IR 05000219/1987010
| ML20214H636 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 05/15/1987 |
| From: | Mcfadden J, Shanbaky M, Sherbini S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20214H626 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.3, TASK-2.F.1, TASK-3.D.3.3, TASK-TM 50-219-87-10, NUDOCS 8705270441 | |
| Download: ML20214H636 (9) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-219/87-10 Docket No.
50-219
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License No. DPR-11 Priority _
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Category C
Licensee: GPU Nuclear Corporation P.O. Box 388 i
Forked River, New Jersey 08731 Facility Name:
Oyster Creek Nuclear Station
Inspection At:
Forked River, New Jersey
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Inspection Conducted: March 31 - April 3, 1987 Inspectors:
5// (/[ 7-7-
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S. Sherbi
,adiati'n Specialist date fee h$ni sh y/ n
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J. McFadden, Senior Radiation Specialist date
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Approved by:
M. 6 ^_4:,##
M/f/O i
M. Shanbaky, Chief, Facilities
'date Radiation Protection Section Inspection Summary:
Inspection on March 31 - April 3, 1987 (Report No. 50-219/87-10)
Areas Inspected:
Special, announced safety inspection of the status of the inspector follow-up items related to the implementation of NUREG-0737.
Results: No violations were identified. Several of the follow-up items remain open.
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8705270441 870518 i
PDR ADOCK 05000219
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t Details 1.0 Persons Contacted 1.1 Licensee Personnel G. Busch, Supervisor, Licensing D. Chandler, Engineer,- EP&I J. Derby, Rad Con Field Operations W. Duda, Project Engineer
- B. DeMerchant, Licensing Engineer
- P. Fiedler, Vice President and Director, Oyster Creek
- C. Halbfoster, Manager, Plant Chemistry R. Harklercad, Supervisor, Plant Engineering
- M. Heller, Licensing Engineer B. Leavitt, Deputy Director, Radiological Controls
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- M. Littleton, Manager, Radiological Engineering
- B. Mingst, Senior Emergency Planner
- M. Radvansky, Manager, Technical Functions M. Slobodien, Director, Radiological Controls
- J. Sullivan Jr., Plant Operations Dir. tor J. Stevens, Engineer B. Stoudnour, Supervisor, Chemistry 1.2 NRC Personnel B. Bateman, Senior Resident Inspector
- Indicates attendance at the exit interview.
2.0 Purpose The purpose of this inspection was to review the status of inspector follow-up items relating to implementation of NUREG-0737, Clarification of TMI Action Plan Requirements. These items were identified during an initial inspection (see NRC Report No. 219/86-01) to verify the adequacy of the if censee's implementation of the following NUREG-0737 task. actions:
Task No.
Title II.B.3 Post-Accident Sampling Capability II.F.1-1 Noble Gas Effluent Monitors
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II.F.1-2 Sampling and Analysis of Plant Effluents II.F.1-3 Containment High-Range Radiation Monitor III.D.3-3
. Improved Inplant Iodine Instrumentation under Accident Conditions
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3.0 Status of Inspector Follow-up Items 3.1 (0 pen) Unresolved 86-01-03:
A.
Demonstrate that the current upper range capability of the installed system would not be exceeded in a worst-case accident.
NUREG-0737, Task Action II.F.1-1 requires a high range noble gas effluent monitor with a capability to measure
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concentrations up to 10 uCi/cc. The licensee's installed
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Constructors (UE&C), dated August 1986, that the maximum noble
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gas concentration in the stack under accident conditions is expected to be about 13 uCi/cc. Therefore, the installed monitor has a sufficient range to measure the expected
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i concentrations in the stack.
This position was presented by
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the licensee to the NRC during a meeting held in Bethesda on I
April 2, 1986 and was found to be acceptable by the Commission. Therefore, this portion of the item is considered closed.
B.
Calibration over multiple decades should be performed. The j
results should be included in the dose assessment function.
