ML18198A423
| ML18198A423 | |
| Person / Time | |
|---|---|
| Site: | 03038939 |
| Issue date: | 08/13/2018 |
| From: | Tappert J R Division of Decommissioning, Uranium Recovery and Waste Programs |
| To: | James Smith All-Star Property Management, Gilbert Clock Properties |
| JAWhited NMSS/DUWP/MDB 415.4090 T5D25 | |
| References | |
| Download: ML18198A423 (54) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555
-0001 August 13, 2018 All-Star Property Management, LLC 153 Main Street Suite 201 Ansonia, CT 06401 ATTN: Jeffrey Smith
SUBJECT:
PROPERTY AT 13 WALLENS STREET
-RESULTS AND CONCLUSIONS OF U.S. NUCLEAR REGULATORY COMMISSION INITIAL SITE VISIT AND SCOPING SURVEY
Dear Mr. Smith:
I am writing to provide you with the results of the U.S. Nuclear Regulatory Commission's (NRC's)
May 1-2, 2018, site visit and June 26
-27, 2018 , scoping survey at your property at 13 Wallens Street, Winsted, Connecticut, which was formerly occupied by the William L. Gilbert Clock Company. As outlined in our letter to you dated October 6, 2016
, 1 the NRC staff conducted these visit s to your property to
- 1) determine if discrete sources of radium
-226 or distributed radium
-226 contamination are present, 2) identify the areas of highest contamination (if any radium contamination is identified), 3) determine if there are any current radiological health and safety concerns, and, 4) determine if further action by the NRC is needed.
The results of the NRC's initial site visit and scoping survey are summarized below and are discussed in further detail in the enclosed report.
During the initial site visit and scoping survey, the staff conducted radiation surveys in all of the apartments in Building A and more than half of the apartments in Building B/C. The staff surveyed approximately 50 percent of the floor area in occupied apartments and 100 percent of the floor area in unoccupied apartments that were entered. Our ability to survey the occupied apartments was limited because of furniture in the apartments. A detailed list of the apartments that were surveyed can be found in the attached report. Additionally, the staff surveyed approximately 30 percent of the area outside of the apartment buildings. The staff did not survey under the parking lot or building foundations.
During our visits, we identified elevated radiation levels at discrete locations in apartment s A-1, A-17, A-19, A-20, A-21, and A-22. In areas where we identified elevated radiation levels, we conducted additional measurements to test for transferable contamination. No tran sferable contamination was identified. These elevated levels of radiation are indicative of discrete sources of radium.
A ll radium identified in the apartments was evaluated conservatively, assuming a residential
-use scenario (i.e., 5,770-hour annual occupancy) as established in the Dose Assessment Technical Basis Document for Potential Exposures to Discrete Sources of Radium-226 and Associated Contamination
.2 As conservatively modeled by the staff , the radium 1 Agencywide Documents Access and Management System (ADAMS) Accession No. ML16277A318.
2 ADAMS Accession No. ML17072A414.
identified does not exceed the NRC's dose limit of 25 millirem per year for unrestricted use in Title 10 of the Code of Federal Regulations (10 CFR), Section 20.1402 , Radiological criteria for unrestricted use. No radium contamination was identified in the other apartments surveyed in Building A, or any of the apartments surveyed in Building B
/C. Because radium contamination was identified, as part of any voluntary cleanup effort, you may wish to consult with an NRC or Agreement State licensed service provider to ensure that there is limited potential for radiological contamination to be spread.
Please be aware that activities at your site may also be subject to State requirements and standards.
However, no further actions on your part are required at this time.
In accordance with 10 CFR 2.390 of the NRC's "Agency Rules of Practice and Procedure," a copy of this letter will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records component of ADAMS. ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading
-rm/adams.html
. The staff will contact you in the near future to answer any questions you may have regarding thi s report, but if you have any immediate questions , please contact Mr. Stephen Koenick, Chief, Materials Decommissioning Branch, Division of Decommissioning, Uranium Recovery and Waste Programs, Office of Nuclear Materials Safety and Safeguards, at (301) 415-663 1 or Mr. Jeffrey Whited, Project Manager
, at (301) 415-40 90. Sincerely, /RA/ AKock for John R. Tappert, Director Division of Decommissioning, Uranium Recovery and Waste Programs Office of Nuclear Material Safety and Safeguards Docket No. 0 30389 39
Enclosure:
Site Status Report REGISTERED LETTER
- RETURN RECEIPT REQUESTED
ML18198A423 *via e-mail OFFICE DUWP DUWP/LA DUWP RI/HP NAME JWhited CHolston CGrossman* LKauffman* DATE 07/19/2018 07/19/2018 07/20/2018 0 8/02/20 18 OFFICE RI/DNMS DUWP OGC* DUWP NAME RPowell* SKoenick TCampbell JTappert (AKock for)
DATE 08/02/2018 08/06/2018 08/06/2018 08/13/2018
Radium Program
- Gilbert Clock Company 5307-SR-27-1 Enclosure OAK RIDGE ASSOCIATED UNIVERSITIES:
SITE STATUS REPORT FOR GILBERT CLOCK SHOP APARTMENTS (FORMERLY WILLIAM L. GILBERT CLOCK COMPANY
) AT 13 WALLENS STREET IN WINSTED, CONNECTICUT AUGUST 13, 2018
Radium Program
- Gilbert Clock Company 5307-SR-27-1 EXECUTIVE
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) requested that Oak Ridge Associated Universities (ORAU) perform a radiation survey of the former William L. Gilbert Clock Company property at 13 Wallens Street in Winsted, Connecticut. Founded in 1866, the Gilbert Manufacturing Company was one of the largest clock
-makers in the world and manufacture d radium-containing products such as "Night and Day Radium Dial Clocks."
The objectives of this survey were to: (1) determine if discrete sources of radium
-226 or distributed radium
-226 contamination are present, (2) identify the areas of highest contamination (if any radium contamination is identified), (3) determine if there are any current health and safety concerns, and (4) determine if further action by the NRC is needed.
ORAU performed radiation survey s in accessible portions of Buildings A and B/C during the initial site visit on May 1-2, 201 8. Surveys identified discrete source s o f radium-226 remai ning in Building A
- no elevated radiation levels were identified in Building B
/C. A detailed dose assessment was performed
, and results led to the conclusion that it is unlikely the identified sources would reasonably result in a dose in excess of regulatory requirements. However, because discrete sources of radium were found in two of the apartments sampled, NRC directed ORAU to return to survey the remaining apartments in Buildings A and C. Additional discrete sources of radium-226 were discovered in Building A during the scoping survey on June 26-27, 2018. Subsequent dose assessment result s again lead to the conclusion that it is unlikely identified sources would reasonably result in a dose in excess of regulatory requirements. Therefore, it is recommended that the NRC not pursue additional action at the 13 Wallens Street property
.
Radium Program
- Gilbert Clock Company 1 5307-SR-27-1 SITE STATUS REPORT Property: Former William L. Gilbert Clock Company 13 Wallens Street Winsted, CT 06098 Docket Number:
03038939 Current Property Name(s):
Gilbert Clock Shop Apartments Current Property Owner(s): Gilbert Clock Properties, LLC Inspection Dates:
May 1-2, 2018 (initial site visit)
June 26-27, 2018 (scoping survey)
Inspector(s):
Raymond Powell, Steve Hammann, Katherine Warner, and Anne DeFrancisco
/ U.S. Nuclear Regulatory Commission (NRC), supported by Kaitlin Engel, Jason Lee, and Andrew Owens/Oak Ridge Associated Universities (ORAU)
1.0 INTRODUCTION
The Energy Policy Act of 2005 amended section 11e.(3) of the Atomic Energy Act of 1954 to place discrete sources of radium
-226 (Ra-226) under NRC regulatory authority as byproduct material. The Gilbert Clock Shop Apartments at 13 Wallens Street in Winsted , Connecticut (CT) were identified as part of the former William L. Gilbert Clock Company property, where clocks were manufactured from 1866 to 1964. During this time, the clock factory employed 500 workers and produced two thousand clocks per day (ORNL 2015). One of Gilbert's products was "Night and Day Radium Dial Clocks" using "LUMA-nous" dial s developed by the Gilbert engineering department (Funk and Wagnalls 1920).
