ML19208B504
| ML19208B504 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 08/16/1979 |
| From: | Lattore V, Mayn B LAWRENCE LIVERMORE NATIONAL LABORATORY |
| To: | |
| Shared Package | |
| ML19208B500 | List: |
| References | |
| NUDOCS 7909200455 | |
| Download: ML19208B504 (23) | |
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SELECTED ISSUES PROGRAM TECHNICAL EVALUATION OF THE ELECTRICAL, INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE LOW TEMPERATURE OVERPRESSURE PROTECTION SYSTEM FOR THE MAINE YANKEE NUCLEAR POWER PLANT by V. R. Latorre B. G. Mayn*
- EG&G, Enerny Measurements Group, San Ramon Operations 872258 70 0.92 00 hff
This report docunents the technical evaluation of the electrical, instrunentation, and control design aspects for the low temperature over-pressure protection system of the Maine Ydee nuclear power plant. Design basis criteria used to evaluate the acceptability of the system included operator action, system testability, single failure criterion, and seismic Category I and IEEE Std-279-1971 criteria.
This report is supplied as part of the Selected Electrical, In strument ation, and Control Systems Is sues Support Program being conducted for the U. S. Nuclear Regulatory Comnission by Lawrence Livennere Laboratory.
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TECHNICAL EVALUATION OF THE ELECTRICAL, INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE LOW TEMPERATURE OVERPRESSURE PROTECTION SYSTEM FOR THE MAINE YANKEE NUCLEAR POWER PLANT 1.
INTRODUCTION By letter to the Maine Yankee Atomic Power Company (MYAPCC) dated
. August 11, 1976, the U. S. Nuclear Regulatory Commission (NRC) requested an evaluation of system designs to detemine susceptibility to overpressuriza-tion events and an analysis of these possible events, and proposed interim and pemanent modifications to the systems and procedures to reduce the likelihood and consequences of such events.
By letter dated December 2,
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1976 and subsequent letters (refer to the Appendix), the Maine Yankee Atoaic Power Company submitted the additional information requested by the NRC staff, including the adninistrative operating procedures and the pro-posed low temperature overpressure mitigating system.
The system hardware includes sensors, actuating mechanisms, alarms, and valves to prevent a reactor coolant system transient from exceeding the pressure and tempera-ture limits of the Technical Specifications for Maine Yankee as required by the Code of Federal Regulations, Title 10, Part 50 (10 'CFR 50), Appendix G.
The purpose of this report is to evaluate the electrical, instru-mentation, and control (EI&C) aspects of the Licensee's equipment and procedures ba' sed on the infomation provided (refer to the Appendix), and to define how well they meet the criteria established by NRC as necessary to prevent unacceptable overpressurization events.
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EVALUATION OF MAINE YANKEE
2.1 INTRODUCTION
Review of the Maine Yankee low temperature overpressure protection system design by MYAPC0 was begun in 1976 at NRC's request.
The proposed overall approach to eliminating overpressure events incorporates admin-istrative, procedural, and haniware controls, with reliance Jpon the plant operator for the principal line of defense.
Preventive administrative /
procedural measures include:
(1)
Procedural precautions.
(2)
Deenergization (power removed) of essential components which are not required to be operable during the cold shutdown mode of caeration.
(3)
Maintenance of a non-water-solid reactor coolant system condition whenever possible.
(4)
Incorporation of a low pressure relief setpoint for the existing solenoid-operated relief valve (50RV) control logic, and the use of the residual heat re-moval (RHR) system.
The design basis criteria that were applied in evaluating the acceptability, of the electrical, instrunentation, and control aspects of low temperature overpressure mitigating system (OMS) are as follows:
(1)
Operator Action.
No credit for operator action is taken until ten minutes after the operator is aware, through an action alarm, that an overpressure trans-ient is in progress.
(2)
Single Failure Criterion.
The CNS shall be designed to protect tne reactor vessel given a single failure which is in addition to the failure that initiated the pressure traneient.
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l (3)
Testability.
