ML20033A595
ML20033A595 | |
Person / Time | |
---|---|
Site: | Clinch River |
Issue date: | 02/10/1981 |
From: | ENERGY, DEPT. OF, CLINCH RIVER BREEDER REACTOR PLANT |
To: | |
Shared Package | |
ML20033A592 | List: |
References | |
CRBRP-3, CRBRP-3-V02-R02, CRBRP-3-V2-R2, NUDOCS 8111250607 | |
Download: ML20033A595 (38) | |
Text
,t CRBRP-3 O
l l
HYPOTHETICAL CORE DISRUPTIVE ACCIDENT CONSIDERATIONS IN CRBRP VOLUME 2:
O ASSESSMENT OF THERMAL MARGIN BEYOND THE DESIGN BASE CLINCH RIVER BREEDER REACTOR PLANT
I e
{
l TITLE Hypothetical Core DOCUMENT NO.
Disruptive Accident Considerations in CRBRP CRBRP-3 CHANGE CONTROL RECORD volume 2 volume a Assessment of Thermal Margin Beyond the Design Base CHANGE REV N0/DATE RELEASE PAGES AFFECTED REMARKS DOCUMENT 0/ March 80 All First formal issue of document Rev 1/5-81 i, 2-4, 2-6, 2-7, 2-10 Pages added 2-16A thru 2-16, 2-24, 2-25, thru 2-16G, 2-34A 2-26, 2-32, 2-34, 2-43, 2-44, 2-76 Rev 2/10-81 2-16B, 2-16C, 2-16F, 2-16G l
l 0116-2
t CRBRP-3 VOL. 2, REV. 1 O
TABLE OF CONTENTS Page
1.0 INTRODUCTION
1-1
1.1 REFERENCES
1-5 2.0 DESIGN FEATURES PROVIDING THERMAL MARGIN BEYOND THE DESIGN BASE 2-1 2.1 TMBDB FEATURES REQUIREMENTS 2-2 2.1.1 General 2-2 2.1.2 Feature Requirements 2-3 2.1.3 Maintenance and Testing Requirements for 2-16A TMBDB Features 1
2.2 DESCRIPTION
OF DESIGN FEATURES 2-17 2.2.1 Reactor Cavity to Containment Barrier 2-17 2.2.2 Reactor Cavity Recirculating Gas Cooling System 2-18 2.2.3 Guard Vessel Support 2-18 2.2.4 Reactor Cavity and Pipeway Cell Liners 2-18 2.2.5 Reactor Cavity and Pipeway Cell Liner Vent 2-19 O
System 2.2.6 Reactor Cavity vent System 2-22 2.2.7 Containment Purge Capability 2-24 2.2.8 Containment Vent Capability 2-25 T 2.9 Containment Cleanup System 2-26 2.2.10 Annulus Air Cooling System 2-27 2.2.11 Containment System Leakage Barrier 2-29 2.2.12 TMBDB Instrumentation System 2-30 2.2.13 Electrical Power System 2-34 2.2.14 Containment Structures 2-34 2.2.15 Control Room Habitability 2-35 2.3 OPERATOR ACTION SEQUENCE 2-38
2.4 REFERENCES
2-41
3.0 ASSESSMENT
OF THERPAL PARGIN 3-1 3.1 THERMAL PARGIN WITHIN THE REACTCR VESSEL 3-2 3.1.1 Core Debris Distribution 3-2 3.1.2 In-Vessel Debris Retention Capability 3-10 3.1.3 Secondary Criticality Considerations 3-15 3.1.4 Penetration of the Reactor and Guard Vessels 3-15 3.2 THERMAL MARGIN EXTERNAL TO THE REACTOR VESSEL 3-18 3.2.1 Scenario 3-18 3.2.2 Containment Transients Prior to Sodium Boildry 3-26 3.2.3 Contaircent Transients Af ter Sodium Boildry 3-60 3.2.4 Secondary Criticality Considerations (Ex-Vessel) 3-70 i
CRBRP-3 Vol.2, Rev.0 T?.BLE OF CONTENTS (Continued)
M
3.3 CONCLUSION
S ON THERMAL PARGIN BEYOND THE DESIGN BASE 3-72
3.4 REFERENCES
3-73
4.0 ASSESSMENT
OF RADIOLOGICAL CONSEQUENCES 4-1 4.1 HCDA RADIOLOGICAL SOURCE TERM 4-1 4.1.1 Non-Energetic Core Meltdown 4-2 4.1.2 Energetic HCDA 4-5 4.2 RADIOLOGICAL DOSES FROM ATMOSPHERIC RELEASES 4-8 4.2.1 Methods and Data Base 4-8 4.2.2 Radiological Doses 4-10 4.3 GROUNDWATER CONSIDERATIONS 4-11 4.4 HETEROGENE0US CORE CONSIDERATIONS 4-13
4.5 CONCLUSION
S ON RAbl0 LOGICAL CONSEQUENCES 4-14
4.6 REFERENCES
4-15 5.0
SUMMARY
AND CONCLUSIONS 5-1 APPENDICES:
A.'0-1 INDEX T0.S'ENSITIVITY STUDIES IN APPENDICES A.0-2 A.
DEVELOPMENT PROGRAMS SUPPORTING THERMAL MARGIN ASSESSMENTS A-1 A.1 S0DIUM-CONCRETE INTERACTIONS DEVELOPMENT PROGRAM A-1
. A.1.1 Purpose A-1 A.1.2 Progra:n A-1 A.1.3 Schedule A-2 A.1.4 Criteria of Success A-3 A.1.5 Fallback Position A-3 A.2 HYDR 0 GEN AUTO-CATALYTIC RECOMBINATION A-4 A.2.1 Purpose A-4 A.2.2 Program A-4 A.2.3 Schedule A-5 A.2.4 Criteria of Success A-6 A.2.5 Fallback Position A-6 e
ii
t CR8RP-3 Vol.2, Rev.0 f.
