ML20211N022
| ML20211N022 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/12/1986 |
| From: | SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | |
| Shared Package | |
| ML20211M991 | List: |
| References | |
| NUDOCS 8612180117 | |
| Download: ML20211N022 (11) | |
Text
Attachment 1 to H. R. Denton letter '
December 12, 1986 Page 1 of 6 INSTRUMENTATION TABLE 3.3-5 (Continued)
ENGINEERED SAFETY FEATURES RESPONSE TIMES INITIATING SIGNAL AND FUNCTION RESPONSE TIME IN SECONDS e.
Reactor Building Purge and Exhaust Isolation Not Applicable f.
Emergency Feedwater Pumps Not Applicable 7 /. 5 ' (4) E 5) g.
Service Water System
< 15.0 16.%4)/.
)
h.
Reactor Building Cooling Units 1 33.0 i.
Control Room Isolation Not Applicable 3.'
Pressurizer Pressure-Low a.
Safety Injection (ECCS) 1 12.0(2)/27.0(1) b.
Reactor Trip (fro: SI) 1 3.0 c.
Feedwater Isolation 1 10.0 d.
Containment Isolation-Phase "A" 1 45.0(4)/55.0(5) e.
Reactor Building Purge and Exhaust Isolation Not Applicable f.
Emergency Feedwater Pumps Not Applicab.le,
4) 5)
g.
Service Water System 7
4) 5)
h.
Reactor Building Cooling Units 1
1.
Control Room Isolation Not Applicable 4.
Differential Pressure Between Steam Lines-High a.
Safety Injection (ECCS) 1 12.0(2)/22.0(3) b.
Reactor Trip (from SI) 1 3.0 c.
Feedwater Isolation
< 10.0 d.
Containment Isolation-Phase "A" 1 45.0(4)/55.0(5)
' SUMMER - UNIT 1 3/4 3-30 8612180117 861212 PDR ADOCK 05000395 p
PDR 1
to H. R. Denton letter Decenber 12, 1986 Page 2 of 6 INSTRUMENTATION TABLE 3.3-5 (Continued)
ENGINEERED SAFETY FEATURES RESPONSE TIMES INITIATING SIGNAL AND FUNCTION RESPONSE TIME IN SECONOS e.
Reactor Building Purge and Exhaust Isolation Not Applicable NotApplica%e bl
- f. - Emergency Feedwater Pumps 7(.T g.
Service Water System
< 0C4)/55:0 5) 4)
(5) h.
Reactor Building Cooling Units 1.
Control Room Isolation Not Applicable 5.
Steam Line Pressure-Low 1 12.0(2)/22.0(3) a.
Safety Injection - ECCS b.
Reactor Trip (from SI) 1 3.0 c.
Feedwater Isolation
< 10.0 45.0(4)/55.0(5) d.
Containment Isolation - Phase "A" e.
Reactor Buildir.g and Purge and Exhaust Isolation Not Applicable f.
Emergency Feedwater Pumps Not,Jpplica le-I M 4)/
(5) g.
Service Water System M I4)/
5) h.
Reactor Building Cooling Units i.
Steam Line Isolation i 10.0 j.
Control Room Isolation Not Applicable 6.
Steam Flow in Two Steam Lines - Hiah' Coincident with T,y --Low-Low a.
Steam Line Isolation d12.0 i
7.
Reactor Buildina Pressure-High-2 a.
Steam Line Isolation i9.0 SUMMER - UNIT 1 3/4 3-31 1
Attachment. I to H. R. Denton letter:
Dece&dr'12, 1986 Page 3 of 6 INSTRUMENTATION BASES s
'^i REACTOR PROTECTION SYSTEM AND ENGINEERfD SAFETY FEATURE ACTUATION SYSTEM INSTRUMENTATION (continued) r Several automatic logic functions included in this specification are not necessary for Engineered Safety Feature System actuation but *. heir functional capability at the specified setpoints enhances the overall reliability of the i
Engineered Safety Features functions. These automatic actuation systems are purge and exhaust isolation from high containment radioactivity, turbine trip and feedwater isolation from steam generator high-high water level, initiation of emergency feedvater on a trip of the main feedwater pumps, automatic transfer of the suctions of the emergency feedwater pumps to service water on low suction pressure, and automatic opening of the containment-recirculation sump suction valves for the RHR and spray pumps on low-low refueling water storage tank level.
