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RS-TD-313196-005, Rev. 0, LACBWR Open Air Demolition Limits
	ML19007A043
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	11/23/2015
From:	Farr H; Energy Solutions
To:	; Office of Nuclear Material Safety and Safeguards
	M VAALER DUWP
Shared Package
ML19007A031	List: ML19007A032; ML19007A033; ML19007A034; ML19007A035; ML19007A036; ML19007A037; ML19007A038; ML19007A039; ML19007A040; ML19007A041; ML19007A042; ML19007A043; ML19007A044; ML19007A241; ML19007A261;
References
	RS-TD-313196-005, Rev 0
	Download: ML19007A043 (116)
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RS-TD-313196-005 Revision 0 Page 2 of 116 Summary of Changes in this Revision:

Rev. 0 -Initial issuance.

RS-TD-313196-005 Revision 0 Page 3 of 116 Table of Contents

1.

PURPOSE............................................................................................................................... 5

2.

DISCUSSION OR BACKGROUND..................................................................................... 5 2.1.

Off-Site Dose Impact Method............................................................................................. 5 2.2.

Radiological Objectives for Open Air Demolition.............................................................. 6 2.3.

Radiological Control Indicator Method and Pre-Test Values............................................. 6

3.

CALCULATIONS.................................................................................................................. 8 3.1.

Summary of Connecticut Yankee Removable Contamination Limit Evaluation................ 8 3.2.

Connecticut Yankee Concrete Demolition Test Results..................................................... 8 3.3.

Summary and Conclusions from Connecticut Yankee Concrete Demolition Test Results........................................................................................................................ 28 3.4.

LACBWR Concrete Gamma Spectroscopy Results.......................................................... 31

4.

CONCLUSION..................................................................................................................... 32

5.

REFERENCES..................................................................................................................... 33

6.

ATTACHMENTS................................................................................................................. 34 6.1..A - CY Test 1 B Charging Pump Cubicle Survey................................... 35 6.2..B - CY Test 1 B Charging Pump Cubicle Sample Data.......................... 39 6.3. - CY Test 2 B Charging Pump Cubicle Survey and Sample................... 42 6.4..A - CY Test 3 B Charging Pump Cubicle Survey................................... 50 6.5..B - CY Test 3 B Charging Pump Cubicle Sample Data.......................... 54 6.6..A - CY Tests 4a and 4b B Charging Pump Cubicle Survey.................... 62 6.7..B - CY Tests 4a and 4b B Charging Pump Cubicle Sample Data........... 69 6.8..A - CY Tests 5 Metering Pump Cubicle Survey and Sample Data............ 87 6.9..B - CY Tests 5 Metering Pump Cubicle Survey and Sample Data............. 93 6.10. Attachment 6.A - CY Tests 6 Metering Pump Cubicle Survey....................................... 101 6.11. Attachment 6.B - CY Tests 6 Metering Pump Cubicle Sample Data.............................. 107 6.12. Attachment 7 - MicroShield Model Embedded Cs-137 for Half Inch Thick Concrete Source............................................................................................................... 115