Because the two remaining original manufacturing buildings were renovated, the extent of Ra
-226 contamination, if any, on original structural materials (exterior walls and heavy floor beams) was unknown prior to this 2018 investigation. Surveys were performed as described within NRC's procedure, Temporary Instruction (TI) 2800/043, Inspection of Facilities Potentially Contaminated with Discrete Radium
-226 Sources (NRC 2018).
During the May 2018 initial site visit, inspectors performed surveys of outdoor areas and 22 percent of the apartments within Buildings A and B/C. Inspectors identified one small area of elevated activity in Apartment A
-17 and two small areas of elevated activity in Apartment A
-22 that produced gamma radiation above ambient background levels (ORAU 2018). Due to this finding, NRC determined that a follow
-up scoping survey should be performed to more thoroughly investigate the property. The scope of the June 2018 scoping survey included the remaining apartments in Building s A and C that were not surveyed during the May site visit. Additionally, Apartment A
-22 was re-surveyed. The objectives of both the initial site visit and scoping survey s were to locate and delineate discrete sources of radium if present and, if so, determine whether these sources could result in a dose above regulatory limits. This site summary report documents findings from the May and June 2018 surveys.
Radium Program
- Gilbert Clock Company 2 5307-SR-27-1 2.0 PROPERTY DESCRIPTION AND INITIAL SITE VISIT CONSIDERATIONS 2.1 Property Description and History The William L. Gilbert Clock Company was established in Winsted, Connecticut in July 1871 to take over the Gilbert Manufacturing Company (1866
-1871), which was one of the various clock making operations of William L. Gilbert (1806
-1890). The historic factory complex was originally located on the north and south sides of Wallens Street and Main Street, on the eastern bank of the Still River. After the original factory was destroyed by fire in 1871, a new factory complex was completed and manufacturing commenced in July 1873 under George B. Owen (1834
-1916). In 1897, the Gilbert firm built a four
-story building for a case shop, another for storage and shipping by 1900, and a three
-story office building in 1902. During this time, the clock company employed 500 workers and produced two thousand clocks per day (ORNL 2015). One of Gilbert's products was "Night and Day Radium Dial Clocks" using "LUMA
-nous" dials developed by the Gilbert Engineering Department (Funk and Wagnalls 1920). Despite financial burdens of the recent expansion and the onset of the recession, the company continued until it was sent into receivership in 1932, due to the Great Depression. In July 1934, a new firm, known as the William L. Gilbert Clock Corporation was formed and was allowed to continue making clocks in the 1940s during World War II because it manufactured clocks with molded papier-mâché cases rather than metal. In 1954, the firm began producing adding machines for General Computing Machines Corporation before being subsumed by General Computing Machines Corporation in 1957. In 1955, two hurricanes (Connie and Diane) within a span of one week caused the Still River and the Mad River, which parallels Main Street, to flood. The flooding damaged the buildings that were located south of Wallens Street. In December 1964, the clock making division was sold to Spartus Corporation of Chicago. In 1975, the buildings south of Wallens Street were destroyed by fire. The two large buildings that survive today are the four-story brick buildings (one building directly on the river bank and the other is set up the hill to the east
). The buildings were renovated and converted into apartments in 1997 after sitting empty for almost 20 years. Most structural materials are presumed new from the 1997 renovation, except for the existing exterior walls and heavy floor beams (ORNL 2015).
In addition, these surviving buildings are a preservation of Connecticut
's history as a center for the manufacture of low
-cost clocks that was one of the town's largest employers for many years. The surviving buildings were listed on the National Register of Historic Places in 1984.
Figure 1 shows a current view of the over 8,9 00-m 2 (2.21-acre) Lot 009 property with the two brick apartment buildings, noting the property boundary outlined in blue. The square footage of the buildings is unknown. Each building contains four floors, and each floor contains seven or eight apartments. Building A is located along Wallens Street, and the long dimension of Building B/C runs along White Street. The first and second floor of Building B/C is associated with Building B, and the third and fourth floors are associated with Building C (thus Building B/C). The buildings contain one
- and two-bedroom apartments with different layouts. The property also contains an asphalt parking lot outside of the apartment buildings and a wooded area that runs along the Still River. 2.2 Initial Site Visit Considerations Prior to commencing survey activities each day, the general property layout was examined for consistency with historical information and to identify impediments to conducting the survey and health and safety considerations. No health or safety issues were noted. However, it was noted that access was limited in the outdoor area due to steep terrain and heavy branches.
Radium Program
- Gilbert Clock Company 3 5307-SR-27-1 Access was also limited in some apartments due to occupancy (e.g., beds, dressers, couches). A schedule for accessing apartments was developed by the property manager and communicated to the applicable residents. The schedule allotted 60 minutes (initial site visit) or 45 minutes (scoping survey
) per apartment to perform and document survey activities. It is also noted that the original flooring has been covered with carpet, with the exception of kitchens, bathrooms, and entryways, where tile or linoleum was used; therefore
, direct measurements could not be performed on the original flooring
. 3.0 SITE OBSERVATIONS AND FINDINGS 3.1 Summary of Activities (Site Visit)
The inspection team conducted the initial site visit survey at the 13 Wallens Street property on May 1-2, 2018. The inspection team included Raymond Powell and Anne DeFrancisco (NRC); and Kaitlin Engel and Andrew Owens (ORAU). Jay Warden (Gilbert Clock Shop Apartments) acted as site escort. The inspection team's intention was to perform general area radiation surveys of the outdoor area of the property as well as inside Buildings A and B/C.
Figure 1. Current View of 13 Wallens Street (Property Outlined in Blue)
Bldg. A Bldg. B/C N Radium Program
- Gilbert Clock Company 4 5307-SR-27-1 Radiological surveys performed by the inspection team consisted of gamma radiation scans within the outdoor area and buildin g s using a Ludlum model 44
-10 2-inch by 2-inch (2x2) sodium iodide detector connected to a Ludlum model 2221 ratemeter/scaler, alpha
-plus-beta radiation direct measurements using a Ludlum model 44
-142 plastic scintillator connected to a Ludlum model 2221 ratemeter/scaler, and radiation exposure rate measurements using a Ludlum model 192 sodium iodide
-based µR ratemeter
- 1. A hand-held identiFINDER R300
-Z was used to confirm, if possible, the presence of Ra
-226 when elevated radiation levels were encountered. Table 1 presents the specific instruments used during the initial site visit. Smear samples were also collected at selected locations to quantify the removable surface activity levels. Table 1. Gilbert Clock Company Survey Instruments for Site Visit Radiation Type (units)
Detector Type Detector Model (Number) Ratemeter (Number) Alpha-plus-beta (cpm)
Plastic Scintillator 44-142 (919) Calibrated 0 4/10/201 8 44-142 (920) Calibrated 04/10/2018 2221 (1139) Calibrated 04/06/2018 2221 (1144) Calibrated 04/06/2018 Gross gamma (cpm)
Sodium Iodide 44-10 (11 51) Calibrated 11/03/2017 44-10 (115 2) Calibrated 11/03/2017 2221 (1139) Calibrate d 04/06/2018 2221 (1144) Calibrated 04/06/2018 Gross gamma (µR/h)
Exposure Meter 192 (11 27) Calibrated 06/02/2017 192 (11 28) Calibrated 06/02/2017 N/A Gamma Spectrum Analyzer (identiFINDER)
Cesium Iodide R300-Z (CG0343)a N/A N/A = not applicable Number = ORAU equipment barcode cpm = counts per minute
µR/h = microRoentgen per hour a A known radium source is used to confirm the identiFINDER will identify Ra
-226.
1Roentgen is a unit of exposure (energy absorbed in air), whereas a rem is a unit of dose delivered to a person (resulting from the radiation energy absorbed in that person). While Roentgen and rem are related, these are different units. Because they are similar for gamma ray energies from Ra
-226, NRC makes the simplifying assumption in this case that these units are equivalent (1 Roentgen = 1 rem).
