ML19340C040
| ML19340C040 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 11/06/1980 |
| From: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8011130206 | |
| Download: ML19340C040 (11) | |
Text
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'N p[c rp/r' rm p rn tmgg SOUTH CAROUNA Ncmc a GAS COMPANY
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7 4 Cot uMe:A, south CAnoLINA 29218
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T. C. Nicsots, J R.
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Mr. Ilarold R. Denton, Director
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Of fice of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission
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Washington, D. C. 20555
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Subject:
Virgil C. Summer Nuclear Station
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Docket No. 50/395 Effluent Treatment Systems Branch TMI Questions
Dear Mr. Denton:
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As requested in your letter dated 10/28/80, South Carolina Electric and Gas Company (SCE&G), acting for itself and agent for South Carolina Public Service Authority, provides forty-five (45) copies of additional information regarding TMI concerns of the Effluent Treatment Systems Branch.
This information will be incorporated into the next FSAR amendment.
If you need additional information on this subject, please let us know.
Very truly yours, c
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T. C. Nichols, Jr.
RBC:TCN:rh cc:
V. C.
Summer G. II. Fischer T. C. Nichols, Jr.
E. 11. Crews, Jr.
O. S. Bradham O. W. Dixon, Jr.
D. A. Nauman R. B. Cla ry W. A. Williams B. A. Bursey J. B. Knotts J. L. Skolds NPCF/Whitake r File 8011180906
I 321.14 Additional Accident Monitoring Instrumentation (Ef fluent) Action Plan II.F.I Your response regarding the above action plan is incompleted. At this time we require clarifications and additional information on the following items:
1.
Will the Hydrogen Purge exhaust be also monitored by RM-A147 2.
In your Faar, you have stated that, based on the process monitor RM-A9 reading, operator action will be undertaken to divert condenser air ejector releases via the main plant vent if needed.
How soon will this manual diversion be completed when needed.?
3.
Will the area radiation monitors RM-G19A, B and C that you proposed to install to moniotr steam dump / safety valve releases provide a doseraterangeequivalent to Xe-133 equivalent concentration range of 10-1 to 10 usi/cc in the discharge? How will you correct the readings of these external monitors for low energy gammas?
4.
Describe the procedures and calculational methods you will employ to convert instrument readings to concentrations and/or release rates.
5.
Describe how you will initially calibrate these monitors and also at what frequency, you will calibrate them periodically.
6.
The additional information you are required to provide should include (a) the energy dependence of these monitors (b) the back-ground correction to the instrument readings, if applicable (c) how these readings will be displayed and disseminated (d) assurance that readings can be obtained at least every 15 minutes during and following an accident.
7.
You should provide information on iodine and particulate ef fluent sampling for the main plant vent and reactor building purge releases.
Response
1.
The hydrogen purge exhaust as shown by figure 6.2-58 passes through the purge vent exhaust flow path which is monitored by radiation monitors RM-A4 and by i
RM-A14.
2.
The normal flow path for the ef fluent from the condenser air ejector is through the Auxiliary Building ventilation system charcoal filters and then through the t
Auxiliary Building vent stack. Revised FSAR sections 10.4.2.1, 10.4.2.2 and 10.4.2.3 are provided and will be incorporated in the next FSAR amendment.
3.
The radiation monitors RM-G19A, B and C are responsive to 0.1 mr/m up to 10 mr/m gamma.
The anticipated dose rate at the detector due to a equivalent concentration of 10 +3 per ci/cc of Xc-133 is 1.7 x 10" mr/m and at 10-1 in ci/cc of Xc-133 is 1.7 mr/m.
The detector has a flat response of Il0% from 80 ker to 3 mer and therefore requires no correction for the low energy gamma dose.
4.
See revised section 12.2.5.
5.
See revised section 12.2.5.
k 6.