RS-TD-313196-005 Revision 0 Page 4 of 116 List of Tables Table 1 - Summary of Offsite Dose Evaluations...................................................................................... 5 Table 2 - Original Connecticut Yankee Contractual Radiological Control Indicators............................ 7 Table 3 - Test 1 Pre-remediation Survey Data....................................................................................... 10 Table 4 - Test 1 Post Remediation Survey Data..................................................................................... 11 Table 5 - Test 1 Debris Gamma Spectroscopy Results and Scaled Air Sample Results........................ 11 Table 6 - Test 2 Pre-remediation Survey Data....................................................................................... 12 Table 7 - Test 2 Post-remediation Survey Data...................................................................................... 13 Table 8 - Test 2 Debris Gamma Spectroscopy Results and Scaled Air Sample Results........................ 14 Table 9 - Test 3 Pre-remediation Survey Data....................................................................................... 14 Table 10 - Test 3 Post Remediation Survey Data................................................................................... 15 Table 11 - Test 3 Debris Gamma Spectroscopy Results and Scaled Air Sample Results...................... 16 Table 12 - Test 4a Pre-Remediation Survey........................................................................................... 17 Table 13 - Test 4a Post Remediation Survey Data................................................................................. 18 Table 14 - Test 4a Masslin Debris Gamma Spectroscopy Results and Scaled Air Sample Results...... 19 Table 15 - Test 4a Debris Gamma Spectroscopy Results and Scaled Air Sample Results.................... 19 Table 16 - Test 4b Pre Remediation Survey Data.................................................................................. 19 Table 17-Test 4b Post Remediation Survey Data.................................................................................. 20 Table 18 - Test 4b Maslin Gamma Spectroscopy Results...................................................................... 21 Table 19 - Test 5 Pre-remediation Survey Data..................................................................................... 22 Table 20 - Test 5 Post Remediation Survey........................................................................................... 23 Table 21 - Test 5 Air Sample Data and Debris Gamma Spectroscopy Results...................................... 25 Table 22 - Test 6 Pre-remediation Survey Data..................................................................................... 25 Table 23 - Test 6 Post Remediation Survey Data................................................................................... 26 Table 24 - Test 6 Air Sample Data and Debris Gamma Spectroscopy Results...................................... 28 Table 25 - Summary of CY Demolition Test Air Sample Results......................................................... 28 Table 26 - Summary of Test Result Maximum Dose Rates and Maximum Beta/Gamma Removable Contamination................................................................................................... 30 Table 27 - Summary of Test Result Average Dose Rates and Average Cubicle Beta/Gamma Removable Contamination................................................................................................... 30 Table 28 - Summary of Post Remediation Gamma Spectroscopy Results............................................. 31 Table 29 - La Crosse Highest Concrete Core Sample and Average....................................................... 31 Table 30 - MicroShield Dose Rate Model Parameters........................................................................... 32 Table 31 - Recommended Open Air Demolition Limits........................................................................ 33

RS-TD-313196-005 Revision 0 Page 5 of 116

1.

PURPOSE This Technical Support Document (TSD) provides the basis for the Open Air demolition Radiological Control Indicators that are applied to buildings and structures for open air demolition. These indicators are designations used to characterize the acceptable removable contamination and concrete contact deep dose equivalent radiation levels that are acceptable for open air demolition. Structural materials other than concrete, such as metals, do not tend to sorb radionuclides and are not evaluated for acceptable embedded total contamination dose rates. Activated materials are also not evaluated under this TSD and should be evaluated and modeled separately using the radiological mix of nuclides present. The radiological control indicators evaluated in this TSD will ensure that open air demolition can proceed without creating a Contaminated Area, requiring radiological PPE, or resulting in environmentally significant airborne radioactivity releases.

2.

DISCUSSION OR BACKGROUND 2.1.

Off-Site Dose Impact Method Several decommissioning facilities established open air demolition criteria based upon the offsite dose impact from airborne radioactivity released during demolition. The facilities (1) (2) (3) used a conventional nuclear industry approach for safety related bounding calculations to establish limits for open demolition. This approach calculates the acceptable levels of fixed and removable contamination based upon re-suspension factors and site specific ground release dispersion models (X/Q). The limits at these facilities are based upon the calculated member of the public dose at the site boundary using Off Site Dose Calculation Manual (ODCM) (4) methodologies for a ground level airborne radioactivity release. As shown in Table 1 this approach results in relatively high levels of removable contamination being acceptable for open air demolition with minor off-site dose consequences.

Table 1 - Summary of Offsite Dose Evaluations Facility Removable Contamination Level Total Contamination Level Offsite Dose (mrem)

Control Criteria Summary SONGS Unit 1 N/A 1.5E+6 dpm/100 cm2 1.7E-3 instantaneous release

> 25,000 dpm/100 cm2 removable of 250,000 dpm/100 cm2 total requires contamination control measure (e.g.,

fixative, local ventilation, enclosures)

Air samples not to exceed 0.05 DAC beta/gamma or >MDA alpha. Personnel contamination controls below 25,000 dpm/100 cm2 required.

