ML061000685
| ML061000685 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 03/27/2006 |
| From: | Entergy Nuclear Operations |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2006-0081 | |
| Download: ML061000685 (13) | |
Text
I-ions Changes Cause #1 Cause #2 Cause #3 U2 Fuel Pool liner is Ground water is draining Small leak in weld at breached out as the wall is corner ofpool traps water exposed. behind steel sheet which then experiences mixing/holdup as it leaks out in the same area, on the concrete walls.
er is the cask- (1)No known Supports Supports inside the SFP. change (NKC) rusted and eas on or in the (2)No known e corner weld. change (NKC)
OE shows Co- (1) NK Fact assumed(1): Refutes: Groundwater would Fact assumed(1): Leaking SFP leaks. Leaking water has a not give us the activity we water has a delay due to delay due to transport are seeing in the soil and in transport OR is mixed with ialf-lives. (2) NK_ OR is mixed with older the leaking water. older water or is washing out water or is washing out contaminants In concrete.
contaminants in concrete.
Supports Supports Supports Fact Assumed(9):
Compartmentalization of leak based on construction of the pool liner.
.__ _ _(Potential conflict with (1 Fact assumed(2) - Refutes: Only a specific area Fact assumed(2) - leakage leakage involves SFP of wall shows moisture. involves SFP liner sheets in liner sheets In vicinity of vicinity of observed leak, and observed leak, and the the leak could affect both leak could affect both surfaces of corner.
surfaces of corner.
Page I of 5 c44
tions Changes Cause #1 Cause #2 Cause #3 U2 Fuel Pool liner is Ground water is draining Small leak in weld at breached out as the wall is corner of pool traps water exposed. behind steel sheet which then experiences mixing/hold tip as it leaks out in the same area, on the concrete walls.
Supports Supports I support. Excavation, Supports Supports curren:ly being performed for crane installation Supports Supports Supports Supports Fact assumed(3): A Refutes: Leak was observed Fact assumed(3): A very very small through-liner after a long period of small through-liner defect..
defect. drought and saw no increase during recent extensive rains.
Fact assumed(3): A Refutes: Would expect to Fact assumed(3): A very very small through-liner see changes in rate tied to small through-liner defedc:.
defect. precipitation/changes In groundwater level.
Page 2 of 5
ions Changes Cause #1 Cause #2 Cause #3 U2 Fuel Pool liner is Ground water is draining Small leak in weld at breached out as the wall is corner ofpool traps water exposed. behind steel sheet which then experiences mixing/holdup as it leaks out in the same area, on the concrete walls.
Fact assumed(4): Leak Fact assumed(4): Leak that that has been there for has been there for some some time. time.
Fact assumed(1): Fact assumed(1): Leaking Leaking water has a water has a delay due to delay due to transport transport OR is mixed with OR is mixed with older older water or is washing out water or is washing out contaminants in concrete.
contaminants in concrete.
Fact assumed(5): The Fact assumed(5): The water has more recent water has more recent activity in it. activity in it.
Fact assumed(6): Fact assumed(6): Small Small leak rate and leak rate and removal by removal by concrete concrete eliminates the Co-eliminates the Co-58 by 58 by decay and removal.
'_ , decay and removal.
Fact assumed(7): Fact assumed(7): 'BoronW Boron contamination on contamination on wall wall dissolved, became dissolved, became entrained entrained in leak, and in leak, and has washed out has washed out to the to the level we currently level we currently observe.
observe.
Fact assumed(8): Fact assumed(8): Concrete Concrete removes boron. removes boron.
Fact assumed(3): A Fact assumed(3): A very very small through-liner small through-liner defec:.
defect.
Ptige 3 of 5
ions Changes Cause #1 Cause #2 Cause #3 U2 Fuel Pool liner is Ground water is draining Small leak in weld at breached out as the wall is corner of pool traps water exposed. behind steel sheet which then experiences mixing/holdup as it leaks out in the same area, on the concrete walls.
Fact assumed (9): This Fact assumed(10):
exceeds the volume of Communication between one void (space between voids.
steel sheet and concrete) so there must This amount of leakage be communication exceeds the volume of one between voids. void (space between steel sheet and concrete) so there must be communication between voids, which may increase the areas where the leak could be.
(Potential conflict with (9 i)
Fact assumed(7A): Fact assumed(7A): Activity Activity on wall on wall dissolved, became dissolved, became entrained in leak, and has entrained in leak, and washed out to the level we has washed out to the currently observe.
level we currently observe.
U._
- i. -_ __4 I _ :i Page 4 of 5
1U2%20SFP%20concrete%20wal I%201eaks/lslsNots.aspx Iress the assumption. Record the results on the web page.
ed by inspection results.
