ML20100D869
| ML20100D869 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/05/1996 |
| From: | Mc Kee P NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20100D872 | List: |
| References | |
| NUDOCS 9602090147 | |
| Download: ML20100D869 (16) | |
Text
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e nau Jt UNITED STATES pe NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 2 4 5 0001
\\*****j#
NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
DOCKET NO. 50-423 MILLSTONE NUCLEAR POWER STATION. UNIT NO. 3 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No.126 License No. NPF-49 1.
The Nuclear Regulatory Comission (the Comission) has found that:
A.
The application for amendment by Northeast Nuclear Energy Company, et al. (the licensee) dated June 9,1995, as supplemented November 9, 1995, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Comission's rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Comission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health 1
and safety of the public, and (ii) that such activities will be conducted in compliance with the Comission's regulations; D.
The issuance of this amendment will not be inimical to the comon defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Comission's regulations and all applicable requirements have been satisfied.
9602090147 960205 PDR ADOCK 05000423 P
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' 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, l
and paragraph 2.C.(2) of Facility Operating License No. NPF-49 is hereby amended to read as follows:
(2)
Technical Soecifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 126, and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto l
are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
3.
This license amendment is effective as of the date of its issuance, to be implemented within 60 days of issuance.
1 FOR THE NUCLEAR REGULATORY COMMISSION Phillip F. McKee, D' rector Millstone Project 17 rectorate Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications Date of Issuance:
February 5, 1996
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4 ATTACHMENT TO LICENSE AMENDMENT NO.126
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FACILITY OPERATING LICENSE NO. NPF-49 1
DOCKET NO. 50-423 Replace the following pages of the Appendix A, Technical Specifications, with j
the attached pages. The revised pages are identified by amendment number and contain vertical lines indicating the areas of change.
Remove Insert i
i ix ix 3/4 6-2 3/4 6-2 3/4 6-20 3/4 6-20 3/4 6-22 3/4 6-22 3/4 6-23 3/4 6-23 B 3/4 6-4 B 3/4 6-4 l
B 3/4 6-5 B 3/4 6-5 l
B 3/4 6-7 B 3/4 6-7 B 3/4 6-8 B 3/4 6-8 B 3/4 6-9 B 3/4 6-10
I!!QEK DEFINITIONS SECTION EME 1.0 DEFINITIONS
]
1.1 ACTION 1-1 l.2 ACTUATION LOGIC TEST 1-1 1.3 ANALOG CHANNEL OPERATIONAL TEST.................
1-1 1.4 AXIAL FLUX DIFFERENCE......................
1-1 1.5 CHANNEL CALIBRATION 1-1 1.6 CHANNEL CHECK..........................
1-1 1.7 CONTAINMENT INTEGRITY......................
1-2 1.8 CONTROLLED LEAKAGE 1-2 1.9 CORE ALTERATIONS 1-2 1.10 DOSE EQUIVALENT I-131......................
1-2 1.11 E-AVERAGE DISINTEGRATION ENERGY.................
1-2 1.12 DELETED l
1.13 ENGINEERED SAFETY FEATURES RESPONSE TIME 1-3 1.14 DELETED 1.15 FREQUFNCY NOTATION 1-3 1.16 IDENTIFIED LEAKAGE 1-3 1.'17 MASTER RELAY TEST.........................
1-3 1.18 MEMBER (S) 0F THE PUBLIC.....................
1-4 1.19 OPERABLE - OPERABILITY 1-4 1.20 OPERATIONAL MODE - MODE.....................
1-4 1.21 PHYSICS TESTS..........................
1-4 1.22 PRESSURE BOUNDARY LEAKAGE....................
1-4 1.23 PURGE - PURGING.........................
1-4 H
1.24 QUADRANT POWER TILT RATIO....................
1-5 1.25 RADI0 ACTIVE WASTE TREATMENT SYSTEMS...............
1-5 1.26 RADIOLOGICAL EFFLUENT MONITORING AND OFFSITE DOSE CALCULATIONAL MANUAL (REMODCM) 1-5 1.27 RATED THERMAL POWER.......................
1-5 1.28 REACTOR TRIP SYSTEM RESPONSE TIME................