Maine Yankee 5000 dpm/100 cm2 beta/gamma 20 dpm/100 cm2 alpha 500,000 dpm/100 cm2 beta/gamma 100 dpm/100 cm2 alpha 6.66E-2 entire decommissioning based upon estimated surface area of buildings and average contamination levels Could result in up to 4600 dpm/100 cm2 deposition within 50 feet of demolition with 10% plate out. May require layer of soil to be removed for FSS. Will have to be managed for equipment release.

Yankee Rowe Average < 5000 dpm/100 cm2 2E-3 mrem/yr max organ Maintain work zone air concentrations less than 0.25 DAC to maintain member of public dose below 0.2 mrem/yr. No other limits specified.

RS-TD-313196-005 Revision 0 Page 6 of 116 Similar offsite dose evaluations of airborne radioactivity ground releases were performed at Connecticut Yankee (CY) as documented in reference (5). This TSD evaluated the offsite dose consequences of an instantaneous release of a 2000 DAC Am-241 source term due to a HEPA filter failure at CY. The calculated member of the public dose at the unrestricted area boundary was 1.77 mrem for a release of this magnitude. Similarly the LACBWR Post Shutdown Decommissioning Activity Report (PSDAR)

Accident Analysis (6) evaluated a series of accidents with potential for source term releases to the environment. These calculations assumed that 30% of the remaining estimated approximately 1.175 Ci of radioactive material present on plant surfaces in 2014 was released (e.g., 0.35 Ci, 7.83E+11 dpm) through the plant stack as airborne radioactivity. Resulting doses at 50, 70 and 120 meters were calculated. The maximum dose was 65 mrem at 50 meters. (6) Thus, demolition and sizing of contaminated structures and materials can be performed at high contamination levels without significantly increasing the radiation exposure of members of the public at the site boundary.

2.2.

Radiological Objectives for Open Air Demolition Other objectives, in addition to the member of the public dose at the site boundary, should be considered when establishing Radiological Control Indicators for open air demolition of structures. The off-site dose based approach does not address additional considerations such as:

Allowing open air demolition without instituting Contaminated Area controls such as, posting, clearance, and protective clothing controls in outside areas.

Impact of the liberated source term on soil concentrations (Derived Concentration Guideline Levels - DCGLs) required for License Termination.

Ensuring radioactivity concentrations in high conductivity, high pH demolition water remain low enough to release without use of demineralizers. Groundwater intrusion during demolition at Connecticut Yankee required large quantities of water to be processed and released as part of the demolition process due to groundwater intrusion.

Given the above considerations, the objectives of the open air demolition limits are the following:

Ensure ground level airborne radioactivity levels and off-site dose consequences remain ALARA and within regulatory limits.

Ensure demolition liquid concentrations remain at levels which can be collected, processed and released using plant water treatment systems and discharge points.

Minimize the spread on contamination within the site boundary such that there is not a significant effect on groundwater or the scope of soil remediation required for License Termination.

Ensure open air demolition activities can be conducted using conventional demolition techniques with minimal radiological restrictions or controls (e.g., without area, equipment or personnel contamination controls).

2.3.

Radiological Control Indicator Method and Pre-Test Values Initial pre-test Radiological Control Indicators (RCI) similar to those at other facilities were developed at Connecticut Yankee as part of the request for proposals and contract agreements with the Decommissioning Operation Contractor (DOC). The RCIs provided the contractual basis for radiologically acceptable levels for various phases and types of structure demolition. These indicators

RS-TD-313196-005 Revision 0 Page 7 of 116 were used to clearly specify contractual requirements for the demolition of buildings with regards to acceptable levels of fixed and removable contamination. The CY RCIs were defined as the following:

R1 was designated for structures where the radiological contamination is indistinguishable from background. This designation was only applied to structures outside a Radiologically Controlled Area (RCA) of the facility. Prior to Release of a structure for R1 demolition, an Unconditional Release Survey (URS) was completed. The URS provides data to demonstrate that secondary side structures are suitable for unconditional release from the Site, (i.e., free released as clean materials). This material is designated as Secondary Side Waste. For structures designated as R1, no radiological controls were required during demolition.