Page 5 of 5
LOWER-TIER APPARENT CAUSE Sheet 1 of 8 REV 0 Condition Report Number: Assigned Department:
CR-IP2-2(105-03986 and IP2-2005-04151 Radiation Protection Radiation Protection PROBLEM STATEMENT: (The WHAT)
Onsite monitoring wells indicated elevated to trace levels of tritium radioactivity. MW-i11 (1P2 transformer yard well) showed tritium concentrations of 211,000 pCi/I and IP3 wells(near the Unit 3 turbine bldg. and discharge canal) showed tritium concentrations ranging from 417 to 960 pCVI, and two core bore wells beneath the Unit 3 turbine bldg showed tritium concentrations ranging from 703 to 1,590 pCi/l. No other plant related radioisotopes were identified in all samples.
A four hour notification report was made to the NRC pursuant to 10CFR50.72, and several other governmental agencies and other stake-holders were also notified.
EXPLANATION OF PROBLEM: (The HOW)
On September 29,2005(date of sample), tritium radioactivity from an onsite monitoring well was found to have 211,000 pCi/I tritium, which is above the ODCM reporting limit of 30,000 pC/I. ,.
This well was previously established in early 2000 for the monitoring of contaminates such as!oil v and PCBs, in preparation for the sale of IP2 to Entergy. The well (MW-1i1), is located inside the site protective area in the Unit 2 transformer yard, an area near both the Unit 1 and 2 facilities.
The well was last sampled for radioactivity (tritium and gamma spectra analysis) in March 2000, and the results showed no detectable plant related radioisotopes. In addition, three other onsite monitoring wells were sampled (MW-1 07,108 and 111) to investigate past leakage associated with the Unit 1 spent fuel pools. These samples also showed no detectable plant related radioisotopes. None of these wells were subsequently sampled for radioactivity until October 2005 as part of the investigation into the apparent Unit 2 spent fuel pool liner leak. These wells were sampled periodically for oil and PCBs only. In mid October 2005; five additional wells were sampled in the general vicinity of the Unit 3 turbine bldg. and discharge canal. Trace concentrations of tritium were identified as discussed above. On November 3, 2005, a 30-day report was filed with the NRC describing these issues and future corrective actions. For perspective, the EPA drinking water regulations (40CFR141) limits tritium to 20,000 pCi/I. All of the onsite wells are for monitoring only and not sources for drinking water for onsite workers or the public Since discovery of elevated tritium activity in these wells, a weekly sampling program was established. Tritium concentrations in MW-i 11 have essentially remained constant except for a one week period of heavy rains in mid October. During that period, tritium concentrations significantly dropped to 6,820 pCi/l. However, one week later, its concentration returned to 284,000 pCi/I, and has generally remained constant between 250,000 to 300,000 pCi/I as of November 10, 2005. Tritium concentrations in the other Unit 3 wells also varied somewhat since discovery. U3-1, U3-2, and U3-4 wells now are less than detectable and have been for the last four weeks. U3-3 well is still exhibiting very low levels of tritium at 471 pCi/I, and the two core bore well samples beneath the Unit 3 turbine bldg. are showing low levels of tritium at 563(T-1) and 1635(T-2) pCi/I respectively. T-1 samples were less than detectable for the last four weeks and now(1 1/10/05) is detectable, where as T-2 has consistently showed tritium concentrations ranging fr m 1420 to 1600 pCi/I. T-2 is at the north end of the five foot elevation and T-1 is at
LOWER-TIER APPARENT CAUSE Sheet 2 of 8 the south end five foot elevation. Of interest, is T-2 tritium concentrations did not vary significantly after the site heavy rains from mid-October 2005.
IPEC has an offsite radiological environmental monitoring program (REMP) which routinely samples offsite drinking water sources and other special water sources for radioactivity.
Quarterly drinking water samples are taken the Campfield reservoir in Peekskill, NY and the Croton reservoir. Further, samples are taken from an abandoned well (5 th street well) in Verplanck, which is no longer used as a drinking water source. Monthly special water samples are also taken from two near site outfalls (Algonquin and Gypsum streams), both of which discharge directly to the Hudson River just of the plant's owner control area. Also, samples are taken at an abandoned flooded rock quarry located in Verplanck. These special sample locations were chosen specifically to monitor any potential offsite tritium releases from the known Unit 1 SFP leakage. Historical sampling results for all of these locations have shcwn no detectable plant related radioactivity for the past ten years or since new monitoring locat ons were added to the REMP program. The Algonquin outfall was first sampled in 1996 and the 5 th street well in August 2002. There are no other known well water drinking water sources near the site.
