ML20214L196
| ML20214L196 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 05/31/1987 |
| From: | DETROIT EDISON CO. |
| To: | |
| Shared Package | |
| ML20214L165 | List: |
| References | |
| NUDOCS 8705290227 | |
| Download: ML20214L196 (24) | |
Text
.
I 4
f i
i r
Detroit Edison Company Feral 2 Nuclear Plant NRC Docket No. 50-341 Facility Operating License No. WPF-43 P
Y l
Petition to Retain Trace Quantities of Licensed Radioactive Materials in Soil at the Fermi 2 Site (Submitted under the provisions of The Code of Federal Regulations, Title 10, Part 20, paragraph 20 302)
May 1987 i
l i
i 9
l 8705290227 87052 PDH ADOCK 050 1
PR
Table of Contents Summary 1.0 Introduction 2.0 -Discussion 30 Site and Material Characterization 4.0 Radiological Assessment 5.0 Evaluation of Alternative 6.0 Conclusion References Figure 1 Layout of Fermi 2 Site Figure 2 Core Boring Soil Sample Results - Dec 1985/Feb 1986 Figure 3 Core Boring Water Sample Results - Dec 1985/Feb 1986 Figure 4 Soil Sample Results - November 1986 Figure 5 Cable Duct System Water Sample Results - November 1986 Report on Subsurface Exploration Results - March 1986 Radiological Assessment d
SUMMARY
As a result of two events, in 198S and 1986, involving leakage from the condensate storage tank, a total of 325,000 gallons of condensate water spilled into the diked retention area surrounding the tank. During each event the 1 caked condensate water soaked into the soll in the diked retention area, depositing trace quantities of radioactive material in the surface layer of the soll.
The condensate storage tank is part of the condensate storage and transfer system, which is designed to store and distribute condensate and demineralized water for use in plant systems during normal and shutdown plant conditions.
Condensate water is a highly purified, deionized water with a neutral pH. l.ow levels of radioactivity are present in condensate water from activation of materials in the water as it passes through the reactor. The chemical and radiological qualities of the condensate water are strictly controlled in accordance with commitments made in the Fermi 2 Updated Final Safety Analysis Report (UFSAR) and plant Technical Specifications.
The diked retention area is located within the fenced Security Area at Fermi 2.
Access to the Security Area is controlled by Detroit Edison in accordance with the NRC approved Fermi 2 Security Plan. The diked retention area is on the east side of the Fermi 2 site, approximately 25 feet from the Office Building Annex, and measures approximately 109 feet wide by 232 feet long. As part of the original design, the area is surrounded by a concrete retaining wall, which is topped by a four foot high chain link fence with a locked gate to control access to the area by site personnel.
Two tanks, the condensate storage tank and the condensate return tank, are located inside of the diked retention area, each with a storage capacity of 600,000 gallons. The floor of the diked retention area is approximately 3 feet below grade and the concrete retaining wall extends approximately 3 feet above grade. The six foot deep basin created by this design is intended to be able to contain the complete 600,000 gallon contents of one tank.
After the 1985 event, approximately 10,000 cubic feet of the soil from the floor of the diked retention area was renoved and placed into 9 scaled cargo van containers which are presently in storage next, to the onsite storage facility building. Following the 1986 event, a leaktight poly liner was installed over the soll in the floor of the diked retention area.
In the event of another leak or spill, the poly liner will prevent the leaked or spilled water from soaking into the soil. Any leaked or spilled water from either of the tanks, which is contained by the poly liner, will be pumped to the radioactive waste facility for processing and disposition in accordance with
Summary Page 2 NRC approved programs, plant procedures, the Technical Specifications, and the UFSAR.
The poly liner will also prevent the radioactive material in the soil from being carried into the air as dust. Thus, translocation of the radioactive material which is presently in the soil, if it should occur, will be through gradual leaching and drainage by rainwater and snowmolt into the groundwater.
This process of drainage of the radioactive material in the soll into the groundwater will be greatly reduced because the leaktight poly liner will also contain and prevent drainage of any rainwater or snowmelt in the diked retention area. Rainwater or snowmolt which accumulates on the poly liner is periodically sampled and analyzed and subsequently is pumped out and discharged in accordance with approved plant procedures.
Detroit Edison estimates that the leaked condensate water from both events contained a total of 297 microcuries of chromium-51, manganese-54, cobalt-58, and cobalt-60, based on the analysis of samples of the leaked water.
Based on core borings and soll sampics taken after each of the events, Detroit Edison has concluded that most of the radioactive material in the leaked water was adsorbed in the top 1.5 foot layer of the soll in the diked retention area when the water soaked through the soll. Approximately 78 millicuries of hydrogen-3 (tritium) was also present in the leaked water from the two events. As indicated by soll and water samples, the tritium, which is in the form of water, has not become adsorbed in the soil. As water, the tritium is draining through the soll and diluting fnto the natural groundwater. Thereafter, the diluted tritium will eventually flow castward with the natural groundwater to Lake Er10.
