ML20041G419
| ML20041G419 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/15/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-0737, RTR-NUREG-578, RTR-NUREG-737, RTR-REGGD-01.097, RTR-REGGD-1.097, TASK-2.E.1.2, TASK-2.F.1, TASK-2.F.2, TASK-TM NUDOCS 8203220241 | |
| Download: ML20041G419 (125) | |
Text
-_
TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374o1 400 Chestnut Street Tower II e
March 15, 1982
/
s 4
ego { D 6
S/
\\
Director of Nuclear Reactor Regulation
[;
9 Attention:
Ms. E. Adensam, Chief
[
fO
}
Licensing Branch No. 4 l
Division of Licensing U.S. Nuclear Regulatory Commission 7.e
/
,/
Washington, DC 20555
Dear Ms. Adensam:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 As required by the Sequoyah Nuclear Plant unit 1 operating license condition 2.C(24), we provided tentative schedules for compliance with Regulatory Guide 1.97 in my April 18, 1981 letter to A. Schwencer and in my July 1, 1981 letter to you. As stated in my November 6, 1981 letter to you on the same subject, we were in the process of reassessing our design criteria and parameter list for post accident monitoring (PAM) instrumentation.
Enclosed is the final PAM instrumentation list and design criteria that include specific upgrade and ambiguity / single failure requirements.
If you have any questions concerning this matter, please get in touch with J. E. Wills at FTS 858-2683 Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, na er Nuclear Regulation and Safety Sworn to d subscr d befpre me this/
day or (fucAA982 14ftb l
L<d Notaby Public
/
My kommission Expires f
s Enclosure cc:
U.S. Nuclear Regulatory Commission Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 d
41 820315 h{K 05000327 P
PDR An Equa, Opportunity Employer J
ENCLOSURE Postaccident Monitoring Design Basis and Parameter List O
S O
~
_m
1.0 DISCUSSION This design basis establishes criteria for determining the key and preferred backup variables to be monitored by the control room operating staff of Sequoyah Nuclear Plant following the initiation of an accident.
1.1 Planned Versus Unplanned Operator Actions The plant safety analyses and evaluations define the design basis accident event scenarios for which preplanned operator actions are required. Accident monitoring instrumentation is necessary to permit the opet ator to take required actions to address these analyzed situations. However, instrumentation is also necessary for unplanned situations (i.e., to ensure that, should plant conditions evolve differently than predicted by the safety analysis, the operator has sufficient information to monitor the course of the event). Additional instrumentation is also needed to indicate to the operator whether the integrity of the in-core fuel clad, the reactor coolant system pressure boundary, or the primary reactor containment has degraded beyond the prescribed limits defined as a result of the plant safety analyses and other evaluations. Such additional requirements are considered by this design basis.
1.2 VARIABLE TYPES Five classifications of variables have been identified (see table 1-1).
Operator manual actions identified in the
~
operating procedures associated with design basis accident events are preplanned. Those variables that provide informatt,n needed by the operator to perform these manual actiors are designated type A.
The basis for selecting type A variables is given in section 1.2.1 below.
Those variables needed to assess that the plant critical safety functions are being accomplished or maintained, as identified in the plant safety analysis and other evaluations, are designated type B.
Variables used to monitor for the gross breach or the poteni.ial gross breach of the in-core fuel clad, the reactor coolant system boundary, or the primary reactor containment, and determine the magnitude of high-level radioactive releases through identifiable paths are designated type C.
Type C variables used to monitor the potential breach of containment may have an arbitrarily-determined, extended range. The l
extended range shall be chosen to minimize the probability of instrument saturation even if conditions exceed those predicted by the safety analysis. The response characteristics of type C information display channels shall allow the control room operator to detect conditions i
indicative of gross failure of any of the three fission product barriers or the potential for gross failure of these barriers.
Those variables needed to assess the operation of individual safety systems and other systems important to safety and backup variables to types B and C key variables are designated type D.
The variables that are required for use in providing information regarding the release of low-level radioactive materials and assessing the releases are designated type E.
1.2.1 Postaccident Monitoring Type A Variables Type A variables are those indications that provide information required to identify the event and take preplanned manual actions for design basis events that result in significant threats to the health and safety of the general public. The variables can be separated into three groups which are those variables required for (1) event identification, (2) event recovery to plant stabilization, and (3) maintaining the stabilized conditions and event recovery to cold shutdown. Event identification may be a required operator action because the operator may need to know the type of event before he can take the correct required mitigative action. Events such as SG tube rupture versus a small LOCA in containment require the operator to complete different required actions. " Required Operator Action" as defined in ANSI N660/ANS 51.4, paragraph 2.5,,is
" Actions which require manual manipulation of equipment during the course of design basis events to enable the safety systems to provide the minimum acceptable performance that will prevent violation of the design requirements for the particular event category." The definition is technically applicable to only groups (1) and (2) operator actions. The required operator actions can fall into further divisions. The operator can (1) take a discrete action based on a discrete indication (e.g., start H2 recombiners when containment H2 level exceeds 0.5 percent) or (2) take all the required actions to maintain a process (e.g.,
cooldown while on natural circulation). The indications for the two situations will be different.
The analysis for determining type A variables did not assume single failures occur. All the safety systems are designed to be single-failure proof, and the type B variables will monitor the safety functions to provide indication to the operator of any additional abnormalitie?.
The type A events were generally limited to events considered as DBEs in chapter 15 of the FSAR.
1.2.2 Postaccident Monitoring Type B Variables The type B variables are used to monitor the success of completing the manual and automatic actions required to maintain the three fission product boundaries (e.g.,
clad, RCS, and containment). The type B variables do not attempt to monitor the actual integrity of the fission product boundary. The fission product boundary status monitors are type C variables even though many of the indications will be the same as type B variables.
The type B variables will apply only to those actions that are required to prevent major failures (i.e.,
system function lost or 10 CFR 100 exceeded). Ac; ions to prevent minor losses of integrity will not be monitored as type B variables. This position is supported by ANS 4.5 and implied by the variable list of Regulatory Guide 1.97.
The safety functions are defined so that the major required actions are monitored; however, the essential supporting systems required for the safety function will be monitored by type D variables.
Overall Goal: To monitor fuel rod integrity, RCS integrity, and containment integrity by ensuring all required actions (automatic or manual) have been or are being completed.
Safety Function
- The minimum number of processes or conditions which, when completed or met, can ensure that the overall goal is achieved. Additionally, the process or condition must be able to be monitored, and the operator must be able to easily understar.d the effects of his actions or the automatic functions on the process or condition.
Type B Variables: Those instruments that provide information to monitor the process of completing critical safety functions.
1.2.3 Postaccident Monitoring Type C Variables The fission products are contained by three principle barriers which are (1) cladding, (2) RCS, and (3) containment. Type C variables are those variables that indicate the potential for breaching and the actual breach of the barriers to fission product releases. The potential for boundary failure and the actual boundary failure were considered separately for each barrier.
-4 TVA has also included the function of determining the magnitude of high-level radioactive releases as a type C variable.
The type C potential failure variables are closely related to the type B variables. The 6jpe B variables monitor the " success" of performing the safety functions which are required to maintain the barriers.
The type C potential failure variables monitor the challenges on the barriers which will include the
" failure" of performing the safety functions. The c5 illenges on a barrier are not necessarily limited to o.ily failures of safety functions. For type C variables that do monitor a failure of a safety function, the success and failure monitor may be the same variable. The type C variable might require an extended range to determine the extent of failure or level of challenge on the barrier.
1.2.4 Postaccident Monitoring Tyoe D Variables Type D variables are those variables required to provide information to indicate operation of individual safety systems. The determination of specific variables was made by considering four categories of safety systems. The categories are (1) safety-related heat removal systems, (2) major components or systems required for type B safety functions, (3) auxiliary and support systems, and (4) types B and C backup variables for the key variables. The third category is used to identify the support systems not covered by the other categories. The ranges of the instruments will only be the normal design range.
Since the type D variables monitor (1) the essential support systems to the critical safety functions for the type B variables (e.g., ERCW, component cooling system) and (2) the safety-related functions that were not included in the type B set of critical safety functions (e.g., control room habitability, EGTS operation, etc.), they require reliable indications.
1.2.5 Postaccident Monitoring Type E Variables Type E variables are those variables that provide the control room operating staff information to:
1.2.5.1 Monitor the plant areas where access may be required to service equipment necessary to monitor or mitigate the consequences of an accident.