The energy dependence of the high range ef fluent monitors; plant vent monitor RM-A13, purge vent monitor RM-A14, and main steam line monitors RM-G19A, l
RM-G19B and RM-Gl9C is 80 key to 3 mov 10 percent.
Background correction for each monitor is achieved by 2-inch lead shielding to reduce background and provide collimation of the detector to respond to the direct gamma radiation from the vent duct or steam line being monitored.
i Continuous readout displays for these monitors are provided in the control room in the radiation monitoring (RMS) panel and the analog signals are recorded on multipoint recorders also in the RMS panel as described in section 11.4.2 and 12.1.4.2.
Analog signals from these monitors are also provided as computer j
inputs to the Technical Support Center.
These monitors will have the detectors supported on a mounting designed to withstand a seismic event independent of the support of the vent ducts or steam lines.
The readouts (ratemeters) will be mounted in the RMS panel which is seismically qualified and thereby provides assurance that readings can be obtained at least every 15 minutes during and following an accident.
7.
Continuous sampling of the plant vent and the purge exhaust for particulate and iodine is provided by the sample filter media in radiation monitors RM-A3 and RM-A4 as described in section 11.4.2 and 12.3.2.2.4.
These samples are replaced and the removed sample media is taken to the in-plant laboratory for analysis of the particulate and iodine. Under post accident conditions, silver zeolite cartridges will be used for iodine collection when conditions dictate and the samples are transported in shicided containers when required.
Carbon filters are normally installed, however, plant procedures will require that a sufficient inventory of silver-zeolite filters be on hand and availabic for immediate use at the first indication of an accident. As a part of the plant emergency operating procedures a health physics technician will be directed to immediately install these filters.
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10.4.2 CONDENSER AIR REMOVAL SYSTEM The condenser air removal system maintains main and auxiliary condenser vacuum by removing noncondensible gases, including dissociated hydrogen and oxygen f rom the mein and auxiliary condensers.
s-10.4.2.1 Design Bases The non-nuclear safety class condenser air removal system is designed to establish main and auxiliary condenser vacuum during plant startup and to maintain vacuum during normal operation.
Mechanical vacuum pumps remove noncondensible gases f rom the condensers and, under normal condi-to w+ m e s thset tions, discharge ::.:xssphae- -"- i : _ :likely ^"c-r-*'::
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gy 22 E dc. ;2;J i
^_h; it: f-- _ y
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p r 3.__ pn:: t= L-1-
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iilc r through the auxiliary building ventilation system charcoal filters.
Mechanical vacuum pumps are designed for the capacities listed in Table 10.4-2 in accordance with Heat Exchanger Institute Standards. Piping and B16.5(2]
and valves are designed in accordance with ANSI B31.1 respectively.
10.4.2.2
System Description
Two subsystems comprisc the condenser air removal system:
the main con-denser air removal subsystem and the auxiliary condenser air removal s ubsystem.
Figure 10.4-1 provides the system diagram.
Each of the two main condenser shells is evacuated by an individual, 100 percent capacity, mechanical vacuum pump.
A third pump is pro-vided for backup. These pumps are used both to establish vacuum during plant startup (hogging) and to maintain vacuum during operation (holding).
10.4-5 A m e~ome"7 EE IVo ves he 11%0
1 One mechanical vacuum pump is used to maintain vacuum in the three aux-iliary condensers. A second pump is provided for backup.
All vacuum pumps can be operated during startup to speed the hogging 1
operation.
4 Cooling water for the mechanical vacuum pumps is supplied from the cir-culating water cooling system.
Seal water is provided by the condensates system.
%e.,A %s A u st,'aey 8 vil),*ug v e."rn irrocu system charsul fo'It<es 2.1 Both subsystems dischargegic 2trcopherc through a common line under normal conditions.
Condenser discharge radiation monitor, FM-A9, is set to alarm at approximately twice normal operating background.