Radium Program
- Gilbert Clock Company 5 5307-SR-27-1 Summary of Daily Activities
-May 1, 2018
- The inspection team arrived at 8:
30 a.m. and met with representatives from the NRC and the apartment complex. The inspection team surveyed apartments A
-3, A-7, A-8, A-10, A-17, A-22, A-23, and A-25. Surveys were conducted on accessible floor space
, with scan coverage ranging from approximately 50 percent (occupied apartments) to 100 percent (vacant apartments). Surveys were also conducted on the four hallways and two stairwells in Building A (100 percent coverage) and the outdoor areas of the site (approximately 30 percent coverage)
. The team identified three discrete areas exhibiting elevated radiation levels: one small area of elevated activity in apartment A
-17 and two small areas of elevated activity in apartment A
-22. The team departed the site at approximately 5:00 p.m.
Summary of Daily Activities
-May 2, 2018
- The inspection team arrived at 8
- 30 a.m. and began surveying Building B/C. Survey activit ies were conducted in apartments B
-32, B-39, B-45, B-48, C-56, C-58, C-64, and C-67. Surveys were conducted on accessible floor space
, with scan coverage ranging from approximately 50 percent (occupied apartments) to 100 percent (vacant apartments).
Surveys were also conducted on the four hallways, two stairwells, lobby area, and leasing office of Building B/C (100 percent coverage). No areas exhibiting elevated radiation levels were identified.
The team departed the site at approximately 2:30 p.m.
3.2 Summary of Activities (Scoping Survey)
As directed, the inspection team returned to the site and conducted a scoping survey at the 1 3 Wallens Street property on June 26-27, 2018. The inspection team included Raymond Powell, Steve Hammann, and Katherine Warner (NRC); and Jason Lee and Andrew Owens (ORAU). Jay Worden, Jeff Smith, and Priscilla O'Malley (Gilbert Clock Shop Apartments) acted as site escorts. The inspection team's objective was to perform general area radiation surveys for the remaining Building A and C apartments not previously surveyed during the initial site visit. Table 2 presents the specific instruments used during the scoping survey. Smear samples were also collected at selected locations to quantify the removable surface activity levels.
Radium Program
- Gilbert Clock Company 6 5307-SR-27-1 N/A = not applicable Number = ORAU equipment barcode cpm = counts per minute
µR/h = microRoentgen per hour aA known radium source is used to confirm the identiFINDER will identify Ra
-226. Summary of Daily Activities
-June 26, 2018
- The inspection team arrived at 8:00 a.m. and met with representatives from the NRC and the apartment complex. The inspection team surveyed all the remaining apartments in Building C (C-53, C-54, C-55, C-57, C-59, C-60, C-61, C-62, C-63, C-65, C-66, C-68, C-69, C-70, C-71, C-72, C-73, C-74), and Building A apartments A-1 and A-22. Surveys were conducted on accessible floor space with scan coverage ranging from approximately 30 percent to 70 percent
, depending on furniture and other obstacles in occupied apartments. The team identified a small discrete area exhibiting elevated radiation levels in apartment A
-1. The team also investigated an area from the initial site visit in apartment A
-22 and found a n additional small area of elevated activity. The inspection team departed the site at approximately 4:30 p.m.
Summary of Daily Activities
-June 27, 2018
- The inspection team arrived at 8:00 a.m. Survey activities were conducted in all the remaining apartments in Building A (A-2, A-4, A-5, A-6, A-9, A-11, A-12, A-13, A-14, A-15, A-16, A-18, A-19, A-20, A-21, A-24, A-26, A-27, A-28, and A-29). Surveys were conducted on accessible floor space with scan coverage ranging from approximately 30 percent to 70 percent
, depending on furniture and other obstacles in occupied apartments.
The team identified six discrete areas exhibiting elevated radiation levels in three apartments: one in apartment A
-19, one in Table 2. Gilbert Clock Company Survey Instruments for Scoping Survey Radiation Type (units)
Detector Type Detector Model (Number) Ratemeter (Number) Alpha-plus-beta (cpm)
Plastic Scintillator 44-142 (920) Calibrated 04/10/2018 2221 (1141)
Calibrated 04/06/2018 Gross gamma (cpm)
Sodium Iodide 44-10 (1151) Calibrated 05/15/2018 44-10 (1152) Calibrated 05/15/2018 2221 (1139)
Calibrated 04/06/2018 2221 (1141)
Calibrated 04/06/2018 Gross gamma (µR/h)
Exposure Meter 192 (1127)
Calibrated 05/21/2018 192 (1128)
Calibrated 05/21/2018 N/A Gamma Spectrum Analyzer (identiFINDER)
Cesium Iodide R300-Z (CG0343) a N/A Radium Program
- Gilbert Clock Company 7 5307-SR-27-1 apartment A
-20, and four in apartment A
-21. The team departed the site at approximately 4:30 p.m. 3.3 Summary of Results Appendix A presents representative photos taken during the survey of vacant apartments, some of the locations that identified exhibit ed elevated radiation levels, and the outdoor area from both the initial visit and the scoping survey. Appendix B
, Figures B-1 through B
-8 present the general layout of each survey area , the location of individual radiation measurements (including small areas of elevated activity), and other relevant information for the outdoor areas and only the six apartments where areas of elevated radiation levels were identified. Note that these ORAU-generated facility drawings are not to scale, and the illustrated features are based on the observations of the inspection team at the time of the survey. Appendix B
, Tables B-1 through B
-8 present the radiation survey data associated with each respective figure. As applicable, results include the measurement location, smear number
, and associated analytical laboratory alpha
-plus-beta removable result in disintegrations per minute per 100 cm 2 (dpm/100 cm 2); gross and net total alpha
-plus-beta responses in cpm and dpm/100 cm 2, respectively
- gross 2x2 sodium iodide and exposure rates on contact in cpm and R/h, respectively; and gross exposure rates in R/h collected at 1 meter from the surface. Smears were submitted for gross alpha and gross beta analysis at a radio
-analytical laboratory. Static field measurements of total alpha-plus-beta activity in unit s of cpm were converted to total Ra-226 surface activity in units of dpm/100 cm 2 using the following equation: /100 = x Where: C = measured count rate (cpm)
B = background count rate (cpm)
G = geometry factor (unitless) = () = 1.0 tot = total weighted efficiency (unitless) = 0.11 Due to the number of emissions from Ra
-226 and its associated progeny, multiple radiation particles are counted during the surface activity measurement. Therefore, a total weighted efficiency for Ra
-226 and its associated progeny was calculated by:
=x,x,Where: F n = fractional abundance of nth emission , i,n = instrument efficiency for nth emission, and s,n = surface efficiency (0.25 for low
-energy beta particles, 0.5 for high
-energy beta particles) for n th emission.
Radium Program
- Gilbert Clock Company 8 5307-SR-27-1 A total weighted efficiency of 0.11 was estimated at the ORAU facility after conducting a series of radiation measurements using alpha/beta sources and a piece of low
-pile carpet. The objective of these measurements was to mimic conditions encountered at the site and, therefore, calculate a realistic efficiency that would not underestimate true radiological conditions. The measurements demonstrate d that all alpha radiation and low
-energy beta radiation is shielded by carpet, thus the plastic scintillator is estimated to identify only a small percentage of the total alpha/beta radiation emanating from the source surface.
Table 3 summarizes survey results from the May 2018 and June 2018 survey effort s for the 55 apartments, 8 hallways, 4 stairwells, and the outdoor areas surveyed.
In general, background gamma radiation levels ranged from 3 to 19 µR/h at 1 meter. Higher background radiation levels are associated with naturally occurring radioactive material (NORM) in the exterior brick walls of the buildings and rock retaining walls on the property. To the extent possible, each room was divided into quadrants and systematic contact 2 x2 sodium iodide (in cpm) and 1 meter model 192 exposure rate measurements (in
µR/h) were collected at the center of each quadrant and at the middle of the room, following the survey design described in ORAU 2018. Surveyors also collected contact gamma and alpha
-plus-beta measurements (in cpm) and contact µR/h data, 1 meter
µR/h data, identiFINDER data, and removable (smear) samples at identified locations exhibiting elevated radioactivity relative to background. Appendix B presents details for the outdoor areas and the six apartments where areas of elevated radiation levels were identified, thus the following discussion presents a general summary for the outdoor and all indoor area s.
