ML20057C017
| ML20057C017 | |
| Person / Time | |
|---|---|
| Site: | 07000371 |
| Issue date: | 09/13/1993 |
| From: | UNITED NUCLEAR CORP. (SUBS. OF UNC, INC.) |
| To: | |
| Shared Package | |
| ML20057B681 | List: |
| References | |
| NUDOCS 9309240288 | |
| Download: ML20057C017 (13) | |
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LIST OF FIGURES Figure 1 Sewage Discharge System Figure 2 Holly Hill Wet Well/ Pumping Station Figure 3 Location of Removed-Discharge Line Figure 4 Influent Pipe - Into Holly Hill Wet Well:
Final Survey Figure 5 Solids Analysis:
Avery Hill Wet Well Montville Waste Water Treatment Plant Figure 6 Sewage Discharge Line: In Situ Final Surveys Figure 7 Sewage Discharge Line: Removed Section Final Survey i
9309240288 930913 PDR ADOCK 07000371 C
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4 FINAL DECOMMISSIONING SURVEY REPORT SEPTIC DISCHARGE LINE AND MUNICIPAL PUMPING STATIONS 1.0 Introduction Frca 1958 to 1987, UNC discharged its sewage to an onsite septic system since no municipal sewage system was available.
During 1973, a major plant expansion included the construction of a new septic field and septic tank.
Beginning in April, 1974, discharges to this new system included licensed discharge of low levels of SNM which had been processed through a rad waste treatment facility.
The use of this tank and system continued until November, 1987 when UNC connected its sanitary effluent discharge to the new municipal sewer system per NRC Condition 27 to SNM License 368.
A pump house, new septic tank and new discharge line were constructed to accomplish this.
Final discharge of SNM to this system occurred on 3/10/92.
The onsite septic system and sewage pump house have been remediated and final surveys were reported in References 1 and 2.
Figure 1 illustrates a schematic of this system.
This report covers the sewage discharge line from UNC's p' Imp house, two municipal sewage pumping stations and the municipal sewage treatment plant.
2.0 Identification / Construction UNC collects its sanitary sewage and pumps it from an on-site pumping station via a dedicated sewage discharge line into a municipal manhole located at the junction of Sandy Desert Road and Connecticut Route 32.
From there the sewage merges with r
other municipal sewage and flows north by gravity into the municipal Holly Hill pumping station.
This station pumps its sewage south into the Avery Street pumping station.
The Avery Street station pumps its sewage south to a point where it can gravity flow into the municipal waste water treatment plant located at Pink Row, Montville, CT.
2.1 Sewage Discharge Line i
UNC's sewage discharge line consists of a nominal 3-3/4 inch diameter steel pipe running approximately 1,800 feet into the municipal manhole.
Page 1
l FINAL DECOMMISSIONING SURVEY REPORT SEPTIC DISCHARGE LINE AND MUNICIPAL PUMPING STATIONS l
l 2.2 Holly Hill Pumping Station i
The sewage collection tank of this pumping station, referred to as a wet well, is a confined space, below grade, concrete structure having access by way of a 4' X4' manway at grade level (Figure 2).
The well is-approximately 20' deep and has a tapered bottom.
There are no rungs for access to the bottom of the well.
The well is vented to the surface via a 6" diameter vent pipe.
No lighting is available in the well.
The well chamber is approximately 12' X 10' X 10'.
The Avery Street station is similar in design and I
construction.
1 i
3.0 Surveys /Remediation 3.1 Pumping Stations UNC has been preparing the Montville plant site for final decommissioning during the past three years in accordance l
with our NRC license and plans submitted to and approved by l
the NRC in 1991.
As this work reached its final phase, UNC took samples of l
material on 5/5/93 from the Hol'y Hill wet well, which is the first municipal pumping stat.\\on servicing UNC sewage l
discharge.
Results showed positive levels of uranium at l
approximately 220 pCi/ gram.