Special independent samples of MW-i 11 were analyzed by Teledyne and confirmed the accuracy of IPEC's laboratory and Fitzpatrick's laboratory for tritium and gamma spectra analysis. Further this well was sampled for Sr-90 and Ni-63, two additional hard-to-detect isotopes of interest as it relates to plant operations, and no detectable activity was identi ied.
The NY Department of Conservation split samples with IPEC at all wells where tritium was detected and their results were in very good agreement with IPEC's results.
To date, IPEC has contracted with a hydrologist firm and other knowledgeable consultants to determine the source(s) of groundwater contamination, the general groundwater flow direction and flow rates, and to determine what additional monitoring is necessary. Currently, an onsite well monitoring modification project has been approved for the installation of nine new wells.
These wells are currently being installed.
An evaluation of the potential radiation doses to offsite receptors from the ground water contamination was done assuming the water went directly to the Hudson River and was not diluted via the discharge canal. Only near site dilution was considered. The exposure pathways considered are the ingestion of contaminated drinking water and of fresh-water fish. The calculations showed potential doses to any organs of an offsite receptor were less than 1.0 E-04 mrem/quailer, significantly lower than the ODCM quarterly limits of 1.5 mrem to the whole body and 5.0 mrem to any organ.
The following actions are necessary in order to determine final cause(s) of the tritium groundwater contamination to onsite monitoring wells;
- Complete the K-T root cause analysis already underway to determine final causes of tritium contamination to onsite monitoring wells-Engineering/WPO
- Complete installation of the onsite monitoring well modification project, Phase one-Facilities
- Complete hydrologist study of site ground water physical parameters such as water flow
LOWER-TIER APPARENT CAUSE Sheets of 8 rate, direction and discharge points to offsite environment-Eng
. Determine if additional onsite monitoring wells are necessary(Phase 2) in order to de':ermine more accurate ground water flow/direction and sources of ground water contamination, plume definition, and potential site remediation-Eng
. Determine if tritium ground water contamination warrants remediation--RP
. Develop and implement ground water tracer program for various onsite systems or facilities of interest to determine sources of ground water contamination-Eng
. Develop a long term onsite well monitoring program including sample frequency, training, procedures methodology, equipment needs, and sampling types-RP.
- Update site licensing documents(FSAR, drawings, etc.) to capture onsite monitoring well modification--Eng
- Identify all onsite underground piping or equipment/tanks, which contain radioactive liquids which may be a contributor to tritium ground water contamination-Eng.
- Update 30-day report to NRC-Licensing
- Update ODCM and RG 1.21 report to reflect needed changes/outcomes from the well monitoring program results, tracer study results and hydrologist report as it relates to offisite dose calculations from HTO releases not previous accounted for--Chem.
Identify existingg site unlined sumps and radioactive storage tanks( i.e., RWST, Waste Distillate tanks, etc.) which may contribute to ground water contamination for inspection, repair(if necessary) and ongoing PM--Eng.
- Update 10CFR50.75(g) file based on outcome of this investigation--RP
- Operations to benchmark other PWRs/BWRs SFP inventory practices as it relates to pool inventory, boron mass balance and leak/level monitoring capabilities--Ops.
- Add new monitoring well, MW-138(P-9) to the offsite REMP program and revise sampling procedure as necessary. Well shall be sampled to the same criteria as The other eight onsite wells-RP/NEM.
. Obtain technical assistance from EPRI organization as it relates to their experience in onsite well monitoring programs and procedures-RP
- RP, Chemistry, Operations and Engineering to discuss this CR during its continual training programs
- Develop OE package for dissemination to INPO-CA&A.
APPARENITCONTRIBUTING CAUSE(S): (The WHY)
ACI The apparent cause(s) of this event is currently undetermined. A special investigation team has been established to investigate these issues and a K-T root cause investigation is currently underway. The team has met several times and continues to meet as new information becomes available. A separate corrective action is issued to WPO engineering to complete the K-T analysis and issue additional corrective actions, if necessary, not discussed in this report.
Contributing causes were as follows:
CC-1)--lnelfective utilization of existing onsite monitoring wells for radioactive contamination of ground water
LOWER-TIER APPARENT CAUSE Sheet 4 of 8 EXTENT OF CONDITION:
The EOC is limited to onsite ground water contamination only as no offsite contamination of any plant related isotopes was identified. The site never had any onsite well monitoring program for testing for radioactivity.
COMPLETED CORRECTIVE ACTION(S): (see Procedure step 5.4[2](e))
ISSUE / PROBLEM SOLUTION / RESOLUTION / ACTION / COMPLETED
[note any Work Orders, MODs, other]
CAl.determine offsite dose impact Completed-offsite dose assessment made and to public from HTO contamination radiological impact was determined to be significantly lower than the ODCM quarterly limits.