Radium Program
- Gilbert Clock Company 9 5307-SR-27-1 Table 3. Summary of Discrete Areas of Elevated Radiation at the Former Gilbert Clock Company Area/Apartment No.
No. Elevated Areas Gross Gamma (cpm) Gross Exposure Rate (µR/h) No. Smears Su rface Activity (dpm/100 cm
- 2) Max Size (m 2) Contact 1 meter Total Ra-226 Removable Outdoor Area - River 0 7,500 to 39,000 NA 8 to 19 0 - - - Outdoor Area - Parking Lot 0 7,000 to 26,000 NA 7 to 17 0 - - - Bldg. A 1st Floor Hallway / S. Stair 0 6,200 to 17,000 NA 5 to 15 0 - - - Bldg. A 2nd Floor Hallway 0 7,700 to 8,900 NA 7 to 8 0 - - - Bldg. A 3rd Floor Hallway 0 6,500 to 8,600 NA 6 to 8 0 - - - Bldg. A 4th Floor Hallway / N. Stair 0 4,800 to 11,200 NA 5 to 9 0 - - - Apt. A-1 1 11,500 to 18,000 18 11 to 15 0 - - 0.01 Apt. A-2 0 10,200 to 14,000 NA 8 to 15 0 - - - Apt. A-3 0 10,100 to 14,200 NA 9 to 12 0 - - - Apt. A-4 0 10,400 to 13,100 NA 8 to 12 0 - - - Apt. A-5 0 9,500 to 13,000 NA 8 to 12 0 - - - Apt. A-6 0 9,700 to 14,500 NA 8 to 13 0 - - - Apt. A-7 0 9,700 to 15,000 NA 8 to 14 0 - - - Apt. A-8 0 9,200 to 11,800 NA 8 to 11 0 - - - Apt. A-9 0 7,500 to 12,600 NA 6 to 12 0 - - - Apt. A-10 0 7,600 to 17,000 NA 6 to 17 0 - - - Apt. A-11 0 7,200 to 13,000 NA 8 to 14 0 - - - Apt. A-12 0 8,200 to 13,900 NA 8 to 12 0 - - - Apt. A-13 0 7,500 to 15,500 NA 7 to 13 0 - - - Apt. A-14 0 8,000 to 15,000 NA 7 to 13 0 - - - Apt. A-15 0 7,400 to 11,400 NA 7 to 10 0 - - - Apt. A-16 0 6,500 to 12,800 NA 6 to 12 0 - - - Apt. A-17 1 6,800 to 28,500 23 6 to 13 1 2,100 < 1 0.01 Radium Program
- Gilbert Clock Company 10 5307-SR-27-1 Table 3. Summary of Discrete Areas of Elevated Radiation at the Former Gilbert Clock Company Area/Apartment No.
No. Elevated Areas Gross Gamma (cpm) Gross Exposure Rate (µR/h) No. Smears Su rface Activity (dpm/100 cm
- 2) Max Size (m 2) Contact 1 meter Total Ra-226 Removable Apt. A-18 0 7,300 to 13,200 NA 7 to 11 0 - - - Apt. A-19 1 6,700 to 62,000 50 6 to 20 1 16,000 < 1 0.01 Apt. A-20 1 7,100 to 122,000 120 7 to 27 1 36,000 < 1 0.1 Apt. A-21 4 7,200 to 60,000 25 to 60 7 to 18 2 14,000 < 1 0.01 Apt. A-22 3 9,200 to 134,000 38 to 100 7 to 23 2 6,900 to 33,000 < 1 to 1 1 Apt. A-23 0 5,700 to 10,000 NA 5 to 10 0 - - - Apt. A-24 0 5,500 to 9,200 NA 5 to 9 0 - - - Apt. A-25 0 6,200 to 11,400 NA 5 to 11 0 - - - Apt. A-26 0 5,200 to 9,400 NA 5 to 9 0 - - - Apt. A-27 0 5,200 to 15,400 NA 5 to 14 0 - - - Apt. A-28 0 5,300 to 9,400 NA 5 to 9 0 - - - Apt. A-29 0 5,600 to 10,200 NA 5 to 10 0 - - - Bldg. B/C 1st Floor Hallway / Office 0 6,000 to 16,300 NA 4 to 16 0 - - - Bldg. B/C 2nd Floor Hallway 0 4,500 to 11,900 NA 4 to 10 0 - - - Bldg. B/C 3rd Floor Hallway / N. Stair 0 4,600 to 12,200 NA 4 to 12 0 - - - Bldg. B/C 4th Floor Hallway / S. Stair 0 3,900 to 12,800 NA 3 to 11 0 - - - Apt. B-32 0 9,100 to 14,600 NA 8 to 14 0 - - - Apt. B-39 0 8,800 to 13,500 NA 7 to 13 0 - - - Apt. B-45 0 4,900 to 11,400 NA 5 to 11 0 - - - Apt. B-48 0 4,700 to 10,300 NA 5 to 10 0 - - - Apt. C-53 0 4,400 to 12,200 NA 5 to 11 0 - - - Apt. C-54 0 4,000 to 10,200 NA 4 to 10 0 - - - Apt. C-55 0 5,400 to 13,300 NA 5 to 13 0 - - - Apt. C-56 0 5,400 to 13,200 NA 5 to 13 0 - - -
Radium Program
- Gilbert Clock Company 11 5307-SR-27-1 Table 3. Summary of Discrete Areas of Elevated Radiation at the Former Gilbert Clock Company Area/Apartment No.
No. Elevated Areas Gross Gamma (cpm) Gross Exposure Rate (µR/h) No. Smears Su rface Activity (dpm/100 cm
- 2) Max Size (m 2) Contact 1 meter Total Ra-226 Removable Apt. C-57 0 3,900 to 10,600 NA 4 to 11 0 - - - Apt. C-58 0 5,000 to 12,700 NA 5 to 12 0 - - - Apt. C-59 0 4,300 to 11,000 NA 4 to 10 0 - - - Apt. C-60 0 5,100 to 13,100 NA 5 to 12 0 - - - Apt. C-61 0 5,400 to 12,500 NA 5 to 12 0 - - - Apt. C-62 0 4,500 to 10,600 NA 4 to 10 0 - - - Apt. C-63 0 5,900 to 16,500 NA 5 to 16 0 - - - Apt. C-64 0 4,500 to 13,000 NA 4 to 14 0 - - - Apt. C-65 0 4,100 to 11,200 NA 4 to 9 0 - - - Apt. C-66 0 5,500 to 14,000 NA 6 to 15 0 - - - Apt. C-67 0 5,200 to 13,400 NA 5 to 14 0 - - - Apt. C-68 0 5,100 to 12,300 NA 5 to 11 0 - - - Apt. C-69 0 4,500 to 11,600 NA 4 to 10 0 - - - Apt. C-70 0 4,300 to 9,600 NA 4 to 9 0 - - - Apt. C-71 0 4,800 to 11,700 NA 4 to 11 0 - - - Apt. C-72 0 5,200 to 12,400 NA 5 to 11 0 - - - Apt. C-73 0 4,100 to 10,200 NA 4 to 10 0 - - - Apt. C-74 0 5,300 to 15,500 NA 5 to 15 0 - - -
Radium Program
- Gilbert Clock Company 12 5307-SR-27-1 Outdoor Areas. Radiation measurements were collected on the north/east riverbank of the Still River, around Buildings A and B/C, in the parking lots, and at any drains on the property. T he outdoor areas exhibited radiation levels consistent with background
-no areas exhibiting elevated radiation levels were identified. Radiation levels ranged from 7,000 to 39,000 cpm on contact using the 2 x2 sodium iodide detector and 7 to 19
µR/h at 1 meter using the 192 exposure ratemeter. The highest readings were near rock/brick walls and are attributed to NORM in the materials.