1-5 1.29 REPORTABLE EVENT 1-5 1.30 SHUTDOWN MARGIN.........................
1-5 1.31 SITE BOUNDARY..........................
1-5 i
NI,LLSTONE - UNIT 3 i
Amendment No. pp, 77,126
a I!ElEX LINITING COMITIONS FOR OPERATION AM SURVEILLANCE REQUIREMENTS SECTION EAGE Air Temperature 3/4 6-9 Containment Structural Integrity...........
3/4 6-10 l
Containment Ventilation System............
3/4 6-11 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS Containment Quench Spray System 3/4 6-12 Recirculation Spray System..............
3/4 6-13 3/4.6.3 CONTAINMENT ISOLATION VALVES.............
3/4 6-15 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Monitors 3/4 6-16 Electric Hydrogen Recombiners 3/4 6-17 3/4.6.5 SUBATMOSPHERIC PRESSURE CONTROL SYSTEM Steam Jet Air Ejector 3/4 6-18 3/4.6.6 SECONDARY CONTAINMENT Supplementary Leak Collection and Release System...
3/4 6-19 Secondary Containment................
3/4 6-22 Secondary Containment Structural Integrity.................
3/4 6-23 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE Safety Valves 3/4 7-1 TABLE 3.7-1 MAXIMUM ALLOWABLE POWER RANGE NEUTRON FLUX HIGH SETPOINT WITH INOPERABLE STEAM LINE SAFETY VALVES DURING FOUR LOOP OPERATION 3/4 7-2 TABLE 3.7-2 MAXIMUM ALLOWABLE POWER RANGE NEUTRON FLUX HIGH SETPOINT WITH IN0PERABLE STEAM LINE SAFETY VALVES DURING THREE LOOP OPERATION 3/4 7-2 MILLSTONE - UNIT 3 ix Amendment No. pp, JJ. 57, 77, JPP, osu JJ7,126
DEFINITIONS 1.12 DELETED l
ENGINEERED SAFETY FEATURES RESPONSE TIME 1.13 The ENGINEERED SAFETY FEATURES (ESF) RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its ESF Actuation Setpoint at the channel sensor until the ESF equipment is capable of performing its safety function (i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc.). Times shall include i
diesel generator starting and sequence loading de' lays where applicable.
1.14 Deleted FREQUENCY NOTATIO8(
1.15 The FREQUENCY NOTATION specified for the performance of Surveillance Requirements shall correspond to the intervals defined in Table _1.1.
IDENTIFIED LEAKAGE 1.1 IDENTIFIED LEAKAGE shall be:
a.
Leakage (except CONTROLLED LEAKAGE) into closed systems, such as pump seal or valve packing leaks that are captured and conducted to a sump or collecting tank, or b.
Leakage into the containment atmosphere from sources that are both specifically located and known either not to interfere with the operation of Leakage Detection Systems or not to be PRESSURE BOUNDARY LEAKAGE, or c.
Reactor Coolant System leakage through a steam generator to the Secondary Coolant System.
MASTER RELAY TEST 1.17 A MASTER RELAY TEST shall be the energization of each master relay and verification of OPERABILITY of each relay.
The MASTER RELAY TEST shall include continuity check of each associated slave relay.
4 f
NILLSTONE - UNIT 3 1-3 Amendment No. pf, 77,126 0383
CONTAllBIENT SYST'315 CONTAllflENT LEAKAGE LIMITING C0lWITION FOR OPERATION 3.6.1.2 Containment leakage rates shall be limited to:
a.
An overall integrated leakage rate of less than or equal to L,
0.3% by weight of the containment air per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at P.,
53.27 psi ~a (38.57 psig);
b.
A combined leakage rate of.less than 0.60 L, for all penetrations and valves subject to Type B and C tests, when pressurized to P,;
and c.