N fasa r 1
N'EAE c
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I s
SUMMER - UNIT 1 B 3/4 3-lb
3 to H. R. Denton letter December 12, 1986 Page 4 of 6 i
The service water response time includes: 1) the start of the service water b
pumpsand,2) the service water pumps discharge valves (3116A,B.C-SW) stroking to the fully opened position. This condition of the valves assures j
that flow will become established through the component cooling water heat exchanger, diesel generator coolers, HVAC chiller, and to the suction of the service water booster pumps when these components are placed in-service.
e Prior to this time, the flow is rapidly approaching required flow and j
sufficient pressure is developed as valves finish their stroke. Each of the above listed components will be starting to perform their accident mitigation 3
function, either directly or indirectly depending upon the use of the component, and will be operational within the service water response time of L
71.5/81.5 seconds V.
Only the service water booster pumps have a direct 4
impact on the accident analysis via the RBCUs' heat removal capability as 3
discussed below.
The RBCU response time includes:
1) the start of the RBCU fans and the service water booster pumps and, 2) all the service water valves which must 2
be driven to the fully opened or fully closed position. This condition of E
the valves allows the flow to become fully established through the RBCU.
3 Prior to this time, the flow is rapidly approaching required flow as the 1
valves finish their stroke. Although the RBCU would be removing heat 7
throughout the Engineered Safety Features response time, the accident 7
analysis does not assume heat removal capability from 0 to 71.5 seconds V
=
because the industrial cooling water system is not completely isolated until 4
71.5 seconds. A linear ramp increase from 95% full heat removal capability j
to 100% full heat removal capability is assumed by the accident analysis to J
start at 71.5 seconds and end at 86.5 seconds V. Full heat removal 2
capability is assumed at 86.5 seconds based on the position of the valve 3107-SW.
5 V
Total time is 1.5 second instrument response after setpoint is reached, 3
plus 10 seconds diesel generator start, plus 10 seconds to reach service water pump start and begin 3116-SW opening via Engineered Safety Features Loading Sequencer, plus 60 seconds stroke time for 3116-SW.
During this total time, the service water pumps start and the service g
water pump discharge valve begins to open at 11.5 seconds and the pump 2
discharge valve is fully open at 71.5 seconds without a diesel generator 4
start required and 21.5 seconds and 81.5 seconds including a diesel generator start.
f a
V Total time is 1.5 seconds instrument response after setpoint is reached i5 plus 10 second diesel start plus 60 seconds
- for valves to isolate 5
industrial cooling water system.
4 m
V Total time is 1.5 second instrument response after setpoint is reach 3
plus 10 second diesel generator start plus 75 seconds to stroke valves k
3107A,8-SW.
g a
- During this time period, the Engineered Safety Features Loading i
Sequencer starts the RBCU fans at 25 seconds and service water 7
booster pumps at 30 seconds after the valves begin to stroke.
. to H. R. Ilanton letter Der 12, 1986 Pye 5 of 6 CONTAINMENT $YSTEMS BASES 3/4.6.2.2 SPRAY ADDITIVE SYSTEM I
The OPERABILITY of the spray additive system ensures that sufficient NaOH is added to the reactor building spray in the event of a LOCA. The limits on NaOH volume and concentration ensure a pH value of between 8.5 and 11.0 for the solution recirculated within containment after a LOCA. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components. The contained solution volume limit includes an allowance for solution not usable because of tank discharge line location or other physical characteristics.
These assump-tions are consistent with the iodine removal efficiency assumed in the accident analyses.
3/4.6.2.3 REACTOR BUILDING COOLING SYSTEM The OPERABILITY of the reactor building cooling system ensures that
- 1) the reactor building air temperature will be maintained within limits during normal operation, and 2) adequate heat removal capacity is available when operated in conjunction with the reactor building spray systems during post-LOCA conditions.
The reactor building ccoling system and the reactor building spray system are redundant to each other in providing post accident cooling of the reactor building atmosphere. As a result of this redundancy in cooling capability,'
the allowable out of service time requirements for the reactor building cooling system have been appropriately adjusted. However, the allowable out of service time requirements for the reactor building spray system have been maintained i
consistent with that assigned other inoperable ESF equipment since the reactor building spray system also provides a mechanism for removing iodine from the reactor building atmosphere.
NU d NN 3/4.6.3 PARTICULATE IODINE CLEANUP SYSTE '
The OPERABILITY of the containment filter trains unsures that sufficient iodine removal capability will be available in the evt.nt of a LOCA.
The reduction in containment iodine inventory reduces the resulting site boundary radiation doses associated with containment leakage. The operation of this system and resultant iodine removal capacity are consistent with the assumptions used in the LOCA analyses.
l 1
SUPMER - UNIT 1 B 3/4 6-4
}
. to H. R. Denton letter December 12, 1986
[Q$6d.-
77_
Page 6 of 6
/
The accident analysis requires the service water booster pump to be passing 4,000 gpm to both RBCU's within 86.5 seconds. This time encompasses the driving of all necessary service water valves to the correct positions, i.e.,
fully opened or fully closed. Reference Technical Specification Bases B3/4.3.1 and B3/4.3.2 for additional details.