Building A. Radiation measurements were collected in hallways, stairwells, and all of the apartments in Building A (A
-1 through A-29). Radiation levels ranged from 4,800 to 134,000 cpm on contact using the 2 x2 sodium iodide detectors and 5 to 27 µR/h at 1 meter using the 192 exposure ratemeter. Areas near exterior (brick) walls and on the lower levels of the building produced higher radiation levels attributed to NORM material. Eleven discrete locations exhibiting elevated radiation levels were identified in Building A. Ten small (0.1 m 2) areas of elevated activity were identified (one each in apartments A
-1, A-17, A-19, a nd A-20; two in apartment A
-22; and four in apartment A
-21) and a larger (approximately 1 m
- 2) area of elevated activity was identified in apartment A
-22. The maximum radiation measurements were recorded at the area in apartment A
-20, with a contact exposure of 1 2 0 µR/h, noting the exposure rate at 1 meter dropped to 2 7 µR/h. Direct measurements were collected with a model 44-142 plastic scintillator on all accessible areas of elevated radiation, with a maximum of 36,000 dpm/100 cm 2 in apartment A
-20. Smears were also collected, producing a maximum of 1 dpm/100 cm 2 in apartment A
-2 2, noting the apartments have carpet and tile in them, so smears were not collected directly from the original radium-contaminated media (presumably a wood floor). The identiFINDER confirmed the presence of radium on the larger area in apartment A
-22 and the small area in apartment A
-20, though radiation levels were too low to confirm the presence of Ra
-226 at the other nine small areas of elevated activity.
Building B/C. Radiation measurements were collected in hallways, stairwells, the office of Building B/C, all of the apartments in Building C (C-53 through C
-74), and select apartments in Building B (B-32, B-39, B-45, and B-48). The inspection team determined that no addition al surveys were necessary for Building B apartments. This was based on the fact that none of the areas surveyed during the initial site visit in Building B/C exhibited elevated radiation levels. Further, experience has demonstrated that if contamination were present, it would be in upper floors as these had better natural lighting for the dial painting to occur. It is using this rationale that the inspection team decided to survey the remaining Building C apartments. Radiation levels ranged from 3,900 to 16,500 cpm on contact using the 2 x2 sodium iodide detectors and 3 to 16 µR/h at 1 meter using the model 192 exposure ratemeter. Areas near exterior walls and on the lower levels of the buildings produced higher radiation levels attributed to NORM material. No discrete locations exhibiting elevated radiation levels were identified in Building B/C. 3.4 Summary of Dose Assessment Results The discussion on the dose assessment results is divided into two subsections: Dose Assessment Method and Dose Assessment Results.
Dose Assessment Method.
TI 2800/043 presents two Action Levels (ALs) that correlate to 100 mrem/yr for a worker (1-meter measurement of 40 /h above background) and a resident (1-ALs account for gamma exposure alone and may be used to quickly identify radiation levels that could conservatively produce a dose above the public dose limit in Title 10 of the Code of Federal Regulations
Radium Program
- Gilbert Clock Company 13 5307-SR-27-1 (10 CFR) Section 20.1301 , Dose limits for individual members of the public. T he 15-appropriate for this site because it is configured for residential use. These ALs were established to define a radiation level above which access controls would be recommended.
Additional radiological criteria are discussed later in this report.
Dose assessment methods described herein rely upon the Dose Assessment Technical Basis Document for Potential Exposures to Discrete Sources of Radium
-226 and Associated Contamination (hereafter the Technical Basis Document) to account for site
-specific conditions and all potential exposure pathways (ORISE 2017). The Technical Basis Document also presents methods for developing site
-specific screening levels and dose estimates, assumi ng a default conceptual model may not apply at a given site. The average member of the critical group is a residential building occupant, who is conservatively assumed to spend up to 5,770 hours0.00891 days <br />0.214 hours <br />0.00127 weeks <br />2.92985e-4 months <br /> in an apartment in one year; and the potential exposure pathways include external gamma, inhalation, and secondary ingestion. However
, contaminated media (floors) identified during the survey are carpeted or otherwise covered with materials that significantly reduce exposure via the inhalation and secondary ingestion pathways. Occupants at some time in the future may engage in activities which uncover the original floors, and be exposed via external gamma, inhalation, and indirect ingestion pathways; therefore, this assessment accounts for all three pathways.
Because measured values are preferable to modeled values, measured exposure rate in
µR/h are used to estimate dose received via the external gamma pathway (assuming 1 µR/h
~ 1 µrem/h). The Technical Basis Document presents dose
-to-source ratios (DSRs) for th e inhalation (1.61x10-8 mrem/hr per dpm/100 cm
- 2) and secondary ingestion (4.30x10
-8 mrem/hr per dpm/100 cm
- 2) pathways, for a total DSR of 5.91x10
-8 mrem/hr per dpm/100 cm 2 (see ORISE 2017, Table 4.3). These DSRs are selected for a small area of elevated activity on the order of 0.1 m 2, given only small areas of elevated activity were encountered during the survey
- s. The dose estimate method, therefore, consists of the following calculations, which include multiplying the occupancy time by the measured exposure rate (for the external dose), and by multiplying the occupancy time by the measured surface activity and total DSR (for the internal dose): External Dose mrem yr=x ~1000 /, Internal Dose mrem yr=x 100 x5.91x10//100 , and finally, Total Dose = External Dose + Internal Dose.
Note that even when doses are averaged over a reasonably conservative area, such as a room, the DSRs for small areas are still used given the sum of the contaminated area is a very small percentage of the total. For example, apartment A
-22 contains three areas of elevated activity, with a total estimated contaminated area of 1 m 2, compared to a total apartment area of approximately 65 m 2. Therefore, an upper estimate of the contaminated area represents approximately 1 percent of total living space.
Because only small areas of elevated activity were identified, the dose assessment was performed assuming two occupancy duration scenarios. The first scenario assumes an Radium Program
- Gilbert Clock Company 14 5307-SR-27-1 individual would spend the entire 5,770
-h/yr occupancy period in the room or area containin g the area of elevated activity identified in a survey unit ("maximum room" scenario). This scenario is very conservative given an individual is highly unlikely to spend all modeled time in only the bedroom, or the kitchen, or the hallway section, etc., of a given survey unit. The second scenario assumes an individual would spend the 5,770
-h/yr occupancy period averaged over the entire survey unit (e.g., the whole apartment). This scenario is still conservative but more closely aligns with the conceptual model described in the Technical Basis Document (ORISE 2017). Therefore, the first scenario is intended to generate an upper bound of the dose within a given survey unit, and the second scenario is intended to generate a still conservative but more realistic representation of conditions expected to be encountered within a survey unit.
The source term for each scenario is a net value (excludes background) and is also conservatively estimated. The source term in the first ("maximum room") scenario is defined by the highest measured radioactivity within the survey unit. The source term in the second scenario is the average of all measured radioactivity in the survey unit. This value is conservative because results for a given small area of elevated activity are weighted equally with background measurements, though the area containing elevated activity is a very small fraction of the total surface area in any survey unit. Background is likewise estimated by averaging all measurements in the room or area, though excluding locations with elevated activity. Because the highest levels of radiation were identified in apartments A-20 and A-22, dose calculations are conservatively performed using source terms for these two apartments. The apartment A
-20 source term is presented in Table B-6, and the apartment A
-22 source term is presented in Table B-8. In summary, the dose assessment method described herein uses multiple conservative assumptions. For example, worst
-case doses assume the receptor spends 100 percent of the occupancy period in a single room. Additionally, an "average" survey unit source term is conservatively biased by combining data from measurements of small areas of elevated activity
, though they represent a very small percentage of the total surface area
, with larger areas of background measurements in an unweighted manner. As a result of this layered conservatism, dose estimates presented in the following discussion should overestimate the true value.
Dose Assessment Results.
Appendix B presents dose assessment results for all survey units. Table B-9 lists dose estimates for the external gamma pathways only and represents potential doses to current occupants of apartments A
-20 and A-22-recalling that floor covering significantly reduces exposure via inhalation and secondary ingestion pathways. Table B-10 lists dose estimates for internal pathways only, representing potential doses via inhalation and secondary ingestion, assuming floor coverings are removed at some time in the future. These values must be added to the corresponding values in Table B-9 to estimate the total dose to the hypothetical future occupant, who may be exposed through all potential exposure pathways. Table B-11 summarizes dose estimated for both the current occupant (external gamma only) and the hypothetical future occupant (all pathway s). As presented in Table B-11, the maximum estimated dose, assuming an individual spends the entire 5,770
-h r/yr occupancy period in a single room/area, is 14 mrem/yr (apartment A
-2 0 living room). The highest estimated dose from across an entire apartment is 5.
