IR 05000325/1979038
| ML19308C661 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 12/05/1979 |
| From: | Jenkins G, Kellogg P, Troup G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19308C658 | List: |
| References | |
| 50-325-79-38, NUDOCS 8002010067 | |
| Download: ML19308C661 (11) | |
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UNITED STATES e
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NUCLEAR REGULATORY COMMISSION O
o REGION 11
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101 MARIETTA ST., N.W., SUITE 3100 f
ATLANTA, GEORGIA 30303
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Report No. 50-325/79-38 Licensee: Carolina Power and Light Company Facility Name:
Brunswick Docket No. 50-325 License No. DPR-71 Inspection at:
Southport, North Carolina Inspected by:
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/z/.t"// P J. E. Ouzts, Re ident Inspector /
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B. W. Riley, Re p.
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Dats Signed
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Y IE{Sl71 G. L. Thlrp,' Radi tion Specialist Date Signed
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G. R. Jen ins, iation Specialist Date Signed Approved by:
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=7 P. J. Kellog6 Section Chieff RONS Branch Date Signed Date of Inspection: October 19-21, 1979 Areas Inspected This special, announced inspection involved 86 inspector-hours onsite in the areas of a reactor trip on October 19, 1979.
Results Of the area inspected, no apparent items of noncompliance or deviations were identified.
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DETAILS 1.
Persons Contacted Licensee Employees
- A. C. To11ison, Jr., Plant Manager
- J. M. Brown, Superintendent, Operations and Maintenance
- J. A. Padgett, Environmental and Radiation Control Supervisor
- S. E. Thorndyke, Operations Supervisor L. F. Tripp, Health Physicist
- G. R. Peeler, Operations Engineer J. L. Kiser, Engineer J. L. McKnight, RC&T Foreman J. M. Kaham, RC&T Foreman R. M., Poulk, NRC Coordinator
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- C. F. Blackmon, Jr., Shif t Specialist Other licensee employees contacted included 5 RC&T technicians and 5 operators.
Other Organizations
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- D. J. Kemppaimen, Senior Operations Engineer, General Electric
- Attended one or more exit interviews 2.
Exit Interview The inspection scope and findings were summarized in meetings on October 20 and 21, 1979 with those persons indicated in Paragraph 1 above.
3.
Licensee Action on Previous Inspection Findings Not inspected.
4.
Unresolved Items Unresolved items were not identified during this inspection.
5.
Event Description On October 19, 1979, Unit 1 experienced a reactor trip due to the main steam line radiation monitors detecting sudden, higher than normal radiation fevels.
It was subsequently determined that the abnormal increase in main steam radiation levels was caused by demineralizer resin movement from the
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Reactor Water Clean Up (RWCU) system into reactor coolant within the reactor vessel.
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-2-The following operational chronology of significant occurrences during the event was developed from plant computer printouts, recorder charts, log books, and discussions with appropriate plant personnel The unit was in normal, stable operation at 99.5% power immediately proceeding the trip.
Time Event 10/19 000000 Maintenance Work clearance lifted on Reactor Water Cleanup System and valve realignment initiated.
005010 RWCU system pressurized and its pumps started Demineralizer resin injection into reactor occurs.
005106 Brief increase in reactor vessel pressure, core flow, feedwater, "A" steam flow and power.
005107 Main steam line radiation monitor A reacts to increased radiation levels and trips reactor protection scram channel A.
005114 Main steam line radiation monitor B reacts to increased radiation level and trips reactor protection scram channel B.
05114 Total reactor scram 05114 Main steam isolation valves close from high radiation signal.
Diesel Generators #2, 3, 4 auto start.
SBGT in service.
Reactor building ventilation isolates.
Reactor Recirc Pumps Trip.
0053 Turbine generator trip.
0110 MSIV's reopened and IA RFPT started (Main steam line radiation monitors had returned to normal levels).
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0114 Loop A 485 F, Loop B 495*F 855 psi.