There -is not a requirement to meet the allowable site boundary or -
low population zone doses of 10CFR100 or the control room dose of 10CFR50 under TMBDB conditions.
2.-
Acceptance Criteria a.
The public risk from accidents beyond the design base shall be comparable to.that from light water reactors for events beyond the design base with similar. probabilit'y of occurrence.
b.
Containment integrity shall be maintained without venting following initiation of an accident leading.to c"e meltdown for a period of time sufficient to allow evacuation procedures to'be implemehted.
Per tRC guidance, the period is taken as 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
2.1.2 Feature Requirements The fol. lowing requirements are imposed on the specific TMBDB features as well as other systems or components to provide thermal margin beyond the design base in CRBRP.
2.1.2.,1. Reactor Cavity-To-Containment Barrier To insure that the heat capacity of the pipeway cells is employed from 1000 seconds to 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> after a HCDA, the total leakage of sodium vapor through the reactor cavity to head access area seals (not throvoh the reactor head or' the' planned vent path defined 'n Section 2.2.6) shal, at exceed 10000 pounds (for requirements before 1000 seconds see Section 2.2).
These leakages shall be based on the pressure differential for the reactor cavity to head access area seals' given on Figure 2-1, on the reactor cavity pressures on Figure 2-2, and on the reactor cavity atmosphere temperatures on Figure 2-3.
hv 2-3
e CRBRP-3 VOL. 2, REV. 1 2.1.2.2 Reactor Cavity Recirculating Gas Cooling System To insure that the Cell 105 hydrogen concentration does not exceed 67., the leakage from the reactur cavity through the recirculating gas cooling system to non-inerted cells shall be less than 4000 pounds of sodium from 1000 seconds to 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> after HCDA. These leakages shall be based on the I
reactor cavity pressures and temperatures on Figures 2-2 and 2-3 and on the differential pressure between the reactor cavity and Cell 105 given on Figure 2-4.
2.1. 2. 3 Guard Vessel Support To insure that sodium ana fuel particulate redistribute in the reactor 2
cavity, a flow area of at least 10 f t shall be provided under the guard vessel skirt bottom flange.
2.1.2.4 Reactor Cavity and Pipeway Cell Liners To insure that tne Reactor Containment Building hydrogen concentration does not exceed 6% (by volume) and to keep from exceeding the containment vent, purge and cleanup system capacities, the reactor cavity wall and pipeway cell liners shall prevent short term (less than 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />) sodium-concrete reactions based on the pressure on Figure 2-2 and the temperatures on Figure 2-9 and Figures 2-11 through 2-16.
The results of structural analysis will be used to determine the liner failure times assumed in the IMBDB scenario.
To limit the consequences of liner failures, the liner system shall have physical barriers behind the liners between the reactor cavity floor and reactor cavity wall and at 8 feet and 26 feet above the reactor cavity floor. Likewise, the pipeway cells shall have physical barriers behind the liners to separate the vent spaces of the walls, floor, and roof of each cell. Only the spaces of adjacent walls with different liner failure ' times will be separated.
O 2
CRBRP-3 Vol.2, Rev.0 O-Q 2.1.2.5 Reactor Cavity and Pipeway Cell Liners Vent System 1.
To insure that the pressure buildup, due to the gases released behind the liners, does not impair the ability of the liners to prevent sodium
~
from reacting with concrete, all reactor cavity and pipeway cell liner vent systems shall prevent a pressure buildup behind the liners in excess of 5 psi.
2.
To insure that sodium would be prevented from reaching Cell 105 in the event of liner failure, the lirer vent system for the reactor cavity.
floor shall vent the gases released from heated concrete to containment above the operating floor. The floor liner vent system shall have a 2
3 capacity of 10 lb/hr-f t of water vapor at a density of 0.02 lb/ft,
3.
The liner vent system for the reactor cavity walls and pipeway cells shall vent the gases released from heated concrete to Cell 105. The liner veet system shall have a capacity of 7 lb/hr-f t2 of water vapor 3
at a density of 0.02 lb/ft,
b 4.
To insure that the Cell 105 hydrogen does not exceed 6%, the sodium leakage from the reactor cavity through the liner vent system to Cell 1,06 shall be less than 1000 pounds. This leakage shall be based on the reactor cavity pressures and temperatures on Figures 2-2 and 2-3 and on the differential pressure between the reactor cavity and Cell 105 on i
Figure 2-4.
2.1.2.6 Reactor Cavity Vent System 1.
To prevent reactor cavity structural and liner f ailure by over pressurization, the vent system shall provide redundant flow paths between the reactor cavity and reactor containment building when the pressure differential between the reactor cavity and containment exceeds 11.5 + 1.5 psi. Af ter passive initiation, the vent path shall remain open.
2-5
e i
CRBRP-3 VOL. 2, REV. 1 2.
The vent system shall have a prassure drop of less than 0.1 psi with a 3
flow rate of 4000 lb/hr of gases, 6 Jensity of 0.03 lb/ft, and a viscosity of 0.05 lb/ft-hr.
It shall remai-functional if up to
)
450 pounds of sodium oxide aerosol enter the vent at a maximum rate of 8000 lb/hr.
3.
The vent system shall be capable of performing all of its intended functions for 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> in the presence of gases and vapors consisting of Ar, N, H, Na, fission products, and compounds resulting from 2
2 fission product reactions.
4 To insure that the heat capacity of the pipeway cells is employed, a minimum of 25% of the mass flow into the pipeway cells shall enter each pipeway cell.
5.
To allow sodium that condenses in the pipeway cells to drain back into the reactor cavity, two drain pipes shall be provided between each pipeway cell and the reactor cavity, at the elevation of the pipeway cell floor. Each drain pipe shall be capable of a minimum flow rate of 2000 lb/hr of sodium at its boiling point with a pressure head of
.2 feet of sodium.
6.
To assure that the flame at the vent exit does not approach the containment vessel, the pipeway cell to containment vent line diameter shall not exceed 12 inches.