The original concentration of radioactive material in the leaked water was less than 2% of the maximum permissible concentration (MPC) limits which are set by the Nuclear Regulatory Commission (NRC) for liquid effluent discharges. As a result, the leaked condensate water would have been acceptable for direct discharge to Lake Erie in accordance NRC requirements and approved plant procedures because of the very low levels of radioactive material involved.
If the radioactive material drains downward into the natural groundwater and eventually migrates into Lake Erie, the radioactive material will be greatly diluted to concentrations far below the initial concentration of less than 2%
of MPC limits. For this reason, Detroit Edison concludes that the eventual migration of the radioactive material into Lake Erie, should it occur at all, would have no adverse impact on public health or safety and would not be distinguishable from the normal levels of naturally occurring radioactivity already existing in the environment.
The radioactive half-life for each of the radionuclides is relatively short, ranging from 28 days for Chromiun-51 up to 5.26 years for Cobalt-60. Because of these short half-lives, approximately 90% of the radiuactive material has aircady decayed away.
As of May 1987, the total quantity of licensed radioactive materials estimated to remain within the soll in the diked retention area is less than 30 microcuries of cobalt-58, cobalt-60, and
Summary Page 3 manganese-54. More than 95% of this remaining radioactivity will decay away by the time that the Fermi 2 Operating License expires in the year 2025. The remaining radioactivity at that time will consist of less than 1 microcurie of Cobalt-60. This amount of radioactivity,1 microcurie of cobalt-60, is equal to the amount which has been established by the NRC as an Exempt Quantity, i.e., exempt from regulation by the government.
The radiation doses related to the CST leakage events have been previously assessed and reported to the NRC by Detroit Edison in the 1985 and 1986 Fermi 2 Semi Annual Effluent Reports. Detroit Edison has made a more detailed and conservative estimate of the potential radiation doses to a member of the public or to a worker at Fermt 2, which would result from leaving in place the radioactive material within the soil in the diked retention area. The total dose to a member of the public or occupational dose to a worker from all likely scenarios are cach less than 1 mrem. This value,1 mrem, is well below the l
related doso limits established by the NRC or the Environmental Protection l
Agency (EPA) for nuclear fuel cycle operations. For perspective, it should l
also be noted that the value of 1 mrom has recently been proposed by the NRC as l
the limit for Below Regulatory Concern, i.e., negligibic.
NRC regulations do not currently provide a level of radiation dose, resulting from disposition of licensed radioactive material, which is Below Regulatory Concern (i.e., negligible), although a level of 1 mrem has recently been proposed and published by the NRC. Current NRC regulations and the Fermi 2 l
Operating Licenso do not provide for disposition of licensed radioactive materials by methods other than burial at a licensed disposal facility or as a part of plant effluents. Accordingly, Detroit, Edison has decided, in l
accordance with the provisions of 10 CFR 20 302, to submit this petition to request approval from the NRC to retain the radioactive material within the l
soll in the diked retention area at the Fermi 2 site.
l The levels of radioactivity and radiation dose which are described in this l
petition are far below comparable levels which result from naturally occurring l
radioactivity and radiation in the environment. Detroit Edison recognizes that these levels are not normally considered by the NRC to represent a potentially i
significant impact upon man or the environment. However, Detroit Edison also l
recognizes its responsibility to assure that all radioactivity is controlled l
and disposed of in the manner which best protects public health and safety and the environment. To that end, Detroit Edison's petition is very conservative relative to the evaluation of impacts upon public health and safety and the environment.
An alternative to leaving the radioactive materini in the soll of the diked I
retention area is to dig up and transport the 30,000 cubic feet of soil to a licensed disposal facility in South Carolina or Washington.
Detroit Edison has evaluated this alternative and included the evaluation in this petition.
In summary, the alternative of digging up the soll and transporting it to a licensed disposal facility is estimated to cost more than $1,500,000 (1987 j
dollars) without any appreciable benefit to pubito health and safety or to the environment.
l Summary i
Page 4 I
i Based on the analysis and evaluation included in this petition, Detroit Edison 4
has concluded that the impact upon public health and safety or to the environment, resulting from leaving the licensed radioactive material in the soll in the CST diked retention area, is negligible. Therefore, Detroit Edison believes that retaining the described radioactive material in its present location within the soil in the diked retention area is the best alternative with regards to public health and safety and the environment.
4 i.
f i
a l
[
j l
i I
l l
L i
i i
I I
i t
1.0 Introduction The purpose of this petition is to request approval from the Nuclear Regulatory Commission (NRC), in accordance with the provisions of Title 10, Code of Federal Regulations, section 20 302 (10CFR20 302), to dispose or licensed radioactive material in a manner which is not currently authorized by the Fermi 2 Operating License.