0115 Restarted Reactor recirculation pump '
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-3-Time Event 0120 Placed RIIR B loop in torus cooling 0146 RWCU pu.mp restarted.
0147 Received RPS trip again from main steam radiation monitors A, B, C, & D.
(Trip due to RWCU resin movement into FW Ioop "B" which passes near MSL radiation monitors.)
One MSIV reopened.
0256 Main steam line radiation monitors showing increase-closed MSIV.
0315 RWCU placed in service.
0500 Evacuated //1 reactor building.
0520 Evacuated (/1 and 2 turbine building.
1230 Loop A 331 F, Loop B 382 F 112 psi.
All plant safeguard equipment responded normally and performed its intended functions except the following:
1.
No. 1 Diesel Generator failed to start on signal.
2)
RHR heat exchanger valve flow problem 3.
RCIC tripped on high exhaust pressure 4.
Reactor coolant chemistry exceeded Technical Specification Values.
The above items identified by the licensee will be the subject of thirty day written licensee event reports by the licensee per reportiag requirements of Technical Specifications.
No items of noncompliance or deviations were identified.
While the Reactor Water Cleanup system was out service for repair the filter cake apparently shed in filter-demineralizer B and when restoration of system to service was initiated it allowed the
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movement of resin into the reactor coolant system. The resin caused a sudden transient in..he chemistry of the reactor coolant which-caused a substantial Short term increase in the amount of nitrogen 16 passing through main stea.n lines resulting in trip of radiation detectors monitoring those line *
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Corrective Measures The inspectors reviewed and assessed the aspects of procedures, personnel actions, equipment performance, and licensees event analysis and corrective measures.
The licensee determined corrective measures involving changes to Operations Procedures, that will require the following (325/79-38-01):
a.
closing of additional isolation valves when RWCU is taken out of service, b.
If RWCU is depressurized for more than approximately thirty minutes filter demineralizer will be recoated prior to return to service.
When returning RWCU to service will first direct effluent to condenser c.
hotwell and verify proper effluent chemistry prior to return to reactor coolant system.
Based upon the inspector comments, the licensee agreed to review the content of existing plant emergency instruction EI-21 Main Steam Line High Radiation and evaluate the need of additional emergency instructions that would recognize the event of resin injection into the reactor vessel (325/79-38-02).
The licensee agreed to review maintenance policies on isolation valves of RWCU system considering optimum balance of operational needs versus minimizing personnel radiation exposure (325/79-38-03).
The circuit design of RWCU system motor operated isolation valve No. F042 will be reviewed by the licensee to evaluate the operational significance of non-maintained contacts in valve closing circuit particularly during use in restoring RWCU system to service (325/79-38-04).
7.
Radiological Sequence of Events NRC radiation specialists reviewed chemistry and radiochemistry sample results, airborne radioactivity sample results, shift operator logs, incident reports, effluent monitor printouts and interviewed plant staff members to determine the sequence of events during the incident.
(Only selected air sample results are shown.)