6 mrem/yr (two rooms in apartment A
-22). As noted earlier, two dose limits are considered in this assessment. The first dose limit is the 100-mrem/yr public dose limit in 10 CFR 20.1301. An estimated dose above 100 mrem/yr to the average member of the critical group would require immediate action, such as access controls to limit current occupant exposures to discreet sources of Ra
-226. The second dose limit is the 25-mrem/yr unrestricted use limit in 10 CFR 20.1402 , Radiological criteria for unrestricted use.
Radium Program
- Gilbert Clock Company 15 5307-SR-27-1 An estimated dose above 25 mrem/yr to the average member of the critical group would not require immediate action, though additional characterization and remediation may be required prior to unrestricted release. In any case, no action is required if the estimated dose is less than 25 mrem/yr. These results demonstrate that current and potential future occupants are unlikely to receive a dose above the 25-mrem/yr unrestricted use limit in 10 CFR 20.1402. Therefore, although discrete sources of Ra
-226 were identified within several apartments, none are present at concentrations that would reasonably produce a dose above regulatory limits.
4.0 OBSERVATIONS AND RECOMMENDATIONS Based on the data collected during the May 2018 , and June 2018
, survey s, the former Gilbert Clock Company property located at 13 Wallens Street contains discrete sources of Ra
-226. However, th e identified sources are not at concentrations or configured in a manner that would reasonably result in a dose in excess of regulatory requirements. This conclusion is based on the following observations:
Elevated direct gamma and/or surface radiation due to discrete sources of Ra
-226 were identified in six Building A apartments (A-1, A-17, A-19, A-20, A-21, and A-22). Identified Ra
-226 contamination is limited to 11 small areas of elevated activity (approximately 1 m 2 total). Dose estimate s show that a residential building occupant would receive an estimated dose less than the 25-mrem/yr unrestricted use limit in 10 CFR 20.1402
, conservatively assuming a n occupancy of 5,770h r/yr averaged over a single room
. Based on these observations, it is recommended that the NRC not pursue additional actions at the former Gilbert Clock Company facility. NRC should, however, communicate to the owner the location and magnitude of identified Ra
-226 contamination, even though isolated areas of elevated activity are unlikely to exceed NRC's dose standards for unrestricted use.
Radium Program
- Gilbert Clock Company 16 5307-SR-27-1
5.0 REFERENCES
Funk and Wagnalls 1920. The Literary Digest Volume LXIV
, Funk & Wagnalls Company, New York, digitized by Google, pp.
383 , 944, and 1463 of 1909, January-March. NRC 201 8. Inspection of Facilities Potentially Contaminated with Discrete Radium
-226 Sources , Temporary Instruction 2800/043, Revision 2 , U.S. Nuclear Regulatory Commission, Office of Nuclear Material Safety and Safeguards, Washington, D.C., May. (ADAMS Accession No. ML17297B921
). ORAU 2018. Project-Specific Plan for the Survey of the Former William L. Gilbert Clock Company Property at 13 Wallens Street in Winsted, Connecticut, DCN 5307
-PL-05-1, Oak Ridge Associated Universities, Oak Ridge, Tennessee, February 22.
ORNL 2015. Historical Non
-Military Radium Sites Research Effort Addendum, "William L. Gilbert Clock Company: Site Summary," pp. 161
-165, Oak Ridge National Laboratory, Oak Ridge, Tennessee, November
- 24. (ADAMS Accession No. ML16291A488).
ORISE 201 7. Dose Assessment Technical Basis Document for Potential Exposures to Discrete Sources of Radium-226 and Associated Contamination
, DCN 5289-TR-01-2, Oak Ridge Institute for Science and Education , Oak Ridge, Tennessee, May 30. (ADAMS Accession No. ML17152A204
).
Radium Program - Gilbert Clock Company 5307-SR-27-1 APPENDIX A PHOTOS FROM THE FORMER GILBERT CLOCK COMPANY SURVEY
Radium Program
- Gilbert Clock Company A-1 5307-SR-27-1 Figure A-1. Bldg. A / Lower Level Parking Lot Figure A-2. Rock Wall Figure A-3. Inaccessible Hill South of Bldg. B/C Figure A-4. Upper Level Parking Lot Bldg. A Bldg. A Bldg. A Bldg. B/C Radium Program
- Gilbert Clock Company A-2 5307-SR-27-1 Figure A-5. Retaining Wall Figure A-6. Outdoor Area Near Still River Figure A-7. Outdoor Area Near Still River Figure A-8. Outdoor Area Near Still River Bldg. A Radium Program
- Gilbert Clock Company A-3 5307-SR-27-1 Figure A-9. Outdoor Area Near Still River Figure A-10. Outdoor Area Near Still River Figure A-11. Outdoor Area Near Still River Figure A-12. West Side of Bldg. A
Radium Program
- Gilbert Clock Company A-4 5307-SR-27-1 Figure A-13. Apartment Kitchen Figure A-14. Apartment Living Room Figure A-15. Apartment Bathroom Figure A-16. Apartment Bedroom
Radium Program
- Gilbert Clock Company A-5 5307-SR-27-1 Figure A-17. Apartment Ceiling Figure A-18. Apartment Ceiling Figure A-19. Bldg. A 1 st Floor Hallway with Rock Wall Figure A-20. Apartment Hallway
Radium Program
- Gilbert Clock Company A-6 5307-SR-27-1 Figure A-21. Apartment A
-22 Figure A-22. Apartment A
-22 5307R0124 5307R0125 Radium Program
- Gilbert Clock Company 5307-SR-27-1 APPENDIX B SURVEY MAPS AND DATA FROM THE FORMER GILBERT CLOCK COMPANY SURVEY Radium Program
- Gilbert Clock Company B-1 5307-SR-27-1 Figure B-1a. Gamma Walkover Survey of Outdoor Area near River Radium Program
- Gilbert Clock Company B-2 5307-SR-27-1 Figure B-1b. Exposure Survey of Outdoor Area near River Radium Program
- Gilbert Clock Company B-3 5307-SR-27-1 Table B-1. Gilbert Clock Apts.
-Outdoor Area near River Location No.
Gamma Comments µR/h at 1 meter 1 19 Rocks 2 12 3 15 4 10 5 8 6 11 7 11 8 11 9 10 10 10 11 9 12 9 13 11 Rocks 14 10 15 15 Rocks 16 10 17 10 18 9 19 15 20 12 Rocks 21 12 22 10 23 11 Rocks 24 9 25 10 26 15 Rocks 27 12 28 12 29 9 30 11 31 9 32 9 33 10 34 9 Rocks 35 8 36 8 37 8 Radium Program
- Gilbert Clock Company B-4 5307-SR-27-1 Figure B-2a. Gamma Walkover Survey of the Parking Lot
Radium Program
- Gilbert Clock Company B-5 5307-SR-27-1 Figure B-2b. Exposure Survey of the Parking Lot
Radium Program
- Gilbert Clock Company B-6 5307-SR-27-1 Table B-2. Gilbert Clock Apts.
-Outdoor Area Parking Lot Location No.
Gamma Comments µR/h at 1 meter 1 11 2 10 North Entrance to Bldg.
3 9 4 10 5 12.5 6 8 7 9.5 AC Units Enclosure 8 10 9 11 South Entrance to Bldg.
10 10.5 11 10 12 10 13 11 14 10 15 8 Drain 16 10 17 11 18 10 19 11 Rock Wall 20 10 21 8 22 10 23 9 24 9 25 9 26 10 27 10 28 10 29 10 30 13 31 12 32 13 33 14 34 14 35 11 36 13 37 15 38 15 Radium Program
- Gilbert Clock Company B-7 5307-SR-27-1 Table B-2. Gilbert Clock Apts.
-Outdoor Area Parking Lot Location No.