The licensed radioactive material addressed by this petition consists of very small quantities of activation products, primarily tritium (H-3), cobalt-58 (Co-58), cobalt-60 (Co-60), and manganese-54 (Mn-54), distributed in low concentrations in soil within the diked retention area at the Fermi 2 site due to events in 1985 and 1986 which resulted in leakage from the condensate storage tank. These events have been assessed and identified in previous reports to the NRC (References 1, 2 and 3).
Detroit Edison has evaluated the radiological and environmental impacts of the proposed method of disposition for the described radioactive material.
Based on this evaluation, Detroit Edison has determined that approval of the proposed method will not present any discernable hazard to public health and safety or to the environment.
In addition, Detroit Edison has evaluated the potential impacts and costs associated with the most feasible alternative method of disposal to that which is proposed.
In comparing the alternatives, Detroit Edison has concluded that the proposed method of disposition, i.e., retaining the radioactive material at its present location at the Fermi 2 site, has minimal impact upon public health and safety and with regards to the public interest.
2.0 Discussion 2.1 1985 Event Resulting in Leakage from the Condensate Storage Tank On November 17, 1985, approximately 50,000 gallons of condensate water leaked from the Condensate Storage Tank (CST) and soaked into the soll within the diked retention area which contains the CST and the Condensate Return Tank (CRT). The diked retention area is located within the fenced Fermi 2 Security Area. As part of the original design, the diked retention area is approximately 109 feet wide by 232 feet long and is surrounded by a reinforced concrete wall designed to contain the contents of a ruptured CST or CRT.
In addition, the area is fenced to control access by site personnel. The area is approximately 25 feet north of the Office Service Building complex (See Figure 1).
The radionuclide quantities and concentrations in the leaked condensate water, based on maximum concentrations in sampics taken at the time of the leak, are shown in Table 1.
As indicated in Table 1, all radionuclides were at concentrations far below (less than 2%) the NRC's maximum permissible concentration (HPC) limits for dischargo directly to Lake Eric.
10CFR20 302 Pctition May 1987 Page 2 Table 1.
Radionuclide Concentrations and Quantitles in Leakage Water from Condensate Storage Tank - November 17, 1985 Concentration MPC#
MPC Total Activity **
Radionuclide (uC1/ml)
(uC1/ml) Fraction (uC1)
Hydrogen-3 1.75 E-5 3 E-3 0.6%
3310 Chromium-51 4.92 E-7 2 E-3 0.02%
93 Manganese-54 6.31 E-8 1 E-4 0.06%
12 Cobalt-58 8.26 E-7 9 E-5 0.9%
156 Cobalt-60 1.26 E-7 3 E-5 0.4%
24
- MPC: Maximum Permissible Concentration limts for radioactivity in liquid effluents to unrestricted areas, prescribed by the Nuclear Regulatory Commission (NRC) in Title 10, Code of Federal Regulations, Part 20, Appendix B, Table I, Column 2
- Total Activity = Concentration (uCi/ml) x Total Volume (1.89 E8 ml)
In December 1985 and February 1986 Detroit Edison made core borings in and around the diked retention area in order to characterize the soil and to determine the distribution of the spilled radioactive material in the soil and the groundwater. A report on the soil and groundwater characteristics of the diked rention area is included with this petition as Attachment 1.
The soil and water sample locations and results are shown in Figures 2 and 3 From the sample results, it was apparent that the spilled radioactive material, with the exception of tritium (hydrogen-3), was retained in the top layer (1.5 feet) of soil. The tritium, as expected, was distributed through the soll to the groundwater, located 4.5 to 6.0 feet below the soil surface.
This distribution of radioactive materials in the soil and the groundwater is consistent with the related assumptions and models which are provided by the NRC in Regulatory Guide 1.109 (Reference 4), and which were also used in performing the radiological assessment in this petition.
As part of the corrective actions generated by Detroit Edison's evaluations of this event, Detroit Edison installed a leaktight poly liner in the floor of the diked retention area to contain any future leaks or spills from the tanks and to provide for recovery of leaked or spilled water. Accordingly, Detroit Edison removed the upper 0.5 foot layer of soil from the floor of the diked retention area in October 1986, in preparation for the poly lince installation. The removed soil was placed into nine (9) cargo van containers.
The sealed containers, holding approximately 10,000 cubic feet of soil, are currently being stored adjacent to the east side of the onsite radwaste storage building at the Fermi 2 site.
10CFR20 302 Patition May 1987 Page 3 Detroit Edison estimates that the approximate 10,000 cubic feet of soil, which was recovered and stored in the cargo van containers, includes between 33% to 99% of the radioactive material in the leaked condensate water, with the exception of the tritium. This estimate is based upon the core boring sample results which showed that the detectable radioactivity was retained in the upper 1.5 feet layer of the soil, and that 1/3 of the upper 1.5 feet layer (i.e., the top 0.5 feet) of the soil was recovered and placed into the cargo van containers.