R2 was designated for structures that reside within the RCA where the radiological contamination is greater than the R1 levels, but less than the limits specified as being suitable for open air demolition (R2Open Air) or interior demolition (R2Interior). When the structure is scheduled for open air exterior demolition, R2Open Air controls are instituted mainly to protect the environment and public whereas R2Interior controls are instituted to protect the worker and to limit the potential for spread of contamination to other interior areas. Prior to structure turnover for R2 demolition, a Contamination Verification Survey (CVS) was completed to verify that pre-demolition contamination levels of primary side structures were below the limits established for open air or interior demolition. The resulting demolition debris was designated as Primary Side Waste. For structures designated as R2, limited radiological controls were required, including but not limited to intermittent health physics coverage, misting, air sampling, periodic surveys, personnel protective equipment and personnel contamination monitoring upon exiting the area.

R3 was designated for structures, or portions of structures, within the RCA where the radiological conditions exceed the R2Open Air or R2Interior criteria. This material was also designated as Primary Side Waste. For structures designated as R3, significant radiological controls were required. These included but were not limited to controls such as constant health physics coverage, application of surface fixatives, use of tents and HEPA ventilation, more intense air and surface sampling and personnel protective equipment such as respirators.

Table 2 shows the original pre-test radiological criteria for fixed and removable contamination levels adopted for demolition at CY. These values were based upon regulatory requirements for R1 structures (e.g., no detectable licensed material for unrestricted release of materials) and estimates of the potential radiological consequences and controls for the demolition. Similar to other facilities, they allowed relatively high R2Open Air contamination levels on structures.

Table 2 - Original Connecticut Yankee Contractual Radiological Control Indicators Demolition Category Total Surface Contamination Loose Surface Contamination

/

R1 Non Detectable Non Detectable Non Detectable R2 Open Air 500,000 dpm/100cm2 Max 50,000 dpm/100cm2 Avg 1000 dpm/100cm2 Max 20 dpm/100cm2 Max R2 Interior 10 mR/h Contact 10,000 dpm/100cm2 Max 200 dpm/100cm2 Max R3

>R2 and <100 mR/h Contact

>R2 and <100,000 dpm/100cm2 Max

>R2 and <5000 dpm/100cm2 Max

RS-TD-313196-005 Revision 0 Page 8 of 116 In 2004 Connecticut Yankee released the Decommissioning Operations Contractor (DOC) and resumed direct management of the decommissioning. Thus the contractual RCI criteria in Table 2 were no longer relevant. However, radiological criteria for building demolition still needed to be established. To ensure the criteria in Table 2 would meet the open air demolition objectives, testing was performed on concrete surfaces in the Primary Auxiliary Building (PAB) to determine empirically the proper R2Open Air fixed contamination levels and the Table 2 removable contamination levels were reevaluated. The objective of the test was to determine the appropriate contact count rate or dose rate on concrete at which the concrete could be demolished or sized and meet the four objectives summarized at the end in Section 2.2 in this document. The results of the evaluation and tests are summarized in Section 3.3 of this TD. The supporting data and surveys from CY Technical Support Document (7) are provided as attachments to this TD.

3.

CALCULATIONS 3.1.

Summary of Connecticut Yankee Removable Contamination Limit Evaluation During plant operations and throughout the decommissioning all of the open air demolition objectives in Section 2.2 were routinely met by maintaining the loose surface contamination levels below 1000 dpm/100 cm2 beta/gamma and 20 dpm/100 cm2 alpha on items stored or transported in outside areas.

Any materials released off-site were surveyed to less than detectable levels as defined by Nuclear Regulatory Commission guidance. The required sensitivity levels for unrestricted release are no detectable contamination with minimum detectable activities under 5000 dpm/100 cm2 beta/gamma total, 1000 dpm/100 cm2 beta/gamma removable and 20 dpm/100 cm2 alpha removable.