A combined leakage rate of less than o_r equal to 0.042 L, for all penetrations that are Secondary Containment bypass leakage paths l
when pressurized to P,.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
With the measured overall integrated containment leakage rate exceeding 0.75 L., or the measured combined leakago rate for all penetrations and valves subject to Type B and C tests exceeding 0.60 L, or the combined bypass leakage rate exceeding 0.042 L., restore the overall integrated leakage rate to less than 0.75 L, the combined leakage rate for all penetrations subject to Type B and C tests to less than 0.60 L., and the combined bypass leakage i
rate to less than 0.042 L, prior to increasing the Reactor Coolant System temperature above 200'F.
SURVEILLANCE REQUIREMENTS 4.6.1.2 The containment leakage rates shall be demonstrated at the following test schedule and shall be determined in conformance with the criteria specified in Appendix J of 10 CFR Part 50 using methods and provisions of ANSI N45.4-1972 (Total Time Method) and/or ANSI /ANS 56.8-1981 (Mass Point Method):
a.
Three Type A tests (Overall Integrated Containment Leakage Rate) shall be conducted at ap)roximately equal intervals during shutdown at a pressure not less tian P., 53.27 psia (38.57 psig), during each 10-year service period.*
b.
If any periodic Type A test fails to meet 0.75 L, the test schedule for subsequent Type A tests shall be reviewed and approved by the Commission.
If two consecutive Type A tests fail to meet 0.75 L.,
a Type A test shall be performed at least every 18 months until two consecutive Type A tests meet 0.75 L, at which time the above test schedule may be resumed;
- The third Type A test will be conducted during the sixth refueling outage. As a result, the duration of the first 10-year service period will be extended to the end of the sixth refueling outage.
MillCTANT. IINTT 1 1 ht R9 Amandmont Nn EG 87 We 777 1%
CONTAllflENT SYSTEMS SURVEILLANCEREQUIREMENTS(Continued) 2)
Verifying, within 31 days after removal, that a laboratory analysis of a representative carbon sample obtained in accord-ance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978,* meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revi-sion 2, March 1978,* for a methyl iodide per.atration of less than 0.175%; and 3)
Verifying a system flow rate of 7600 cfm to 9800 cfm during system operation when tested in accordance with ANSI N510-1980.
c.
After every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation, by verifying, within 31 days after removal that a laboratory analysis of a repre-sentative carbon sample obtained in accordance with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1978,*
meets the laboratory testing criteria of Regulatory Position C.6.a of Regulatory Guide 1.52, Revision 2, March 1978,* for a methyl iodide penetration of less than 0.175%:
d.
At least once each REFUELING INTERVAL by:
l 1)
Verifying that the pressure drop across the combined HEPA filters and charcoal adsorber banks is less than 6.25 inches Water Gauge while operating the system at a flow rate of 7600 cfm to 9800 cfa, 2)
Verifying that the system starts on a Safety Injection test signal, and 3)
Verifying that the heaters dissipate 5015 kW when tested in acco,rdance with ANSI N510-1980.
I i
- ANSI N510-1980 shall be used in place of ANSI N510-1975 referenced in Regulatore Guide 1.52, Revision 2, March 1978.
MILLSTONE - UNIT 3 3/46-20 Amendment No. 1, 57, 77, ypp,pgy,126
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CONTAINNENT SYSTENS SECONDARY CONTAINNENT LINITING CONDITION FOR OPERATION 3.6.6.2 Secondary Containment shall be OPERABLE.
l APPLICABILITY: N0 DES 1, 2, 3, and 4.
ACTION:
With Secondary Containment inoperable, restore Secondary Containment to OPERABLE l
status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIRENENT 4.6.6.2.1 OPERABILITY of Secondary Containment shall be demonstrated at least l
once per 31 days by verifying that each door in each access opening is closed except when the access opening is being used for normal transit entry and exit.
4.6.6.2.2 At least once each REFUELING INTERVAL, verify each Supplementary Leak Collection and Release System produces a negative pressure of greater than or equal to 0.4 inch water gauge in the Auxiliary Building at 24'-6" elevation within 120 seconds after a start signal.
I NILLSTONE - UNIT 3 3/4 6-22 Amendment N>. 77,199,126 OM4
CONTAIMENL11SIEMS SECONDARY CONTAINNENT STRUCTURAL INTEGRITY l
LINITING CONDITION FOR OPERATION 3.6.6.3 The structural integrity of the Secondary Containment shall be maintained l
at a level consistent with the acceptance criteria in Specification 4.6.6.3.