The soil in the cargo van containers is considered to be solid radwaste in storage, and it is not the subject of this petition. Its method of disposal will be determined in accordance with the radwaste storage limitations in the Fermi 2 License, i.e., 5 years, and will be based on applicable regulations and considered alternatives for disposal which are in effect at that time.
2.2 1986 Event Resulting in Leakage from the Condensate Storage Tank Before Detroit Edison had completed installion of the poly liner in the floor of the diked retention area, a second event occurred on November 17, 1986, in which approximately 275,000 gallons of condensate water leaked from a broken weld at the base of the CST. The spill water soaked into the soil within the diked retention area and also flowed into the plant underground cable duct system. The radionuclide quantities and concentrations in the leaked condensate water, based on maximum concentrations in spill water samples taken at the time of the leak, are shown in Table 2.
Similar to the 1985 data, the radionuclide concentrations in this second spill were also far below (less than 2.5%) the MPC limits established by the NRC.
Table 2.
Radionuclide Concentrations and Quantitles in Leakage Water from Condensate Storage Tar 4 - November 17, 1986 Concentration MPC#
MPC Total Activity **
Radionuclide (uC1/ml)
(uCi/ml) Fraction (uC1)
Hydrogen-3 7.08 E-5 3 E-3 2.4%
73,700 Cobalt-58 1.18 E-8 9 E-5 0.01%
12
- HPC: Maximum Permissible Concentrations for radioactivity in liquid offluents to unrestricted areas, prescribed by the Nuclear Regulatory Commission (NRC) in Title 10, Code of Federal Regulations, Part 20, Appendix B, Tablo I, Column 2
- Total Activity: Concentration (uC1/ml) x Total Volume (1.04 E9 ml)
Following this event, surface soil samples were taken within the diked retention area and water samples were taken from manholes in the cable duct system. The locations and results of these samples are shown in Figures 4 and
10CFR20 302 P tition May 1987 Page 4 l
5.
Because'the characteristics of the soil and the groundwater in the diked retention area had been previously characterized, following the 1985 event, no core borings were made after the 1986 event.
Samples of water in the cable ducts showed small concentrations of tritium, which were less than the concentrations of tritium in the actual spill water.
The lower concentrations of tritium which were found in the water samples from the cable duct system indicated that the spill water had been diluted by the natural groundwater which is in the cable duct system. Detroit Edison f
recovered approximately 80,000 gallons of the diluted spill water from the cable duct system and returned it to the radioactive waste facility for processing and discharge in accordance with the Fermi 2 Technical Specifications.
Based on the water samples taken from the cable duct manways, Detroit Edison esticates that approximately 2 millicuries of tritium was included in the recovered spill water. The remainder of the tritium, approximately 75 millicuries, has distributed and diluted through the soil-water matrix and into the natural groundwater.
The results of the soil sample which were taken after the November 1986 event showed low levels of Cobalt-58 and Cobalt-60 in the soil of the diked retention area. As shown in Table 2, Cobalt-60 was not detected in the samples of the leaked condensate water which were taken after the 1986 event. The presence'or the Co-60 in the soil samples is attributed to either being residual radioactive material from the previous 1985 event or as being a result of the different detection sensitivities for detecting Cobalt-58 and Cobalt-60 in soil samples and in water samples.
Based on an evaluation of the total quantities of radionuclides in the spill water samples and of the maximum radionuclide concentrations in the soil samples, Detroit Edison made an estimate of the maximum quantity and concentration of radioactive material resident in the soil of the diked retention area (as of May 1, 1987), which is shown in Table 3 Based on the results of the core boring samples which were taken after the 1985 event, in November 1985 and February 1986, the radioactive material is determined to reside in the upper 1.5 feet layer of the soil.
l l
l I
)
~
PT 10CFR20 302 Patition.
May ;1987 i
Page.5
~,
l n
~
4
^
w Table 3. Estimated Maximum Residual Radioactivity intthe soil of the CST /CRT Diked Retention Area
[
3
_a
-1 Total in Total in Soil' Maximum Con-Radio-1 Spill Water Radioactive as of May 1987 centration in
-nuclide (uC1)#
Half-Life ##
(uci)###
Soil (pC1/g)####
Chromium-51 93 (1985) 27.8 days 3 0.0002 none detected Manganese-54 12 (1985) 303 days 3.6-none deteeted Cobalt-58 15'6 (1985)
'71 3 days 12 (f986) 34 q 0.078.
Cobalt-60 24 (1h85) 5.26 years 20 1 0.120 TOTAL 27 0002 uCi 1 0.198 pCi/g w
~
T
.., g 7
s, c 1l.,,, 0 s
Figures in parentheses indicate the year of the'shf11
?