2.1.2.7-Containment Surge System 1.
To insure that the Reactor Containment Building hydrogen concentration does not exceed 6% (by volume), the purge system shall be capable of injecting outside air into containment at a maximum rate of 12,000 scfm at pressures not exceeding otmospheric.
O 2-6
CRBRP-3 von _. 2 REV. 1 2.
To insure containment v
nixing before venting, the purge air shall be injected into went below elevation 840'.
3.
The purge system shall preu nt backflow from containment to the outside atmosphere.
j 4.
The purge system, in combination with the containment vent and cleanup systems, shall maintain containment at a negative pressure after the containment pressure is reduced by the' initial venting after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
5.
The purge system operations shall be by remote manual actuation from the control room.
1 2.1.2.8 Containment Vent System 1.
To prevent containment failure by excessive pressure, the vent system shall have a capacity between 24,000 and 26,400 acfm with a containment pressure of 30 psia, a containment atmosphere density of 0.07 lb/ft and a viscosity of 0.06 lb/ft-hr.
It shall remain functional if up,to j
300,000 pounds of aerosol enter the system at a maximum rate of 5,600 lb/br.
2.
The vent system shall exhaust the containment atmosphere from the top I
of containment into the containment cleanup system.
1 i
3.
The containment vent system shall be compatible with the following
~
gases, vapors and aerosols: Ar, N, H, H 0, CO, CO, 0, Na 0, Na 0 '
2 2
2 2
2 2
22 Na0H, Na CO, fission products, and compounds resulting from fission 2 3 product reactions. The system must remain functional for inlet gas l
temperatures and pressures given on Figures 2-5 and 2-6.
4.
The vent system operations shall be by remote manual actuation from the control room.
)
4 2-7
~ ~ " :. -.
CRBRP-3 Vol.2, R v.0 2.1.2.9 TMBDB Contair. ment Cleanup System 1.
The containment cleanup system efficiency shall be a minimum of 99% for vented materials in the solid or liquid state, 97% for vapors (Na!,
Se0, and Sb 0 ) subject to condensation in the cleanup. system, 2
23 and'0% for noble gases. These efficiencies shall apply when subjected to the vent rates on Figure 2-7 and containment atmosphere temperatures 3
on Figure 2-5 with a containment atmosphere density of 0.07 lb/ft,
It shall be capable of perfor.T.ing all of its intended functions in the presence of Ar, N ' H ' H 0, CO, CO, 0, Na 0, Na 0, NaOH, Na 00,
2 2
2 2
2 2
22 2 3 fission products, and compounds resulting from t ssion product reactions.
2.
The containment cleanup system shall remain functional at an aerosol mass flow rate of up to 5,600 lb/hr and a total mass of 300,000 pounds of aerosol entering the cleanup system. The principal constitutents of the aerosol are NaOH and Na 0, the proportions of which can vary from 2
0 to 100% of the aerosol, and Na 00 which can vary from 0 to 8% of 2 3 the aerosol.
The aerosol particle properties are:
Mass Mean Radius (microns):
5 < r50 < 10 Aerodynamic Equivalent Radius (microns):
2.3 < AER < 4.7 Density (g/cc):
2.1 < p < 2.5 Mas,s Geometric Standard Deviation:
3.0 < a < 3.5 Aerodynamic equivalent radius is based on AER = r50 (PG)0.5 where p = 2.21 and a = 0.1 l
2-8
CRBRP-3 l
Vol.2. Rev.0 -
l 3.
The containment cleanup system shall remain functional at fission products power levels in the' accumulated filter aerosol of:
Time Fission Product Power (hours)
(MW) 0 0-24 3.1 x 10-5 48 0.16*
96 0.16*
240 0.11 720 0.05 4.
The containment cleanup system design shall be capable of performing all its' intended functions with the following chem 1 cal and physical states of the 10 most radiologically significant fission products in the containment atmosphere:
- Maximum _value.
MAXIMUM PERCENTAGE OF THE FISSION PRODUCTS BY CHEMICAL Af'] PHYSICAL FORM Elemental Oxide Element Vapor Liquid or Solid Vapor Liquid or Solid Se 1%
1%
100%
100%
Rb 1
1 1
100 6r 1
1 1
100 Zr 1
1 1
100 Sb 1
1 100 100 Te 1
1 1
100 Cs 1
1 1
100 Ba 1
1 1
100 Ce 1
1 1
100 Nal I
1 1
33 100 i
2-9
CRBRP-3 VOL. 2, REV. 1 9
5.
The exhaust from the containment cleanup system shall have a temperature compatible with operation of the TMBDB Exhaust-Plant Effluent Radiation Monitoring System.
6.
The containment cleanup system operations shall be by remote manual actuation from the control room.
j 2.1.2.10 Annulus Cooling System 1.
To insure containment and confinement do not fail from excessive temperatures, the annulus cooling system shall remove the heat load into the containment steel shell on Figure 2-8.
2.
Steel containment temperatures shall be below those that cause structural failure or excessive containment leakage.
3.
Concrete confinement temperatures shall be below those that cause structural failure.
4.
The annulus cooling system operations shall be by remote manual actuation from the control rocm.
)
2.1.2.11 Containment System Leakage Barrier At any given time, containment leakage shall not exceed the greater of:
1.
The design leakrate (0.1 volume percent per day).
2.
The design leakrate adjusted for pressures above. the containment design pressure of 10 psig. Leakrate = Design Leakrate x (Actual Pressure (psig)).5/3.2.
3.
One percent of the mass leaving the containment through the containment vent system.
2-10
CRBRP-3 r3 VOL. 2, REV. 1
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2.1.2.12 TMBDB Instrumentation Syttem
~
Operator action to initiate TMBDB systems operation is required only for events beyond the design base. However, mis-operation of TMBDB systems, because of incorrect instrument readings in the control room, could defeat l1 Engineered Safety Features (ESFs) required to mitigate design basis accidents.