Date Time Event Results 10/16 1440 Routine Reactor Coolant Gross activity Sample 2.66 E-1 uCi/gm
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10/18 Routine Turbine and 7.90E-11 - 9.85E-13
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Reactor Buildings air uCi/cc
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samples 10/19 0051 Reactor scram, MSIVs closed 0110 MSIVs opened by operators 0140 Air sample, Reactor
_ Gross activity Building, el. 50 feet 6.70E-9 uCi/cc 0.111 x MPC 0147 Mainsteam radiation monitors Hi-Hi alarm, MSIVs closed automatically 0150 Reactor Coolant Sample Gross activity SE-1 uCi/gm dose equivalent I-131, 1.92E-4 uCi/gm 0425 Reactor Coolant Sample Gross activity 2.12 uCi/gm dose equivalent I-131, 1.52E-4 uCi/gm 0450 Air sample, reactor Gross activity Building-e1. 20 feet 3.83E-8 uCi/cc 0.387 x MPC 0500 Unit 1 Reactor Building evacuated 0520 Unit 1 and 2 Turbine Buildings evacuated 0535 Air sample, Turbine Gross activity, Building-e1. 20 feet 2.12E-8 uCi/cc 0.06 x MPC
0800 Heactor and Turbine Buildings cleared as airborne radioactivity areas 0900 Reactor coolant sample Dose equivalent
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I-131, 1.26E-4 uCi/gm 0900 Unit 1 Environs monitor 0.3 mR/hr
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-6-0940 Survey of Condensate Gross activity, Storage Tank; Air Sample 6.38E-11 uCi/cc near CST 1145 Reactor Coolant Sample Gross activity, 1.48 uCi/gm 1345 Reactor Coolant Sample Gross activity, 8.91E-1 uCi/gm dose equivalent I-131, 2.9E-5 uCi/gm
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10/20 0830 Reactor Coolant Sample Gross activity, 2.78E-1 uCi/gm 8.
Implementation of Emergency Instructions The main steam line radiation monitors A and B alarmed on high radiation and initiated a reactor scram and Group I isolation at 0051 (monitor Hi-Hi-trip). Following this, the control room operators implemented the actions of Emergency Instruction (EI)-31, Reactor Scram, to ensure an orderly and safe shutdown of the plant. The operators requested that RC and T sample the reactor coolant and stack gas.
After the trip and isola-tion, the radiation monitors dropped off to normal shutdown levels (approx-imately 5 mR/hr). A licensee representative stated it appeared that the trip was caused by a spike rather than a steady, high level. At 0110, the main steam isolation valves (MSIVs) were opened to provide a heat removal path to the condenser in accordance with El-31.
At 0147, a main steam line radiation monitor Hi-Hi-trip alarm was received from monitors A, B, C, and D which initiated closure of the MS1Vs. Following the second trip alarm, the monitor readings remained high; this was interpreted by the operators as a valid main steam line high radiation condition. The control room operators initiated the actions of EI-21, Main Steam Line High Radiation, and started notification of on-call personnel. At approximately 0500, evacuation of personnel in the Unit 1 Reactor Building was initiated by RC and T when airborne radioactivity levels exceeded the 25 percent MPC action level of RC and T Instruction 7017, airborne levels did not reach the
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levels requiring the initiation of the EI for high airborne activity. At approximately 0520, the Turbine Buildings were evacuated. At this time a local emergency was in effect. At approximately 0800, the Reactor Building and Turbine Buildings were cleared for access.
Based on the review of control room logs, review of procedures and charts and discussions with licensee representatives, the inspector had no further questions on the
, implementation 'of emergency actions.
9.
Teactor' Coolant Chemistry Technical Specifications 3.4.5.b.2(a) requires that following a thermal a.
power change of more than 15 percent in one hour, the licensee 'shall perform the sampling and analysis per item 4C of Table 4.4.5-1.
Item 4C of Table 4.4.5-1 requires that an iodine isotopic analysis be
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-7-performed between 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> following the change in thermal power.
Technical Specifications 3.4.5,b.1 requires that sampling and analysis be performed if the specific activity exceeds 0.2 uCi/ gram dose equiva-lent iodine-131. An inspector reviewed the counting analyses data sheets and chemistry sheets and determined that the licensee had performed the dose equivalent iodine-131 analyses at 0150, 0425, 0900, and 1345 on October 19.
All saqle results showed the dose equivalent fodine-131 was less than 2 X 10 uCi/gm, which is less than 0.1 percent of the Technical Specification limit.
b.
The licensee collected samples of the reactor coolant and analyzed them for principal isotopes ant' gross radioactivity concentration at 0150, 0425, 1145, 1345, on Octose-19 and 0830 on October 20.