Reference:
Radiological Health Handbook, published by the,US Dept. of Health Education and Welfare, Public Health Service, January 1970
- No credit is taken for the 10,000 cubic feet of soil recovered in-October 1986 I
- Data is based upon the highest radionuclide concentrations which were l
~ detected in the soil samples taken after the November 1986 event i
After completing a radiological asses'sment of the 1986 spill,' Detroit Edison completed installation of the poly liner.
In December, 1986, a leaktight poly liner was installed over the soil in the diked retention area to contain any future discharges from the tanks and to provide further assurance that.the.
small amounts of radioactivity in the soil would not be resuspended as dust or otherwise disturbed.
7 3 0 Site and Material Characterization N
3 1 -Site Characteristics The diked retention area surrounding the Condensate StoragdiTank (CST) and the
+
Condensate Return Tank (CRT) is located on the east boundary of the Fermi 2 l
site within the fenced Security. Area (Figure 1). Access to the fecurity' Area is controlled by Detroit Edison in accordance with the NRC approsed Farmt 2 Security Plan to prevent unauthorized entry.
9 i
i The diked retention area measures approximately 109 feet wide by 232 feet long and is contained by a single concrete wall around the entire perimeter. The i
concrete wall is 3 feet high (above grade) on the north, west and south sides and is 9 feet high (above grade) on the east side, adjacent to Lake Erie. The e
i l
~,,
_ _, _ _ _. _ _. ~ _ _
10CFR20 302 P;tition May 1987 Page 6 concrete wall includes a removable section to allow vehicular and equipment s
access to the CST /CRT area on the west side of the diked retention area. The diked area is approximately 25 feet north of the Office Building Annex and approximately 50 feet west from Lake Erie, and is separated from Lake Erie by the concrete retaining wall and to the impermeable clay core of the site shore barrier.
A four feet high chain link fence is installed on the top of the concrete wall on the north, west and south sides to prevent unauthorized access to the area.
The chain link fence includes a locked access gate on the west side. The key to the gate lock is controlled in accordance with plant procedures to limit access to the area to authorized personnel only.
The floor of the diked retention area is approximately 3 feet below grade, which provides a 6 feet deep retention basin within the diked retention area, including the 3 feet high concrete wall. The floor of the diked retention area has been covered and sealed with a 90 mil thick poly liner to contain any discharge of condensate water in this area. The poly liner is of the same design and manufacturo that is widely used to line holding ponds and reservoirs.
The retention area floor beneath the liner has been contoured to drain any
' leaked condensate water or rainwater runoff to two lowpoints, one at the north end and one at the south end of the retention area. Each lowpoint drain area includes a blind sump at the west side corners of the retention area to facilitate the transfer of water from the retention area using portable pumps.
The poly liner also will prevent suspension of the radioactive material in the soil as dust and will minimize the movement of the radioactive material to the natural groundwater because rainwater and snowmelt will be contained by the liner, rather than draining through the soil.
The design basis of the retention area provides for a total capacity of one full tank of water (i.e. 600,000 gallons), plus approximately 5,000 gallons of excess capacity to account for accumulated snowmelt and rainwater. Accumulated snownelt and rainwater in the retention area are periodically sampled for radioactive and chemical constituents and transferred from the retention area in accordance with plant procedures. Radioactively contaminated water will be returned to the radwaste facility for appropriate processing in accordance with plant procedures. No radioactivity in accumulated rainwater or snowmelt has been noted to date. Non-contaminated water is discharged in accordance with applicable plant procedures and National Pollutant Discharge Elimination System (NPDES) permits.
f.ttachment 1 includes a detailed description of the soil and groundwater characteristics within and around the diked retention area.
In general, the scil type encountered was gray crushed limestone, overlaying a partial layer of brown silty clay. The groundwater table below the retention area was encountered in the elevation range of 574 to 575.5 feet versus an average elevation of 580 feet at the soil surface within the diked retention area
10CFR20 302 Pstition May 1987 Page 7 (i.e., the groundwater was approximately 4.5 to 6.0 feet below the soil surface).
From the description which is documented in the Fermi 2 Updated Final Safety Analysis Report (UFSAR), leakage from the CST or CRT will seep downward through the diked retention area soil to mix and dilute with the groundwater.
Thereafter, the diluted material would move eastward toward Lake Erie at the same rate of flow as the natural groundwater. Direct access into Lake Erie by water leaking into the diked retention area is prevented by the clay core of the Fermi 2 site shore barrier, which is maintained in accordance with plant Technical Specifications. Thus, the spilled water could not simply flow directly into the lake, but would be retained behind the clay shore barrier to filter out at a slower rate.
3 2 Radiological Properties The licensed radioactive material addressed in.this petition consists of trace quantities of cobalt-58 and cobalt-60, and potentially includes undetected quantities of chromium-51 and manganese-54.