Gamma Comments µR/h at 1 meter 39 12 Rock Wall 40 14 Rock Wall 41 12 Rock Wall 42 9 43 8 Northern Street Entrance 44 9 45 10 46 10 47 10 48 9 49 10 50 7.5 51 7 52 11 53 14 54 14 Chimney 55 10 Chimney 56 15 Chimney 57 10 58 15 Rock Wall 59 17 Rock Wall 60 15 Rock Wall 61 10 62 10 Lobby Entrance 63 13 64 12 65 12 66 12.5 67 12.5 Radium Program
- Gilbert Clock Company B-8 5307-SR-27-1 Figure B-3. Survey Map of Apt. A
-1 aBackground varied depending on naturally occurring radioactive material in the area. Site: Gilbert ClockArea: Apt. A-1Date(s): 06/26/18Time: 1530/1600Surveyor(s): JDLPurpose: ScopingRadiation TypeInstrumentDetectoraGamma2221/114144-10/115211 - 16 kcpm aGamma192/1128 NABackground
- =General area measurements provided in attached table.
N Radium Program
- Gilbert Clock Company B-9 5307-SR-27-1 Table B-3. Gilbert Clock Co.
-Apt. A-1 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm 1 - - - - 11,500 - 12 2 - - - - 13,500 - 12 3 - - - - 14,000 - 12 4 - - - - 12,700 - 12 5 - - - - 12,200 - 11 6 - - - - 12,300 - 11 7 - - - - 12,100 - 11 8 - - - - 13,300 - 12 9 - - - - 12,800 - 12 10 - - - - 13,200 - 12 11 - - - - 12,200 - 12 12 - - - - 11,500 - 11 13 - - - - 12,800 - 11 14 - - - - 12,800 - 11 15 - - - - 13,100 - 11 16 - - - - 14,200 - 13 17 - - - - 15,100 - 13 18 - - - - 14,600 - 15 19 - - - - 12,800 - 12 20 - - - - 15,500 - 13 21 - - - - 14,000 - 13 22 - - - - 11,500 - 11 23 - - - - 13,200 - 12 24 - - - - 14,500 - 14 25 - - - - 15,200 - 13 26 - - - - 16,000 - N/A Radium Program
- Gilbert Clock Company B-10 5307-SR-27-1 Table B-3. Gilbert Clock Co.
-Apt. A-1 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm 27 - - - - 12,400 - 11 28 - - - - 18,000 18 15 Wall, < 0.01 m 2 Rm Background
- - - 0 16,560 - 12 Living Room Rm Average
- - - 0 14,400 - 13 Living Room, locations 22
-28 Apt Background
- - - 0 13,296 - 12 Apartment Apt Average
- - - 0 13,464 - 12 Apartment a) Ludlum 44
-142 plastic scintillator with Ludlum 2221 ratemeter b) Ludlum 44
-10 NaI with Ludlum 2221 ratemeter; Ludlum 192 NaI
- indicates measurement not collected at this location
Radium Program
- Gilbert Clock Company B-11 5307-SR-27-1 Figure B-4. Survey Map of Apt. A
-17 Radium Program
- Gilbert Clock Company B-12 5307-SR-27-1 Table B-4. Gilbert Clock Co.
-Apt. A-17 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm 1 - - - - 9,300 - 8 2 - - - - 7,600 - 6 3 - - - - 14,200 - 12 4 - - - - 25,000 - 13 5 - - - - 25,000 - 12 6 - - - - 14,400 - 10 7 - - - - 15,500 - 9.5 8 - - - - 10,400 - 11 9 R0123 < 1 723 2,100 28,500 23 10 Living Room, < 0.01 cm 2 10 - - - - 24,000 - 10 11 - - - - 10,400 - 9 12 - - - - 11,500 - 10 13 - - - - 10,000 - 6 14 - - - - 9,100 - 6 15 - - - - 8,200 - 7 16 - - - - 8,400 - 6 17 - - - - 9,200 - 8 18 - - - - 8,300 - 6 19 - - - - 10,000 - 10 20 - - - - 10,400 - 10 21 - - - - 7,400 - 8 22 - - - - 7,200 - 6 23 - - - - 6,800 - 6 Radium Program
- Gilbert Clock Company B-13 5307-SR-27-1 Table B-4. Gilbert Clock Co.
-Apt. A-17 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm Rm Background
- - - 0 16,711 - 11 Living Room Rm Average
- - - 210 17,890 - 11 Living Room, locations 3
-12 Apt Background
- - - 0 11,923 - 8.6 Apartment Apt Average
- - - 91 12,643 - 8.7 Apartment a) Ludlum 44
-142 plastic scintillator with Ludlum 2221 ratemeter b) Ludlum 44
-10 NaI with Ludlum 2221 ratemeter; Ludlum 192 NaI
- indicates measurement not collected at this location
Radium Program
- Gilbert Clock Company B-14 5307-SR-27-1 Figur e B-5. Survey Map of Apt. A
-19 aBackground varied depending on naturally occurring radioactive material in the area. Site: Gilbert ClockArea: Apt. A-19Date(s): 06/27/18Time: 0940/1015Surveyor(s): JDLPurpose: ScopingRadiation TypeInstrumentDetectorBeta2221/114144-142/920322 cpmGamma2221/114144-10/11526 - 13 kcpm aGamma192/1128 NABackgrounda# =General area measurements provided in attached table.
Radium Program
- Gilbert Clock Company B-15 5307-SR-27-1 Table B-5. Gilbert Clock Co.
-Apt. A-19 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm 1 - - - - 6,700 - 6 2 - - - - 7,000 - 7 3 - - - - 7,000 - 6 4 - - - - 8,600 - 9 5 - - - - 11,000 - 10 6 - - - - 10,500 - 10 7 - - - - 11,800 - 11 8 - - - - 11,800 - 10 9 - - - - 11,200 - 10 10 - - - - 10,300 - 10 11 - - - - 12,500 - 11 12 - - - - 13,000 - 12 13 - - - - 12,300 - 11 14 - - - - 10,800 - 10 15 - - - - 12,500 - 11 16 - - - - 12,300 - 12 17 - - - - 11,600 - 11 18 R0127 < 1 2,100 16,000 62,000 50 20 Bedroom, < 0.01 m 2 Rm Background
- - - 0 11,750 - 11 Bedroom Rm Average
- - - 2,286 18,929 - 12 Bedroom, locations 6
-8 & 15-18 Apt Background
- - - 0 10,641 - 10 Apartment Apt Average
- - - 889 13,494 - 10 Apartment a) Ludlum 44
-142 plastic scintillator with Ludlum 2221 ratemeter b) Ludlum 44
-10 NaI with Ludlum 2221 ratemeter; Ludlum 192 NaI
- indicates measurement not collected at this location
Radium Program
- Gilbert Clock Company B-16 5307-SR-27-1 Figure B-6. Survey Map of Apt.
A-20 aBackground varied depending on naturally occurring radioactive material in the area. Site: Gilbert ClockArea: Apt. A-20Date(s): 06/27/18Time: 0850/0940Surveyor(s): JDLPurpose: ScopingRadiation TypeInstrumentDetectorBeta2221/114144-142/920350 cpmGamma2221/114144-10/11527 - 15 kcpm aGamma192/1128 NABackgrounda# =General area measurements provided in attached table.
Radium Program
- Gilbert Clock Company B-17 5307-SR-27-1 Table B-6. Gilbert Clock Co.
-Apt. A-20 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm 1 - - - - 7,700 - 7 2 - - - - 7,400 - 7 3 - - - - 7,800 - 8 4 - - - - 7,100 - 7 5 - - - - 9,100 - 8 6 - - - - 10,800 - 10 7 - - - - 12,800 - 12 8 - - - - 9,500 - 10 9 - - - - 9,700 - 10 10 - - - - 10,500 - 11 11 R0126 < 1 4,270 36,000 122,000 120 27 Living Room, ~0.1 m 2 12 - - - - 8,000 - 8 13 - - - - 7,800 - 8 14 - - - - 9,400 - 9 15 - - - - 11,900 - 12 16 - - - - 10,200 - 10 17 - - - - 9,800 - 10 18 - - - - 10,900 - 10 19 - - - - 10,100 - 9 20 - - - - 13,200 - 12 21 - - - - 13,600 - 12 22 - - - - 14,400 - 14 23 - - - - 9,200 - 10 Radium Program
- Gilbert Clock Company B-18 5307-SR-27-1 Table B-6. Gilbert Clock Co.