The OMS must be testable on a periodic basis prior to dependence on the OMS to perform its function.
(4)
Seismic Category I and IEEE Std-279-1971 Criteria.
The OMS should satisfy both the seismic Category I and IEEE Std-279-1971 criteria.
The basic objective is that the OMS should not be vulnerable to a failure mode that would both initiate a pressure transient and disable the low temperature overpressure mitigating system.
Events such as loss of instrtrient air and loss of offsite power must be considered.
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2.2 MYAPC0 OVERPRESSlRE MITIGATING SYSTEM DESIGN The MYAPC0 overpressure mitigating system design information detailed in this section was derived from the references listed in the Appendix.
The MYAPC0 design for the Maine Yankee OMS is based on the use of two pressurizer solenoid-operated relief valves (50RV's) along with two passive spring-loaded safety valves (SV's) which are located on the suction line of the RHR system piping.
These valves, in conjunction with specific procedural controls, fann the bases for the following conditions:
(1)
Each pressurizer 50RV will provide sufficient and redundant relief capacity to ensure that the reactor coolant system (RCS) pressure remains pelow 589 psig when the RCS temperature is below 220 F.
The pres-surize,r SORV low pressure setpoint is 500 psig.
(2)
The two RHR SV's together will provide sufficient and redundant rel ief capacity to ensure that the RCS pressure remains pelow 589 psig when the RCS tempera-ture is below 220 F.
The RHR SV low pressure setpoint is 400 psig.
(3).
A 225 F temperature switch will be provided to ensure that the RHR-SV isolation valves and the pressurizer-SORf isolation valves are open at temperatures below 225 F.
Valves that are not open will be annunciated on the main control board.
(4)
Additional assurance of preventing inadvertent blow-g down at RCS temperatureg above 300 F is provided by the inclusion of a 300 F temperature switch.
This switch will ensure that the RHR-SV ' isolation valves are closed and that the pressurizer SORV's have been 2-2 872262 es e emome g
e reset to the high setpoints required for normal plant operation.
Failure of the RHR-SV isolation valves to close or failure of the pressurizer 50RV's to be reset to the high setpoint will be annunciated on the main control board.
The two pressurizer 50RV's are equipped with a low pressure set-point feature.
This feature, when enabled by the operator by means of a key lock switch, causes each pressurizer 50RV to open when the pressurizer pressure reaches a setpoint of 500 psig.
In accordance with pl ant cooldown procedures, the pressurizer SCRV's are set to the low pressure setpoint when the system pressure is less than 450 psig.
This low pressure setpoint is to be established prior 0
to decreasing the RCS temperature below 220 F.
Plant operating procedures provide that normally the RHR system suction isolation valves are open below 220 F thereby making available the relief capacities of these two safety valves as reactor vessel overpressure protection devices.
An RHR interlock does exist, however, whfch prevents the opening of the isolation valves at all pressures in excess of 400 psig.
It is concluded, therefore, that when the pressure is decreasing, the RHR SV's offer no overpressure protection until the pressure is reduced to 400 psig or below and the RHR-SV isolation valves are allowed to open.
For decreasing press'ures between 5co psig (pressurizer SORV low setpoint) and 400 psig (RHR-SV maximum isolation valve opening pressure for decreasing RCS pressure), it appears that the overpressure protection system is vulnerable to an overpressure transient if the single failure criteria is applied and the pressurizer SORV actuation circuitry fails.
Although this is true,-it should be cmphasized that the MYAPC0 OMS will not be enabled unless the RHR-SV isolation valves are open, which implies that the pressure is equal to or less than 400 psig.
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2.3 EVA1.UATION OF MAINE YANKEE USING DESIGN BASIS CRITERIA Maine Yankee was evaluated under the guidance of the four design basis criteria sttted in Section 2.1 of this evaluation, and with specific attention given to various pertinent NRC staff positions resulting from these criteria.
Sections 2.3.1 through 2.3.4 are concerned with the four design criteria.