In accordance with this importance to maintain ESF capability, plant instrumentation has been designated "TMBDB Instrumentation", shall be designed, manufactured and qualified to all standards applied to Class lE instrumentation. Specifically the following subsystems of the Reactor Containment Instrumcntation System (RCIS) and of the Radiation Monitoring System (RMS) shall be considered TMBDB icstrumentation:
(1) Containment Pressure (RCIS)
(2) Containment Atmosphere Temperature (RCIS)
(]
(3) Containment Hydrogen Concentration (liCIS)
'x./
(4) Containment Vessel Temperature (RCIS)
(5) TMBDB Exhaust-Plant Effluent Radiation Monitoring (RMS)
(6) High-Range Containment Area Radiation (RMS)
Note that subsystems (5), and (6) are not in the category of instrumentation which could be used to defeat ESFs; however, because of their importance in assessing releases from the plant during a TMBDB scenario they are included 1
in the TMBDB instrumentation.
1.
The.TMBDB instrument ranges shall be:
Minimum Maximum Containment Atmosphere Temperature (degrees F) 60 1100 Containment Steel Dome Temperature (degrees F) 40 700 Containment Atmosphere Pressure (psia) 14.7 55 1
Containment Hydrogen Concentration (Volume %)
0 8
g; t'%./
2-11
CRBRP-3 VOL. 2, REV. 1 O
Minimum Maximum 7
High-Range Containment Area Radiation (R/hr) 1 10 (60 Kev to 3 Mev photons. This range applies inside the RCB.
If the detectors are located outside the RCB, appropriate adjustments in conditions shall be made.)
l Radioactivity of Released Products (ci/sec)*
Particulates 0
7 Radioiodines 0
30 Radiogases 0
6000 Fuels and Transuranics 0
0.01 2.
Instrument accuracy shall be:
Temperature (Percent of Maximum Value)
+5 Pressure (Percent of Maximum Value)
+5 Hydrogen Concentration (Percent of Maximum Value) 15 Radioactivity of Released Products at 95% SCL (Percent of Maximum Value)
+100, -50 High-Range Containment Area Radiation (Percent of reading)
-+20**
1 l
3.
Instrument response time shall be:
l Temperature Less ttpn 5 minutes Pressure less than 5 minutes l
- These are based on total amounts released.
Instrument ranges will depend on the sampling rate.
I
- For photons of 0.1 to 3 Mev.
1 0 2-12
CRBRP-3 o
VOL. 2, REV. 1
(
)
n./
Hydrogen Concentration Less than 10 minutes Radioactivity of Released Products Less than 5 minutes High-Range Containment Area Radiation Less than 5 minutes
)
4.
Measurement capability after initiation of the TMBDB condition shall be provided for:
Temperature 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> Pressure 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> Hydrogen Concentration 8,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> Radioactivity of Released Products 8,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> High-Range Containment Area Radiation
.8,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />
)
5.
The instrument sensor / sampling elevations inside of containment shall be:
,/
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k Hydrogen Concentration Above 970' Containment Atmosphere Temperature Above 955' Containment Atmosphere Pressure Above 823' Containment Steel Dome Temperature At 817', 823', 833', 854',
875', 902', 964', and 974' 1
6.
TMBDB sensors inside containment shall be fur.ctional with a maximum containment atmosphere temperature of 1100 F and pressure of 55 psia.
l1 7.
TMBDB sensors inside containment shall be functional with containment atrnosphere maximum constituent concentrations of:
Oxygen 21% (volume)
Nitrogen 90% (volume)
Water Vapor 10% (volume)
Hydrogen 8%
/3 N.)
2-13
CRBRP-3 VOL. 2. REV. 1 Carbon Dioxide 6%
Na0H + Na 0 (any proportion of the 6 x 10-3 lb/ft,
3 2
two from 0 to 100%)
Na.C0 5 x 10-4 lb/ft,
3 3
8.
TMBDB sensors inside containment shall be functional with the following masses of settled and plated aerosols (NaOH, Na '), and ha C0 )
2 g 3 any unprotectea horizontal or vertical surf aces in containment.
2 Horizontal Surface 80 lb/ft 2
Vertical Surface 0.5 lb/ft 9.
1MBDB sensors inside containment shall be functional with radiation levels of:
b Peak radiation level (High-Range 1 x 10 R/hr Containment Area Radiation) 6 Peak radiation level (other sensors) 1 x 10 R/hr 1
5 Average radiation level over 30 aays 1 x 10 P/hr 8
Total accumulated dose 1 x 10 R The above doses are the som of a and y releases, wnich are estimated to be of equal magnituae.
The High-Range Containment Area Radiation Sensors may be locatea outside containment.
)
- 10. The instruments monitoring radioactivity of products leaving the cleanup system shall provide count rates for particulate (including Pu), radiciodine and gaseous release.
- For 0-500 hours.
O 2-14
CRBRP-3 VOL. 2, REV. 1
- 11. The TMBDB Exhaust-Plant Effluent Radiation monitoring sensors shall be 3
functional with atmosphere maximum constituent concentrations of:
Oxygen 21%
Nitrogen 90%
Water Vapor Saturated Hydrogen 8% (volume) 4 Carbon Dioxide 6%'(volume) 3 Na0H + Na 0 (any proportion of the 6 x 10-5 lb/ft 2
two from 0-100%)
Na 00 5 x 10-6 lb/ft 3
2 3
- 12. The TMBDB instrumentation systems shall be capable of remote manual actuation from t,he control room. The indicators shall be located in the control room, fmy) 2.1.2.13 Electr'ical Power System 1.
Class lE electrical power shall be provided to all TMBDB systems and components that require electrical power to perform their post accident functions.
2.
Electrical loads for TMBDB features shall be remote manually actuated from the control room except for the TMBDB instrumentation which shall lj be normally connected to Class lE electrical power.
2.1.2.14" Containment Structures 1.