1.2.5.2 Provide information regarding the release of low-level radioactive materials.
1.2.5.3 Estimate the magnitude of unplanned low-level releases of radioactive material from unidentified pathways.
1.3 Design and Qualification Criteria The types A, B, and C variables serve a primary safety function. They are used by the operator to ensure (a) the capability to shut down the reactor and maintain it in a safe shutdown condition, (b) the integrity of the fission product boundaries, and (c) the capability to mitigate the consequences of accidents which could result in potential offsite exposures comparable to the exposure guidelines of 10 CFR Part 100. The type A variables are used for the required operator actions that are needed to give the design basis behavior for the design basis events (accidents). The types B and C variables are used to monitor whether or not the events are following the design basis behavior and to indicate the need for major contingency actions if the event goes beyond the acceptable design basis behavior. Thus, the instrumentation for the types A, B, and C variables needs to be generally safety grade.
The types D and E variables do not serve a primary safety function. They are not needed for ensuring design basis behavior or for major contingency actions. The variables only supply additional information by indicating system operating status, diverse variables, and low-level radiation releases.
The variables can be used to enhance safety by allowing the operator to improve the system operation over the minimum required for design basis behavior, determining what system has failed, etc. The types D and E variables are not essential, and the instrumentation does not need to be safety grade. At the present, no types D or E variable has bs3n identified as category 2'in accordance with the above design basis.
Therefore, in the opinion of TVA there are only two design and qualification criteria, i.e., category 1 and Category 3 (See table 1-2.)
All TVA types A, B, and C variables will meet the intent of category 1 Regulatory Guide 1.97 requirements. All TVA types D and E variables will meet or exceed category 3 Regulatory Guide 1.97 requirements.
The primary differences between the category requirements are in qualification, application of single failure criteria, power supply, and display requirements. Category 1 instrumentation requires seismic and environmental qualification, the application of single failure criteria, power supply, and display requirements.
Category 3 instrumentation does not require single failure criteria or an immediately accessible display and does not always require emergency standby power. We believe this meets the intent of the regulatory guide in that all primary information which is
n -,
supplied by key variables (types A, B, and C) will meet the intent of category 1 requirements while backup, diagnostic, supplemental, and confirmatory information (types D and E) will meet or exceed Regulatory Guide 1.97 category 3 requirements.
1.4 Functional Requirements 1.4.1 Reliable indication of the variables listed (attachment 2) is required at the beginning of an accident and until the plant is in a cold shutdown condition.
Indication of the variables permits the operator to:
1.4.1.1 For type A, take preplanned manual action to accomplish plant cold shutdown.
1.4.1.2 For type B, monitor the process of accomplishing critical safety functions.
1.4.1.3 For type C, determine the potential for causing a gross breach of the barriers to radioactivity release, determine if a breach of a barrier has occurred, and determine the magnitude of high-level radioactive release through identifiable release points.
1.4.2 7.so listed in attachment 2 are type D variables that furnish data regarding the operation of plant safety 2,ystems and other systems important to safety as well as preferred backup variables for types B and C variables.
1.4.3 The re 31ning type E variables in attachment 2 provide information regarding the release of low-level radioactive materials to allow for early indication of the need to initiate action necessary to protect the public and for an estimate of the magnitude of any impending threat.
1.5 Environmental Requirements Currently installed instrumentation will be used even if it is not now environmentally qualified. Eventually, all instrumentation required to monitor the course of an accident will be environmentally qualified in accordance with the pending NRC rule on environmental qualification.
1.6 Specific Instrumentation Requirements 1.6.1 Category 1 1.6.1.1 Existing instrumentation shall be qualified in accordance with the methodology described in NUREG-0588, " Interim Staff Position on Environmental Qualification of Safety-Related Electrical Equipment." The seismic portion of qualification for existing instrumentation shall be in accordance with appendix F of the Sequoyah Naclear Plant Design Criteria Manual.
New instrumentation shall be qualified in accordance with Regulatory Guide 1.89,
" Qualification of Class 1E Equipment for Nuclear Power Plants." Type C instruments shall be qualified in the same manner as other category 1 instrumentation except:
For purposes of equipment qualification, the assumed maximum value of the monitored parameter shall be the value equal to the maximum range for the instrument. The monitored parameters shall be assumed to approach this peak by extrapolating the most severe ramp associated with the design basis accidents. The decay for this parameter shall be considered proportional to the decay for this parameter associated with the design basis accidents. The extended range qualification shall also address any other parameters which must necessarily increase if the measured parameter increases. No additional qualification margin needs to be added to the extended range parameter. All er.vironmental envelopes except that pertaining to the parameter measured by the instrument shall be those associated with the design basis accidents.
1.6.1.2 Qualified continuous indication of one channel shall be provided. Qualification applies from sensor to display where the display is a direct-indicating meter or recording device.
The redundant channel need not necessarily be displayed on a qualified display device, but the channel must be fully qualified from the sensor to a location which is accessible during accident conditions.
1.6.1.3 The instruments designated as category 1 will be specifically identified on the control panels se that the operator can easily discern that they are intended for use under accident conditions.
1.6.1.4 The instrumentation channel should be avr.ilable before an accident except as provided in paragraph 4.11, " Exemption," as defined in IEEE Standard 279 or as specified in technical specifications.
1.6.1.5 See attachatit 1 for the single failure analysis ap9: led to each category 1 variable.
1.6.2 Category 3 1.6.2.1 The instrumentation should be a nigh-quality commercial grade.
1.6.2.2 The instrumentation signal may be displayed on an individual instrument or it may be processed for display on demand by a CRT or by other appropriate means.
1.6.3 The Following Requirements Should Apply to Categories 1 and 3 1.6.3.1 The monitoring instrumentation design should minimize the development of conditions that would cause meters, annunciators, recorders, alarms, etc., to give anomalous indications potentially confusing to the operator. Human factors principles should be used in determining type and location of displays.
1.6.3.2 To the extent practical, monitoring instrumentation inputs should be from sensors that directly measure the desired variables.
1.6.3.3 To the extent practical, the same instruments should be used for accident monitoring as are used for th3 t.ormal operations of the plant to enable the operators to use, during accident situations, instruments with which they are most familiar. However, where the required range of monitoring instrumentation results in a loss of instrumentation sensitivity in the normal operating range, separate instruments should be used.
1.6.3.4 Where direct and immediate trend or transient information is essential for operator information or action, the recording of categories 1 and 3 instrumentation readouts should be continuously available. Otherwise, it may be displayed on an individual instrument or it may be continuously updated, stored in computer memory, and displayed on de mand. Intermittent displays such as data loggers and scanning recorders may be used if
_9_
no significant transient response information is likely to be lost by such devices.
1.7 Electrical Requirements 1.7.1 Category 1 1.7.1.1 Circuits shall be divided into two redundant divisions of separation, PAM1 and PAM2. PAM1 cables shall be routed independently from PAM2 cables and shall be separated in accordance with SQN-DC-V-12.2, Separation on Electrical Equipment and Wiring, except as noted below.
PAM2 cables may be routed in raceways with non-cafety-related cables provided the voltage levels are compatible. Except as noted in paragraph 1.7.1.3, PAM1 cables shall be routed in seismically supported conduit with nothing other than PAM1 cables, thus providing separation such that no single failure in the 4
cables for PAM1 or PAM? devices would cause both indicating systems to fail simultaneously. This separation scheme satisfies the intent of Regulatory Guide 1.97 for the following reasons:
1.7.1.1.1 PAM1 cables are routed in a dedicated conduit system which is seismically supported and contains no other cables.
1.7.1.1.2 PAM2 cables are routed in nonsafety-related raceways which meet the following conditions:
1.7.1.1.2.1 Are seismically supported 1.7.1.1.2.2 Contain cables of similar voltage levels 1.7.1.1.2.3 Contain cables which are subject to the same requirements as class 1E circuits such as cable derating, flame retardance, environmental qualificiation, splicing restrictions, and raceway fill 1.7.1.1.2.4 Contain medium-and low-level signal-and instrument-type cables used to convey in formation.
Medium-level signal cables include instrument control loop cables, digital computer cables, shielded annunciator input cables used with solid-state equipment, and instrument signal cables associated with transmitters, recorders, and indicators other than thermocouples.
Low-level signal cables consist of thermocouple cables, strain gauge cables, vibration detector cables, thermal converter cables, and resistance-type temperature detector signal cables. These type circuits carry a small amount of power.
Instrument control loop and associated instrument signal cables operate in a range of 10-50 MA with power supply voltages up to 85 V do.
