ML19211D289
| ML19211D289 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 01/14/1980 |
| From: | PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | |
| Shared Package | |
| ML19211D285 | List: |
| References | |
| NUDOCS 8001170431 | |
| Download: ML19211D289 (12) | |
Text
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PBAPS Unit 2 LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.1 REACTOR PROTECTION SYSTEM 4.1 REACTOR PROTECTION SYSTEM Applicability: Applicability:,
Applies to the instrumenta- Applies to the surveillance tion and associated devices of the instrumentation and which initiate a reactor associated devices which scram, initiate reactor scram.
Obiective Obiective To assure the operability To specify the type and of the reactor protection frequency of surveillance system. to be applied to the pro-tection instrumentation.
Specification: Specification:
When there is fuel in the vessel, A. Instrumentation systems the setpoint, minimum number shall be functionally of trip systems, and minimum tested and calibrated number of instrument channels as indicated in Tables that must be operable for 4.1.1 and 4.1.2 each position of the reactor respectively.
mode switch shall be as given in Taole 3.1.1. The B. Daily during reactor power designed system response operation, the peak times from the opening heat flux and peaking of the sensor contact up factor shall be checked to and including the and the SCRAM and APRM opening of the trip Rod Block settings given actuator contacts shall by equations in not exceed 100 milli-seconds. Specification 2.1.A.1 and 2.1.B ahall be calculated if the peaking factor exceeds 2.62 for 7x7 fuel, 2.44 for 8::8 fuel, or 2.51 for 8x8R fuel.
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PBAPS Unit 3 LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.1 REACTOR PROTECTION SYSTEM 4.1 REACTOR PROTECTION SYSTEM Applicability: Applicability:
Applies to the instrumenta- Applies to the surveillance tion and associated devices of the instrumentation and which initiate a reactor associated devices which scram. initiate reactor scram.
Obiective Obiective To assure the operability To specify the type and of the reactor protection frequency of surveillance system. to be applied to the pro-tection instrumentation.
Specification: Specification:
When there is fuel in the vessel, A. Instrumentation systems the setpoint, minimum number shall be functionally of trip systems, and minimum tested and calibrated number of instrument channel s as indicated in Tables that must be operable for 4.1.1 and 4.1.2 each position of the reactor respectively.
mode switch shall be as given in Table 3.1.1. The B. Daily during reactor power designed system response operation, the maximum frac-times from the opening tion of limiting density of the sensor contact up factor shall be checked to and including the and the SCRAM and APRM opening of the trip Rod Block settings given actuator contacts shall by equations in not exceed 100 milli-seconds. Specification 2.1.A.1 and 2.1.B shall be calculated if the maximum fraction of limiting power density exceeds the fraction of rated power.
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PBAPS 3.1 BASES The reactor protection system automatically initiates a reactor scram to:
- 1. Preserve the integrity of the fuel cladding.
- 2. Preserve the integrity of the reactor coolant system.
- 3. Minialze the energy which must be absorbed following a loss of coolant accident, and present inadvertant criticality.
When there is no fuel in the reactor, the scram serves no function; therefore, the reactor protection system is not required to be operable.
This specification provides the limiting conditions for operation necessary to preserve the ability of the system to perform its intended function even during periods when instrument channels may be out of service because 'f maintenance. When necessary, one channel may be made inoperable for brief intervals to conduct required functional tests and calibrations.
The reactor protection system is of the dual channel type (Reference subsection 7. 2 FSAR) . The system is made up of two independent trip systems, each having two subchannels of tripping devices. Each subchannel has an input from at least one instrument channel which monitors a critical parameter.
The outputs of the subchannels are combined in a 1 out of 2 logic; i.e. an input signal on either one or both of the subchannels will cause a trip system trip. The outputs of the trip systems are arranged so that a trip on both systems is required to produce a reactor scram.