Based on the results of the core boring samples which were taken after the 1985 event, the majority of these radioactive materials have been determined to reside within the upp r 1.5 feet of soil. This equates a total volume of approximately 30,000 cubic feet of soil.
The maximum total quantity and concentration of radionuclides in the soil of the retention area are shown in Table 4.
The values are shown as of May 1987 (the date of this petition) and also are projected as of March 2025, accounting for radioactive decay, which is the expiration date of the Fermi 2 Operating License. After the expiration of the Operating License in March 2025, the Fermi 2 site, irduding the retention area may be decommisioned and released for use by the petlic.
Table 4.
Maximum Total Inventory and Maximum Detected Concentrations of Radionuclides in soil (decayed to April 30, 1987)
Radio-Max. Total Quantity (uC1)
Max. Concentration (pCi/g) nuclide May 1987 March 2025 May 1987 March 2025 Chromium-51 0.0002 negligible
- none det.**
negligible Manganese-54 36 negligible none det.
negligible Cobalt-58 3.4 negligible 0.078 negligible Cobalt-60 20 0.13 0.120 0.0008 negligible is used to denote quantities which are essentially zero, i.e.,
less than one trillionth (0.000000000001) of a picocurie, due to extensive radioactive decay
10CFR20 302 Patition i
May 1987 Page 8 none det. indicates that this radionuclide was not detected in any of' the soil-samples 4
As shown-in Table 4, by March 2025, the maximum total l amount of radioactivity l
will be 0.13 microcurie of cobalt-60. This value is about 1/10th of the 1 microcurie limit for cobalt-60 which is specified by the NRC as an Exempt Quantity (Reference 4), i.e., a quantity which is exempt from federal regulation.
i The estimated maximum concentration of radioactive material in the soil in March 2025, which is shown in Table 4, is less than 1/1000th of a picocurie per gram. For perspective, it.should be noted that the average concentration of t
naturally occurring radioactivity in limestone, which is the same material as the soil in the retention area,-is more than 3 picocuries per. gram (Reference 5), which is more than one thousand times the amount shown in Table 4.
t Also present are low concentrations (less than 2% of MPC, based on the spill water concentrations) of tritiated water absorbed in the soil matrix and in groundwater, eatimated as:a total of 72 millicuries.. Further recovery of ~the tritiated water is not considered feasible. The calculated potential-doses.to a member of the public due to the 1985 and 1986 spills have been previously assessed and reported in the respective Fermi 2 Semi Annual Effluent Reports (References 1 and 2).
33 Chemical Properties The licensed radioactive material addressed in this petition consists of small quantities of activation products carried by leaked condensate water into soil.
Condensate water is highly purified, deionized water with a neutral pH. The condensate water is controlled by Technical Specifications to ensure-maintenance of its chemical qualities within a very restrictive. range of 4
limits. Records of chemical analyses which demonstrate.the quality of the l
condensate water are maintained in accordance with NRC requirements. The condensate water is free of chemical agents which might pose a hazard to public i
health or the environment due to corrosivity, explo'sivity, reactivity, 'etc.
4.0 Radiological Assessment j
Detroit Edison made a detailed and comprehensive assessment of the maximum i
potential radiation dose-to a member of the public and to an occupationally exposed worker which might result from retaining the radioactive material in the soil of the retention area. This assessment is summarized below. The details of the radiological assessment are included with this petition as.
The radiation dose estimates are based on the highest concentrations found in samples which were taken at the time of the events and have been calculated using the conservative methods and assumptions recommended by the NRC in Regulatory Guide 1.109 and NUREG/CR-3332 (References 4 and 6). These methods i
i
10CFR20 302 Petition May'1987-Page 9
!~
i were used.instead of the BRC-IMPACTS code which has recently been recommended in NUREG/CR-3585 (Reference 7). The Reg Guide 1.109 methods were used because of the minimal number and small amounts of radionuclides involved, which did not necessitate the use of the computer-based BRC-IMPACTS code.
In addition, use of.the Reg Guide 1.109 methods makes the assessment consistent l
with the previous analyses which were included in the original license application and the FSAR.
During the postulated transit of the radioactive material from the soll of the retention area to the natural groundwater, holdup and decay of the radioactive material will occur in the soil matrix and additional decay and dilution will occur during leaching and drainage of the radioactive material into the natural groundwater beneath the retention area. These factors will significantly reduce the amount of radioactive material which might eventually reach Lake Erie through the groundwater. As a result, the maximum potential radiation dose to a member of the public would be significantly reduced.
l No credit was taken in the assessment of radiation dose to a member of the public due to migration of the radioactive material from the retention area soil to Lake Erie to account for holdup,. radioactive decay, or dilution, because no credit for these factors was previously taken in the original design basis of the retention area which is documented in the Fermi 2 UFSAR.~
l Accordingly, it should be noted that the related calculated potential radiation dose to a member of the public, which is included in Section 4.0 of this petition, is considered by Detroit Edison to be an extremely conservative 4
estimate.