2.3.1 Operator Action In each design basis transient analyzed, no credit for operator action was taken until 10 minutes after the initiation of the RCS over-pressurize transient and after le operator was made aware of the over-pressure transient by the low tenperature overpressure transient al am.
The crierion for operator action is consistent with that suggested at the recent meetings between pressurized water reactor (PWR) bwners and the NRC:
1.e., when a plant is op 'ated in accordance with established operating procedures, the protection afforded by nomal operating procedures is a vital part of the overall plan for protection against overpressurization.
In the analysis of postulated overpressure events presented in Appendix G,10 CFR 50, operator action to mitigate the consequences of the event are conservatively assuned not to occur for ten minutes after the event.
The operator is alerted to a possible overpressure event by means of the impending transient and pressurizer SORY open alams on the master control board.
In this analysis, it is seen that adhere'nce to normal operating procedures is the only requirenent placed upon the operator to guarantee overpressure protection.
Although the above criterion has been established, there is no dependence on operator action after the ten-minute interval to mitigate the effects of an overpressurizatica event.
The pressurizer SORV's and the nomally available capability of the RHR SV's provide redundant protection from overpressurization in all the events analy:ed.
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2.3.2 Single Failure Criterion The NRC staff position requires that the OMS shall be designed to protect the reactor vessel given a single failure which is in addition to the failure that initiated the pressure transient.
The NRC staff position also requires that the power supplies and power sources for the pressurizer SORV's be completely separate and distinct from those of the RHR-SV's.
The MYAPC0 Maine Yankee OMS is intended to protect the reactor vessel given a single failure in addition to the failure that initiated the overpressure transient.
The single faiiure criterion has been appl'ed to both the initiating events and the means of mitigating the effects of these overpressurization events.
It was assumed that either a single equipment malfunction or a single erroneous operator control manipulation can ini-tiate each of the overpressurization events considered. '
Protection against overpressurization events is provided by the two pressurizer SORV's whose combined capacity is sufficient to maintain the reactor coolant pressure below 589 psig at all temperatures below 0
220 F, assuming the worst case event.
In addition, the RHR SV's provide redundant relief capacity whenever nomal operating procedures require the RHR system to be open to the RCS.
c Means have been empl oyed to provide the margin of protection afforded by the single failure criterion both in preventing.an event ini-tiation and in limiting the effects of an event once it is initiated.
The use of pressuri+ SORV's in conjunction with RHR SV's is an acceptable concept.
We conclude that the MYAPC0 Maine Yankee OMS does satisfy the NRC staff single failure criterion.
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I 2.3.3 System Testability The NRC
- staff position re:;uires that the OMS control circuitry from the pressure sensor to the valve solenoid should be tested prior to each heatup or cooldown.
The RHR SV's, and pressurizer SORV's should be tested during each refueling.
Deviations from this criterion should be justified.
There are two aspects associated with the testability of the MYAPC0 ~ Maine Yankee OMS.
The first aspect is concerned with the pressurizer-SORY testing program for low pressure protection system oper-ability. These tests are as follows:
(1)
Verification of upstream isolation valves functioning once per cold shutdown.
(2)
Perfomance of a channel functional test of the con-trol circuitry from the pressure s'ensor to the valve solenoid once per refueling outage.
(3)
Perfomance of a channel calibration of the pres-surizer pressure sensors once per 18 months.
The second aspect of the testing program involves the plant. tests during cold shutdown which could result in an RCS overpressurization above the minimun operating ' limit curves.
These tests are as follows:
(1)
Actuation of the containment isolation system (CIS).
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(2)
Actuation of the safety inj ection actuator system (SIAS).
(3)'
Flow testing of the high pressure safety injection (HPSI) punp.
(4 )
Testing of the CIS trip valve.
(5)
Calibration of the RHR interlock circuitry.
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The following preventative measuras have been instituted to prevent in-advertent RCS overpressurization during this testing:
(1)
T6e initial conditions for the CIS actuation test require that the charging, letdown, and purification systems are secured prior to the test.
(2)
A procedural step in the SIAS actuation test closes the discharge valve on the charging (HPSI) pmp to be tested prior to SIAS actuation.