This system meets'the intent of IEEE - 279 for Nuclear Power Plant Protection Systems. The system has a reliability greater than that of a 2 out of 3 system and somewhat less than that of a 1 out of 2 system.
With the exception of the Average Power Range Monitor (APRM) channels, the Intermediate Range Monitor (IRM) channels, the Main Steam Isolation Valve closure and the Turbine stop Valve closure, each subchannel has one instrument channel. When the minimum condition for operation on the number of operable instrument channels per untripped protection trip system is met or if it cannot be met and the af fected protection trip system is placed in a tripped condition, the effectiveness of the protection system is preserved.
The APRM instrument channels are provided for each protection trip system. APRM's A and E operate contacts in one subchannel and APRM's C and E operate contacts in the other subchannel. APRM's B, D and F 'are arranged similarly in 1762 287 PBAPS LIMITING CONDITIONS FOR OPERATION SURVLILLANCE REQUIREMENTS ____
3.5.F Minimum Low Pressure Cooling 4.5.F Minimum Low Pressure and Diesel Generator Cooling and Diesel Availability Generator Availability
- 1. During any period when one 1. When it is determined that one diesel generator is inoper- diesel generator is inoperable,al:
able, continued reactor oper- low pressure core cooling and ation is permissible only containment cooling subsystems during the succeeding seven shall be demonstrated to be days unless such diesel gene- operable immediately and daily rator is sooner made operable, thereafter. In addition, the provided that all of the low operable diesel generators pressure core and containment shall be demonstrated to be cooling subsystems and the operable immediately and daily remaining diesel generators thereafter.
shall be operable. If this requirement cannot be met, an orderly shutdown shall be initiated and the reactor shall be placed in the Cold Shutdown Condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
- 2. Any combination of inoperable c omp onent s in the core and containment cooling systems shall not defeat the capabi-lity of the remaining oper-able comp onen t s to fulfill the cooling functions.
- 3. When irradiated fuel is in the reactor vessel and the reactor is in the Cold Shutdown Condi-tion, both core spray systems, the LPCI and containment cooling subsystems may be inoperable, provided no work is being done which has the potential for draining the reactor vessel.
- 4. During a refueling outage, fuel and LPRM removal and replacement may be performed provided at least one of the f ollowing conditions below is satisfied:
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PBAPS L IM IT IN G CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS .__
3.5.F.3 (Cont'd) 4.5.F.2 (Cont'd)
- a. B ot h. . c ore spray systems and the LPCI system'shall be operable except that one core spray system or the LPCI system may be in-operable for a period of thirty days, or
- b. The reactor vessel head is removed, the cavity is flooded, the spent f uel pool gates are removed, and the water level is maintained at least 21 feet over the top of irradiated fuel assemblies seated in the spent fuel storage p ool racks and no work is being perf ormed which has the potential f or draining the reactor vessel.
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PBAPS 3.5.E BASES (C on t 'd . )
With one ADS valve known to be incapable of au t oma t i c operation, four valves remain operable to perform their ADS function.
However, since the ECCS Loss-of-Coolant Accident analysis for small line breaks assumed that all five ADS valves were operable, reactor operation with one ADS valve inoperable is only allowed to continue for seven (7) days provided that the HPCI system is demonstrated to be operable and that the actuation logic for the (remaining) f ou r ADS valves is demonstrated to be operable. The ADS test circuit permits continued surveillance on the operable relief valves to assure that they will be available if required.
F. Minimum Low Pressure Cooling, and Diecel Generator Availability The p u rp os e of Specification F is to assure that adequate core cooling capability is a va i la b le at all times. It is during refueling outages that major maintenance is performed and during such time that all low pressure core cooling systems may be out of service. This specification p rovides that s h ou ld this occur, no work will be p erf ormed on the p rima ry system which could lead to draining the vessel. This work would include work on certain control rod drive c omp on ent s and recirculation system.
