ML19259B942
| ML19259B942 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/26/1979 |
| From: | GEORGIA POWER CO. |
| To: | |
| Shared Package | |
| ML19259B941 | List: |
| References | |
| NUDOCS 7906040010 | |
| Download: ML19259B942 (3) | |
Text
'
NARRATIVE
SUMMARY
NBC DOCKET 50-321 OPCRATION LICENSE DPR-57 EDWIN I.
!!ATCil NUCLEAR PLANT - UNIT 1 NONROUTINE'DADIOLOGICAL ENVIRONMENTAL OPERATING REPORT ANOMALOUS MEASUREMENT REPORT Pursuant to Section 3 2 and 5.7.2 of the Environmental Technical Specifications (ETS),
Appendix B
of the Operating
- License, this noncoutine report describes the elevated tritium concentrations in ground water samples collected from two locations within the protected area.
These concentrations exceed the reporting level of 3
,X 104 pCi/1 specified in Table 3 2-2 of the ETS.
A sanple taken from Piezometer No. P17B on December 1, 1978, showed al 1cvel of 2.6 X 105 pCi/1.
After receiving the laboratory report
/87 from this sample, a new sample was collected on January P4,
- 1979, tol f confirm this elevated level.
Confirmation was established on March V
'#" f(IL 12 by receipt of the lab report for the January sample; the concentration was 1.7 X 105 pC1/1.
Piezometer No. P17p is a well about 13 feet deep which is located adjacent to the SE corner of the Diesel Generator Building.
The laboratory results of the previous samples at this location (all in 1978) were 8.5 X
- 102, 7.o x
103 and 1.1 X
104 pCi/1 for collections on E/18, '8/8 and 8/31, respectively.
The laboratorv results for samples collected on 2/16/79 and 3/13/79 have not yet been received.
The second location from which ground water was collected with elevated concentrations of tritium was Piezemeter No. P16.
This well n
is also about 13 feet deep; it is adjacent to the south side or the condensate storage tank (CST).
The laboratory results received on P A March 12, for a anmple collected on January 26,
- 1970, showed a
d L
concentration of 1.4 X 105 pCi/1.
Previous samples fall in 1078) were 1.4 X 105, 1.6 X
- 105, and 1.5 X
105 pCi/1 for collections on 6/18, 8/8, and 8/31, respectively.
The laboratory results for samples collected on 2/14/79 and 3/9/79 have not yet been received.
These previous elevated levels were not reported since there were no reporting levels for radiological environmental samples prior to an amendment to the ETS on November 16, 1978.
This am en dr.e n t also eliminated the requirement of sampling for ground water.
Prior to this amendment quarterly sampling was required only in -the event of an accident or unusual circumstance; the ETS specified sampling from a background station, a well at Deen's Landing 2 miles
- upstream, and from an on-site control station, the subsurface drainage ditch.
This subsurface drainage network encircles the plant yard and has two outfalls from which. samples are collected; its purpose is to control the water level in the unconfined ground water table.
The U.
S. Department of the Interior in their comments dated June 28,
>& WM d N o MOtontnism OTstc4L 3);$9 H-] ttAs Bs u s pediiGtG1 od 'WLu Thw FAem I (, AueTavn $4eu ums nave of s a ostett s o o,,
3,76, n c. y e q, 3,,,,,, g c p g,,g 7,g NO n 40'u tn n ri M ed 0 W6.
7 9 0 6 0 4 0 0 to Wo6c : c c 4,9 -## Acymr 1 4 Ae# B it }
17 /)pp e T)es a L 6 4 c. 7 e 0 *- D A iLL E O,
'J %fLE J oF O s te rt-w e t t. wo mt vjH NL DA.n.3 d o R e e %Tio rh ^8 6 v4 6 tQ.
(w6u e st-t. ' n ge]
.- 2yrr un i. e m u r a 4 s,
- r. n, s r u n m - r w. a a s e m -n w s na i iur 60e na6cu i..
Plant Unit 2 suggested ground water sampling of the minor confined acquifer which underlies the plant.
Consequently in the 4th quarter of 1977, samples were collected from three piezometer wells which have depths on the order of 80 feet.
Samples from one of these wells,.N7A which is adjacent to the south side of the
- CST, showed a
' level of 1.6 X 103 pC1/1; samples from the other two wells showed the trit.iu= levels to be less than the lower limit of detection (about 102 pCi/1).
Also in the 4th quarter of 1977 the samole fron the north outfall of the subsurface drainage ditch showed a level of 9.5 X
102 pC1/1.
As explained in the Annual Environnental Surveillance Report for Calendar Year 1977, these two readings were a
matter of concern since the previous maximum reading was 2.4 X
IOP pCi/1.
When sdditional sampics co11ceted at N7A in February and May of 1978 showed the level to be consistent, it was decided to sample the unconfined water table.