The maximum radioactivity concentration was determined to be 2.12 uCi/gm at 0425 on October 19. The principal isotopes were sodium-24 and fluorine-18. All radioactivity sample results were less than the
, limit of 100/E uCi/gm as specified in Technical Specifications 3.4.5.b.
The licensee performed analyses of chemistry parameters of the reactor c.
coolant (pil, conductivity, chloride ion, silica), measuring the parameters at various times.
Sample results taken at 0015 on October 19 (prior to the scram) were, pH-7.1, conductivity-0.6 umho/cm, chloride ion-
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less than 50 ppb. Following the scram, the parameters reached the following maximum values, pH-4.8 (2020, 10/19), conductivity-6.63 umho/cm (0425, 10/19), chloride ion-250 ppb (0250,10/19). For Mode 3 (condition following the scram), the chloride ion concentration exceeded the limit of Technical Specification Table 3.4.4-1, but was restored to within limits in the required time as specified time of Technical Specification 3.4.4.
d.
The inspector reviewed the results of the reactor coolant samples and compared the results with the results of a sample collected at 1440 on October 16.
From the review of the radioiodine analyses and principal isotopic analyses, the inspector determined that no fuel degradation had occurred from the transient and that no radioactivity limits of the Technical Specifications had been exceeded.
The inspector had no further questions.
10.
Effluent Monitoring An inspector reviewed the monitor recorder charts for the Steam Jet Air Ejector (SJAE) monitor, the Unit 1 Reactor Building vent monitor and the main stack monitor and discussed the magnitude of any releases with licensee representatives.
Immediately following the scram the SJAE monitor
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and RB vent monitor showed a sudden increase in the readings and then went back to the previous reading or a lower reading. The SJAE monitor went from 1.2 mR/hr up tc 3mR/hr and dropped back to 1.2 mR/hr in approximately one-half hour, the RB vent monitor went from 1.1 mR/hr to 1.5 mR/hr and dropped to 0.6 mR/hr in approximately 15 minutes. The stack monitor showed l
a slight increase in the monitor count rate but did not indicate a sudden
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-8-change; at the time of the scram Unit 2 was increasing in power which would result in an increase in the monitor count rate. Neither of increase in monitor response reached an alarm setting.
Based on the monitor responses and subsequent analysis of air and gas, the liccasee concluded that there had been no significant releases of radioactivity to the environment. The inspector had no further questions.
11.
Personnel Radiation Exposures Personnel exposures during the events were determined by routine use of TLDs and self-reading pocket dosimeters.
In addition to operations related to the scram, such as surveys, decontamination, sampling, and inspection, a special inspection was performed of the resin strainer and filter /demin-eralizer in the reactor water clean-up system (RWCU).
Licensee personnel reviewed the exposures received by personnel based on the pocket dosimeter readings and determined that the total exposure received over the three day period following the scram was 1.3 man-rem, of which 0.876 man-rem (67 percent of the total exposure) was received by personnel doing the RWCU inspection.
No exposures in excess of plant administrative or regulatory limits were received.
12.
Airborne Radioactivity Following the scram, the licensee commenced air sampling to supplement a.
the routine sampling program and the installed continuous air monitors (CAMS).
The analyses included isotopic identification in addition to gross radioactivity measurements. The initial air sample collected in the Unit 1 Reactor Building was collected at 0140 at elevation 50 showed a concentration of 6.7E-9 uCi/ml and an MPC ratio of 0.111. A sample collected at 0450 in the Reactor Building, elevation 20 showed a concentration of 3.83E-8 uCt/ml and an MPC ratio of 0.387.
Based on this result, evacuation of the Unit 1 Reactor Building was initiated at approximately 0500 in accordaace with RC and T Instruction 7017, which requires that an area be considered an airborne radioactivity area when the MPC ratio exceeds 0.25.
Subsequent entries into the building were made using respiratory protection equipment until the airborne concentration was less than an MPC ratio of 0.25; the area was cleared for access at approximately 0800.
No samples had an MPC ratio greater than 1.
b.