The reactor cavity and pipeway structures shall not collapse prior 'to sodium boildry. Structural conditions at boildry for the various scenarios are enveloped by the temperatures on Figures 2-9 through 2-18.
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2-15 4
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- - - - -, ~, -, _. -
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o CRBRP-3 VOL. 2, REV. 1 2.
The reactor containment building.ind confinement structure shall retain their integrity above the basemat as Icng as the contair. ment structural integrity is important in limiting thJ risk to the health and safety of the public based on the limiting temperatures on Figures 2-19 through 2-31.
This time is taken to be 8000 hours0.0926 days <br />2.222 hours <br />0.0132 weeks <br />0.00304 months <br />.
1 2.1.2.15 Control Room Habitability 1
The exposure to the control room operators following a TMBDB condition shall l1 not exceed the following limits in 30 days:
Organ Dose (rem)
Whole Body
- 25 Thyroid 300 Lung 75 Bone 150 0
Skin (beta) 150
- The whole body gamma dose consists of contributions from airborne radioactivity I
inside and outside the control room, as well as direct shine from fission products inside the RCB.
(Because the postulated occurrence of the TMBDB scenario is of.such a low probability as to be excluded from the category of a design basis accident, exposure limits intended for design basis accidents should not apply. The 25 rem whole body dose limit for the control room operators corresponds to lj the once in a lifetime accidental occupation exposure limit recommended in Reference 2-1.
The thyroid limit is based on the 10CFR100 equivalent of a 25 rem whole body dose. The corresponding bone and lung limits are the accepted equivalents to the 25 rem whole body dose (Reference 2-2).)
O 2-16
CRBRP-3 VOL. 2. REV. 1 p]
'w 2.1.3 Maintenance and Testing Requirements for TMBDB Features To assure the TMBDG features will be fully functional and available on.
demand during nonnal reactor operation, testing shall be periodically performed to demonstrate that the TMBDB systems / components satisfy the required functional levels. Maintenance on the TMBDB features shall be performed based on this testing and the'necessary preventive maintenance program. The following requirements define the Maintenance Testing for the CRBRP TMBDB features.
2.1.3.1 General 2.1.3.1.1 General Requirements 1.
The Maintenance'and Testing of the TMBDB features shall not adversely impact the overall safety, availability, maintainability, reliability, and operability of the total plant.
2.
Maintenance of the TMBDB features shall be performed based on the results of the shutdown testing program and vendor specifications.
Preventive maintenance shall be scheduled if possible during reactor shutdown; however, if maintenance of the TME,DB features is required during reactor power operation, one TMBDB feature train shall be continuously available.
3.
The full functional test to be performed periodically shall be performed for all of the specific active components of each TMBDB features train in a given test sequence, since they interface with each other. The specific active TMBDB features are the isolation valves of the Reactor Cavity Vent System, Containment Purge System, Containment Vent System, Containment Cleanup System, Annulus Cooling System, and the i nlation valves of the RC-Recirculating Gas Cooling System.
j 2-16A
CRBRP-3 Vol. 2, Rev. 2 0
2.1.3.1.2 Precautions and Limitations 1.
To minimize the risk of an accidental radiation release, minimize the impact on availability, and achieve a full functional test, the periodic full functiona' testing of the TMBDB features shall be performed during refueling or other reactor r:1utdown after the radioactive cover gas has been processed / decayed, while the refueling hatch is closed, inerted cells have not been deinerted for maintenance, and maintenance is not being performed on auxiliary systems / components containing radioactivity in the RCB.
2 2.
During the TMBDB f ull functional tests, maintenance shall not be performed on the systems / components in the RCB containing radioactive material that could, as a result of a single f ailure, be released to containment and cause site boundary dose limits to be exceeded.
3.
After each full functional test, access to TMBDB equipment, or any TMBDB panel activity, the status of the TMBDB componenti shall be checked to verify the proper status.
4.
The reactor shall not be operated at power following pre-service or periodic full functional testing of TMBDB features until the Acceptance Criteria of Section 2.1.3.1.3 are satisifed.
2.1.3.1.3 Acceptance Criteria 1.
The pre-service testing ana inspection of the TMBDB features shall assure that the TMBDB features would be capable of performing their f ull functions on demand.
2.
The periodic full functional testing of TMBDB features shall assure that both redundant trains of specific active TMBDB features are capable of performing their full functions on demand.
1 2-16B
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1 CRBRP-3 Vol. 2, Rev. 2 2.1.3.2 Specific Features Maintenance and Testing Requirements Throughout this section the term "desiga base surveillance requirements" means the inspection and/or testing that will be specified (for each system) to assure that the CRBRP systems and components are capable of performing 2
their functions within the design base envelope.
2.1.3.2.1 Reactor Cavity-to-Containment Barrier The Reactor Cavity to Head Access Area seals will have surveillance I
performed as part of the design base. The design base surveillance requirements shall be specified so as to assure. in conjunction with design 2
and analyses, that the augmented (TMBDB) requirements of Section 2.1.2.1 f])
will be met.
\\
2.1.3.2.2 Reactor Cavity Recirculating Gas Cooling System The Reactor Cavity Recirculating Gas Cooling System will have surveillance performed as part of the design base. The design base surveillance requirements shall be specified so as to assure, in conjunction with design and analyses, that the augmented (TMBDB) requirements of Section 2.1.2.2 will be met.
In addition, the isolation valves shall be tested as part of the periodic full functional test.
2.1.3.2.3 Guard Vessel Support The Guard vessel Support requirement of Section 2.1.2.3 is not testable, but will be assured by design and the normal construction surveillance.
2.1.3.2.4 Reactor Cavity and Pipeway Cell Liners
/
The Reactor Cavity and Pipeway Cell Liner requirements of Section 2.1.2.4 are not testable, but will be assured by analysis and the normal construction surveillance.