The licensee has performed calibrations of the noble gas stack effluent monitors over approximately seven decades using i
Xenon-133 gas. The energy response of the high range channel was determined by theoretical calculations performed by UE&C.
These calculations show that the high range channel will overrespond by a factor of about 1.5 to Xenon-133 gamma rays.
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Studies of the noble gas concentrations in the stack following a LOCA indicate that Xenon-133 will account for over fifty percent of the noble gas activity after the accident, and that this fraction will increase with time.
If.this channel is
calibrated using Xenon-133, there will be'an underestimation of the total noble gas release rate during the early part of the
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accident.
The licensee has not performed an energy response study for the low range noble gas channel in the stack RAGEMS. The licensee stated that such a study is not necessary, partly because the response of the detector, which is a sodium iodide crystal, is expected to be lower for Xenon-133 than for the other noble
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gases in the effluent stream. Therefore, calibration of the channel with Xenon-133 will result in a conservative estimate of the release rate. However, the licensee did not supply any data to support this position and to indicate the degree of conservatism involved. This item will therefore be reviewed in
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a later inspection.
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The calibration data for the monitor, as well as any provisions for allowing for the decay of the isotopic mix in determining the change in calibration factor with decay time, does not appear to have been incorporated into the dose projection procedures. This item will be reviewed in a future inspection.
C.
A low range capability should be installed on the turbine building RAGEMS or it should be demonstrated that it is not required.
The licensee stated that a low range channel will be installed on the turbine building RAGEMS. A tentative date for completion is October 1987.
This item will be reviewed in a future inspection.
D.
The overlap of the high and low range monitors should be demonstrated.
NUREG-0737, Task Action II.F.1-1 requires that the range capacity of individual monitors used to cover the range of concentrations should overlap by a factor of ten. The licensee
uses two monitors to cover the range up to 10 uCi/cc.
Calibration data obtained by the licensee by performing onsite calibration using Xenon-133 gas indicates that the range of overlap between these two monitors may not extend over a factor of ten. The highest available data point for the low range monitor is 0.5 uCi/cc.
This takes the detector into it's upper nonlinear response region.
The reading obtained at the 0.5 uCi/cc concentration is about forty percent below that expected on the basis of a linear response curve.
Concentrations above this point would lead to a much greater departure from linearity.
The low range channel can therefore not be used reliably above 0.5 uCi/cc.
The lowest calibration point for the upper range channel is 0.5 uti/cc. Thus the available data indicates that the two channels overlap at least one point, namely 0.5 uCi/cc, although the lower range channel will underestimate this value by about forty percent.
It is not clear whether the upper range monitor is capable of giving a reliable reading below 0.5 uti/cc, and thus satisfying the range overlap requirements.
However, the calibration data show that the current output from the channel at 0.5 uCi/cc is 2x10-10 amps. The background current reading of the channel is-13 about 2x10 amps.
It is therefore likely that the channel is capable of giving reliable readings well below 0.5 uC1/cc, and thus providing the needed range overlap.
This is speculative, however, and data must be provided to support the existence of a range of overlap between the low-range and the high-range monitors in RAGEMS.
Based on these findings, this item will be reviewed in a future inspectio T
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E.
A method to deactivate the low range monitor near the upper bound of its dynamic range and to reactivate it when the high range monitor returns to the low end of its range should be devised.
A system to automatically deactivate the low range monitor near the upper bound of its range and to reactivate it when the high range monitor returns to the low end of its range has been designed and is to be installed on the stack RAGEMS within a few months of this inspection.
This item will be reviewed in a future inspection.
The licensee stated that such a deactivation system is not needed for the turbine building RAGEMS.
This system will eventually contain both high range and low range noble gas channels. However, the licensee stated that the expected noble gas concentrations in the turbine building following an accident will be relatively low.
The low range monitor will not be driven close to its upper range.
Thus saturation and detector burnout are not expected to be a problem. Although the licensee stated that determination of the expected source term for the Turbine Building effluent pathway has been performed, the results were not available for review at the time of the inspection.
