82)
(AM241*12 9) 01.P2550-001 153.5
-17 0.15 U
0.00 U
0.05 U
0.00 U
0.03 U
0.00 U
4.30 0.30 0.000 0.000 01.P2253-001 152
-16 0.52 0.52 0.04 U
0.00 U
0.14 0.00 2.29 0.00 1.466 6.708 01.P2552-001 155
-16 0.13 0.13 0.04 U
0.00 U
0.05 0.00 3.16 0.00 0.367 1.677 01.P2554-001 152
-18 5 0.19 0.19 0.04 U
0.00 U
0.05 U
0.00 U
2.86 0.00 0.536 2.451 01.P2555-001 155
-18.5 4.00 4.00 0.04 U
0.00 U
0.13 0.00 3.17 0.00 11.280 51.600 P:rt 2: Showing adjusted values divided by their respective limits followed by the sum-of-the-fraction calculations.
SUM OF Grid I
Sample #
X Y
Am.241/30 PU R y25 PU241t1250 coeOS cs137i15 TOTAL. urso FRACTIONS Average 01.P2550-001 153.5
-17 0.000 0.000 0.000 0.000 0 000 0.01G 0.010 01.P2253-001 152
-16 0.017 0 059 0.005 0.000 0.000 0.000 0.081 01.P2552-001 155
-16 0 004 0.015 0.001 0.000 0.000 0 000 0.020 i
01.P2554-001 152
-18 5 0 006 0.021 0 002 0.000 0.000 0 000 0.030 I
I 01.P2555-001 155
-18.5 0.133 0.451 0.041 0.000 0 000 0 000 0.62s 0.153 i
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- Tug *e s Measurements:
5 Average:
0.15 Standard Deviation:
0.24 Mwwnum Value:
0 01 Maximum Value:
0 63 Confidence interval:
0.23 95% Upper Confid Level:
0.38 Guideline Value:
1.00 f
Meets Criteria:
YES (1) Below describes the sum-of-the-fraction calcula. -n methodology used by BWSI:
- If a radionuclide is not detected in a sample (LLD) and the detection limit was less than 10% of the respective guideline value, it is not considered to be present, i.e., it will be reported as zero for the sum-of-the-fraction calculation.
- The guideline value used for Am-241 is scaled to less than 10% of the respective guideline value to ensure that TRU (alpha) would also be less than 10% of its
[
i guideline to relelse for unrestricted use.
- If the detection limit is 10% or above, nondetects are considered to be present at 1/2 the sample mean. For all results above the detection limit for the sample, the sample mean is used.
(2) Background of 4.0 pCi/g for Total Uranium and 0.2 pCi/g for Cs-137 was subtracted from the gross values. If this resulted in a negative value, then zero was used.
i U = LLD = Non-detect Page 1 of 1 l
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OUTFALL 3 ST
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I LEGEND PRE-REME[1ATION SAWLE LOCATIONS & RESULTS ll ORGINAL (UTFALL '3 PIPE 297 pct /g (19951 OUTFALL *3 RE-ROUTI:
1532 pCa/g (19951
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NOTE: SANPLE RESULTS ARE CONCENTRATIONS
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227I C /g m) p 0F AKRICIUM-241.
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84 pC /g (1995) 0 3 eC /.
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-20 KISKIMINETAS RIVER 140 150 160 FINAL SURVEY REPORT Note: This is e color coded drawing. Using OUTFALL 3 o block and white copy of this drawing could D=g.N
405-0128-A lead to e misunderstanding of the conditions shown, or a misinterpretation of the data.
D***1/20/99 Rev.0 ELEVATED CONCENTRATIONS OF Am 241, Co 60, Cs 137 AND TOTAL U, TO DEPTH, WERE DETECTED FIGURE 2
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-is OUTF#LL 3 LEGEND OUTFALL 3
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-28 KISKIMINETAS RIVER 16e 148
- 50 FINAL SURVEY REPORT OUTFALL 3 Note
- This is a color coded drawing. Using a black and white copy of this drewang could g9' g 495-8128-A leed to a misunderstanding of the conditions Dow shown. or a misinterpretation of the data.
1/29/99 Rev.O AREAS REMEDIATED IN 1996 AT OUTFALL 3 FIGURE 3 l'
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-18 LEGEND OUTF/LL 3 J
Oe FINAL SURVEY RADIOLOGICAL SAMPLE LOCATIONS OUTFALL 3 DIVERS 13N PIPE 0
$ BIASED POSTREMEDIATION SAMPLE LOCATIONS (PREVIOUSLY SUBMITTED IN THE ' PARKS FACILITIES DECOMMISSIONING PROJECT-0UTFALLS 2 & 3
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CHARACTERIZATION AND REMEDIATION PLAN')-
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148 ISO FINAL SURVEY REPORT OUTFALL 3 Note: This as a color coded drawing. Using Dw9 No* 405-9128-A a block and white copy of this drawing could leed to a misunderstanding of the conditions shown, or e missnterpretetson of the date.
U*** 1/28/99 Rev.0 FINAL SURVEY LOCATIONS AT OUTFALL 3 FIGURE 4
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