)
i 2-16C
a CRBRP-3 VCL. 2, REV. 1 2.1.3.2.5 Reactor Cavity and Pipeway Cell Liners Vent System The Liners Vent System requirements of Section 2.1.2.5 are not testable, but will be assured by analysis and the normal ccnstruction surveillance.
2.1.3.2.6 Reactor Cavity Vent System 1.
The Reactor Cavity Vent System requirements of Section 2.1.2.6 are not testable, but will be assured by analysis and the normal construction surveillance.
2.
After construction, a pre-service full functional test of the rupture disk isolation valves shall be performed using diesel power (to verify that the valves can actually be operated on emergency power).
3.
During plant lifetime the rupture disk isolation valves shall be tested approximately once a year during a refueling shutdown (or other shutdown that meets the Precautions and Limitations of Section 2.1.3.1.2).
This testing shall be a full functional test of each valve using normal power.
4.
The reactor cavity vent system rupture disks shall be inspected at the end of each refueling or other extended reactor shutdown to ensure the disks have not been accidentally penetrated.
2.1.3.2.7 Containment Purge System 1.
After construction a pre-service full functional t'est of the containment purge system shall be performed using diesel power (to verify that the valves can actually be operated on emergency power).
1 0
2-160
CRBPR-3 VOL. 2. REV. 1-2.
During plant lifetime the cont'ainment purge system shall be tested l
-approximately once a year during a refueling shutdown (or other
^
shutdown that meets the Precautions and Limitations of Section 2.1.3.l.2).
The test shall be a full functional test of each redundant train of active components using normal power.
2.1.3.2.8 Containment Vent System 1.
After construction a pre. service full functional test of the containment vent system shall be performed using oiesel power (to verify that the system can actually be operated on emergency power).
2.
During plant lifetime the containment vent system shall be tested approximately once a year during a refueling stutdown (or other shutdown that meets the Precautions and Limitations of Section 2.1.3.1.2).
The test shall be a full functional test of each redundant train of active components using normal power.
2.1.3.2.9 TMBDB Containment Cleanup System 1.
After construction a pre-service full functional test of the containment cleanup system shall be performed using diesel power (to verify that the system can actually be operated on emergency power).
2.
During plant lifetime the containment cleanup system shall be tested approximately once a year during a refueling shutdown (or other shutdown that meets the Precaut ons and Limitations of Section 2.1.3.1.2).
The test shall be a full functional test of each redundant train of active components using normal power.
1 0
2-16E-
CRBRP-3 Vol. 2, Rev. 2 0
2.1.3.2.10
'.nnulus Cooling System 1.
Af ter construction a pre-service full functional test of the Annulus Cooling System shall be per-formed using diesel power (to verify that the system can actually be operated on emergency power).
2.
During plant lifetime the Annulus Cooling System shall be tested approximately once a year during a refueling shutoown (or other shutdown that meets the Precautions and Limitations of Section 2.1.3.1.2).
The test shall be a full functional test of each redundant train of active components using normal power.
2.1.3.2.11 Containment System Leakage Barrier The Containment System Leakage Barrier will have surveillance performed as part of tile design base. The design base surveillance requirements shall be 7
specified so as to assure, in conjunction with design and analyses, that the augmentea (T;tBDB) requirements of Section 2.1.2.11 will be met.
2.1.3.2.12 TMBDB Instrumentation System The TMBDB Instrumentation System will have surveillance performed as part of the design base. The design base surveillance requirements shall be 2
specified so as to assure, in conjunction with design and analyses, that the augmented (TMBDB) requirements of Section 2.1.2.12 will be met.
2.1.3.2.13 Electrical Power System The Class IE Electrical Power System will have surveillance performed as part of the design base. The design base surveillance requirements shall be 2
specified so as to envelop the augmented (TMBDB) requirements of Section 2.1.2.13 and to demonstrate the capability of the Class lE power system to 1
energize the TMBDB Equipment.
2-16F
i CRBRP-3 s
i Vol. 2, Rev. 2 2.1.3.2.14 Containment Structures The containment structures requirements of Section 2.1.2.14 are not testable, but will be assured by analysis and the normal construction I
surveillance.
2.1.3.2.15 Control Room Habitability i
The Dual Control Room Air Intakes will have surveillance performed as part of the design base. The design base surveillance requirements shall be 2
specified so as to assure, in conjunction with design and analyses, that the augnented (TMBDB) requirements of Section 2.1.2.15 will be met.
j l
i i
i 2-16G
CRBRP-3 Vol.2, Rev.0
[ i The arrangimient of the system reflects these f unctions as follows. The gases and vapors f rom the Reactor Cavity are vented thru the pipeway cells, which are isolated from the PHTS cells by flexible, low leakage bellows.
The venting to the operating floor is accomplished from the North (No. 2) pipeway cell through shielding labyrinths and straight upward pipes, to minimi'ze reactor cavity back pressure due to head losses and to promote local flaring of the vented hydrogen. Up to 50% of the vented gases enters the North (No. 2) PHTS pipeway cell directly and the remaining gases are-first vented through the East and West (No.'1 & 3) pipeway cells (>25%
each), then through the North (No. 2) pipeway cell. To assure this flow distribution a gas flow labyrinth is provided in the North pipeway cell, to balance the flow and pressure thru the different vent paths.
In this way, maximum heat exchange between the gases and the building structures is f acilitated. This will reduce the maximum internal building pressure in the containment before venting.
In addition, this arrangement ensures that if only one rupture disk breaks, flow through all pipeway cells occurs,.
whereas, if a rupture disk were provided for each pipeway, the rupture of y/
one disk could lower the pressure in the cavity below the setpoints of the other two without providing heat exchange between all of the pipeway cells and the vented gases.
Isolatibn of the rupture disks is provided by remote manually operated gate valves located between the cavity and the rupture disk assembly. These valves are provided to allow periodic replacement of the rupture disks and to provide isolation of the reactor cavity atmosphere should a disk be ruptured under other than TMBDB conditions. To prevent inadvertant operation of these valves, no local operators will be provided, valve position indication will be displayed in the Control Room, and appropriate physical restraints and warning plates will be used for the valve actuation switches. These valves are normally open.