Follow-up samples collected from this well confirmed the presence of uranium.
Analysis of sewage samples from the Avery Street Pumping Station and the municipal treatment plant were acceptable to NRC and soil release criteria.
Independent confirmatory l
acceptable results were also obtained by ORISE on similar j
samples.
L Remediation of the Holly Hill Pumping Station was l
accomplished by diverting the sewage flow and removing all accumulated material from the wet well.
Approximately 15 cubic feet of material was removed and solidified for LLRW burial.
3.2 Sewage Discharge Line UNC has already cleaned out and surveyed its on-site pumping station and ORISE has performed confirmatory surveys, with acceptable results.
l Page 2
FINAL DECOMMISSIONING SURVEY REPORT SEPTIC DISCHARGE LINE AND MUNICIPAL PUMPING STATIONS e
A clean discharge line due to normal flushing actions was anticipated based on the small pipe ID of less than four inches and the large 20 H.P. header pumps in UNC's pumping station.
To confirm this, the line was excavated at the UNC pump house end, opened, and visually inspected with a camera probe up to 160 feet.
The other end of the discharge' pipe i
opens into a culvert accessible via a manhole on Route 32.
There was no accumulation of material in this structure.
Camera probe inspection of the pipe to 160 feet from the manhole discharge end indicated the pipe was clean.
This inspection has been recorded on VCR tape and retained.
Although the TV inspection showed no material accumulation in the pipe, the discharge pipe was high pressure back washed to a distance of 100 feet at the pumphouse end of the line.
i Swipes were taken at the pipe opening at the Route 32 manhole.
At the pump station end (Figure 3), a section of l
excavated pipe approximately 4 feet in length was removed and cut along its horizontal axis.
The inner surfaces were then surveyed for fixed contamination.
This pipe would be representative of " worst case" based on its proximity to the sewage source.
All survey data was acceptable to NRC release limits and is presented in Section 4.0.
3.3 Montville Waste Water Treatment Plant (MWWTP)
A sample of sediment from the bottom of the MWWTP wet well j
was taken 5/5/93 and analyzed for uranium with acceptable results.
Processed sludge samples off the MWWTP processing line were also taken on 5/5/93 and found to be acceptable.
These same samples were shipped to ORISE laboratory which independently verified the acceptable results.
i 4.0 Survey Findinas/ Compliance Criteria 4.1 Pumping Stations The Holly Hill pumping station was completely cleaned and rinsed.
A visual inspection confirmed the absence of accumulated sludge.
The influent pipe into the wet well was surveyed with cloth smears.
Alpha / beta results are reported in Figure 4 and do not exceed the values of 1
license condition 11 of SNM 368 which are equivalent to NRC Reg. Guide 1.86.
i Page 3
I
' FINAL DECOMMISSIONING SURVEY REPORT SEPTIC DISCHARGE LINE AND MUNICIPAL PUMPING STATIONS The Avery Street pumping station did not require remediation based on sampling results.
A representative sludge sample was taken on 5/20/93 and data was obtained from gamma ray spectroscopy analysis.
Estimated concentrations of total uranium are based on energy lines from the gamma spectra as follows:
U-345 assumed to be (R X the U-235 concentration).
R = 41.0 for Soil Samples.
U-238 the 93 kev from Th-234, and 1001 kev from Pa-234m (U238 + U235 + (R X U235))
Total U
=
Note:
Secular equilibrium assumed for Th-234 and Pa-234m.
Note:
R=
The Isotopic ratio of U234/U235 and has been calculated at 41 (avg.) for use at this site.
Results are reported in Figure 5.
The sample was split and also analyzed at the ORISE lab with acceptable results.
A second sample was taken at the Avery Street Station on 6/8/93.
The sample was split with the Connecticut Department of Environmental Protection.
UNC's results are reported in Figure 5; we have not yet received the State DEP data results.