Additionally, the specification provides minimum core flooding requirements during refueling operations. Specification 3.9 must als o be consulted to determine other requirements for the diesel generators.
G. Maintenance of Filled Discharge Pipe If the discharge piping of the core spray, LPCI subsystem, HPCI, and RCIC are not filled, a water hammer can de ve lop in this pip ing when the pump and/or pumps are started. If a water hammer were to occur at the time at which the system were required, the sy s t em wou ld still perform its design function. However, to minimize damage to the discharge piping and to ensure added margin in the operation of these systems, this Technical Specification requires the discharge lines to be filled whenever the system is in an operable condition.
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PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS _
3.7 CONTAINMENT SYSTEMS 4.7 CONTAINMENT SYSTEMS Applicability: Applicability:
Applies to the operating Applies to the p rima ry and status of the p rimary and secondary containment secondary containment integrity.
systems.
Objective: Objective:
To assure the integrity of To verify the integrity of the p rimary and secondary the p rimary and secondary containment system. containment.
Specification: Specification:
A. Primary Containment 1. The suppression chamber water lerel and temperature
- 1. Whenever the nuclear shall be checked once per system is pressurized day.
above atmospheric p ressure or work is being done 2. a. Whenever there is in-which has the potential dication of relief valve to drain the vessel, operation (e xcep t when the p ressure suppression the reactor is being p ool water volume shutdown and torus and temperature shall be cooling is being es-maintained within the tablished) or testing following limits except which adds heat to the as specified by suppression p ool, the 3.7.A.2, or when inopera- pool temperature shall bility of the core spray be continually monitored systems, the LPCI and and also observed and containment cooling sub- logged every 5 minutes systems is permissible until the heat addition as provided f or in is terminated.
3.5.F.3 and 3.5.F.4.b.
- a. Minimum water volume- 3. Whenever there is indication 122,900 ft 3 of relief valve operation with the temperature of the
- b. Maximum water volume- suppression pool reaching 160'F 127,300 ft 3 or more and the primary coolant system pressure greater than 200 psig, an external visual examination of the suppression chamber shall be conducted before resuming p owe r operation
- 4. A visual inspection the sup-pression ch amb e r interior, in-ciuding water line regions shal be made at each major re f ue ling outage.
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PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE RPOUIREMENTS 3.10.A.5.b (Cont'd) 4.10.A directional control valves for remaining control rods shall be disarmed electrically and sufficient margin to criticality shall be demonstrated,
- c. If maintenance is to be performed on two control rod drives, they must be separated by more than two control cells in any direction.
- d. An appropriate number of SRM's are available as defined in specification 3.10.B.
- 6. Any number of control rods may be withdrawn or removed from the reactor core provided the following conditions are satisfied:
- a. The reactor mode switch is locked in the " refuel" position. The refueling interlock which prevents more than one control rod from being withdrawn may be bypassed on a withdrawn control rod after the fuel assemblics in the cell containing (controlled by) that control rod have been removed from the reactor core.
All other refueling interlocks shall be operable.
B. Core Monitoring B. Core Monitoring
- 1. Except as specified in 3.10. B. 2, 1. Prior to making any alterations 3.10.B.3 and 3.10.B.4, to the core, the SRM's shall be during core alterations two SRM's functionally tested and checked shall be operable, one in the for neutron response. Thereafter, core quadrant where fuel or while required to be operable, controls rods are being moved and the SRM's will be checked daily one in the adjacent quadrant. for response.
For an SRM to be considered operable, the following conditions shall be satisfied:
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PBAPS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.10.B (Cont'd) 4.10.B (Cont'd)
- a. The SRM shall be inserted to 2. Prior to unloading or the normal operating level. reloading of fuel as provided (Use of special movable, for in sections 3.10.B.2 6 dunking type detectors during 3.10.B.3, the SRM's fuel loading and major core shall be functionally tested.
alterations in place of normal Prior to unloading of fuel, detectors is permissible the SRM's should also be as long as the detector checked for neutron response.
is connected to the normal SRM circuit.)