APPLICABILITY: N0 DES 1, 2, 3, and 4.
ACTION:
With the structural integrity of the Secondary Containment not conforming tothe ab hours or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE REQUIRENENT 4.6.6.3 The structural integrity of the Secondary Containment shall be determined during the shutdown for each Type A containment leakage rate test (reference Specific tion 4.6.1.2) by a visual inspection of the exposed accessible interior and exterior surfaces of the Secondary Containment and verifying no apparent changes in appearance l
of the concrete surfaces or other abnormal degradation. Any abnormal degradation of the Secondary Containment detected during the above required inspections shall be l
reported to the Comission in a Special Report pursuant to Specification 6.9.2 within 15 days.
NILLSTONE - UNIT 3 3/4 6-23 Amendment No. 77, Jpp.126 0304
i CONTAINMENT SYSTEMS l
i BASES l
3/4.6.6 SECONDARY CONTAINMENT 3/4.6.6.1 SUPPLEMENTARY LEAK COLLECTION AND RELEASE SYSTEM i
Backoround The OPERABILITY of the Supplementary Leak Collection and Release System (SLCRS) ensures that radioactive materials that leak from the primary contain-ment into the Secondary Containment following a Design Basis Accident (DBA) are filtered out and adsorbed prior to any release to the environment.
Ano11 cable Safety Analyses The SLCRS design basis is established by the consequences of the limiting DBA, which is a LOCA. The accident analysis assumes that only one train of the SLCRS and one train of the auxiliary building filter system is functional due to a single failure that disables the other train. The accident analysis accounts for the reduction of the airborne radioactive material provided by the remaining one train of this filtration system. The amount of fission products available for release from the containment is determined for a LOCA.
The SLCRS is not normally in operation. The SLCRS starts on a SIS signal. The modeled SLCRS actuation in the safety analysis (the Millstone 3 FSAR Chapter 15, Section 15.6) is based upon a worst-case response time following an SI initiated at the limiting setpoint. One train of'the SLCRS in conjunction with the Auxiliary Building Filter (ABF) system is capable of drawing a negative pressure (0.4 inches water gauge at the auxiliary building 24'6" elevation) within 120 seconds after a LOCA. This time includes diesel generator startup and sequencing time, system startup time, and time for the system to attain the required negative pressure after starting.
I MILLSTONE - UNIT 3 B 3/4 6-4 Amendment No. 77,126 OM4
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a CONTADelENT SYSTEMS BASES 3/4.6.6.1 SUPPLEMENTARY LEAK COLLECTION AND RELEASE SYSTEM (Continued)
LL.0 In the event of a DBA, one SLCRS is required to provide the minimum postulated iodine removal assumed in the safety analysis. Two trains of the SLCRS must be OPERABLE to ensure that at least one train will operate, assuming that the other train is disabled by a single-active failure. The SLCRS works in conjunction with the ABF system.
Inoperability of one train of the ABF system also results in inoperability of the corresponding train of the SLCRS. Therefore, whenever LCO 3.7.9 is entered due to the ABF train A (B) being inoperable, LCO 3.6.6.1 must be entered due to the SLCRS train A (B) being inoperable.
When a SLCRS LCO is not met, it is not necessary to declare the secondary containment inoperable. However, in this event, it is necessary to determine that a loss of safety function does not exist. A loss of safety function exists when, assuming no concurrent single failure, a safety function assumed in the accident analysis cannot be performed.
Anolicability In MODES 1, 2, 3, and 4, a DBA could lead to a fission product release to containment that leaks to the secondary containment. The large break LOCA, l on which this system's design is based, is a full-power event. Less severe LOCAs and leakage still require the system to be OPERABLE throughout these MODES. The probability and severity of a LOCA decrease as core power and reactor coolant system pressure decrease. With the reactor shut down, the probability of release of radioactivity resulting from such an accident is j
low.
In MODES 5 and 6, the probability and consequences of a DBA are low due to the pressure and temperature limitations in these MODES. Under these conditions, the SLCRS is not required to be OPERABLE.