It is questionable that the ground water samoles gathered at Pl7B and P16 should be considered as environmental samples due to their remoteness froc unrestricted areas; thus there is considerable doubt that the nonroutine reporting requirements of Sections 3.2 and 5.7.2 of the ETS are spplicable in this case.
The maximum environmental impact of these elevated tritium levels in ground water may be assessed as the dose to a hypothetical individual who regularly drinks this water where it enters the unrestricted area, that is, from the outfalls of the subsurface drainage ditch.
The highest quarterly average concentration from the outfalls during 1978 was 1.8 X 103 pCi/1 and the annual average concentration was 7.4 X
102 pC1/1.
Using the assumptions and constants from Regulatory Guide 1.109 Revision 1, these constants translate to whole body and organ doses of 0.046 mrem for the maximum quarter and 0.077 crem for the year.
The dose limits from Appendix I to 10 CFR 50 for liquid effluents are 1.5 mrem whole body and 5
mrem organ for any quarter, and 3 mee= whole body and 10 mrem organ for the year.
The_
MPQ for tritium i n u n r e s t r i c t eJ_a r e a_s_ a s given in 10 CFR 20 is 3
X 100 pCi/1.
~
The cause of the elevated tritium levels in samples collected from Pienometer No.
Pl7B is believed to have been found.
Luring construction a temporary line carried nitrogen to the feedwater heaters from a tank in the yard which was located adjacent to Pienometer No. P17B.
Afterwards the tank in the yard waa removed leaving a buried cpen line about 8
inches below yard grade.
The heater end of this temporary line was not removed after the tents were completed.
The presence of the line went undetected Jntil the events of March 20 led to its discovery.
ground On !!a r c h 20, 1979, water wac observed to be flowing out of
+
near Pietometer P17B from this spot to a height of from o o to two inches.
Water would flow for around 10 e.
an n 1 y
..e*
- 6..
- w. e se e a s.
.b s ee.,,
,e t"
- seconds, then stop for perhaps 5
minutes or so.
This cyclic phenomenon occurred several times over a few hours.
Water samples fron the fl ow and mud samples on the ground at this spot were 2.45 E4 collected.
Gamma scans of these sampics show Xe 133 ue/m1, Xe 139m - 7.23 E-6 ue/m1, Xe 135 - 5.00 E-5 ue/n1 and Kr-85m 1.68 E 6 uc/ml in the water and Cs 134-1.34 E-5 ue/ge, Cs 137 1.51 E-5 uc/gm.
Co 58 - 1.11 E-6 ue/gm, 2n 65 - 9.65 E-7 ue/gm.
Co 60 4.98 E-6 l 1.88 X 10-6 ue/gn, Ba La 140 - 4.51 E-7 uc/gm, Xe 133 6.87 E-7 uc/gm isotopes in the soil.
The laboratory uc/gn, Xe 135 results of a tritium analysis is not yet available.
A ' check of the valve on this temporary nitrogen line at the feed water heater on March 21, 1979, showed the valve to have been partially open.
This
-valve was promptly closed.
The open end of this temporary nitrogen line was unearthed on March 22, 1979.
The line lies horizontal pointing north.
There was no measurable activity in the soil beyond 2 feet from the pipe's end.
The contaminated soil was placed in drums for shipment to a licensed burial grqund.
The open end of this temporary line was capped off.
The line was also broken by removing a pipe coupling in the line inside the turbine buildiEg and capping the line.
The frequency of sampling has been increased at P17B to monitor the tritium level closely now that the probabic tritium source to this area has been eliminated.
During the forthcominE shutdown of Unit I
scheduled to begin in late April or early May of 1979, it is planned to disconnect this temporary nitrogen line from the feedwater heater and cap-off the connection.
An investigation of the elevated tritium levels in the piezometer wells has been in progress for some months.
The underground piping systcca which carry high tritium icvels have been identified.
Some of these piping systems have been hydroed to some extent; but the results of the hydro do not pasitively confirm or exclude leaka6e to the ground from these systems.
Dr. Janes E.
- Wallace, a
Professional Engineer and Chief Hydrologist for Law Engineering Testine Corpany of Atlanta, Georgia has been engaged as a
consultant in' planning and implementing this investigation.
A study of the piping
- diagrams, ground water levels and tritium levels is in progress to determine seepage paths to the source where tritium 'is entering the ground.
Additional surface borings are being considered; the loestion and the priority for these borinEs are being determined.
The gamma levels in the soil and ground water from these new borings may be indications of the proxicity of any tritium source other than.the one found at Piezometer Pl?B.
xc:
U.
S.
..sclear Regulatory Commission Office of Nuclear Reactor Regulation ATTN:
Director of Regulation Washington, D.
C.
20555 March 26, 1979