The control switch for the other charging pmp is in the " pull-to-lock" position.
(3)
The HPSI pump flow test is perfomed while flooding the refueling cavity with the reactor vessel head
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removed.
(4)
The CIS trip valve test includes a caution statement, imediately preceding the test stroking of the letdown CIS trip valve, that requires an alternate letdown path if the plant is in a water-solid condition.
(5)
The prerequisite section of the calibration procedure for the RHR interlock circuitry requires that the RCS is depressurized and does not require relief protec-tion (i.e., the reactor utssel head is removed or a pressuri zer safety valve is removed for pressurizer venting).
When component testing is required which might cause an RCS pressure rise above the minimum pressure / temperature limit curves, the OMS will be operational consistent with the RCS temperature consideration.
e For the Maine Yankee nuclear power plant, each pressurizer SORV can be isolated from the pressurizer by means of an upstream isolation valve.
Once isolated, the solenoid-operated pilot actuator can be tested for operabili.ty prior to plant.cooldown.
Normal operating procedures will be modified to require this test pricr to plant cooldown for each refueling shutdown.
Since the Maine Yarikee nuclear power plant uses two pressurizer 50RV's driven by one pressure transmitter plus the safety / relief valves installed in the RHR system, the NRC staff position also applies to the RHR system valves and control circuitry that are used in the low temperature OMS.
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We conclude that the MYAPC0 Maine Yankee OMS satisfies the EI&C testability criteria if the valves and control circuitry in the RHR system, which are used for overpressurization mitigation, are tested in accordance with the NRC staff position stated at the beginning of this section.
2.3.4 Seismic Design and IEEE Std-279-1971 Criteria 2.3.4.1 Seismic Design Criteria.
The Licensee states that the Maine Yankee pressurizer 50RV's and RHR system safety valves have been designed to meet the requirements of seismic Category I criteria.
2.3.4.2 IEEE-279-1971 Criteria For the Maine Yankee nuclear power pl ant, the primary design purpose of the pressurizer SORV during normal plant operation is to provide the means by which an excess pressurizer pressure condition can be correct-ed without necessitating the opening of the safety-class mechanical safety valves.
This capability eliminates the consequential potential leakage condition in case the safety valves reset and reseal incorrectly. A second feature allows the operator, using a main control board-mounted switch, to manually energize (and open) the relief valve and decrease system pressure in the pressurizer. A third feature, the " dual setpoint", was added during original system design to provide a means of potential reactor vessel low temperature overpressurization (LTO) protection.
This' existing dual set-point feature permits the operator, using a main control board-mounted oermissive keylock switch, to arm the pressurizer-SORV trip circuit for both normal (2335 psig trip) and LTU (500 psig trip) plant operation.
The Licensee has stated that none of these three features con-stituted a requirement for a redundant safety class electrical actuation system and, therefore, no part of the electrical system was designed to meet IEEE-279-1971 and/or seismic Category I criteria.
The " dual setpoint" LTO protection system is not a system that they are proposing be added to their plant, but rather it is an existing system which was implenented 2-8 872268
during original plant start-up.
Since their proposed niodification to the existing OMS requires no additional equi pnent, they believe that major system modifications are unnecessary to meet the IEEE-279-1971 criteria for the following reason:
The proposed modification of the " auto-isolation" feature of the RHR-SV isolation valves will resul t in a mechanically redundant relief capability by providing an alternate means (via the RHR SV's actuated at 400 psig) through which excess RCS pressure can be relieved.
The pressurizer SORV's depend only on electrical power to operate; they are not air-operated valves.
The solenoids actuate a pilot which allows fluid pressure to open the valves.
Thus, a loss of station or instrunent air pressure will have no effect on the operability of these valves.
The RHR SV's, on the other hand, are spring-loaded valves, and the RHR-SV isolation valves are motor-operated.
In the erent of an electrical
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failure, the RHR-SV isolation valves will " fail open," and the RHR SV's will still function.