At approximately 0500, individuals in the Unit 1 Turbine Building were found to be,ontaminated with radioactive material which was identified as rubidium-88. This was indicative of radioactive gas in the building.
Both the Unit I and 2 Turbine Buildings were evacuated at approximately 0520.
Licensee representatives informed the inspector that this
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condition had occurred previously and apparently was not related to the scram. Although the building was evacuated as a precaution, air sample results for samples in various areas of the Turbine Buildings showed MPC ratios less than 0.25.
The buildings were cleared for access at approximately 080 _ _ _ _. _._
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13. Surface Contamination
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As the result of the settling of airborne particulates and overflow of j
liquids from floor drains, as the result of the overflow of the Reactor t
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Building equipment drain tank, surface contamination of areas in the
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ReactorBuildingwasdegerminedtobeinexcessofthelicenseescontrol
limit of 200 dpm/100 cm.
Contamination levels of 400-600dpm/1g0cmwere
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detected on most levels; the highest levels were 1600 dpm/100 cm on elevation 117. Once the reactor building was cleared as an airborne radio-activity area, decontamination work was initiated.
By approximately 1800, elevations 20 and 50 were cleared for access except for selected areas
requiring additional decontamination.
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14.
Environmental Monitoring
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A licensee employee conducted a radiation survey using a sensitive j
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instrument (microR meter) around the p1' ant property line and a various l
locations within the boundary on the afternoon of October 19.
Radiation
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levels around the property line were 2-3 uR/hr except for one area
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i which was 20 uR/hr. This elevated reading was attributed to the stack plume which was flowing in that direction. At that time, the atmospheric stability was Pasquill Category D.
The inspector reviewed the survey results and discussed the readings with licensee representatives. A licensee representative stated that the readings were consistent with
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these found during normal operations and showed the inspector previous
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survey results which confirmed this; the inspector had no further
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questions.
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b.
At approximately 0900 on October 19, a licensee representative observed that the Unit 1 environs monitor was indicating a reading of approxi-
mately 0.3 mR/hr, a normal reading for the monitor is less than 0.1
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mR/hr. An air sample was collected in the vicinity of the monitor at 0940, which showed an airborne concentration of 6.38E-11 uCi/cc, a
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normal levc1 for outside areas. Radiation surveys of the area showed
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i that the source of radiation was the Unit I condensate storage tank i
(CST). The highest radiation level on the tank was 165 mR/hr. An
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examination of the recorder chart for the monitor indicated that the
increase in radiation level started at approximately 0500. A water I
sample from the CST at 1210 showed a gross activity of 2.55E-3 uCi/ml.
The cause of the increase in radiation levels was attributed to return of condensate from the condenser hotwell to the CST during the plant cooldown. The isotopic composition of the water in the CST was con-sistent with the isotopic coraposition of the coolant, gross activity I
was consistent with that of water in the hotwell based on a sample at 1400. The condensate system was aligned so that water going to the
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CST was passed through the condensate polishers to reduce the activity
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level of the water in the CST. A radiation survey at 1515 indicated that highest radiation level in the CST had decreased to 65 mR/hr. On October 20, the inspector accompanied two licensee representatives who performed a radiation survey of the tank. The highest reading found-
.was 50 mR/hr. A water sample from the tank at 1025 on October 20
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showed a gross radioactivity concentration of 2.27E-4 uCi/ml. The inspector reviewed the licensees evaluation of contents of the tank to
i demonstrate that no more than 10 curies were contained in the tank, as specified in Environmental Technical Specifications 2.5.1.g.
hTe actual content was approximately 0.5 curies.
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c.
Starting on October 21, the licensee collected the TLDs for environ-t j
mental monitoring and the filters from the environmental air sampling
stations and sent them to the Harris Energy and Environmental Center l
for analysis. All TLDs showed no dose above background. The highest
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air sample indicated an average air concentration of IpCi/m.
These results indicated no environmental affects from the scram and subsequent operations.
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