-Apt. A-20 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm Rm Background
- - - 0 9,929 - 10 Living Room Rm Average
- - - 4,500 23,938 - 12 Living Room, locations 4-11 Apt Background
- - - 0 10,041 - 10 Apartment Apt Average
- - - 1,565 14,909 - 10 Apartment a) Ludlum 44
-142 plastic scintillator with Ludlum 2221 ratemeter b) Ludlum 44
-10 NaI with Ludlum 2221 ratemeter; Ludlum 192 NaI
- indicates measurement not collected at this location
Radium Program
- Gilbert Clock Company B-19 5307-SR-27-1 Figure B-7. Survey Map of Apt. A
-21 aBackground varied depending on naturally occurring radioactive material in the area. Site: Gilbert ClockArea: Apt. A-21Date(s): 06/27/18Time: 1040/1115Surveyor(s): JDLPurpose: ScopingRadiation TypeInstrumentDetectorBeta2221/114144-142/920400 cpmGamma2221/114144-10/11527 - 17 kcpm aGamma192/1128 NABackgrounda# =General area measurements provided in attached table.
Radium Program
- Gilbert Clock Company B-20 5307-SR-27-1 Table B-7. Gilbert Clock Co.
-Apt. A-21 Removable Alpha-plus-Beta a Gamma b Location No. Smear No. Alpha-plus-Beta Gross Total Contact 1 m Comments dpm/100 cm 2 cpm dpm/100 cm 2 cpm 1 - - - - 7,200 - 7.0 2 - - - - 7,500 - 7.0 3 - - - - 8,800 - 7.0 4 - - - - 11,000 - 10 5 - - - - 14,400 - 12 6 - - - - 29,000 25 14 Could not directly access 7 - - - - 14,000 - 13 8 - - - - 16,500 - 14 9 - - - - 30,000 28 15 Could not directly access 10 - - - - 13,000 - 13 11 - - - - 12,400 - 12 12 R0128 < 1 1,924 14,000 60,000 39 15 0.01 m 2 13 R0129 < 1 1,921 14,000 40,000 60 18 0.01 m 2 14 - - - - 15,000 - 14 15 - - - - 12,500 - 12 16 - - - - 9,800 - 9.0 17 - - - - 8,800 - 7.0 Rm Background
- - - 0 13,225 - 13 Bedroom Rm Average
- - - 4,000 26,129 - 14 Bedroom, locations 9
-15 Apt Background
- - - 0 18,819 - 11 Apartment Apt Average
- - - 1,647 18,229 - 12 Apartment a) Ludlum 44
-142 plastic scintillator with Ludlum 2221 ratemeter b) Ludlum 44
-10 NaI with Ludlum 2221 ratemeter; Ludlum 192 NaI
- indicates measurement not collected at this location
Radium Program
- Gilbert Clock Company B-21 5307-SR-27-1 Figure B-8. Survey Map of Apt. A
-22 aBackground varied depending on naturally occurring radioactive material in the area. Site: Gilbert ClockArea: Apt. A-22Date(s): 05/01/18Time: 1400/1500Surveyor(s): ASORadiation TypeInstrumentDetectorPurpose: Site Visit (Reinvestigated on Scoping Survey)Gamma2221/113944-10/11519 - 19 kcpm aGamma192/1127 NABackgrounda# =General area measurements provided in attached table.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Radium Program
- Gilbert Clock Company B-22 5307-SR-27-1 Table B-8. Gilbert Clock Co.
-Apt. A-22 Location No. Removable Alpha-plus-Beta a Gamma b Comments Smear No. Alpha-plus-Beta Gross Total Contact 1 m dpm/100 cm 2 cpm dpm/100 cm 2 cpm 1 - - - - 9,300 - 7 2 - - - - 9,500 - 8 3 R0125 < 1 1,410 6,900 74,000 55 13 Kitchen, < 100 cm 2 4 - - - - 13,200 - 11 5 - - - - 11,400 - 10 6 - - - - 11,500 - 11 7 - - - - 10,000 - 10 8 - - - - 11,300 - 10 9 - - - - 12,000 - 10 10 - - - - 10,500 - 10 11 - - - - 12,000 - 10 12 - - - - 9,500 - 10 13 - - - - 10,000 - 9 14 - - - - 10,500 - 10 15 - - - - 13,000 - 15 16 - - - - 11,900 - 10 17 - - - - 12,300 - 11 18 - - - - 13,900 - 7.0 19 - - - - 18,500 - 12 20 - - - - 17,300 - 13 21 R0124 1 4,324 33,000 134,000 100 23 Bedroom, ~1 m 2 22 - - - - 9,200 - 7 23 - - - - 43,000 38 14 Kitchen, < 100 cm 2 Rm Background
- - - 0 10,850 - 9 Kitchen Rm Average
- - - 1,380 26,733 - 11 Kitchen, locations 1
-5 & 23 Rm Background
- - - 0 12,217 - 11 Bedr o om Radium Program
- Gilbert Clock Company B-23 5307-SR-27-1 Table B-8. Gilbert Clock Co.
-Apt. A-22 Location No. Removable Alpha-plus-Beta a Gamma b Comments Smear No. Alpha-plus-Beta Gross Total Contact 1 m dpm/100 cm 2 cpm dpm/100 cm 2 cpm Rm Average
- - - 4,125 28,925 - 13 Bedroom, locations 14
-21 Apt Background
- 0 11,840 - 10 Apartment Apt Average
- - - 1,735 21,209 - 11 Apartment a) Ludlum 44
-142 plastic scintillator with Ludlum 2221 ratemeter b) Ludlum 44
-10 NaI with Ludlum 2221 ratemeter; Ludlum 192 NaI
- indicates measurement not collected at this location
Radium Program
- Gilbert Clock Company B-24 5307-SR-27-1 Table B-9. Estimated Dose from the External Pathway Only Area/Apartment No.
Measured µ R/hr at 1 m Gamma-only Dose Locations used in max room calcu lations a Survey Unit Avg Max Room Avg (mrem/yr) All Data Bkg All Data Bkg Survey Unit Max Room Apt. A-20 Living Room 10 9.7 12 10 4.3 12 Calculated from 8 living room measurements Apt. A-22 Kitchen 11 10 11 9.0 5.0 8.7 Calculated from 6 kitchen measurements Apt. A-22 Bedroom 11 10 13 11 5.0 8.6 Calculated from 8 bedroom measurements Survey Unit Avg
= the average value considering all data collected in the survey unit (apartment or common area)
Max Room Avg = the average value for the room or area with the highest measured radioactivity All Dat a= results from across the entire apartment or room, as applicable Bkg = all results excluding results from hot spots aSee survey maps for gross measurement data by location.
Table B-10. Estimated Dose from the Internal Pathways Only Area/Apartment No.
Measured dpm/100 cm 2 Internal Dose Locations used in max room calculations a Survey Unit Avg Max Room Avg (mrem/yr) All Data Bkg All Data Bkg Survey Unit Max Room Apt. A-20 Living Room 1,565 0 4,500 0 0.5 1.5 Locations 4
-11; living room Apt. A-22 Kitchen 1,735 0 1,380 0 0.6 0.5 Locations 1
-5, 23; kitchen Apt. A-22 Bedroom 1,735 0 4,125 0 0.6 1.4 Locations 14
-21; bedroom Survey Unit Avg = the average value considering all data collected in the survey unit (apartment or common area)
Max Room Avg
= the average value for the room or area with the highest measured radioactivity All Dat a= results from across the entire apartment or room, as applicable Bkg = all results excluding results from hot spots aSee survey maps for gross measurement data by location.
Radium Program
- Gilbert Clock Company B-25 5307-SR-27-1 Table B-11. Total Estimated Dose for Current or Future Occupants Area/Apartment No.
Current Dose a Future Dose b (mrem/yr) (mrem/yr) Survey Unit Max Room Survey Unit Max Room Apt. A-20 Living Room 4.3 12 4.9 14 Apt. A-22 Kitchen 5.0 8.7 5.6 9.1 Apt. A-22 Bedroom 5.0 8.6 5.6 10 aCurrent dose is due to the external pathway only (values from Table B-9) bFuture dose is comprised of all pathways and is a summation of the values from Tables B-9 and B-10; rounded to two digits or to the nearest 0.1 mrem/yr.