We conclude that the OMS would not be susceptible to a common mode failure involving loss of offsite electrical power and air supply.
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2.4 Al. ARM SYSTEMS DESIGNS AND OPERATION Specific details concerning acceptable alam systens design and operation for the 0MS are described hel s.
2.4.1 High-Pressure Alam The NRC staff position requires that a high-pressure audio / visual alam shall be used during low RCS temperature operations as an effective means to provide unambiguous infomation to the operator that a pressure transient is in progress.
A description of the MYAPC0 high-pressure alann system design is as follows:
(1)
A computer high-pressure alam is avaii5le at a pres-surizer pressure setpoint of 375 psig.
This alarm derives its pressure signal from a. differential pres-surizer pressure transnitter than is used to provide the low pressure setpoint feature for the pressurizer SORV's.
The alam is always present in the computer when the pressure is greater than 375 psig; however, an operator keyboard procedure removes this alam from the computer printout routines during normal plant operation.
Therefore, operator action to reinstate this alarm in the computer printout routines is pro-vided in plant operating precedures where needed to ensure the presence of the alam.
(2)
The ccraputer L am actuates an annunciator on the main control board.
It requires operator acknowledgment and prints out the alam message on the computer alam typewriter.
This al am obviously depends upon the plant computer being operable, and there are times during cold shutdown plant conditions when the com-puter must be removed frcxn service.
(3)
Another high-pressure alarm is associated with the actuation of the pressurizer SORV's.
At 530 psig increasing, the pressurizer SORV's receive an actu-ation signal to open.
The same signal actuates an annunciator on the main control board and alerts the operator that the pressurizer SORV's have actuated.
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(4)
The RHR SY's are needed to mitigate overpressurization in the event of a pressurizer SCRV OMS failure, but the RHR SV's do not appear to be instrtsnented for a main control board alarm.
Also, in the event of a pressurizer 50RV OMS failure, it is conceivable that the pressurizer SORY actuation alarm would not func-tion to alert the pl ant operator that a pressure transient is in progress.
We conclude that this design is
. adequate to annunciate all overpressure transient conditions and does satisfy all of the NRC staff position.
2.4.2 Pressurizer-SORV ! solation and RHR-SV-Isolation Valve Alarms
- The NRC staff position requires that (1)
The upstream isolation valves to both the pressurizer 50RV's and the RHR SV's shall be wired into the over-pressure protection alarm in such a way that the alarm will not clear unless the system is enabled and the isolation valves are open. Means shall be provided to ensure proper alignment of the isolation valves during OMS operatior..
(2)
The al ams shall be of the audio / visual type and provide unambiguous information to the operator.
A description of the MYAPCO isolation valve alann system design is as follows:
(1)
An alarm will be provided to alert the operator to align the OMS on pl ant cooldown.
Both the pressurizer-SORV and RHR-SV i solation valves are included in this alarm.
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- It should be noted that the enable alarm (Section 2.4.3) and the isolation valve alarm (Section 2.4.2) are the same alam.
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(2)
Since the OMS is to be activated at reactor coolant n
temperatures below 220 F, the proposed alarm will annunciate at 225 F decreasing if either pressurizer-SDIV upstream isolation valve is closed or if either i
RHR-SV inlet isolation valve is closed.
We conclude that this design satisfies the NRC staff position.
2.4.3 Enable Alarm
- The NRC staff position requires that (1)
An alann shall be activated as part of the plant cooldown process to ensure the pressurizer 50RV " low pressure" setpoint is activated before the RCS tem-g perature is equal to or less than 220 F.
Prior to g
cooling the RCS below 220 F, operating procedures will require the activation of the OMS by setting the keylock pennissive switch to the " low pressure" set-point and by setting the RHR-S V i sol ation and pressurizer-50RV isolation valve switches to the "open" position.
(2)
The alann shall be of the audio / visual type and pro-vide unambiguous infomation to the operator.
A description of the MYAPC0 enable. alarm system design is as follows:
(1)
An alarm will be provided to alert the op5rator to align the LTO system on plant cooldown.