- b. The SRM shall have a minimum of 3 cps with all rods fully inserted in the core.
- 2. Prior to unloading of fuel, the SRM's shall be proven operable as stated above; however, during unloading of fuel, the SRM count rate may drop below 3 cps, provided all control rods are full inserted and rendered electrically inoperable with the exception of the following provision. Individual control rods outside the periphery of the then existing fuel matrix may be electrically armed and moved after all fuel in the cell containing that control rod have been removed from the reactor Core.
- 3. Prior to reloading of fuel, two, three, or four fuel assemblies may be returned to their previous core positions adjacent to each of the 4 SRM's to obtain the required 3 cps. Until these assemblies are loaded, the SRM 3 cps count rate is not required.
- 4. The SRM 3 cps count rate is not required with all fuel removed i162 293 from the core.
C. Spent Fuel Pool Water Level C. Spent Fuel Pool Water Level Whenever irradiated fuel is stored Whenever irradiated fuel is stored in the spent fuel pool, the pool in the spent fuel pool, the water
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PBAPG water level shall be maintained at level shall be recorded daily.
or above 8 1/2' above the top of the fuel.
D. Heavy Loads Over Spent Fuel Loads in excess of 1000 lbs (excluding the rigging and transport vehicle) shall be prohibited from travel over fuel assemblies in the spent fuel storage pool.
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- 9 PBAPS 3.10 BASES (Cont' d)
The requirements for SRM Operability during these core alterations assure sufficient core monitoring.
B. Core Monitoring The SRM's are provided to monitor the core during periods of station shutdown and to guide the operator during refueling operations and station startup. Requiring two operable SRM's in or adjacent to any core quadrant where fue? or control rods are being moved assures adequate monitoring of that quadrant during such alterations. The requirement of 3 counts per second provides assurance that neutron flux is being monitored and insures that startup is conducted only if the source range flux level is above the minimum assumed in the control rod drop accident.
During unloading of fuel, it is permissible to allow the SRM count rate to decrease below'3 cps. Since all fuel moves during core unloading will reduce reactivity, the lower number of counts will not present a hazard. Requiring the SRM's to be functionally tested prior to fuel removal assures that the SRM's will be operable at the start of fuel removal. The daily response check of the SRM's ensures their continued operability until the count rate deminishes due to '.uel removal. Control rods in cells from which all fuel has been removed and which are outside the periphery of the then existing fuel matrix may be armed electrically and moved for maintenance purposes during fuel removal, provided all rods that control fuel are fully inserted and electrically disarmed.
During core loading, the loading of adjacent assemblies around the four SRM's before attaining the 3 cps is permissible because these assemblies were in a subcritical configuration when they were removed and therefore will remain subcritical when the same assemblies are placed back into their previous positions. Since specification 3.10.A.2 requires that all control rods be fully inserted prior to loading fuel, inadvertent critical whenity is precluded during core loading.
C. Spent Puel Pool Water Level To assure that there is adequate water to shield and cool the irradiated fuel assemblies stored in the pool, a minimum pool water level is established. The minimum water level of 8 1/2' above the top of the fuel is established because it provides adequate shielding and is well above the level to assure adequate cooling.
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PBAPS 4.10 BASES A. Refueling Interlocks Complete functional testing of all refueling interlocks before any refueling outage will provide positive indication that the interlocks operate in the situations for which they were designed. By loading each hoist with a weight equal to the fuel assembly, positioning the refueling platform and withdrawing control rods, the interlocks can be subjected to valid operational tests. Where redundancy is provided in the logic circuitry, tests can be performed to assure that each redundant logic element can independently perform its functions.
B. Core Monitoring Requiring the SRM's to be functionally tested prior to any core alteration assures that the SRM's will be operable at the start of that alteration. The daily response check of the SRM's ensures their continued operability.
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