The results of the assessment of the maximum potential radiation dose to a i
member of the public, to an intruder after 40 years (i.e., after plant decommissioning with no mitigating actions), and to an occupationally exposed individual are summarized in Table 5.
i I
Table 5.
Radiological Dose Assessment of the Maximum Potential Whole Body Doses Associated with Retention of Contaminated soil in the CST /CRT Diked Retention Area 1
)
A.
Maximum Potential Whole Body Dose to a Member of the Public (during the period of the Fermi 2 Operating License - until March 2025)
Due to water and fish ingestion 0.042 arem Due to direct exposure to shoreline sediments 0.002 arem l
Total 0.044 meem Note: This value of 44/100ths of-a millirem is less than 2% of the NRC Annual Limit for Whole Body Dose to a Member of the Public from Liquid Radioactive Effluents - 3 mrem per year (Reference 8)
B.
Maximum Potential Whole Body Dose Rate to a Member of the Public (after expiration of the Fermi 2 Operating License - if the area is released for public use without any further remedial actions)
I
10CFR20 302 Patition May-1987 Page 10 Due to direct exposure to contaminated soil 0.004 mrem /yr Due to resuspension of soil into the air 0.675 mrem /yr Total 0.675 mrem /yr Note: This value of approximately 7/10ths of a millirem per year is less than 3% or the Environmental Protection Agency (EPA) limit for dose to a member of the public from radiation and radioactivity in the environment resulting from nuclear fuel cycle operations - 25 mrem per year (Reference 9)
C.
Maximum Potential Whole Body Dose to a Fermi 2 Worker Due to direct exposure from the soil 0 3 mrem Note: This value of 3/10ths of a millirem is less than 0.03% of the NRC quarterly limit for occupational dose to a worker - 1,250 mrem per quarter (3 months) (Reference 10)
As shown in Table 4, the maximum doses to a member of the public or occuputional dose to a worker from probable scenarios are less than 1 mrem.
The value of 1 mrem is below related dose limits established by the NRC or the Environmental Protection Agency (EPA) for nuclear plant operation and is comparable to the value currently proposed by the NRC as Below Regulatory Concern (BRC) (Reference 11).
5.0 Evaluation of Alternative - Excavation, Packaging and Shipment of the Contaminated soil to a Licensed Disposal Facility Detroit Edison believes that the most feasible alternative to retaining the contaminated soil in its present location is to retrieve and dispose of the material in the manner which is currently authorized by NRC regulations, i.e.,
burial at a licensed disposal facility. Recovery of a large fraction of the radioactive materials, with the exception of tritium, could be accomplished by excavation of the top layer of the soil (approximately 1.5 feet) from the diked retention area, and subsequent packaging and shipment of the soil to a licensed disposal facility. This option would consist of digging up 30,000 cubic feet of soil, placing the soil into approximately 1,300 55-gallon steel drums and transporting the drums to either South Carolina or Washington State via 10 to 15 tractor-trailer vanload shipments.
The following points are made to support the conclusion that this proposed alternative, i.e., excavation, transport and burial at a licensed disposal facility, is less beneficial to the public interest or the environment than the option requested in this petition:
1.
The calculated maximum potential radiation doses associated with retaining the contaminated soil in its present location are less than l
t
10CFR20 302 Pstition May 1987 Page 11 4
'the values currently proposed by the NRC in the Federal Register as Below Regulatory Concern, i.e., they are considered to be negligible.
2.
The current direct cost for low level radwaste disposal via this method is more than $50.00 per cubic foot, for a total of $1,500,000 for the 30,000 cubic feet of soil. Under current regulations, this cost would be borne by the utility rate payers without any significant improvement in public health and safety or the' environment.
3 There is a small risk relating to the possible further leakage of
~
condensate water if the condensate storage tank or condensate, return tank were damaged during excavation activities. This might result in additional radioactive material being_ deposited in the soil, because 1
the poly liner would be removed during the excavation to. prevent it from being punctured or torn by equipment.
4.
Excavation, transport and burial of such small quantities and low contentrations of radioactive materials would result in an inefficient use of the limited available burial space at existing disposal facilities.-
!~
l 6.0 conclusion 1
j Based on the analysis and evaluation included in this petition,_ Detroit' Edison has concluded that the impact upon public health and safety or to the environment, resulting from leaving the licensed radioactive material in the soil in the CST diked retention area, is negligible..The most feasible alternative, i.e., digging up the soil and shipping it to a licensed disposal facility, would involve a risk of further leakage of radioactive material into the soil, and would cost more than $1,500,000 without any discernable benefit-to public health and safety or the environment. Therefore, Detroit Edison believes that retaining the described radioactive material in its present-3 location within the soil in the diked retention area is the best alternative with regards to public health and safety and the environment.
j 4
i 4
i 3
e 1
, _ _. _ ~ _ _. - _ _ _ _ _ _ _ _..