1
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l l
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. to H. R. Denton letter December 12, 1986 Page 1 of 3 i
REACTOR BUILDING COOLING UNIT FUNCTIONAL DESIGN During a design basis accident, for the reactor building cooling unit (RBCU) to be considered operable, cooling water from the Industrial Cooling Water (CI) system must be isolated, service water (SW) cooling water must be made available to the RBCU and the RBCU fan must be started in low speed.
After a Engineered Safety Features (ESF) setpoint is reached, a 1.5 second instrument response time is assumed to initiate the start of the diesel generator (DG). The starting time of the DG is required to be 10 seconds before loading on the diesel may begin. Thus, the total time from the ESF setpoint until loading on the diesel can begin is 11.5 seconds and is referred to as reference time in the Final Safety Analysis Report (FSAR).
The valves which are required to stroke to put the RBCU in service along with the function and as-purchased stoke times are:
3106-SW SW booster pump discharge (open) 60 seconds 3110-SW CI supply isolation (close) 60 seconds 3111-SW CI return isolation (close) 60 seconds 3112-SW CI return isolation (close) 60 seconds 3103-SW RBCU return t'o SW (open) 75 seconds 3107-SW RBCU return to SW (open) 75 seconds The Engineered Safety Features Loading Sequencer (ESFLS) loads the SW pumps onto the Class 1E busses at 10 seconds after the reference time. An interlock with the SW pump start begins to open the SW pump discharge valve 3116-SW in the non-running loop also at this time.
In the operating loop, valve 3116-SW fails as-is in the open position on a loss
. to H. R. Danton letter December 12, 1986 Page 2 of 3 of offsite power. Upon restoration of power to the Class 1E busses, valve 3116-SW starts to cycle to a partially closed position, but is reversed and driven back to full open at 20 seconds after the reference time. Valve 3116-SW strokes to the full open position in 60 seconds in the non-running loop. Therefore, the worst case for 3116-SW valve opening time is that in the non-running loop, which is fully open in 81.5 seconds. The 81.5 seconds is determined from addition of 1.5 seconds instrument response time after setpoint is reached plus DG startup time of 10 seconds plus 10 seconds ESFLS time, plus 60 second valve stroke time.
The ESFLS loads the RBCU fan's low speed motors (one per Train) onto Class 1E busses at 25 seconds after the reference time.
The ESFLS loads the SW booster pump onto the Class 1E busses at 30 seconds after the reference time. The SW valves which provide water to the RBCU are fully positioned 86.5 seconds after setpoint is reached. The 86.5 seconds is determined from adding 1.5 second instrument response time plus 10 second DG startup time plus 75 second stroke time of 3107-SW valve.
No flow to the RBCU is conservatively assumed until isolation of SW from the non-safety, non-seismic CI system is complete by closure of valve 3110-SW in 71.5 seconds. The 71.5 seconds is determined from addition of 1.5 second instrument response time after setpoint is reached, plus 10 second DG startup, plus 60 second valve stroke time. Significant flow to the RBCU will therefore commence when valve 3110-SW is closed.
REACTOR BUILDING COOLING UNIT SAFETY ANALYSIS 1
The sensitivity study of the safety analysis to an assumed condition of no RBCU heat removal capability available for 71.5 seconds until the valves i
close which isolate the CI system was performed. The results indicate no increase in reactor building peak pressure and temperature above that originally submitted in the FSAR.
l The safety analysis sensitivity accounted for a ramp of increasing RBCU heat removal capability from 71.5 seconds to 86.5 seconds. This is required to account for all valves being fully positioned at 71.5 seconds with the exception of two valves 3116-SW and 3107-SW which continue to stroke until 3116-SW is fully open at 81.5 seconds and 3107-SW is fully open at 86.5 seconds. The RBCU heat removal rate was conservatively assumed to be linear, ramping from 95% of design basis due to valve positioning at 71.5 seconds to 100% of the design basis heat removal capability at 86.5 seconds when all valves have fully stroked.
The safety analysis sensitivity is based on mass energy balance analyses for the worst case pressure and temperature main steam line breaks (MSLB).
One analysis used input from the post-boron injection tank (BIT) removal MSLB i
analysis and demonstrated that for the worst pressure case MSLB (1.4 ft2,
. to H. R. Denten letter December 12, 1986 Page 3 of 3 double ended rupture, 102% power per FSAR FCN-867 Section 6.2.1.3.1.1),the peak pressure was 45.96 psig which remained below the previous peak pressure of 47.1 psig. This analysis indicates a pressure increase of 0.16 psig above the pressure (45.8 psig) which was obtained in the analysis performed to justify removal of the BIT.