Uncertainties in rupture disk performance were considered in the reactor cavity venting system. The overall scenario analysis results are not sensitive to the exact pressure at which the rupture disk breaks because the rate of pressure increase is large enough so that the rupture disk will
'w.)
2-23
CRBRP-3 VOL. 2, REV. 1 break at about the same point in time regardless of the exact reactor cavity pressure. Commercially available rupture disks are usually guaranteed to break within 10% of set pressure.
In addition, it was assumed in the TMBDB analysis that only one of the rupture disks breaks.
Analysis has shown that clogging of the piping by sodium rer. tion products should not be a problem because of the small quantity of aerosol expected and because of the large surface areas availa'le for deposit in reactor and a
pipeway cells as compared to the small surface areas of the vent system piping. Appendix G.3 shows that margin exists to accommodate a wide range of postulated vent malfunctions.
The system piping material will be suitable for high temperature service.
The piping is sloped toward the cavity to provide drainage of condensed sodium. Cell liner penetrations will utilize a combination of bellows sleeves and flued heads in order to reduce pipe stress to a minimum value for the non-embedded portions of the piping. For the embedded piping, anchorage will be provided to prevent piping failure due to thermal expansion and degradation of the supporting concrete.
2.2.7 Containment Purge Capab'.lity The containment purge cabability is provided by the containment cleanup system exhaust blowers which draw a negative pressure in the containment building and by the opening of the redundant containment purge penetrations. The system is shown on Figure 2-34 and has total active redundant capability.
The two purge pipes penetrating the containment are 24 inches in diameter 1
and are designed to the requirements of the ASME Boiler and Pressure Vessel Code,Section III, Division I, Class 2.
Each purge line is provided with redundant normally closed isolation valves outside of the steel containment vessel (see Section 2.2.11).
O 2-24
s CRBRP-3 VOL. 2, REV. 1 Should a purge of the RCB be required, it would be necessary to vent the RCB first. The venting, along with operation of the containment cleanup system exhaust blowers, decreases the RCB pressure below atmospheric pressure.
Operation of the purge requires the opening of the purge line isolation valves from a remote-manual station in the main control room. Flow direction sensing instrumentation is provided to automatically close the purge isolation valves in the event a backflow condition occurs. To prevent inadvertent operation of the purge, the switc'hes for the valve operators are
. located on a control room panel; no local operators are provided at the valve locations. Valve position indication will be displayed in the Control Room and appropriate physical restraints and warning plates will.be used for the valve switches.
2.2.8 Containment Vent Capability The RCB vent capability is proviaed by the vent line connected to the Containment Cleanup System. The connected system is shown in Figure 2-34.
This vent capability allows the blowdown of the RCB af ter some time period to_ reduce the internal pressure and to subsequently reduce the hydrogen; concentration through purging. Prior to venting complete isolation of the RCB would be maintained. The vent line is connected to the TMBOB cleanup system through two redundant 24-inch' diameter pipes which penetrate the RCB 1
with isolation valves located outside the steel containment vessel (see section 2.2.11). The vent line and pipes penetrating the RCB are designed to the requirements of the ASME Boiler and Pressure Vessel Code,Section III, Division I, Class 2.
The pipes penetrating the RCB which are used for TMBDB have their valves in the normally closed position.
At the time of venting (estimated to be approximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />), the isolation valves would be opened to allow the depressurization of the RCB at
[-
a maximum rate of 24,000 cfm. The effluent of the depressurization is processed through the Containment Cleanup System.
To prevent inadvertent operation of the valves, no local operators would be provided and the valve actuation system would be equipped with appropriate physical restraints and warning plates.
t' 2-25 t
CRBRP-3 VOL. 2, REV. I 2.2.9 Containment Cleanup System The Containment Cleanup System is shown in Figure 2-34 cod is provided for filtering of the Reactor Containment Building iRCB) atmosphere prior to release to the environment. The RCB atmosphere exhausted by the Containment Vent System is treated by a wet scrubber filtration system. The discharge from the filters is then directed through an exhaust pipe for release at the top of the confinement structure.
In addition, the effluent stream is continuously monitored for the levels of particulates, radiciodine, radiogases, and plutonium.
The exhaust filter train is comprised of a jet venturi scrubber in series with a high efficiency wetted fiber bed scrubber unit and redundant blowers. An air washer is located upstream to ensure that virtually all of the sodium oxide is reacted to sodium hydroxide prior to reaching the scrubbers. Additionally, the air washer effectively reduces the air stream U
U temperature from a maximum of Il00 F to approximately 160 F during system operation.
The filter train is rated for 24,000 acfm at an air 3
density of 0.06 lbs/ft and will provide a minimum overall filtration -
system efficiency of 99 percent for all vented solids and liquids and 97%
for all vented vapors (excluding noble gases).
The wet scrubber filter system is designed such that the temperature of the U
aerosol leaving the scrubbers would be maintained below 160 F during the course of the accident. The 150,000 gallon storage capacity of the scrubbing system would accommodate the design level of 300,000 lbs. of containment reaction products.
The wet scrubber filter system requires protected water storage on the order of 150,000 gallons.
The recirculation pumps supply approximately 1500 gpm j
of continuous water flow from the storage tanks to the sodium scrubbers and air washer.
Discharge water is then returned to the water supply system. A maximum concentration of sodium hydroxide of 30 percent (by weight) with a corresponding pii of 13 will result trc.n this recirculation in the storage 2-26 I
CRBRP-3 Vol.2, Rev.0 77 temperature and hydrogen levels. Each of these measurements will be
)
redundant, designed to remain functional following a Safe Shutdown Earthquake, and qualified to assure operability under the environmental conditions in Section 2.1.7.l?.
The locations of the various detectors are shown schematically in Figure 2-35.