The annunciator circuits operate at approximately 1MA, 140 V de intermittent duty. The computer cables operate at 160 MV into a high impedance.
Thermocouples, strain
- gauges, accelerometers, and resistance-type temperature detectors are low excitation voltage devices; these cables operate at 15 volts and carry negligible current.
Conductor heating of these circuits is considered insignificant.
1.7.1.1.2.5 Where routed in cable trays, the trays contain cables whose exposed surfaces are coated with fire-resistant flamemastic in areas outside primary containment containing sa fety-related equipment.
1.7.1.1.2.6 Wh te.' outed in cable t.*a : that are in a t3.. beneath other caf e trays containing clasu 1E cables, the cables will also be protected by a fixed water suppression system.
1.7.1.1.2.7 PAM1 and PAM2 cables from inside primary containment shall be routed through separate electrical penetrations.
1.7.1.2 The control power supply for PAM1 is derived from the 125 V vital battery channel I or channel III. The control power supply for PAM2 to unit 1 is derived from the 125 V vital battery channel II or channel IV.
These control power cables will be separated in accordance with SQN-DC-V-12.2, Separation of Electrical Equipment and Wiring.
1.7.1.3 Cables, for existing instrumentation, routed in trained cable trays will remain in those cable trays.
l 1.7.2 Category 3 1.7.2.1 Circuits shall not be divided into redundant divisions of separations.
1.7.2.2 The instrumentation should be energized from a reliable power source, not necessarily standby i
l l
l l
1 power, and should be backed up by batteries where momentary interruption is not tolerable.
1.8 Mechanical Requirements f
1.8.1 PAM components and their mounts located in seismically qualified buildings shall continue to function following a seismic event.
1.8.2 PAM components and their mounts that are not located in seismically qualified buildings shall be designed to continue to function, to the extent practical, following seismic events. An acceptable method for enhancing the seismic resistance of this instrumentation would be to design it to meet the seismic criteria applicable to like instrumentation installed in scismically qualified locations although a lesser overall qualification results.
2.0 LAYOUT AND ARRANGEMENT
]
2.1 General Description i
2.1.1 The PAM system will consist of two redundant divisions, l
PAM1 and PAM2, for category 1 variables. PAM1 display instruments will be distinguishable from PAM2 category 1 instruments. The two redundant divisions of i
category 1 PAM display instrumentation will also be distinguishable from other display instrumentation available in the main control room.
2.1.2 The PAM system for category 3 variables will consist of at least one channel of display instruments. These I
instruments will not be specifically identified or distinguishable from other instrumentation in the main control room, but these instruments will provide systems status, diagnostic, and backup indications during accident conditions.
2.2 Location PAM display instruments will be located with related system controls and displays as required and where practical will be part of the instrumentation used by the operator. New display instruments used to implement redundancy requirements for category 1 PAM variables will be very similar to existing display instruments.
i 30 TESTS AND INSPECTIONS 3.1 Component and System Testing 3.1.1 Servicing, testing, and calibration programs should be specified to maintain the capability of the monitoring instrumentation. For those inetruments where the required interval between testing will be less than the normal time interval between generating station shutdowns, a capability for testing during power operation should be provided.
3.1.2 Periodic checking, testing, calibration, and calibration verification should be in accordance with the applicable portions of Regulatory Guide 1.118,
" Periodic Testing of Electric Power and Protection Systems," pertaining to testing of instrument channels.
(Note: Response time testing not usually needed.)
32 Inservice Inspection 3.2.1 The instrumentation should be designed to facilitate the recognition, location, replacement, repair, or adjustment of malfunctioning components or modules.
3.2.2 Whenever means for removing channels from service are included in the design, the design should facilitate administrative control of the access to such removal means.
3.2.3 The design should icilitate administrative cor. trol of the access to all setpoint adjustments, module calibration adjustments, and test points.
4.0 QUALITY ASSURANCE The commitments to quality assurance for Sequoyah Nuclear Plant are given in chapter 17 of the Final Safety Analysis Report.
5.0 DEVIATIONS FROM OUTLINED CRITERIA Deviations from the outlined criteria are identified in attachment 2, e.g., references to NUREG and previous NRC submittals are made.
l
.. 6.0 EXCEPTIONS As our design and procurement phases progress, we may identify exceptions we must take in the implementation of Regulatory Guide 1.97 for Sequoyah Nuclear Plant.
TDK:0JZ:REA:JLH 02/24/82 Attachments i
f
Table 1-1 Summary of Selection Criteria Type Category 1 Category 3 A
KEY variables that are used for diagnosis or providing information for necessary operator action.
None.
l B
KEY variables that are used for monitoring the process of accomplishing or maintaining critical safety functions.
None.
C KEY variables that are used for monitoring the potential for breach of a fission product barrier and determining the magnitude of high-level radioactive releases.
None.
D None.
Variables that are used for j
monitoring the performance of j
safety and safety-related systems or provide preferred l
backup diagnostic, confirmatory, or supplemental information concerning performance of plant systems.
E None.
Variables to be monitored which provide information regarding i
the release of low-level radioactive materials and for assessing such releases.
i Table 1-2 Summary of Design, Qualification, and Interface Requirements Qualification Category 1 Category 3 Environmental Yes As Required Seismic Yes As Required Design Single Failure Yes No Power Supply Emergency Standby As Required Channel Out of Service Technical Specifications As Required Testability Yes As Required Interface Minimum Indication Immediately Accessible As Required Recording
'Where direct and immediate trend or transient information is essential for operator action, the recording of categories 1 and 3 inst.rumentation readouts should be continuously available on recorders, f
SINGLE FAILURE ANALYSIS FOR RG 1.97
References:
1.
Regulatory Guide 1.97, Rev. 2 2.
ANSI /ANS 4.5 - 1980 3
ANSI N660/ANS 51.4
Background
The requirement for a channel failure analysis is RG 1.97, Rev. 2, Regulatory Position 1.3.1, paragraph (b). The regulatory guide states, "Where failure of one accident monitoring channel results in information ambiguity (that is, the redundant displays disagree) that could lead operators to defeat or fail to accomplish a required safety function, additional information should be provided to allow the operators to deduce the actual conditions in the plant." The SQN Design Criteria for Postaccident Monitoring will incorporate the requirement for this single failure criteria.
Discussion The requirement involves several aspects. First, the failure of one of the channels must present an ambiguity because redundant channels disagree. Second, the ambiguity must cause the operator to defeat or fail to perform a required safety function. For resolution of the ambiguity, either (1) a separate instrument which provides sufficient information or, (2) a third channel is required.
ANSI N660/ANS 51.4 provides additional information that can be used to evaluate the instruments. It states that three channels of instrumentation are required for operator actions which affect more than one train of safety equipment unless (1) there is a safe course of action for the operator to take if presented with the ambiguity, or (2) appropriately qualified indications of diverse related variables are available to give similar information.
Using the principles from RG 1.97, Rev. 2, and ANSI N660/ANS 52.4, the following criteria were used to evaluate the parameters.
Criterion 1: Does the failed instrument cause the redundant PAM instruments to present an ambiguous reading to the operator?
Even if the answer to this criterion is "no," criterion 2 should also be checked. This will provide a check of the acceptability of using only one channel monitoring a particular variable.
Criterion 2: Can the ambiguous (or incorrect) information cause the operator to defeat or fail to perform a required safety function?
. Criterion 3: Are there any other equivalently qualified inatruments (i.e., diverse variables) that can resolve the ambiguity?
Criterion 4: If there is no presently qualified diverse variable, either add a third channel or qualify a diverse variable that can resolve the ambiguity.
The four criteria were used to evaluate each variable for the -sfrects of a single failure.
All of the types A, B, and C variables were evaluated.
TDK:0JZ:REA:JLH 02/24/82 1
a i
_.~,
m PARAMETER LIST VARIABLE: ACS Pressure TYPE:
A,B,C CATEGORY:
1 NUMBER:
3 DIVERSE VARIABLE: Not required due to adequate redundancy; however, pressurizer pressure can provide diverse indication for 1,700-2,500 psig.
RANGE: 0 to 3,000 psig UTILIZATION: Determine if plant is in safe shutdown condition.
Maintain proper relationship between RCS pressure and temperature.
Verify vessel NDT criteria.
Maintain primary inventory subcooled (particularly with loss of offsite power).
Establish correct conditions for RHR operation.
Determine whether ECP operation should be continued.
Determine whether high-head SI should be terminated or reinitiated.
COMMENTS: A dedicated recorder will be provided for the PAM1 channel.