The other mass-energy balance analysis used input from the post-BIT removal MSLB analysis and demonstrated that the worst temperature case (0.645 ft2 split, 102% power per FSAR FCN-867 Section 6.2.1.3.1.2), the peak temperature was 321.5'F which remained below the tertperature of 324*F. This analysis indicates a temperature increase of 0.7"F above the temperature (320.8*F) which was obtained in the analysis performed to justify removal of the BIT.
SERVICE WATER SYSTEM FUNCTIONAL DESIGN To satisfy assumptions used in the accident analyses for heat removal and operability of other safety related equipment, the SW system must deliver water to the following components:
- 1) component cooling water /SW heat exchanger (CCW/SW HX), 2) DG coolers, 3) heating ventilation and air conditioning (HVAC) chiller, and 4) the suction of the SW booster pumps.
In addition, to enhance reliability of the Emergency Feedwater (EFW) system, the SW system can supply water to the suction header of the EFW pumps as an emergency backup to the EFW system.
SERVICE WATER SYSTEM SAFETY ANALYSIS The SW system design response times are summarized below for the SW pump and its discharge valve. These response times are after an ESF setpoint is reached and are based on startup of the nonrunning SW loop as the worst case for providing SW flow.
The SW system's response time includes:
- 1) the start of the SW pump and, 2) the SW pump discharge (3116A,B,C-SW) valves which must be driven to the fully opened position. This condition of the valves allows the flow to become fully established through the CCW/SW heat exchanger, DG coolers, HVAC chiller, and to the suction of the SW booster pump when these components are placed in service. Prior to this time, the flow is rapidly approaching required flow and sufficient pressure is developed as valves finish their stroke. Each of the above listed components will be starting to perform their accident mitigation function, either directly or indirectly depending upon the use of the component, and will be operational within the SW system response time of 71.5/81.5 seconds.
The total time is 1.5 second instrument response after setpoint is reached, plus 10 seconds DG start, plus 10 seconds to reach SW pump start and begin 3116-SW opening via ESFLS, plus 60 seconds stroke time for 3116-SW. During this total time, the SW pumps start and the SW pump discharge valve begins to open at 11.5 seconds and the pump discharge valve is fully open at 71.5 seconds without a DG start required and 21.5 seconds and 81.5 seconds including a DG start.
. to H. R. Denton letter December 12, 1986 Page 1 of 2
~
BASIS FOR NO SIGNIFICANT HAZARDS CONSIDERATION The containment peak pressure predicted by the accident analysis via the CONTEMPT computer code demonstrates that the reactor building cooling unit's (RBCU) contribution to peak pressure control is not a significant factor in the short term. The mass and energy release from the postulated design basis accident together with containment heat sinks are the dominant factors. The peak pressure predicted by this analysis is less than the containment design pressure of 57 psig and provides a considerable margin over the regulatory guide recommendation that maximum containment pressure be 10% (51.3 psig) below the design pressure.
The maximum containment temperature predicted by this analysis was below the equipment qualification temperature, and therefore, the equipment which required transient heat transfer analysis will still be bounded by the equipment surface temperature profiles of Final Safety Analysis Report (FSAR)
Figures 3.11-8, 3.11-9, 3.11-10.
The dose levels reported in FSAR Table 15.4-16 are bounded and remain well below 10CFR100 levels. Additionally, the operator dose levels in the control room remain below 10CFR 50 Appendix A GDC-19 guidelines.
The service water system has been demonstrated by calculation, analysis, and plant surveillance testing to meet design basis accident analyses required times to support safety related fuctions of components and interfacing systems.
This proposed amendment has been reviewed and determined not to involve a significant hazards consideration for the following reasons:
(1) The probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report is not increased.
The change in Engineered Safety Features (ESF) response times for the service water system and RBCUs does not result in a reactor building peak pressure or temperature increase above that originally submitted in the FSAR. The analyzed pressure provides a considerable margin to the containment design pressure. The equipment qualification will also not be affected.
(2) The possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report is not created.
The plant hardware configuration has not been affected by the change to the ESF response times. Therefore, the results of previously postulated accidents remain unchanged, and the possibility of a different accident or malfunction other than those previously analyzed has not been introduced.
- to H. R. Danton letter December 12, 1986 Page 2 of 2 (3) The margin of safety as defined in the basis for any Technical Specification is not reduced.
The previously evaluated accidents or malfunctions have not been changed by the revision of ESF response times; thus-the margin of safety as defined in Technical Specifications remains unchanged.
Therefore, based on the above considerations, SCE&G has determined that this change does not involve a significant hazards consideration.
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