The high alarm is set at approximately one decade above background to provide a positive indication of leakage. Provision is made for obtaining local samples for analysis and evaluation.
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th e ilic:j-b uilding -vent ilation cyatcm c' weeaL fi-lte= ic rcqu& sed.
10.4.2.3 Safety Evaluation The condenser air removal system is not required to operate under emer-gency conditions nor is it necessary to achieve safe plant shutdown.
j Each subsystem is provided with a backup mechanical vacuum pump.
Thus failure of an operating pump is not detrimental to continued plant op-
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cration.
Under normal conditions, the condenser air removal system as no effect upon the reactor coolant system and radioactive Icakage is negligible.
However, should primary to secondary reactor coolant Icakage occur, re-(
sulting in detection of radioactivity in the condenser air removal system 10.4-6 gjg 22 Nweder 1150
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-- e e flowpath through the auxiliary building charcoal 7t
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linirs fbc l
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filters f-p._Itr 1! -! t release of radioactivity to the environment.
Anticipated release rates during normal operation are presented in Sec-tion 11.3.6.
10.4.2.4 Tests and Inspections The condenser air removal system is operated continuously during normal plant operation.
Therefore, periodic testing is not required.
System
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operation is verified prior to initial plant startup by preoperational and startup testing. During subsequent plant startups, system operation is verified by observation during hogging operations.
System components are rea111y accessible for visual inspection under normal plant conditions.
10.4.2.5 Ins t rumen t ation 1.
Main Condenser Air Removal
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Local pressure and flow indication is provided to monitor vacuum pump performance.
Lube oil pressure and discharge air temperature switches are provided for startup and shutdown interlocks.
Ala rms att sounded in the control room to alert the operator to vacuum pump trip, vacuum puup lube oil pump trip, low oil pressure, high off gas air temperature and high of f gas radiation.
2.
Auxiliary Condenser Air Removal im
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Local pressure indication is provided to monitor vacuum pump per-fo rman ce.
Lube oil pressure and discharge air temperature switches are provided for startup and shutdown interlocks.
Alarms are sounded in the control roem to alert the operator to vacuum pump trip and high
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lube oil tecperature.
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10.4-7 An<~Js<~r LI Hearn k-19 90
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minimized during operations and maintenance by using the following methods and procedures to determine and cope with potential hazards:
1.
Monitoring E
High volu=e air saeplers of various flow rates are used to collect particulates on high efficiency filter media, at regularly scheduled intervals, for subsequent counting.
For tritium sampling, freezeout methods, bubblers or dessicants are used to obtain sa=ples for counting by the use of liquid scintillation techniques. Assay of noble gases is performed on a regular schedule by drawing an air sa=ple into an evacuated chamber f'or appropriate analysis.
2.
' Respiratory Protection It is the responsibility of the health physics group to conitor and post areas of airborne radioactivity, to establish the requirements
.4, for respiratory equipcents to. control the use 'of respiratory equip.
cent and to control access to areas through the radiation work permit program. Training progra=s for respiratory protection are the resp'onsibility of the Health Physics Supervisor.
i Experience gained during operation and maintenance of several nuclear plants with whom SCE&G has contact is used to provide one basis for further evaluation and development of respiratory protection pro-grams. Guidance contained in Regulatory Guides 8.2, 8.8 and 8.10 is utilized in the development and review of these programs.
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12.2.6 STIMATES OF INHALATION DOSES The annual inhalation doses to plant personne. -rom airborne activity in the various plant buildings depend upon the occupancy of the various plant areas in which airborne activity can occur. The dose to plant 12.2-10 i
AJ -T a w a r,neo i
Rwsd k w It.. W Insert A - Page 12.2-10 In relation to TMI Action Plan Item II.F.1, " Additional Acci, den.t Monitoring Instrumentation", Station procedures will contain the following information for converting instrument readings to concentrations or/and release rates:
a) Graphs relating cpm readings to concentration (pCi/al) for ef fluent radiation monitors based on the manufacturer's recommendation or measurements from on-site analyses.
b) Graph or formula for determining the release rate (Ci/sec) based on effluent radiatica monitor readings and measured flow rates of the main vent.
c) Graph or formula for determining the volume of steam discharged after opening of main steam safety valves. A concentration based on the average reading of the radiation monitors can be used to quickly approximate the total amount of radioactivity released.