Since the contamination level in the representative samples does not exceed Option 1 of the NRC's Branch Technical Positionentitled"DisposalofOnsite{orageofThoriumor I
remediation was Uranium Wastes from Past Operations, not necessary.
4.2 Sewage Discharge Line Survey data reviewed was obtained from both ends of the discharge line as discussed.
A section of the excavated discharge line, pump house end, was cut and removed to enable video inspection and cleanout.
This created two open pipe ends which were surveyed.
(1)
Published in the Federal Reaister on October 23, 1981.
Page 4
FINAL DECOMMISSIONING SURVEY REPORT SEPTIC DISCHARGE LINE AND MUNICIPAL PUMPING STATIONS Survey data was also obtained from the manhole end of the discharge pipe.
Results are reported in Figure 6.
Survey data from the four foot.section of pipe removed (discussed in 3.2) is reported in Figure 7.
All results meet the Iteg Guide 1.86 criteria for releasing the discharge pipe.
4.3 Montville Waste Water Treatment Plant (MWWTP)
The wet well receiving influent was sampled and analyzed.
Results are reported in Figure 4 and verify that remediation is not necessary.
MWWTP process line sludge was also sampled and analyzed on 5/5/93.
Analysis results verify that remediation is not necessary.
These same samples were also analyzed by ORISE with acceptable results reported.
Page 5 l
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l Figure 3 LOCATION OF REMOVED SEWAGE DISCHARGE LINE Pump House Grade J
Foundation
. ~ > ~ ~ ~.,.~~~~~~~~~~~~~.~:
PIPE SECTION REMOVED FOR EVALUATION 12 feet deep 1
I 4
~ 4 feet
HEALTH PHYSICS UNC Nava/ Products survey secord Surveyed By/Date:
ALARON / 6/22/93 Counted By/Date:
T.PROSPERT / 7/6/93 Counter Efficiency A'ohn Egta' Gamma Aloha htaGamma Backcround:
Number.
Factor.
o 3pp o 3g o7 pg S urce Check SURVEY Initials Date Instrument SN Probe SN Bkod
- Eff.f%)
Mutti. Facto' Cat Due Alpha T.P.
89664 7/13/93 080916 1.1 20 10.0 9/18/93 x
Beta' Gamma FAcro R
- Background for meters taken in non-fuel area.
Area HOLLY HILL PUMPING STATION Descriotion: INFLUENT PIPE END FtXED REMOVABLE OBJECT or AREA Raw CPM DP!A100 cm2 Micro R'hr Raw CPM DPtN100 cm2 CORRECWf ALPHA BET ACAMMA ALPHA BETACAMuA ALPHA FIE T AGAMM A AL PHA BE1 AGAMM A FMW wr sutan ei N/A N/A N/A N/A N/A N/A 0
2 0
C per sutaa n N/A N/A N/A N. A N:'A N/A 0
6 0
E wrsutaani N/A N/A N/A N/A N/A N/A 0
4 0
3 mr uG WWE m N/A N/A N/A N/A N/A N/A 2
N/A 9
N/A
_ (1) COUNTED BY ALPHA SURVEY
- METER l
t Figure 4 Influent Pipe - into Holly Hill Wet Well:
Final Survey
t e
Figure 5 Solids Analysis Avery Hill Wet Well R ADIOCHEMISTRY DATA REPORT One sigma Collection Lab Sample Analytical Results S mple I.D.
^""IY neertainty Date No.
Method (pCligm)
(pCilgm)
Avery Hill /1st Sample 5/20/93 25578 Gamma Spec.
Total Uranium 11.97 3.71 Avery Hill / 2nd Sample 6/8/93 26076 Gamma Spec.
Total Uranium 12.52 6.14 MWWTP Wet Well 6/8/93 26077 Gamma Spec.
Total Uranium 5.36 0.86 1
MWWTP Dewatered Digester Solids 5/5/93 25238 Gamma Spec.