CA2.determine initial EOC of HTO Establish weekly monitoring program for all wells were HTO ground water contamination
- lwas identified PROPOSED/ASSIGNED CORRECTIVE ACTIONS ITEM # ISSUE/CAUSE SOLUTION i TYPE CA Assigned Due Date PCRS RESOLUTION Department CA#
[note any Work Orders, MODs, other]
CA1 determine apparent Complete the initial Perform Eng 12/15/05 cause(s) K-T root cause analysis already underway to determine final causes of tritium contamination to onsite monitoring wells-Engineering/WPO CA2 Need additional Complete Perform Faclities 2/28/06 onsile monitoring installation of the wells to characterize onsite monitoring plume, water flow and well modification direction project, Phase one-Construction Need additional site Complete CA3 hydrology information hydrologist study of Perform Eng 3/31/06 site ground water _-
LOWER-TIER APPARENT CAUSE Sheet E; of 8 physical parameters such as water flow rate, direction and discharge points to offsite environment-Eng Are the new Determine if additional nine wells additional onsite Perform Eng 6/25/06 CA4 sufficient to monitoring wells are characterize site necessary(Phase 2) ground water flow? in order to determine more accurate ground water flow/direction and sources of gpuLnd,.,
water contamination, plume definition, and potential site remediation-Eng CA5 HTO ground Determine if tritium Perform RP 4/15/2006 contamination ground water exceeds EPA contamination standards warrants remediation--RP CA6 Identify which HTO Develop and Perform Eng 3/31/2006 source is implement ground contaminating MW- water tracer 111 program for various onsite systems or facilities of interest to determine sources of ground water contamination-Eng CA7 Need site well Develop a long term Perform RP 2/28/2006 monitoring program to onsite well meet objectives monitoring program including sample frequency, training, procedures
_ methodology, _-
LOWER-TIER APPARENT CAUSE Sheet 6 of 8 equipment needs, and sampling types-RP CA8 Well modification Update site licensing Perform Eng 4/15/2006 program needs to be documents(FSAR, reflected in licensing drawings, etc.) to bases capture onsite monitoring well modification--Eng CA9 Several underground Identify all onsite Perform Eng 3/31/2006 piping systems underground piping contain HTO and may or equipment/tanks, be a contributor which contain radioactive liquids which may be a contributor to tritium,-.,,
ground water contamination-Eng _-
CA10 NRC 30-day report Update 30-day Perform Licensing 4/15/2006 needs updating report to NRC-Licensing CA1 1 OD(,M may need Update ODCM and Perform Chem 4/15/2006 updating/modification RG 1.21 report to if H1T0 is identified as reflect needed new release point changes/outcomes from the well monitoring program results, tracer study results and hydrologist report as it relates to offsite dose calculations from HTO releases not previous accounted for--
_Chem CA12 Several liquid waste Identify existing site Perform Eng 2/28/2006 sumps are unlined unlined sumps and and holding tanks radioactive storage may also be tanks( i.e., RWST, degraded all of which Waste Distillate contain significant tanks, etc.) which levels of HTO may contribute to I ground water _-
LOWER-TIER APPARENT CAUSE Sheet 7 of 8 contamination for inspection, repair(if necessary) and ongoing PM--Eng_
CA13 Wells identified with Update Perform RP 4/14/2006 HTO are not captured 10CFR50.75(g) file in 10CFR50.75(g) based on outcome of this investigation--
RP CA14 U2 SFP does not Operations to Perform Ops 4/15/2006 have a tell-tail drain to benchmark other quickly identify a leak PWRs/BWRs SFP and SFP water inventory practices inventory practices as it relates to pool need to be re- inventory, boron evaluated mass balance and leak/level monitoring l-
. capabilities--Ops CA15 One of the new nine Add new monitoring Perform RP/NEM 3/31/2006 wells is located offsite well, MW-38(P-9) to and represents a the offsite REMP potential indicator for program and revise offsite radiological sampling procedure impact as necessary. Well shall be sampled to the same criteria as the other eight onsite wells-RP/NEM.
CA16 IPEG lacks Obtain technical Perform RP 3/31/2006 experience in onsite assistance from ground water EPRI organization monitoring for HTO as it relates to their experience in onsite well monitoring programs and procedures-RP CA17 Varies department RP, Chemistry, Perform RP Eng 4/15/2006 CAl 8 need to brief staff on Operations and Chem CA19 lessons learned from Engineering to Ops CA20 this CR discuss this CR during its continual
.___ _training programs _-
LOWER-TIER APPARENT CAUSE Sheet E of 8 CA21 Share OE with Develop OE Perform CA&A 3/31/2006 industry package for dissemination to INPO-CA&A.