ACTIONS With one SLCRS train inoperable, the inoperable train must be restored to OPERABLE status within 7 days. The operable train is capable of providing 100 percent of the iodine removal needs for a DBA. The 7-day Com)1etion Time is based on consideration of such factors as the reliability of tie OPERABLE redundant SLCRS train and the low probability of a DBA occurring during this period. The Completion Time is adequate to make cost repairs.
If the SLCRS cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and MODE 5 within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full-power conditions in an orderly manner and without challenging plant systems.
M.I.LLSTONE - UNIT 3 8 3/4 6-5 Amendment No. 77,126
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CONTAlletENT SYSTEMS BASES 3/4.6.6.2 SECONDARY CONTAINMENT The Secondary Containment is comprised of the containment enclosure building and all contiguous buildings (main steam valve building [ partially),
engineering safety features building [ partially), hydrogen recombiner butiding
[ partially), and auxiliary building). The Secondary Containment shall exist -
when:
a.
Each door in each access opening is closed except when the access opening is being used for normal transit entry and exit, b.
The sealing mechanism associated with each penetration (e.g.,
welds, bellows, or 0-rings) is OPERABLE.
Secondary Containment ensures that the release of radioactive materials from the primary containment atmosphere will be restricted to those leakage paths and associated leak rates assumed in the safety analyses. This restriction, in conjunction with operation of the Supplementary Leak Collection and Release System, and Auxiliary Building Filter System will limit the SITE BOUNDARY radiation doses to within the dose guideline values of 10 CFR Part 100 during accident conditions.
The SLCRS and the ABF fans and filtration units are located in the auxiliary building. The SLCRS is described in the Millstone Unit No. 3 FSAR, Section 6.2.3.
In order to ensure a negative pressure in all areas within the Secondary Containment under most meteorological conditions, the negative pressure acceptance criterion at the measured location (i.e., 24'6" elevation in the auxiliary building) is 0.4 inches water gauge.
Lla The Secondary Containment OPERABILITY must be maintained to ensure proper operation of the SLCRS and the auxiliary building filter system and to limit radioactive leakage from the containment to those paths and leakage rates assumed in the accident analyses.
Anolicability Maintaining Secondary Containment OPERABILITY prevents leakage of radioactive material from the Secondary containment.
Radioactive material may enter the Secondary Containment from the containment following a LOCA.
Therefore, Secondary Containment is required in MODES 1, 2, 3, and 4 when a design basis accident such as a LOCA could release radioactive material to the containment atmosphere.
NILLSTONE - UNIT 3 8 3/4 6-7 Amendment No. 77, D 0305
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CONTAH91ENT SY9TEMS BASES J/4.6.6.2 SECONDARY CONTAINMENT fcontinued)
In MODES 5 and 6, the probability and consequences of a DBA are low due to the RCS temperature and pressure limitation in these MODES. Therefore, Secondary Containment is not required in MODES 5 and 6.
ACTIONS In the event Secondary Containment OPERABILITY is not maintained, Secondary Containment OPERABILITY must be restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Twenty-four hours is a reasonable Completion Time considering the limited leakage design of containment and the low probability of a DBA occurring during this time period. Therefore, it is considered that there exists no loss of safety function while in the ACTION Statement.
Inoperability of the Secondary Containment does not make the SLCRS fans and filters inoperable. Therefore, while in this Action Statement solely due to inoperability of the Secondary Containment, the conditions and required actions associated with Specification 3.6.6.1 (i.e., Supplementary Leak Collection and Release System) are not required to be entered.
If the Secondary Containment OPERABILITY cannot be restored to OPERABLE status within the required completion time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full-power conditions in an orderly manner and without challenging plant systems.
Surveillance Reauirements 4.6.6.2.1 Maintaining Secondary Containment OPERABILITY requires maintaining each door in each access opening in a closed position except when the access opening is being used for normal entry and exit. The normal time allowed for passage of equipment and personnel through each access opening at a time is defined as no more than 5 minutes. The access opening shall not be blocked open. During this time, it is not considered necessary to enter the action statement. A 5-minute time is considered acceptable since the access opening can be quickly closed without special provisions and the probability of occurrence of a DBA concurrent with equipment and/or personnel transit time of 5 minutes is low.