(2)
Since the LTO system is to be activated at reactar coolant temperatures bejow 220 F, the proposed alann will annunciate at 225 F decreasing if the keyl ock pennissive switch is positioned to "HPSR" (only the nonnal, high pressure setpoint is~ activated).
- 1t should be noted that the enable alann (Section 2.4.3) and the isolation valve alarm (Section 2.4.2) are the same alann.
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We conclude that this design satisfies the NRC staff position.
2.4.4 Disable Alarm The NRC staff position requires that (1)
An al arm shall be activated as part of. the plant heatup process to ensure that the 50RV's are reset to the "high" getpoint when the RCS temperature is great-er than 300 F.
(2)
The alarm shall be of the audio / visual type and pro-vide unambiguous infonnation to the operator.
A description of the MYAPCO disable alam system design is as follows :
(1)
An alam will be provided to alert the operator to align the components of the OMS for power operation.
(2)
This alam will annunciate at a temperature of 300 F increasing to warn the operator that the relief selector switch should be set-to the "high" setpoint position and/or that the RHR-SV isolation valves are o pen.
We conclude that this design satisfies the NRC staff position if it can be shown that the alann is of the audio / visual t'ype.
2.4.5 Pressurizer-SORV Open and RHR-SV Open Alarms The NRC staff position requires that (1)
An alam be activated to alert the operator that a pressurizer SORY is in the "open" position.
(2)
An alam be activated to al ert the operator that either of the RHR SV's are in the open position.
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(3)
All alarms shall be of t:e audio / visual type and pro-vide unarbiguous infomation to the operator.
A description of the MYAPC0 pressurizer-SORY open al arm system design is as follows:
(1)
A high-pressure alarm is associated with the actuation of the pressurizer SORV's.
At 500 psig in:reasing, the pressurizer 50RV's receive an actuation signal to open.
(2)
The same signal actuates an annunciator on the main control board alarting the operator that the pres-surizer SORV's have been activated.
This alarm is also used to ale. '. the operator that a pressure trans-ient is in progress.
We conclude that this desion satisfies the NRC staff position for the pressurizer-SORV open alam.
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- 2. 5 PRESSURE TRANSIENT REPORTING AND RECORDING REQUIREMENTS The NRC staff position is that a pressure transient which causes the OMS to function, thereby indicating the occurrence of a serious pres-sure transient, is a 30-day repo. table event.
In addition, pressure-recording and temperature-recording instrumentation are required to provide a pemanent record of the pressure transient.
The response time of the pressure / temperature recorders shall be compatible with press'ure transients that increase at a rate of approximately 100 psig per second.
The Maine Yankee nuclear power plant does not possess provisions for continuously recording temperature and pressure at low temperatures (including cold shutdown).
The plant does, however, utilize the process computer which provides a camputer alarm at 375 psig increasing.
The computer alarm activates an annunciator on the main control board.
It requires operator acknowledgnent and prints out the alam message on the computer alarm typewriter.
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- 2. 5 DISABLING 0F ESSENTIAL COMPONENTS NOT REQUIRED DURING COLD SHUTDOWN The NRC staff position requires the deenergizing of safety injec-tion system (SIS) pinps and the closure of safety injection (SI) header /
discharge valves during cold shutdown operations.
MYAPC0 states that the disabling of essential components during cold shutdown is as follows:
(1)
The " pull-to-lock" position associated with the con-trol switches for the charging ptnps deenergizes the charging ptmp and inhibits all the automatic start signals and the SIAS from starting the ptsp.
(2)
The Maine Yankee Technical Specifications require one HPSI (charging) pump to be operable along with all associated valves and controls set for autpatic initiation, whenever the RCS is greater than 210 F and 400 psig.
Below these conditions, a charging pump is still required if a reactor coolant pump is operating in order to supply the reactor coolant pinp,with seal injection water.
The nonoperating charging pump control switch is placed in the " pull-to-lock" positon to remove the pinp from service, but it still retains its capability to be started from the main control board should the operating pump become unavailable.