=
1 VARIABLE: RCS Hot Leg Temperatura TYPE:
A,B,C,D CATEGORY:
1 NUMBER:
1 each loop plus diverse variable DIVERSE VARIABLE: The variable being monitored is coolant temperature at the core exit. Sixteen core exit thermocouples in two trains (8/ train) will provide diverse indication (see comment 2).
RANGE: 0 to 700oF UTILIZATION: Maintain adequate reactor heat sink.
Maintain the proper relationship between RCS pressure and temperature.
Verify vessel NDT criteria.
Maintain primary inventory subcooled (particularly with loss of offsite power).
Establish correct conditions for RHR operation.
Monitor RCS heatup and cooldown rates.
Determine if plant is in a safe shutdown condition.
Determine whether SI should be terminated.
Determine core differential temperature during natural circulation.
COMMENTS:
1.
The RCS temperature instrumentation will be upgraded as follows:
a.
Presently all Thot loops are associated with protection channel I and all Toold loops are associated with protection channel II.
Appropriate electrical cables will be rerouted such that two RCS loops' That and Tcold parameters are protection channel I and the remaining two loops are protection channel II.
b.
Temperature recorder configurations will be revised such that a Thot and a Teold channel are displayed on the associated recorder for each RCS loop (human factors considerations for determining loop differential temperatures).
. c.
Isolators will be added to each of the four loops for dedicated recorders.
2.
The maximum temperature the RCS will reaun during short transients, including ATWS transients, is below 7000F.
Any temperature above the maximum expected temperature would be a measure of inadequate core cooling. The core exit thermocouples are the primary indication for ir. adequate core cooling; this thermocouple system will meet the criteria outlined in TVA's response to NUREG-0737, II.F.2, attachment 1, and NUREG-0578, 2.1.3(b).
_4 VARIABLE: RCS Cold Leg Temperature 4
TYPE:
A,B,C,D CATEGORY:
1 NUMBER:
1 h loop DIVERSE VARIABLE: For determination of natural circulation, 2 channels of steamline pressure per loop provide diverse indication.
1 RANGE: 0 to 7000F i
UTILIZATION: Determine differential temperature under natural circulation conditions in conjunction with T hot-Maintain the proper relationship between RCS temperature and pressure.
1 Maintain primary inventory subcooled.
COMMENTS: See comments for RCS Hot Leg Temperature.
4 b
-.. )
VARIABLE: Pressurizer Level TYPE:
A, D CATEGORY:
1 NUMBER:
3 DIVERSE VARIABLE: Not required due to adequate redundancy.
RANGE: 0 to 100 percent UTILIZATION:
Confirm if plant is in a safe shutdown condition.
Monitor RCS inventory.
Maintain pressurizer water level.
3 Determine whether SI should be terminated or reinitiated.
COMMENTS: Rack will be wired to provide a dedicated indicator in order to meet category 1 reciuirements.
l i
r J
4
,,. _., _ ~
r--m
--r.
~. VARIABLE: Primary Reactor Containmer.t Pressure, Narrow Range (NR)
TYPE:
A,B,C,D CATEGORY:
1 NUMBER: 4 DIVERSE VARIABLE: Not required due to adequate redundancy.
RANGE:
-1 to 15 psig UTILIZATION: Determine if break is inside or outside containment.
Monitor containment conditions following a break inside containment.
Verify if accident is properly controlled.
Determine actual containment breach.
COMMENTS: TVA will add an isolator to meet category 1 requirements.
e i
._ VARIABLE: Steamline Pressure TYPE:
A,B,D CATEGORY:
1 NUMBER: 3 each loop DIVERSE VARIABLE: Not required due to adequate redundancy.
RANGE: 0 to 1,200 psig UTILIZATION: Determine if high energy secondary line rupture occurred.
Maintain an adequate reactor heat sink.
Verify AFW to steam generator associated with pipe rupture is isolated.
Monitor secondary side pressure to:
(1) verify operation of pressure control steam dump system, (2) maintain plant in safe shutdown condition, and (3) monitor RCS cooldown rate.
Diverse to Teold for natural circulation determination.
Identification of SG tube rupture.
Determination that faulted SG is isolated.
COMMENTS:
1.
'An isolator will be added to one channel per loop to meet category I requirements.
2.
The range required by Regulatory Guide 1.97 is 0 to 1,277 psig. This is slightly greater than the O to 1,200 psig listed above, but the difference is small and the lower range can provide the required information.
~.. -.
8-VARIABLE: RWST Level TYPE:
A, D CATEGORY:
1 NUMBER: 4 DIVERSE VARIABLE: Not required due to adequate recundancy.
l RANGE: 0 to 100 percent UTILIZATION:
Verify water source to ECCS and containment spray system.
Determine time for initiation of cold leg recirculation following a LOCA.
Event diagnosis (i.e., steam generator tube rupture).
COMMENTS: An isolator will be added to one channel to meet category 1 requirements.
l i
1 4
i I
4 l
3 1
=
,,e e--e
,%..w
,-m-.-.
y
-v
-g-VARIABLE: Containment Water Level, Wide Range (WR)
TYPE:
A, C CATEGORY: See comment 1 NUMBER: 4 DIVERSE VARIABLE: Not required due to adequate redundancy.
RANGE: 0 to 20 feet (See comment 3)
UTILIZATION: Verify water source for recirculation mode cooling.
Determine whether high energy line rupture has occurred inside cr outside containment.
Determine potential for containment breach caused by very high water levels.
COMMENTS:
1.
This system will meet the criteria outlined in TVA's response to NUREG-0737, II.F.1, attachment 5, and NUREG-0578, 2.1.9(c).
2.
Cable routing for one loop will be upgraded.
3.
If 600,000 gallons of water were introduced into containment in addition to the fluid volume of the reactor coolant system, safety injection accumulators, and a total ice melt, the containment water level would not exceed 20 feet.
VARIABLE: Aux FW Flow TYPE:
A, D CATEGORY: See comments NUMBER:
1 each loop DIVERSE VARIABLE: Narrow-range and wide-range steam generator level.
RANGE: 0 to 440 gpm UTILIZATION: Determine if sufficient flott exists to maintain heat sink.
SI termination.
COMMENTS: This system will meet the criteria outlined in TVA's response to NUREG-0737, II.E.1.2, and NUREG-0578, 2.1.7(b).
- VARIABLE: RCS Subcooling TYPE:
A, D CATEGORY: See comments NUMBER:
1 each unit DIVERSE VARIABLE: RCS pressure and temperature can be used in conjunction with ASME steam tables to determine subcooling.
RANGE: 2000F subcooled to 350F superheat UTILIZATION: SI termination or reinitiation.
Maintenance of subcooling during depressurization.
COMMENTS: This system will meet the criteria outlined in TVA's response to NUREG-0737, II.F.2, and NUREG-0578,
.1 3(b).
i P
y
= = - - -
-'--'e-
- ' - - ~ * " " * - - - ' ' * - - *
" ~
i VARIABLE: Neutron Flux, Source Range TYPE:
A, B CATEGORY:
1 NUMBER: 2 DIVERSE VARIABLE: Not required since the failure of ene channel will not cause the operator to violate the required safety function.
RANGE:
1 to 106 CPS UTILIZATION:
KEY variable for monitoring reactivity control.
Determine if plant is in a suboritical condition.
Diagnose positive reactivity insertion.
COMMENTS: This is the preferred variable for monitoring reactivity control after flux is below the intermediate detectors' range.
. VARIABLE:
Containment 11 Concentration 2
TYPE:
A,B,C CATEGORY:
1 NUMBER: 2 DIVERSE VARIABLE: Postaccident sampling can provide diverse indication (see "Postaccident Sampling," a type E variable in this report).
RANGE: 0 to 10 percent UTILIZATION:
Controlling the H2 ecombiners.
r Monitering H2 levels to indicate possibility of explosion.
COMMENTS: This system will meet the criteria outlined in TVA's response to NUREG-0737, II.F.1, attachment 6, and NUREG-0578, 2.1.9(b).
TVA has glow plugs installed in the containment by way of our licensing commitment. Worst-case studies (well beyond DBA) indicate that the H2 concentration will not exceed 8 percent with the glow plugs in service.
1 I
f I
t
VARIABLE: High-Head Injection Pump Running TYPE: A t
CATEGORY:
1 3
NUMBER:
1 each pump DIVERSE VARIABLE: Safety injection flow indication provides diverse indication that the high-head pumps are running. In addition, since there are two pump trains, failure of one indicator would not preclude indication that safety injection is proceeding.