In practice, containers, tools, equipment were decontaminated down to less than detectable contamination levels that range from 30 dpm/100 cm2 to several hundred dpm/100 cm2 depending on the survey method, instrumentation, and background before they are released from buildings. The impracticality of instituting Contaminated Area Controls in outside areas, in addition to the regulatory scrutiny that such controls would illicit, is simply outweighed by the relative ease with which removable contamination can be removed or fixed. Removable contamination is easily locked down by applying a fixative such as latex paint prior to demolition. It was determined that there was already sufficient precedent and experience to justify use of these practices as acceptable targets for R2Open Air removable contamination limits. To meet the above objectives removable beta gamma contamination limits for open air demolition should not exceed 1000 dpm/100 cm2 and should on average be less than 300 dpm100 cm2. The removable alpha contamination should not exceed 20 dpm/100 cm2.

3.2.

Connecticut Yankee Concrete Demolition Test Results The remaining question was what levels of fixed contamination would be acceptable to maintain work area loose surface contamination levels below 300 dpm/100 cm2 beta/gamma and 20 dpm/100 cm2 alpha during demolition. Maintaining loose surface contamination levels within acceptable ranges depends upon the amount of loose radioactive material present on the structure at the time of demolition and the amount of radioactive material that is liberated during the demolition process as concrete dust.

Conventional demolition uses large excavators with hydraulic rams to rubbelize concrete and mechanical or thermal methods to cut metallic materials. Embedded surficial fixed contamination becomes loose as part of the dust generated when concrete is fractured or cut by the demolition equipment. Typically, the vast majority of the contamination in the concrete surfaces of building interiors is embedded in the upper most portion, near the surface. Most of the concrete structure and rebar is not contaminated and therefore the fracture dust and metallic dust or cutting smoke is clean.

Dust generated fracturing the contaminated surface is diluted by uncontaminated dust from fracturing of

RS-TD-313196-005 Revision 0 Page 9 of 116 subsurface material. To develop an R2Open Air fixed contamination limit for concrete, the relationship between fixed contamination levels as indicated by surface dose rates and the resulting loose surface contamination from the fracture dust liberated was evaluated. Tests were conducted at Connecticut Yankee to determine this correlation empirically, rather than by calculation.

In order to determine the appropriate R2Open Air fixed contamination criteria for concrete a series of in-situ tests were conducted in the Primary Auxiliary Building (PAB) at CY. The PAB was chosen because it had a series of cubicles with concrete floors exhibiting a range of contact dose rates which varied from as low as no detectable radiation levels above background to as high as 20 to 30 mR/hr contact. The cubicles could be decontaminated to low pre-test loose surface activity levels then sealed off to contain dust and contamination generated during demolition of concrete test areas of various dose rates, then surveyed after the test to evaluate the resulting contamination levels. The objective of these tests was to rubbelize concrete surfaces with different contact dose rates in the absence of engineering controls or dust suppression methods and monitor the airborne radioactivity and removable contamination levels generated.

The tests were performed by pre-surveying the area to determine average contact dose rates in order to select a test location with the appropriate contact levels to be evaluated. The cubicle was then decontaminated or locked down to provide low levels of initial removable contamination and sealed off using clear poly with no negative pressure ventilation applied. This provided a static environment in which airborne radioactivity levels and removable contamination levels resulting directly from the demolition could be evaluated. A test location was then remediated using needle guns, or jack hammers while an air sample was running. After the remediation was completed, the test area and cubicle contamination levels were assessed by smear survey and large area swipes (LAS). The test area was also re-surveyed to determine the post remediation contact dose rates and evaluate the amount of source term removed.

The first test area was in B Charging Pump Cubicle. The Test 1 surveys, air samples, and demolition debris gamma spectroscopy results from reference (7) are provided in Attachment 1. The pre-remediation survey was conducted on 3/3/04 at 16:00. The maximum pre-remediation test area contact dose rate was 1.5 mR/hr and averaged 0.66 mR/hr. Table 3 summarizes the pre-test data from this survey.

RS-TD-313196-005 Revision 0 Page 10 of 116 Table 3 - Test 1 Pre-remediation Survey Data Test Area Removable Test Area Contact Cubicle Removable Outside Test Area Smear Location beta/gamma dpm/100 cm2 alpha dpm/100 cm2 LAS ccpm mR/hr Cpm Smear Location beta/gamma dpm/100 cm2 Alpha dpm/100 cm2 LAS ccpm 31

ML19007A043

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