The HPSI header isolation valves are nomally closed, but must remain egergized until the plant conditions are less than 210 F and 400 psig.
Below these con-ditions, the breakers for the valve motor operators will be opened, tagged, and placed under administra-tive control.
We conclude that thi s impl ementation satisfies the NRC staff position.
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TECHNICAL SPECIFICATIONS The Technical Specifications infonnation detailed in this section was derived from the RSB/ DOR SER entitled, " Safety Evaluation Report of the Overpressure Mitigating System for Maine Yankee Atmic Power Plant", dated November 1978.
To ensure operation of the OMS,Nlte has required the Licensee to subnit Technical Specifications consistent with the analysis provided.
MYAPC0 has submitted tentative Technical Specifications (refer to Reference 9 in the Appendix), and we find these to be acceptable with the following exception:
The Licensee must add a statement to ensure that a reactor coolant pump may be started (or jogged) only if there is a steam bubble in the pressurizer with a max' mum level of 80 percent, or the steam generator /
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0 RCS tenperature differenra is less than 100 F.
The tenativa technical specifications for Maine Yankee are as follows :
Technical Specification #3.4 (add the following)
D.
Low Temperature Overpressurization Protection
- 1. a. Tne power operated rel ief val ves, aligned for the low pressure setpoint, and the RHR spring relief valves shall be operable for RCS overpressure protection whenever the RCS js less than the minimun pressurization temperature and the RCS is not vented, b.
If the conditions of D.1.a are not met, the RCS shall be depressurized and vented within eight hours.
EXCEPTION:
One power operated relief or RHR spring rqlief may be inoperable for seven days.
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2.
No more than one gPSI ptrnp may be energized at RCS tem-perature below 200 F.
EXCEPTION:
A second HPSI pump may be energized for up to 5 minutes for the purpose of rotating operating equipment.
Technical Specification #4.1 - Table 4.1.3 (add the following)
Channel Description Surveillance Function Frecuency Surveillance Method
- 10. Pressurizer a) Calibrate R
Apply known pressure Power Operated to the pressure sensor.
s Reliefs - Low b) Test R(5)
Manual actuation of' Pressure Set-each POR to verify point solenoid operation.
(5) Must be performed prior to cooldown below 220 F.
We concur with the Reactor Safety Branch acceptance of these tenative technical specifications.
e 3-2 872277
i 4.
CONCLUSIONS The electrical, instrtmentation, and control design aspects of the low temperature overpressure mitigating system (OMS) for Maine Yankee were eval uated using those design criteria originally prescribed by the NRC staff and later expanded during subsequent discussions with the Licensee.
de conclude that the MYAPC0 Maine Yankee OMS design as described does satisfy all of the NRC criteria, requirements, or staff oositions.
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APPENDIX
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REFERENCES o
1.
" Staff Discussion of Fifteen Tecbnical Issues Listed in Attachnent G November 3, 1976 Memorandum from Di rector, NRR to NRR Staff",
NUREG-0133, November 1976.
2.
NRC Letter (Reid) to MYAPC0 dated August 11, 1976.
3.
MYAPC0 Letter (Naudenburgh) to NRC dated December 2,1976.
4.
NRC Letter (Reid) to MYAPC0 (Groce) dated January 28, 1977.
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5.
MYAPCO Letter (Johnson) to NRC dated March 25, 1977.
6.
NRC Letter (Reid) to MYAPC0 (Groce) dated August 22, 1977.
7.
MYAPC0 Letter (Johnson) to NRC dated October 24, 1977.
8.
NRC Letter (Reid) to MYAPC0 (Groce) da:2d January 10, 1978.
9.
MYAPC0 Letter (Johnson) to NRC dated February 24, 1978 10.
NRC Memoranden (Check to Reid), " Review of Maine Yankee Overpressure Mitigating System (TACS s6741)," December 18, 1978.
- 11. " Combined He at up, Cool down and Pressure-Temperature Limi ta ti ons,"
Maine Yankee Appendix G Infonnation, Section 3.4 of Anendnent No. 31, June 19,1977.
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