This item will therefore be reviewed in a future inspection.
F.
A study of the effects of nearby sources on the response of the low range channel should be made.
Although the licensee provided data on the effects of ambient fields on the detector, the data was based on the response of a different detector with similar shield thickness to that provided on RAGEMS.
It was not possible, however, to determine during this inspection if l
the data for the similar detector was directly applicable to RAGEMS.
Details must be supplied that show that this comparison is valid.
This item will therefore be reviewed in a future inspection.
G.
Additional personnel should be trained so as to provide round-the-clock readout of the effluent monitors or a simple readout should be provided in the control room.
All of the chemistry technicians (15) have been trained in the theory and operation of the RAGEMS system.
This training will enable the technicians to obtain readouts from the system and also to retrieve cartridges for analysis.
This portion of the item is considered closed.
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Routine calibration and maintenance procedures should be provided
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and training to the operational personnel be accomplished such that normal surveillance of RAGEMS will be performed.
Procedures for calibration of that part of the system that has been completed have been written and implemented.
However, since much of RAGEMS is still in the design and construction phase, routine maintenance and surveillance procedures have not been developed and must await completion of construction, or at least final acceptance
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of design changes.
This item will be reviewed in a future t
inspection.
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3.2 (0 pen) Unresolved Item 86-01-04:
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A.
Document a site specific iodine source term.
An iodine source term has been developed by United Engineers and Constructors (UE&C).
The results of the calculations are documented in the UE&C report entitled " Analysis In Support of
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GPUN Responses to NRC Questions On The Post-Accident Radiation Monitoring Capabilities (at Oyster Creek) Following a LOCA",
dated August 1986.
The report tabulates the concentrations of the different radiciodine species inside the Drywell, Reactor Building, and the plant stack as a function of time post-LOCA.
This portion of the item is considered closed.
B.
Increase sampling time to ensure representative sample.
The sampling time has been increased from 2 seconds to 30 minutes.
Data provided by the licensee suggests that the r
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accumulation of radioiodines on the cartridge during the 30
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minute collection time will result in a total activity that is
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within the measurement capabilities of the emergency gamma
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spectrometer systems on site.
This portion of the item is j
considered closed.
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C.
A procedure to apply appropriate correction factors during non-isokinetic conditions should be applied.
The licensee stated that there is no need for such correction factors because procedures call for adjusting the flow into the
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sampling lines to match the flow in the stack.
This adjustment is to be made manually until a system is installed to make these adjustments automatically.
The licensee stated that the range of adjustment to be provided by this automatic system will be sufficient to accomodate expected flow rate variations
in the stack.
This portion of the item is considered closed.
0.
Heat tracing of the sample lines on vital power should be
extended to the sample flow paths within the sampling shack.
The licensee stated that heat tracing has been extended to the
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sample lines inside the RAGEMS building.
The heat tracing is-currently on the A diesel supply circuit, but will be changed to an A/B diesel supply circuit.
This change will place the
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heat trace on the vital power supply.
This item will be reviewed in a future inspection.
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E.
A comprehensive time / motion and exposure study should be made to ensure GDC-19 criteria can be met for the retrieval and analysis of the filters.
A time and motion study has been made by the Oyster Creek audit section for plant chemistry.
The study shows that the maximum dose expected for chemistry and radiological controls personnel assigned to collect, transport and measure post accident iodine and particulate samples from the stack RAGEMS is 3.1 rem. This is within GDC-19 guidelines.
The licensee stated that doses incurred during performance of similar activities on the turbine building RAGEMS are expected to be much lower than those involved in the stack RAGEMS because of much lower release rates expected in that pathway. This portion of the item is therefore considered closed.
F.
Appropriate procedures should be provided and the needed training of personnel conducted.
Fifteen chemistry technicians have been trained in retrieving the samples from the RAGEMS building.
Procedures have also been developed for operation of RAGEMS.