RANGE: Running /Not running UTILIZATION:
Determine that SI is proceeding.
Determine whether RCPs can be tripped.
COMMENTS: No upgrading required.
l 4
i i
i
)
i 1 VARIABLE: Containment Sump Isolation Valves' Position Indicator 2
TYPE: A CATEGORY:
1 NUMBER:
1 each valve DIVERSE VARIABLE: Not required (see comments).
i RANGE: Open/ Closed 3
UTILIZATION: Verification of proper system alignment.
t COMMENTS: Since these are redundant valves, a single indication on each valve is sufficient to satisfy the single failure criteria (i.e., unambiguous indication).
4 4
i A
i i
l j
A i
i i
l 4
s 1
-. - - ~...,,, _..
- -. - ~ -
VARIABLE: Secondary System Radiation TYPE: A CATEGORY:
1 The purpose of this variable is to identify SG tube ruptures including determination of the faulted loop. This must be accomplished in an unambiguous single-failure-proof manner. In order to do this, TVA has several options available:
Condenser Steamline SG Blowdown Exhaust Radiation Radiation Radiation SG Level Option Monitor Monitor Monitor (NR)
A Not required 1 each plant 1 each plant 1 each loop (The SG blowdown radiation monitor and the SG level must be on separate trains.)
B 2 each loop Not required 1 each plant Not required C
1 each loop 1 each plant 1 each plant Not required (The SG blowdown and steamline instruments must be on separate trains.)~
TVA will use option A; however, if a suitable steamline radiation monitor is deve' loped, options B and C may be considered.
The individual parameters are discussed on following pages.
4
i VARIABLE: Steam Generator Blowdown Radiation TYPE: A CATEGORY:
1 NUMBER: 2 DIVERSE VARIABLE: This variable is used to aid in determining the occurrence of SG tube rupture. Condenser exhaust radiation monitor and SG narrow range level provide diverse indication.
RANGE:
1.5 x 10-6 pCi/cc to 1.4 x 10-2 pCi/cc (I-131) 1 UTILIZATION: Determine occurrence of SG tube rupture.
COMMENTS: The main steam radiation monitor may be developed or this paramater may be upgraded.
i 1
l
..-sc y-
., ~ -. -
.. -.., _ ~ _.
w VARIABLE: Main Steamline Radiation TYPE: A CATEGORY:
1 Since an instrument is not now available to perform this function, TVA is not committing to this variable. As instruments become available, TVA will evaluate cach and determine if installation is justified.
The purpose of this variable is to detect SG tube rupture. This will be accomplished as described under " Secondary System Radiation" in this report.
VARIABLE: Steam Generator Level, NR TYPE:
A, B CATEGORY:
1 NUMBER: 3 each steam generator DIVERSE VARIABLE: Not required because of adequate redundancy.
RANGE: 0 to 100 percent (taps located above tube bundle and up into separators, actual range is temperature dependent)
UTILIZATION: Monitor heat sink.
Maintain steam generator water level.
Determine whether SI should be terminated.
Determine which loop has SG tube rupture.
COMMENTS: An isolator will be added to one loop each steam generator to meet category I requirements.
I I
r
~-' VARIABLE: Effluent Radioactivity - Noble Gas in Condenser Air Exhaust TYPE: A CATEGORY:
1 NUMBER: Design not completed and the number is a function of the design DIVERSE VARIABLE: Steam generator blowdown radiation.
RANGE: Not finalized yet (design not completed)
UTILIZATION: Determine occurrence of SG tube rupture.
Determine success of SG isolation after tube rupture.
COMMENTS: This instrument is in the turbine building which is not a seismic structure; upgrading will be to the extent practicable under that condition.
VARIABLE:
Containment Area Radiation TYPE:
A,C,D,E CATEGORY: See comments NUMBER: 4 DIVERSE VARIABLE: Not required due to adequate redundancy.
RANGE:
10 to 107 R/hr (see comments)
UTILIZATION: Accident diagnosis; SI Termination /Reinitiation.
COMMENTS: This system will meet the criteria outlined in TVA's responses to NUBEG-0737, II.F.1, attachment 3, and NUREC-05J8, 2.1.8(b).
1 l
1
+--s er-r VARIABLE: Reactor Vessel Level TYPE: B CATEGORY:
1 TVA and Westinghouse Electric Corporation were involved with the original design of the reactor vessel water level indicating systems.
In the course of this work, TVA expressed several concerns about the system. NRC has recently expressed similar concerns. TVA will continue to review the system design and evaluate the capability of the system to resolve the concerns with the intent of ensuring that the system will provide useful and correct information for operator action.
This will be a preferred variable for monitoring the approach to inadequate core cooling (in conjunction with core exit thermocouples) pending resolution of the outstanding concerns.
i !
VARIABLE:
Containment Isolation Valves Position TYPE: B l
CATEGORY:
1 NUMBER:
1 each valve i
j DIVERSE VARIABLE: The variable being monitored is containment isolation. Since there are two valves in series, a I
single indication on each valve is sufficient to I
satisfy the single failure criteria (i.e.,
j unambiguous indication of isolation).
i RANGE: Closed /Not closed i
UTILIZATION: Verification of containment isolation.
l COMMENIS: The containment isolation valve indicating lights presently located on panel M-9 are pcwered from nondivisional supplies, j
routed in nondivisional cable trays, and therefore do not i
meet the requirements for postaccident monitoring. This j
system will be upgraded to provide a qualified indication for l
these valves.
The handswitches and associated indicating lights for several valves, which are presently located on local control l
stations, will be relocated in the main control room.
I l
'I 1
1 1
1 1
j
1
- VARIABLE
- Neutron Flux, Intermediate Range l
TYPE: B i
i CAT 9 GORY:
1 NUMBER: 2 l
1 1
DIVERSE VARIABLE: Not required sinde the failure of one channel will i
not cause the operator to violate the 3 quired safety function.
I l
RANGE:
10-11 to 10-3 Amps I
{
UTILIZATION: KEY variable for monitoring reactivity control.
I Determine if plant is suboritical.
1 Diagnose positive reactivity insertion.
I COMMENTS: This is the preferred variable for monitoring reactivity during the initial stages of an event.
6 i
i i
i i
i l
l t
i I
l l
, VARIABLE:
Core Exit Temperature TYPE:
B, C CATEGORY:
1 NUMBER: 2 trains, 8 T/Cs each train, 1 reference junction each train DIVERSE VARIABLE: Wide Range RCS Thot (1 each loop)
RANGE: 200 to 2,3000F (primary indication), O to 2,0000F (backup)
UTILIZATION: Verify that core is being adequately cooled.
Verify that RCS remains subcooled.
Monitoring the potential for fuel clad breach.
COMMENTS:
1.
The selection criteria for these thermocouples (T/Cs) contains 3 primary considerations:
(a) must satisfy separation requirements, (b) must have centrally-located T/Cs for detection of inadequate core cooling and monitoring the potential for fuel clad breach, and (c) must have equally distributed T/Cs for verification of adequate natural circulation.
2.
The present T/C connectors are not reliable with respect to the effects of thermal expansion and stresses. As more reliable types are developed, TVA will evaluate them and determine if replacement is justified.
3 This system will meet the criteria outlined in TVA's response to NUREG-0737, II.F.2, attachment 1, and NUREG-0578, 2.1.3(b).
4.
See our November 6,1981, submittal to Ms. E. Adensam for T/C cable routing specifications as well as other exceptions to the requirements of Regulatory Guide 1.97.
__ - - _ - ~.-..__
4 6 VARIABLE: Containment Pressure, WR TYPE: C CATEGORY: See comments NUMBER: 2 DIVERSE VARIABLE: The only credible failure modes of the wide-range indicators are off-scale high and off-scale low; therefore, single failure does not cause ambiguity.
In addition, at lower pressures, narrow-range containment pressure provides diverse indication.
RAIGE: 0 to 60 psia I
1 UTILIZATION: Determination of potential for containment breach.
COMMENTS: This system will meet the criteria outlined in TV?t's response i
to NUREG-0737, II.F.1, attachment 4, and NUREG-0576, i
2.1.9(a). Two pressure transmitters will be replaced with environmentally qualified instruments.
I i
t i
i
)
l i
2
'l e-w - wr=
- - - ' ~ -- - - - - - ' + ~~
'+-r-P-
-wi 7
ri--e
=
w --r we-
--err
=mr-*----
w-rw---
~
- 7 j
VARIABLE: Primary Coolant Radiation Level TYPE: C I
1 CATEGORY:
1 NUMBER: See comments DIVERSE VARIABLE: Manual sampling (see comments).
l RANGE: See comments i
UTILIZATION: Determination of clad failure.
i COMMENTS: Since an instrument for this function is not presently available, TVA is not committing to this requirement. As 4
instruments become available, TVA will evaluate them on a case-by-case basis and datermine if installation is l
justified.