4 j
. References 1.
Fermi 2 Semi Annual Effluent Report,' June --December 1985 2.
Fermi 2 Semi Annual Effluent Report, June - December 1986
]
3 Fermi 2 Licensee Event. Report No.'86-045-00, January 12, 1987 4.
NRC Regulatory Guide 1.109,~ Revision 1, Calculation of Annual ~
~
Doses to Man from Routine Releases of Reactor Effluents for the l'
Purpose of Evaluating Compliance with'10 CFR Part 50, Appendix-I, October 1977 5.
Eisenbud, M.,. Environmental Radioactivity, Second Edition,-
j Academic Press, New York 1973, page 170, Table 7-6 6.
Till, J.E., and Meyer, H.
R., Radiological Assessment, A Textbook j
of Environmental Dose Analysis, NUREG/CR-3332, USNRC, Washington, D. C. 1983 7
Forstom, J. M., and Goode, D.
J., De Minimus Waste Impacts Analysis Methodology, NUREG/CR-3585, USNRC, Washington, D.-C.~
1984 8.
Code of Federal Regulations (CFR), Title 10,'Part 50, Appendix I, Numerical Guides for Design Objectives and Limiting Conditions for Operation to Meet the Criterion "As. Low As Is Reasonably l
Achievable" for Radioactive Material in Light-Water-Cooled L
Nuclear Power Reactor Effluents-t 9
CFR, Title 40, Part 190, Paragraph 190.10, Environmental Radiation Protection Standards-for Nuclear Power Operations
- 10. CFR, Title 10, Part 20, Paragraph 20.101,' Radiation Dose Standards for Individuals in Restricted Areas f
- 11. Nuclear Regulatory Commission Staff Implementation of Nuclear-Regulatory Commission Policy on Radioactive Waste Below Regulatory Concern, published in the Federal Register, Vol. 51, No. 168, Friday, August 29, 1986, page 30840 L
l
L a,.
..m t
FIGURE 1 Q
LAYOUT OF FERMI 2 SITE N
D"#d
~
~
(
FENCE OM U
%oO o'
=
~
ELDG W
W nan W
SLDG w
o c=
m vs w
w
==
TSC' 034
" = ~
u-
FIGURE 2
CORE BORING SOIL SAMPLE LOCATIONS DECEMBER 1985
/
FEBRUARY 1986 KEY
@<u,
@ umzTocana
< u. 2.", ",%*
m a
g _== -
< us e
i m _ __
0'ua".%
m m
N m
m
< u.
}
n',@ ~
u a
- g 4glin:
N
, g _-
. g _- e 3-'
'g a
a
@ < us 4M
< 113
< EB
< LLD
FIGURE 3
CORE BORING VATER SAMPLE LOCATIONS DECEMBER 1985
/
FEBRUARY 1986 KEY
@c u.
g 1""
< u "" "O
- - =m m
g
- -=
g
<m e
[s] me==.
=,=4 -
a w.
m m
N.
m
-,.4 A
g
=,=4
-=
v v
m,an a
- m. -
e "$-2 5'*^ *"
,=4
@ = - *=
- 'a^ *"
< u.
< u.
< u.
a
h FIGURE 4
SOIL SAMPLE RESULTS 21 NOVEMBER 1986 KEY 3
g sa-. e.-se A m" m" E T @,,o e *-m est a rgi 0
rs uc-.
-=
o c-.
m--
A A
~ -
g accrmc A
g"-j'm*.-,.
--n m
o=%
i A
A
)
N m
m
\\
= * - "
s o
A A
g 12!c-7 cco-san
1 a
m.
O FIGURE 5 CABLE DUCT SYSTEM i
VATER SAMPLE RESULTS - NOVEMBER 1986 NOTE:
Att Values refer to trithan concentrations in uCi/nl
@a Less than (O values indicate Lower Limit of Detectability
< ur-s
_ Sanple Dates are give in parentheses A4P
~
CIII.2ME TOWuts I
N l
1 M'
M -4 sums A
O C
~.,
.ox v'
t EAc
< 151C EJG AIB i
Y 8E~4 0t/4)
M"BG
( UX 6 A
N -S GR/D[ h G2/4
< ur-.
s n==c v
CE/tp EUIL=eG w
l W.AB A
C3ic use sTE eu=>h VMTDt 4.35E-d N-5 02/D r3
< Mr 6 W
g N
s34E-4 as/4 ggy-VISUAL D35.
C3tc W
w g
3 VATUt V tdt 5
w FJ s-w
=== =mc W@
,r De T
% a./4 i
one -
VISU.AL DBS, Mg V Toi 0 g rv.ac PAD TmT V w
i "5m 55 g
w w
w w
P EfCLOSURE 1