Total Uranium 4.86 1.21
HEALTH PHYSICS UNC NavalProducts Survey Record Su:rveyed by/Date:
T.PROSPERT / 6/8/93 Counted By/Date:
T.PROSPERT / 7/13/93 Counter Efficiency A'oha Beta' Gamma Afohn BetarGamma Ba& rom.
Number.
Factor:
0 375 0377 06 16 S urce Check SURVEY Initials Date Instrument SN probe SN Bkad
- Efff%)
Mv!:tFactor Ca' Ne l
Alpha T.P.
8 6M 6/8/93 080916 1.1 20 10.0 9a 8/93 x
Beta' Gamma Micro R
- Background for meters taken in non-fuel area.
l Area SEWAGE DISCHARGE LINE Deseriotlon: ROUTE #32 MANHOLE PIPE END, UNC PUMPHOUSE PIPE ENDS FIXED REMOVABLE OBJECT or AREA Raw CPM DPM/100 cm2 Micro R'hr RawCPM DPM/100 cm2 ALPH A BETAGAMMA ALPHA BETAGAMMA RAW COrFtECTE C ALPH A DETACAMMA ALPHA BETA-GAMMA l
PIPE END, ROUTE 32 MANHOLE wraseser mesun N/A N/A N/A N/A N/A N/A 3
3 7
4 WE AR AT END N/A N/A N/A N 'A N/A N/A 1
1 1
0 uanwt mar mt run 2
N/A 9
N/A N/A N/A N/A N/A N/A N/A CUT PIPE ENDS, EXCAVATED LINE, l
UNC PUMPHOUSE wran orw srcTm N'A N/A N 'A N 'A N/A N/A 1
6 1
12 unart om sttTm n, N.A N/A N/A N/A N/A N/A 4
M'A 29 N/A wr an scam sr cTm N'A N/A N/A N/A N 'A N/A 4
5 10 9
a: mer sxm srcTm m NA N/A N/A N/A N/A N/A 1
N/A 0
N/A
. (1) COUNTED BY ALPHA SURVEY
- METER l
l l
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l F1gure 6 Sewage Disharge Line:
In Situ Final Surveys
HEALTH PHYSICS Fi ure 7 UNC NavalProducts Survey Record Sewage D scharge Line:
In Situ Pinal Survevu St(rveyed 'By/Date:
T.PROSPERT / 7/22/93 Counted By/Date:
/
CoJnter Efficienev -Alpha Beta' Gamma A!pha Beta' Gamma BahouM.
Numbe'.
Factor.
1 S urce Check SURVEY initials Data Instrument SN probe SN Bkod
- Eff.f%)
Ms!ti Factor Cat Due Alpha T.P.
89630 7/22/93 089385 2.1 13 15.4 9/7/93 x
Beta? Gamma Micro R
- Background for meters taken in non-fuel area.
Area SEWAGE DISCHARGE PIPE SECTION Descriotion: HORIZONTAL AXIS CUT OPEN SECTION FIXED SURVEY -INSIDE SURFACES FIXED REMOVABLE OBJECT or AREA Raw CPM DPM100 cm2 Micro R'hr Raw CPM DPM/100 cm2 ALPHA ET AC.AMM A ALPHA ETAGAMMA F%W CORRECTEc ALPHA DETA<.AMMA ALPHA BETA-GAMMA acTm eA 1
N/A 0
N/A N/A N/A N/A N/A N/A N/A wcTm te 1
N/A 0
N/A N/A N/A N/A N/A N/A N/A acim a 4
NA 29 N:A N/A N/A N/A N/A N/A N/A wc m m 4
N/A 29 N'A N/A N'A N'A N/A N/A N/A a cTm 3A 2
N/A 0
N/A N/A N/A N/A N/A N/A N/A ucra n 4
N/A 29 N'A N/A N/A N/A N/A N/A N/A l
acTm 44 2
N/A 0
N/A N/A N/A N/A N/A N/A N/A WCTm da 3
N/A 14 N;A N/A N/A N/A N/A N/A N/A i
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