1 l
The postaccident sampling system will be used to meet the intent of the RG for this parameter.
4 5
i i
I i
t
,-y,r,
,,,rm-._m---
r,-,-,
VARIABLE: ABGTS Exhaust Radiation Monitor TYPE: C CATEGORY:
1 NUMBER: See comments DIVERSE VARIABLE: See comments.
RANGE: See comments UTILIZATION: Release assessment.
COMMENTS: This variable is monitored by the shield building vent radiation monitor.
1
.29-VARIABLE: Annulus Vent Radiction TYPE: C CATEGORY:
1 NUMBER: See comments DIVERSE VARIABLE: See comments.
RANGE: See comments UTILIZATION: Release assessment.
COMMENTS: This variable is' monitored by the shield building vent radiation monitor.
VARIABLE: ERCW Radiatict. Monitor TYPE: C CATEGORY:
1 NUMBER: 4 DIVERSE VARIABLE. Not required due to adequate redundancy.
RANGE:
1.5 x 10-6 to 2.4 x 10-2 pCi (I-131)
CC UTILIZATION: Monitor for radiation releases through the ERCW system.
COMMENTS: No upgrade required.
VARIABLE:
Containment Effluent Radioactivity - Noble Gases from Identified Release Points TYPE:
C, E CATEGORY: See comments NUMBER: See comments DIVERSE VARIABLE: See commenta.
RANGE: See comments UTILIZATION: Determination of magnitude of release.
COMMENTS: This system (radiation monitor on shield building vent. will meet the criteria outlined in TVA's response to NUREG-0737, II.F.1, attachment 1, and NUREG-0578, 2.1.8(b).
It is possible that at the time of implementation, technical deviations may be requested to facilitate compromises between different criteria. For example, the location of sample collection equipment to reduce radiation exposure of employees during sample removal, transport, and analysis may require sample line lengths that would not meet the criteria for representative or isokinetic sampling.
)
. VARIABLE: Steam Generator Level, WR TYPE: D CATEGORY:
3 NUMBER:
1 each steam generator l
RANGE: 0 to 100 percent (taps located just above tube sheet and up into separators, actual range is temperature dependent) 4 r
UTILIZATION: Determine if heat sink is being maintained.
SI termination for secondary break outside containment.
COMMENTS: Wide-range level is a preferred backup variable for auxiliary feedwater flow and narrow-range level in the termination of safety injection and the determination of adequate secondary heat sink.
i
-,,,--.-.-..,n..
VARIABLE: RCS Boron Concentration TYPE: D CATEGORY: 3 NUMBER: See comments RANGE: See comments UTILIZATION: Backup variable for monitoring reactivity control.
COMMENTS: This variable will be measured by manual sample analysis by way of the postaccident sampling facility.
I l
I
T VARIABLE:
Containment Water Level, NR TYPE: D CATEGORY: 3 NUMBER: 2 RANGE: 0 to 64 inches (Containment Floor and Equipment Drain Sump) o to 37 inches (Pocket Sump)
UTILIZATION: Backup determination of leaks inside containment.
COMMENTS: No upgrade required.
t 4 VARIABLE: RRR System Flow TYPE: D CATEGORY:
3 NUMBER: 2/ train RANGE: 0 to 1,500 gpm 1,500 to 5,500 gpm UTILIZATION: Verification of proper system operation.
Backup indication of adequate core cooling.
COMMENTS: This is a backup variable for monitoring core cooling. If it j,
is impractical to qualify the preferred instrumentation, this may be upgraded to type B, category 1.
Otherwise, no upgrade required.
l 5
4 i
1 M
l 4
i I
r.--..
_,_r
,_._,_x.,.,..
c, y,
,,m,.. _,
s VARIABLE:
RHR Heat Exchanger Inlet / Outlet Temp TYPE: D CATEGORY: 3 NUMBER:
1 inlet and 1 outlet each train RANGE: 50 to 4000F UTILIZATION:
Verification of effective heat removal.
COMMENTS: Tin also used to monitor containment sump temperature when suction is taken from there.
l l q VARIABLE: Accumulator Tank Level TYPE:
D' CATEGORY: 3 NUMBER: 2 each tank r
i RANGE: Top 20 inches (see Comments)
UTILIZATION: Verification of adequate emergency cooling capability.
COMMENTS: The presently installed level range covers about 20 inches at the top of the tank. This narrow range is required to obtain 1
the accuracy needed to meet technical specification conditions. This parameter in conjunction with accumulator tank pressure is adequate to tell if the accumulators have performed their function.
l i.
~
1
.i i
i
+
I i
. 1 VARIABLE: Accumulator Tank Pressure TYPE: D i
CATEGORY:
3' 2
NUMBER: 2 each tank RANGE: 0 to 700 psig UTILIZATION: Verification of adequate emergency cooling capability.
COMMENTS: No upgrade required. Sequoyah's cold leg accumulators are maintained between 385 and 447 psig. Therefore, 700 psig is well above the maximum expected pressure.
i 1
J I
1 1
J
}
(
l i
a l
l i
4..
. VARIABLE: Accumulator Isolation Valve Position TYPE: D CATEGORY: 3 NUMBER:
1 set of indicator lights each valve RANGE: Open/ Closed UTILIZATION:
Verification o' proper system operation.
C0! PINTS:
No upgrade required.
, VARIABLE: Boron Injection Flow TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 100 percent UTILIZATION:
Verification of proper system operation.
Backup variable for reactivity control.
COMMENTS: If it is impractical to qualify the NIS, this variable may be upgraded to type B, category I.
Otherwise, no upgrade required.
t I
t l
r
, VARIABLE: HPI System Flow TYPE: D CATEGORY:
3 NUMBER:
1 each SIS pump, 1 for flow from both CCP's RANCE: 0-to 1,000 gpm (comment 1), O to 800 gpm (comment 2)
UTILIZATION: Verification of proper system operation.
Backup indication of adequate core cooling.
COMMENTS:
1.
Centrifugal Charging Pump Flow--No upgrade required.
2.
Safety Injection Pump Flow--No upgrade required.
3 These indications are backup variables for. monitoring core cooling. If it is impractical to qualify the preferred variables, these may be upgraded to type B, category I.
. VARIABLE: Reactor Coolant Pump Status TYPE: D CATEGORY: 3 NUMBER:
1 each pump RANGE: 0 to 110-percent current (0 to 800 ao amps)
UTILIZATION: Verification of pump operation.
COMMENTS: No upgrade required.
, VARIABLE: PRZR PORY Position TYPE:
D CATEGORY: 3 NUMBER:
1 set of indicating lights each valve, 1 acoustic monitor each valve RANGE: Open/ Closed UTILIZATION: Veritication of proper system operation.
Maintenance of RCS integrity.
COMMENTS: Acoustio monitors and status lights on MCR handswitches. No upgrade required.
- -... _ _ _ _ _ VARIABLE:
PRZR Safety Relier Valve Position TYPE: D CATEGORY:
3 NUMBER:
1 each valve RANGE: Close/Not closed UTILIZATION:
Maintenance of RCS integrity.
Verification of proper system operation.
COMMENTS: Acoustic monitors used.
No upgrade required.
VARIABLE: PRZR Heater Status TYPE: D CATEGORY: 3 NUMBER:
1 each heater group RANGE: On/Off UTILIZATION: Verification of proper system operation.
COMMENTS: Status lights on MCR handswitches. No upgrade required.
VARIABLE: PRZR Relier Tank Temperature 1
TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 500 to 3000F UTILIZATION:
Verification of proper system operation.
COMMENTS: No upgrade required.
14 7 -
VARIABLE: PRZR Relier Tank Level TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 100 inches UTILIZATION:
Verification of proper system operation.
COMMENTS: No upgrade required.
.a
-__ VARIABLE:
PRZR Relier Tank Pressure TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 100 psig UTILIZATION:
Verification of proper system operation.
COMMENTS: No upgrade required.
e
, VARIABLE: Emergency Boration Flow TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 150 gpm UTILIZATION: Monitoring of boron injection during emergency boration.
COMMENTS: No upgrade required.
t h
4 VARIABLE: Hsin Steam Flow TYPE: D CATEGORY: 3 NU!GER: 2 each loop RANGE: 0 to 4.5 x 106 PPH UTILIZATION: Monitoring system operation COMMENTS: No upgrade required.