The 31-day frequency for this surveillance is based on engineering.
Judgment and is considered adequate in view of the other indications of access opening status that are available to the operator.
MILLSTONE - UNIT 3 B 3/4 6-8 Amendment No. pf, 126 0385
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CONTAlfflENT SYSTEMS 1
i BASES 3/4.6.6.2 SECONDARY CONTAINMENT (continued) l 4.6.6.2.2 1
{
The ability of a SLCRS to produce the required negative pressure during the test operation within the required time provides assurance that the 1
Secondary Containment is adequately sealed.
With the SLCRS in postaccident configuration, the required negative pressure in the Secondary Containment is achieved in 110 seconds from the time of simulated emergency diesel generator breaker closure. Time delays of dampers and logic delays must be accounted for in this surveillance. The time to achieve the required negative pressure is 120 seconds, with a loss-of-offsite power coincident with a SIS. The surveillance verifies that one train of SLCRS in conjunction with the ABF system will produce a negative pressure of 0.4 inches water gauge at the auxiliary building 24'6" elevation relative to the outside atmosphere in the Secondary Containment. For the purpose of this surveillance, pressure measurements will be made at the 24'6" elevation in the auxiliary building. This single location is considered to be adequate and representative of the entire Secondary Containment due to the large cross-section of the air passages which interconnect the various buildings within the Secondary Containment.
In order to ensure a negative pressure in all areas inside the Secondary Containment under most meteorological conditions, the negative pressure acceptance criterion at the measured location is 0.4 inch water gauge.
It is recognized that there will be an occasional meteorological condition under which slightly positive pressure may exist at some localized portions of the boundary (e.g., the upper elevations on the down-wind side of a building).
For example, a very low outside temperature i
combined with a moderate wind speed could cause a slightly positive pressure at the upper elevations of the containment enclosure building on the leeward face. The probability of occurrence of meteorological conditions which could result in such a positive differential pressure condition in the upper levels of the enclosure building has been estimated to be less than 2% of the time.
The probability of wind speed within the necessary moderate band, combined with the arobability of extreme low temperature, combined with the small portion of tie boundary affected, combined with the low probability of airborne radioactive material migrating to the upper levels ensures that th; overall effect on the design basis dose calculations is insignificant.
The SLCRS system and fan sizing was based on an estimated infiltration rate. The fan flow rates are verified within a minimum and maximum on a monthly basis.
Initial testing verified that the drawdown criterion was met at the lowest acceptable flow rate. The new standard Technical Specification (NUREG-1431)3.6.6.2 surveillance requirement requires that the drawdown NILLSTONE - UNIT 3 8 3/4 6-9 Amendment No. 77,126 oun
CONTAINMENT SYSTEMS BASES 3/4.6.6.2 SECONDARY CONTAINMENT (continued) criterion be met while not exceeding a maximum flow rate.
It is assumed that the purpose of this flow limit is to ensure that adequate attention is given to maintain the SLCRS boundary integrity and not using excess system capacity to cover for boundary degradation.
The SLCRS system was designed with minimal margin and, therefore, does not have excess capacity that can be substituted for boundary integrity.
Additionally, since SLCRS fan flow rates are verified to be acceptable on a more frequent basis than the drawdown test surveillance, and by means of previous testing the minimum flow rate is acceptable, verifying a flow rate during the drawdown test would not provide an added benefit. Historical SLCRS flow measurements show a lack of repeatability associated with the inaccura-cies of air flow measurement. As a result, the more reliable verification of system performance is the actual negative pressure generated by the drawdown test and a measured flow rate would add little.
3/4.6.6.3 SECONDARY CONTAINMENT STRUCTURAL INTEGRITY This limitation ensures that the structural integrity of the Secondary Containment will be maintained comparable to the original design standards for the life of the facility. Structural integrity is required to provide a secondary boundary surrounding the primary containment that can be maintained at a negative pressure during accident conditions. A visual inspection is sufficient.to demonstrate this capability.
MILLSTONE - UNIT 3 B 3/4 6-10 Amendment No. 77,126 0305