The procedures do not, however, reflect the mode of operation of RAGEMS after construction on the system is completed.
The procedures will therefore have to be revised to reflect the finished system.
This portion of the item is considered closed.
G.
Routine maintenance and calibration of the particulate and radioiodine samplers should be implemented.
Calibration procedures for the flow meter in the flow path to the iodine and particulate samplers have been implemented for the installed flow meter.
The radiation measurements for the iodines and particulates are not performed on the RAGEMS but are carried out in separate counting laboratories.
Therefore, procedures for this aspect of the system are not required as part of RAGEMS operation.
Routine maintenance and surveillance
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procedures for the system have not been developed because the system is still in the design modification stage.
The licensee stated that these procedures will be developed and implemented upon completion of the system modifications currently in progress.
3.3 (Closed) Inspector Follow-up Item 86-01-05:
A.
Reviewsystem drawings and layouts to verify that the proposed detector locations are not close to any equipment or piping that may contain radioactive fluids during an accident.
The containment high range monitors have been installed inside the drywell at about the 51' elevation. The monitors were installed about 180 degrees apart, as required by NUREG-0737, Task Item II.F.1-3.
The licensee also stated that the chosen locations are expected to be relatively free from interference from nearby systems containing radioactive material.
The licensee stated that one of the area high range monitors is
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mounted close to a main steam line and that the steam line is expected to contain radioactive fluids during an accident.
However, the expected exposure rate from the steam line at the detector location is expected to be about 1 R/hr.
This is a relatively small rate and is near the lower limit of the detector's range, and is therefore not expected to pose any significant interference problems with respect to the high range monitor's functions. This portion of the item is considered closed, however the matter of environmental qualification of detector cables and junction connections for postulated post-
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accident conditions is not closed and will receive additional review during subsequent NRC inspection.
B.
Verification of the nature of the signal sent out by the detector when the radiation field is below the lower limit of detection of the system.
This signal is to be used to produce a failure indication upon detector failure.
The detector is equipped with an electronic self-testing capability that is automatically activated every seventeen minutes. A failure alarm is generated if the system fails this electronic check.
There is no offscale low failure alarm generated by the system, even if the field at the detector is below the low limit of the detector dynamic range. This portion of the item is considered closed.
3.4 (0 pen) Inspector Follow-up Item 86-01-06:
A.
The ability to count the air samples collected. Questions in this area relate to the availability of sufficient counting systems to handle the expected large volume of samples, as well as the susceptibility of such systems to being disabled by high ambient radiation.
The licensee stated that instructions for radiological controls field personnel to collect inplant iodine air samples during an accident will be issued by the radiological assessment coordinator in the control room. The samples can be counted on one of several onsite gamma spectrometers, including one in the radiological controls field operations counting room, and others in two chemistry department counting rooms at two different onsite' locations.
Other counting facilities include a spectrometer located in the training center offsite, as well as TMI counting facilities and the TMI mobile laboratory. The training center spectrometer is currently operational but is not equipped with a shield.
The licensee stated that a shield could be erected quickly if needed. The licensee also stated that methods for collecting the samples, use of protective clothing and respiratory equipment, and other instructions are contained in the regular radiological controls procedures used in daily operations.
These instructions are supplemented by training in emergency operations and participation in emergency drills and exercises.
Two. problems remain unresolved. One is the effect of radiation fields on the operability of the gamma
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spectrometers on site or in the training center, which is less
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than a mile from the reactor building.
These fields may arise from overhead gas plumes, radioactive gases in the counting facility, or shine from adjacent buildings and equipment.
The other unresolved issue is the maximum activity of iodines on a cartridge that can be counted on the spectrometers without saturation or excessive counting losses. The licensee stated that these issues will be studied to determine their effect on the ability to measure airborne iodine lesels on site.
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item will be reviewed in a future inspection.
4.0 Exit Interview The inspector met with licensee representatives at the conclusion of the
inspection on April 3, 1987. The inspector summarized the scope of the
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inspection and the findings.
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