A VARIABLE: Main Feedwater Flow TYPE: D CATEGORY: 3 NUMBER: 2 each loop RANGE: 0 to 4.5 x 106 ppg UTILIZATION:
Monitoring system operation COM:iENTS: No upgrade required.
VARIABLE:
Condensate Tank Level TYPE: D CATEGORY: 3 NUMBER:
1 each tank RANGE: 0 to 32 feet UTILIZATION: Verification of adequate condensate.
COMMENTS: This indication is not required to be' catagory I because the CST is automatically backed up by the safety-grade ERCW header supply. The ERCW has four supplies to the AFW suction. No upgrade required.
1 VARIABLE: Containment Spray Flow TYPE: D CATEGORY: 3 NUMBER:
1 each pump RANGE: 0 to 6,000 gpm UTILIZATION: Verification of proper system operation.
COMMENTS: No upgrade required.
- VARIABLE
- Heat Removal by Containment Fan System TYPE: Not required CATEGORY: Not required
)
NUMBER: See comments RANGE: See comments UTILIZATION:
See comments.
COMMENTS: For Sequoyah Nuclear Plant, the containment fan heat removal system is not required to remove heat during accidents when heat removal is a critical function--the fans isolate on phase B containment isolation. Instead, Sequoyah has an ice a
condenser system to perform the heat removal function.
1 f
4 4
+
)
l
+
- - - VARIABLE: Containment Atmosphere Temperature TYPE: D CATEGORY: 3 NUMBER:
16 computer-monitored, 18 backup RANGE: 40 to 4000F UTILIZATION: Maintenance of containment integrity.
COMMENTS: No upgrade required.
VARIABLE:
Containment Sump Water Temperature TYPE: D CATEGORY: 3 NUMBER: See comments RANGE: 50 to 4000F UTILIZATION: See comments.
COMMENTS: This information is useful during a LOCA when it provides a measure of heat removal from the circulating water. The RHR heat exchanger inlet temperature will provide this information under LOCA conditions.
, VARIABLE: ERCW to Auxiliary Feedwater System Valve Position TYPE: D CATEGORY: 3 NUMBER:
1 each valve RANGE: Open/ Closed UTILIZATION: Verification of heat sink availability.
COMMENTS: No upgrade required VARIABLE: Makeup Flow TYPE: D CATEGORY:
3 NUMBER:
1 RANGE: 0 to 200 gpre UTILIZATION:
Verifica. ion of proper system operation.
COMMENTS: TVA will monLtor this parameter with charging header flow.
No upgrade required.
VARIABLE: Letdown Flow TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 110 percent (0 to 200 gpm)
UTILIZATION: Verification of proper system operation.
COMMENTS: No upgrade required.
O VARIABLE: Volume Control Tank Level TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 70 inches UTILIZATION: Verification of proper system operation.
COMMENTS: No upgrade required.
9
~
] i t
. VARIABLE:
Component Cooling Water Flow to ESP System TYPE: D CATEGORY:
3 2
NUMBER:
1 each train RANGE: 0 to 13,000 gpm UTILIZATION: Y3rification of coolant supply to ESF components.
l COMMENTS: TVA will use CCW heat exchanger flow which includes the flow to some non-ESF equipment. This indication will still provide the required information.
i l
f i
1
3 i 1
VARIABLE: Component Cooling Water Temperature to ESF System TYPE: D CATEGORY: 3 NUMBER:
1 each train, 3 trains J
RANGE: 50 to 1500F UTILIZATION: Verification of heat sink for ESF components.
COMMENTS: This is a noncategory I parameter, and there is no technical basis for increasing the present range. No upgrade required.
c.
i 1
i 1
4 4
i
' l
.,,, - -. ~ _. - - -.,-
7
- _ -. - -. = -
,m_-
- l
VARIABLE: Tritiated Drain Collector Tank Level (High-Level Radioactive Liquid Tank)
TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: 0 to 122 inches 1
UTILIZATION: Monitoring liquid wastes.
COMMENTS: No upgrade required.
e
3,
VARIABLE: Waste Gas Decay Tank Pressure (Gas Holdup Tank)
TYPE: D CATEGORY: 3 NUMBER:
1 each tank RANGE: 0 to 150 psig UTILIZATION: Monitoring gaseous wastes.
COMMENTS: This tank has relief valves which will prevent the pressure from exceeding the design pressure. Thus, there is no reason to increase the instrument range. No upgrade required.
e
.~,
i a
VARIABLE: Emergency Ventilation Damper Position 1
I TYPE: D CATEGORY: 3 i
. NUMBER:
1 each major damper
- l RANGE: Open/ Closed UTILIZATION: Verification of proper system alignment.
COMMENTS: No upgrade required; indication provided for major dampers, i.
?
i I
i 1
1 e
i d
k i
j i
i j
l T
i enn c---
-~..,-e,e---
,n,.-
.-,,,. ~,, -- - - - - -,, - - - - - - --
-w, r---
VARIABLE: Diesel Power Status TYPE: D CATEGORY: 3 NUMBER:
1 each diesel generator RANGE: 0 to 110-percent design output (0 to 7.2MW ac)
UTILIZATION:
Verification of diesel power.
COMMENTS: Diesel watt meter. No upgrade required.
(.
4 i VARIABLE: Status of Energy Sources Important to Safety j
Tr?E: D CATEGORY: 3 NUMBER: See comments RANGE: See comments UTILIZATION: Monitoring power status.
COMMENTS: Voltages and ammeters are provided in the MCR for all 6,900V boards and voltmeters for 480V boards. Ammeters are provided locally on 480V boards. No upgrade required.
Essential air header pressure, diesel generator fuel oil day tank le'rel, and starting air pressure are alarmed in the MCR i'
to indicate abnormal operation. Local indication is provided for analysis of problems. No upgrade required.
4 1
I l
l l
. VAv.IABLE: UHI Accumulator Tank Pressure TYPE: D CATEGORY:
3 NUMBER: 2 (surge tank pressure)
RANGE: 0 to 2,000 psig UTILIZATION: Monitoring systam status.
COMMENTS: No upgrade required.
VARIABLE: UHI Isolation Valve Position TYPE: D CATEGORY:
3 NUMBER:
1 each valve RANGE: Open/ Closed UTILIZATION:
Verification of proper system performance.
COMMENTS: No upgrade required.
. VARIABLE: UHI Surge Tank Level TYPE: D CATEGORY:
3 NUMBER: 2 RANGE: 0 to 19 inches UTILIZATION: Monitoring system status.
C0!NENTS: No upgrade required.
VARIABLE: Air Return Fans Status TYPE: D CATEGORY: 3 NUMBER:
1 each ran RANGE: Running /Not running UTILIZATION:
Verification of system operation.
COMMENTS: No upgrade required.
. ' VARIABLE:
Control Rod Position TYPE: D CATEGORY: 3 NUMBER:
1 each rod RANGE: Full in or not full in UTILIZATION: Backt p variable for monitoring reactivity control.
COMMENTS:
Individual control rod bottom lights. If it is impractical to qualify the NIS, this variable may be upgraded to type B, category I.
Otherwise, no upgrade required.
I
{
1 I
i 1
i l
.I 1
VARIABLE: Hydrogen Igniters Operating TYPE: D CATEGORY: 3 NUMBER:
1 each train RANGE: On/Off UTILIZATION:
Determination of system operation COMMENTS: Alarm lights in MCR will be provided.
VARIABLE: Hydrogen Recombiners Operating TYPE: D CATEGORY:
3 NUMBER:
1 each recombiner RANGE: On/Off TILIZATION:
Verify system operation.
COMMENTS: No upgrade required.
P,
VARIABLE: MCR Pressure TYPE: D CATEGORY:
3 NUMBER: 2 RANGE: 0 to 1/2-inch water column
)'
UTILIZATION: Maintenance of MCR habitability.
COMMENTS: No upgrade required.
d JP*
f
/
6 '
' VARIABLE: Auxiliary Building Pressure TYPE: D
- CATEGORY: 3 l
NUMBER: 2 l
j
?
RANGE: 0 to 1/2-inch water column UTILI7ATION: Monitoring ABGTS operation.
t t
' COMMENTS: No upgrade required.
l
- a I
v.