2.2.12.1.1 Reactor Containnant Pressure The Reactor Containment Building pressure is measured at two widely separated locations. The instrumentation penetrations are at 108 and 2850 (0 is plant north). The design will be such that the pressure element and transmitter are located outside of-the Reactor Containment Building and will sense pressure with an impulse or capillary line. This arrangement will allow sensing of containment pressure at temperature up to 1100 F.
Each transmitter will send a signal to the main control room.
The channels will be completely independent and physically separated in accordance with Regulatory Guide 1.75.
Each channel will be powered from the Class 1E power system.
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~
Reactor Containment Atmosphere Temperature 2.2.12.1.2 The Reactor Containment atmosphere temperature is measured near the top, of the RCB., The measurement will be redundant so that any single f ailure will not pr'eclude the operator from receiving temperature data. The channel will 0
be designed to operate 500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> to a maximum temperature of 1100 F.
The signal conditioning for the temperature sensors will be located in the Steam Generator Building. Each transmitter will send a signal to the main cont.ol room. Each channel will be physically separated in accordance with IEEE~384-1974 and will be powered from the Class 1E power system.
2.2.12.1.3 Reactor Containment Vessel Temperature The Reactor Containment Vessel temperatures will be measured at selected locations on the inside of the steel shell.
A I
h v
2-31
CRBRp-3 VOL. 2, REV. 1 2.2.12.1.4 Hydroger, Measurement System The containment atmosphere hydrogen concentration measurement system consists of redvadarit, independent and continuous hydrogen analyzers located in the Intermediate Bay of the Steam Generator Building.
T'ese are h
connected to the containment atmosphere through redundant and independent sampling lines.
The inlet to the sampling lines is located at the top of containment to prudently protect against tydrogen stratification even though stratification would not occur (Section 3.2.1).
Sample transport time and sample plate out will be considered in establishing the exact location of these sampling stations. Each sampling station will include a hydrogen analyzer which wi'll transmit a signal to the main control room. The channels will be physically separated and powered from the Class IE power system.
The hydrogen measurement system involves severe environmental conditions arising from high temperature and aerosol contamination which may limit instrument lifetime.
In view of this, early procurement of this equipment will be initiated.
It is anticipated that the procurement process will provide confirmation as to whether this equipment can be obtained from' existing sources or whether additional develcpment or design verification requirements are necessary.
2.2.12.2 Radiation Monitoring l3 2.2.12.2.1 TMBDB Exhaust Plant Effluent Radiation Since containment could be vented beyond 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (although such venting is not needed for 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />) and therefore most of the radiological release woulo be through the vent and filter systems, radiation monitors are provided downstream of the filter system where the releases to the atmosphere would occur.
O 2-32
CRBRP-3 Vol.2, Rev.0 The redundant filter train monitors provide for determination of the radioactivity being released from the filter train. Monitoring will be
'~ -
acenmplished using isnkinetic sampling nnr71es and associated three channel continuous air monitors (CAMS) which provide one channel each for particulates, radiciodines, and radiogases. ~ The detectors and associated
. electronics are shielded to reduce the accident induced radiation background to levels suitable for system operation.
The three channel CAMS will provide _ gross count rates'for each channel. The-predicted radioisotopic inventories within the RCB coupled with gross count rate data will allow estimates of off-site doses to be made and will provide early identification of rapid and/or.significant changes in release concentrations.
In addition, a suitably shielded plutonium air particulate monitor (PAPM) specifically designed to measure very low concentration of the long half-life alpha emitters, such as Pu-239, will be provided and will 'also
.pg continuously isokinetically sample the cocnon exhaust. The PAPM provides~
- d.
capability for identifying the plutonium releases at the point where such releases would be the most concentrated and in this way maximizes the sensitivity of the measurement.
Redunda'ncy is provided for the CAMS by the common exhaust monitor and is required due to the inaccessibility of the channels under accident conditions. Redundant PAPMs are not required due to the inherent redundancy of a typical PAPM which is provided as a means of accounting for the natural radonithoron background (switching collection between dual channels allows the radon-thoron on the " idle" channel to decay (leaving behind the longer lived isotopes)).
The power requirements for the plant radiation monitoring system are supplied by the 1E power distribution system.
a 2-33
~
l CRBRP-3 VOL 2, REV. 1 Provisions for off-site monitoring are described in the TVA Radiological Emergency Plan, as discussed in Section 13.3.11 of the PSAR.
2.2.12.2.2 High-Range Containment Area Rad:ation Three High-Range Containment Area Radiation Monitors are provided to indicate the radiation levels within containment to assist in determining actions to protect the public.
These monitors have a seven decade range to 7
10 R/Hr gamma. The detectors are located approximately 120 degrees apart around the Reactor Containment Building periphery in the annulus space, to take advantage of the relatively benign environment. The monitors are classified as Safety Class lE and powered from three independent divisions of power. All tnree monitors have continuous display in the Control Room and one channel is recorded.
j 2.2.13 Electrical Power System The electrical power requirements for motors, controls, and instruments will be distributed as part of the Class lE electric power system using the appropriate standards of quality assurance, structural support, and physical separation.
These loads will, however, be remote manually connected to the IE power source from the control room after removing other loads which are not essential during TMBOB conditions.
2.2.14.. Containment Structures As a result of the structural analysis of the containment building, a few changes in the design have been ide to provide increased thermal margins.
These include:
O 2-34
~
CRBRP-3 VOL. 2, REV. I 1.
Modifications of the typical cell liner design have been made in the Reactor Cavity and the pipeway cells. Specifically the modifications are in the wall studs anchor size, spacing, and length, and in the size I
of the supporting beams in the pipeway floor.
2.
Additional reinforcing bars and stirrups are provided in the reactor cavity wall to resist shear, compressive forces, and bending moments at.
the base, near the top and in the regions restrained by vertical walls.
3.
Additional reinforcing bars and stirrups are provided in the pipeway.
cells to resist the thermal forces and moments.
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