Subsequent laboratory analysis more accurately determines the quantity and spectrum of radionuclides released.
Computer capabilities can also be used to assist with these calculations.
Alco, as required by TMI Action Plan Item II.F.1, the Station Radiation Monitor Calibration Program is as follows:
Initial vendor calibration included the determination of response to various radioactive isotopes where they were calibrated to provide trace-ability to the National Bureau of Standards. The Liquid monit'rs were checked against Cs-137 and Mn-54; Particulate monitors were checked against Cs-137 and Ce-144; Iodine monitors were checked against Cs-137 and Ba-133; Cas monitors were checked against Kr-SS and Cs-137.
The Condenser Offgas monitor was checked against Xe-133 and Cs-137.
Area monitors were checked against Ra-226.
Inplant calibration will normally use calibrated sources for determination of monitor response. These sources will typically be Cs-137 or Co-60 for Area Camma monitors; Cs-137 for Particulate monitors; Ba-133 for Iodine monitors; and Cs-137 for Liquid monitors. Frequency of periodic calibra-tion is normally on a yearly basis except for those channels identified in the Technical Specification where frequency has been fixed. The High Range Camma Area monitors require electronic verification as described in section 12.1 as the use of high level isotopes is not practical.
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321.15 Primary Coolant Sources Outside Containment - III.D.l.1 Your response regarding the above action is inadequate.
1.
Provide a list of the systems that you propose to test for leakage in the immediate future.
2.
Provide information on the countinuing leak reduction program you plan to implement. The information should include (a) frequency of the integrated leak tests (b) method and summary of procedures for testing each system or subsystem (c) steps that will be taken for minimizing occupational exposures and (d) details on the preventive maintenance steps to reduce leakage to as-low-as prac-tical levels.
Response
1.
Operational leak tests will be performed on the appropriate portions of the Chemical and Volume Control letdown, Safety Injection, Residual Heat Removal, Nuclear Sampling, Radwaste Liquid Handling, Radwaste Gas Handling and Reactor Building Spray Systems outside Reactor Containment.
2.
Testing of liquid containing systems will be performed by pressurizing the system with a hydro pump and determining makeup by measuring level changes in a graduated tank, or by normal operating pressure sources. During pres-surization, each system will be walked down and visually inspected for leaks.
Any leaks discovered during the walkdown will be evaluated to determine the approximate leakage from that system.
Baseline leakage rates will be recorded af ter appropriate measures to eliminate undesirable leakage paths have been taken.
Testing of Gaseous Radwaste System will consist of pressurizing the system and maintaining the pressure using a regulated nitrogen source. The system makeup rate will be determined utilizing a gas flow-meter at the nitrogen regulator.
All potential leakage sources will be checked with a soap and water solution to located leaks and appropriate means taken to eliminate them. After system has been in operation, a routine radiation monitoring program will be implemented to detect minute changes in the activiity of air and the areas occupied by the system.
If leakage is indicated by an increase in the airborne activity, appropriate means, such as Helium Gas and soap and water, will be used to localize the leak.
In order to minimize radiation exposure associated with this program, the leakage test will be performed as part of the ASME Section XI Hydrostatic Test Program.
A Preventive Ibintenance Program has been established to periodically adjust packing glands and flanged connections. All leakage will be reduced to as-low-as achievable when discovered.
A summary description of the Leak Test Program along with the initial leak test results will be submitted prior to Fuel Load.
321.16 Post Accident Sampling - Action Plant II.B.3 Your response regarding the above action plan is incomplete.
1.