E 0
F V
['
9 w
w*
. ?.c l
l
~
1 J
9 4
J i
1
-/
/
e p
. VARIABLE: Annulus Pressure TYPE: D OATEGORY:
3 NUMBER: 2 RANGE: 0 to 10-inches water column ( Annt:1us/ Atmosphere differential pressure)
UTILIZATION: Determination of potential for breach.
COMMENTS: No upgrade required.
4
.&.i.
a - -+--- VARIABLE: ERCW Supply Temperature TYPE: D CATEGORY: 3 NUMBER:
1 RANGE: Up to 1200F UTIL^f 2ATIO!!:
Verification of heat sink for components.
COMMENTS: No upgrade required.
s
. VAHIABLE: Containment Spray Inlet Temperature TYPE: D CATEGORY: 3 NUMBER:
1 each train RANGE: 50 to 14000F UTILIZATION:
Verification of heat sink.
COMMENT 3: No upgrade required. Measurement provided by RHR inlet temperature since water supply to containment spray and RHR is always the same source.
)
VARIABLE: ERCW Header Flow TYPE: D CATEGORY: 3 NUMBER: 2 (1 each header)
RANGE: 0 to 20,000 gpm UTILIZATION: Verification of coolant flow.
COMMENTS: No upgrade regt. ired.
VARIABLE: AFW Pump Steam Supply Valves Position Indication TYPE: D CATEGORY: 3 NUMBER:
1 each valve RANGE: Open/ Closed UTILIZATION: Verification of steam supply to turbine-driven AFP.
C0!C4ENTS: No upgrade required.
___ VARIABLE: Position Indication for the Following Valves:
TYPE: D CATEGORY: 3 NUMBER:
1 each valve Valve Number Indication Utilization Comments MSIV 1/ loop Open/ Closed Verification No upgrade of proper required alignment MSIV Bypass 1/ loop Open/ Closed Verification No upgrade of proper required alignment SG Blowdown 1/ loop Open/ Closed Verification No upgrade Isclation of proper required alignment PRZR Block 1/ valve Open/ Closed Verification No upgrade (2 vlvs) of proper required alignment PRZR Normal Spray 1/ valve Closed /Not Closed Verification No upgrade (2 vlvs) of proper required alignment PRZR Auxiliary 1/ valve Open/ Closed Verification No upgrade Spray of proper required l
alignment RHR Hot Leg 1/ valve Open/ Closed Verification No upgrade l
Letdown Isolation of proper required alignment CVCS Letdown 1/ valve Open/ Closed Verification No upgrade Orifice Valves of proper required alignment CVCS Letdown 1/ valve Open/ Closed Verification No upgrade Isolation Valves of proper required alignment CVCS Charging 1/ valve Open/ Closed Verification No upgrade Isolation Valves of proper required alignment RCP Seal Return 1/ valve Open/ Closed Verification No upgrade Isolation Valves of proper required alignment
_ VARIABLE: RCP Seal Injection Flow TYPE: D CATEGORY: 3 NUMBER:
1 each loop RANGE: 0 to 15 gpm UTILIZATI0ft:
Verification of proper system operation.
COMMENTS: No upgrade required.
e VARIABLE: MCR Radiation TYPE: D CATEGORY: 3 NUMBER:
1 RANGE:
0.1 to 104 mR/hr UTILIZATION: Verify MCR habitability.
COMMENTS: No upgrade required.
VARIt.BLE: Postaccident Sampling TYPE: D CATEGORY:
3 NUMBER: See comments RANGE: N/A UTILIZATION: See comments.
COMMENTS: TVA has Engineering Change Notices to implement this system which will meet the criteria outlined in SQN-DC-V-9 3 VARIABLE:
Condenser Vacuum Vent Flow Rate TYPE: E CATEGORY:
3 NUMBER:
1 RANGE: 0 to 7,000 SCFM UTILIZATION: Release assessment.
COMMENTS: No upgrade required.
4 0
-.- VARIABLE: Shield Building Vent Flow TYPE: E CATEGORY: 3 NUMBER:
1 RANGE: 0 to 28,000 CFM (present range)
UTILIZATION:
Release assessment.
COMMENTS: Present instruments will be replaced with more reliable ones.
VARIABLE: Plant and Environs Radiation TYPE: E CATEGORY: 3 The following portable detectors are onsite:
Detector Model Radiation Type Range Eberline: Teletector y
to 103 R/h h
Eberline: R07A y
to 2 x 10 R/h Eberline: R03A B/V to 50 R/h Eberline: R02A S/y to 50 R/h Nuclear Research: CP10 S/y to 10 R/h Nuclear Research:
CP2 B/y to 2 R/h Nuclear Research: CP10X
.S/y to 100 R/h Ludlum 5 y
to 5 R/h UTILIZATION: Detection of potential release.
COMMENTS: No upgrade required.
i
l i VARIABLE: Plant and Environs Radioactivity TYPE: E CATEGORY:
3 NUMBER:
1 single-channel spectrometer in HP lab 1 multichannel spectrometer in mobile lab facilities sent to plant during accident.
RANGE: N/A UTILIZATION: Release assessment.
COMMENTS: No upgrade required.
s
VARIABLE: Meteorological System TYPE: E CATEGORY: 3 i
NUMBER: See comments RANGE: See comments UTILIZATION: Determination of meteorological conditions affecting releases.
COMMENTS: The current meteorological system complies with Regulatory Guide 1.23.
A description of proposed improvements to the i
existing system is described in our response to item III.A.2 of NUREG-0737.
1 i
1 i
i i
9 i
- =
i l
VARIABLE:
Radiation Exposure Meters (Continuous Indication at Fixed Locations)
TYPE: E CATEGORY: See comments i
NUMBER: See comments RANGE: See comments UTILIZATION:
Determination of release severity and path.
COMMENTS:
Currently installed systems comply fully with all requirements of NUREG-06511, items II.H.5(b) and II.H.6(b).
\\
i l
5 t
i i
4 i
VARIABLE: Radiation Exposuro Rate TYPE: E CATEGORY: 3 NUMBER: As required to monitor areas where access is required to equipment and areas where high radiation would indicate l
containment breach.
RANGE:
10-1 to 104 mR/h UTILIZATION: Determine whether access is possible.
Determine exposure to maintenance employees.
l Monitor for containment breach.
COMMENTS: A range higher than 104 mR/h is inconsistent with the function of the instrument (employee access). Bntry into an area will be precluded by the off-scale reading of an instrument with the given range. Moreover, portable monitoring is typically a requirement fcr entry into an area with levels above 100 mR/h. In addition, the indicated "ange, in conjunction with portable monitoring, is sufficient to monitor for containment breach. Therefore, the present instruments meet the intent of the range requirements.
l f
i
. - _ _ VARIABLE: Airborne Radio-Halogens and Particulates TYPE: E CATEGORY: 3 NUMBER:
14 RANGE: Function of background, detector efficiency, and counting geometry. Can be calibrated to a lower level of detection of
)
approximately 10-15 pCi/cc and an upper limit on the order of mci /cc.
UTILIZATION:
Release assessment and analysis.
COMMENTS: No upgrade required.
1 l
l l
1 I
l VARIABLE: Shield Building Vent' Particulate Radiation TYPE: E CATEGORY: 3 NUHBER: See comments RANGE: See comments UTILIZATION: Release assessment.
COMMENTS: TVA will provide instrumentation required to meet the criteria outlined in TVA's response to NUREG-0737, II.F.1, attachment 1, and NUREG-0578, 2.1.8(b).
Present technical instructions provide guidance for sampling and analyzing particulates, if radiation doses permit, from the shield building vent monitor. It is possible that at the time of implementation, technical deviations may be requested to facilitate compromises between different criteria. For example, the location of sample collection equipment to reduce radiation exposure of employees during sample removal, transport, and analysis may require sample line lengths that would not meet the criteria for representative or isokinetic sampling.
i
'N.
VARIABLE: Shield Building Vent Iodine Radiation TYPE: E CATEGORY: 3 NUMBER: See comments RANGE: See comments UTILIZATION:
Release assessment.
COMMENTS: TVA will provide instrumentation required to meet the criteria outlined in TVA's response to NUREG-0737, II.F.1, attachment 1, and NUREG-0578, 2.1.8(b).
Present technical instructions provide guidance for sampling and analyzing halogens, if radiation doses permit, from the shield building vent monitor. It is possible that at the time of implementation, technical deviations may be requested to facilitate compromises between different criteria. For example, the location of sample collection equipment to reduce radiation exposure of employees during sample removal, transport, and analysis may require sample line lengths that would not meet the criteria for representative or isokinetic sampling.
TDK:0JZ:REA:JLH 02/24/82