You should provide information on (a) time for completion of sample analysis (this should not exceed 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) (b) isotopes that,ill be detected (c) concentration range for reactor coolant that can be sampled (d) quantification of dissolved gases in unpressurized reactor coolant samples.
2.
Your information should include assurance that backup sampling through grab samples will be provided for systems using in-line monitoring for samples. You should also give the frequency of such grab sampling.
3.
You should commit to (a) sampling containment atmosphere under both positive and negative containment atmosphere (b) not having to place in operation, to use the sampling systems, any system that may be isolated during an accident and (c) returning residues of sample collection to containment or a closed system.
Response
la.
Time for sample analysis completion.
Time / Action Sequence Table Minutes from Time Zero Sample Purge / Collect 25 min.
Inline, Gross Rad Level, Boron, pH Cond.
30 min.
Total Gas Calculation 35 min.
Isotopic Sample Collection for RCS Gas and Liquid 45 min.
Isotopic Results and H2 and 09 Results 65 min.
All Results Tabulated and to Control Room 90 min.
b.
Isotopes sampled will be taken from our Reactor Coolant and Gas Isetopic Library.
These include all major emitters listed in Technical Specifications y
for gas and liquid monitoring.
1.
For liquid, the following isotopes as a minimum:
Fh-54, Fe-59, Co-58, Co-60, 2n-65, Mo-99, Cs-134, Cs-137, Ce-141, Ce-144, I-131 through 135.
2.
For gas the following isotopes as a minimum:
Kr-87, 88, Xe-133, 133m, 135, 138.
NOTE: Our standard coolant gas and liquid libraries are still being formulated. The above isotopes will be the minimum contained in each.
If you desire other certain isotopes to be looked for, let us know and we will add them to our libraries.
c.
By the use of an in-line radiation monitor, the amount of necessary dilution is estimated then desired sample volume with a dilution range of 10,000-10 to one for liquid and 3,000-10 to one for gases is obtained.
Sensitivity of onsite liquid sample analysis capability permits measurement of nuclide i
concentration in the range from approximately 1 uCi/g to 10 Ci/g.
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T d.
The hydrogen and oxygen concentrations will be determined after gases have been stripped from the sample and diluted using argon carrier gas. _ Method of analysis will be gas chromatography.
Use of agron as the carrier gas is considered desirable because of sensitivity advantages gained through its use.
To preclude accidential introduction of argon into the reactor coolant system, argon is automatically purged out of the system with nitrogen after its use.
The sample system is isolated from the reactor coolant system whenever argon is in use.
2.
Post accident sample system includes the capability to take grab samples.
Grab samples are obtained and analyzed for boron and chlorides within the required time frames.
On-line gamma isotopic analysis are not used.
Gamma isotopic analysis are off-line. The capability to ample and analyze grab samples for isotopes on an indefinite basis is provided.
3.
To protect samplers while taking containment air samples, the evolution is perrormed remotely from a control panel approximately 40 feet from the sample station.
Samples are diluted and sample lines are purged with N2 Prior to sample retrieval.
Since the containment atmosphere is isolated on high radiation, a significant radiation hazard is not expected to be present at the main plant vent; there-fore no additional precautions are necessary.
A discussion of shielding consideration is provided in Appendix 12A.
Nitrogram is purged through the sample filters prior to sample retrieval for counting. Therefore only iodine and particulate activity will be counted, n.
The pump used for motive force for containment sampling is a deaphragm pump and will pump under pressure or partial pressure to vacuum conditions.
b.
The sample system at Virgil C. Summer Nuclear Station is designed to sample the reactor coolant system directly and only the sample line isolations need be overridden for sampling.
The capability to sample the reactor heat removal system exists, but :'ould be used only if systems were already in service, c.
Sample residue and sample line flushing waste will be directed back into containmant to the pressurizer relief tank.
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