ML20127A149
| ML20127A149 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/31/1985 |
| From: | GENERAL PUBLIC UTILITIES CORP. |
| To: | |
| Shared Package | |
| ML20127A123 | List: |
| References | |
| NUDOCS 8508050429 | |
| Download: ML20127A149 (62) | |
Text
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SAFETY EVALUATION REPORT FOR SIMPLIFICATION OF TECHNICAL SPECIFICATIONS FOR CLASS lE ELECTRICAL POWER SYSTEM Three Mile Island Unit 2 Revision 0 July 1985 ggg8050429 0507h320 ADOCK 0500 p
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TABLE OF CONTENTS 1.0 PURPOSE, SCOPE AND ORGANIZATION 1.1 Purpose 1.2 Scope 1.3 Organization 2.0 PROPOSED TECHNICAL SPECIFICATION REVISIONS 2.1 Present Technical Specification Systems Considered 2.2 Proposed Technical Specification Revisions 3.0 REASONS FOR PROPOSED TECHNICAL SPECIFICATION REVISIONS l
l 3.1 Plant Resource Allocation I
3.2 Critical Function Considerations 4.0 SAFETY EVALUATIONS 4.1 Technical Approach and Criteria 4.2 Evaluation of Class lE Emergency Diesel Generator Loads 4.3 Evaluation of Station Battery Capacity 5.0 EVALUATION OF SAFETY FUNCTIONS OF AFFECTED SYSTEMS AND COMPONENTS l
6.0 10 CFR 50.92 EVALUATION
7.0 CONCLUSION
S i
e TABLE OF CONTENTS (continued)
8.0 REFERENCES
9.0 APPENDICES 9.1 Emergency Diesel Generator Load Tables 9.2 Evaluation of Existing Station Batteries i
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1.0 PURPOSE, SCOPE AND ORGANIZATION 1.1 Purpose f
The purpose of this Safety Evaluation Report (SER) is to f
provide technical justification for simplification of cer-tain portions of the Three Mile Island Unit Two (TMI-2)
Technical Specifications to reflect the current status of the plant.
The Technical Specification requirements pro-posed for simplification in this SER relate to the Class lE electrical system, particularly the emergency diesel generators.
I This SER demonstrates that emergency diesel generators can be eliminated from the Technical Specifications without adversely affecting the present safe condition of the plant or causing undue risk to the health and safety of the public.
This SER also shows that the Nuclear Service River Water System (NSRWS) can be removed from the Technical Spe-cifications.
With the elimination of the emergency diesel generator Technical Specifications, the NSRWS no longer serves any Technical Specification equipment.
The basic justification for these proposed Technical Spec-ification changes is the recognition that the fundamental condition of the plant has changed since it was first licensed.
The plant is no longer capable of producing the potential mass and energy releases discussed in Chapter 15 of the TMI-2 FSAR and, consequently, is no longer in need of many of the large safeguard systems mentioned in Chapters 6 and 9 of the TMI-2 FSAR on a continuing basis.
Specifi-cally, due to the stable shutdown condition of the nuclear fuel, the minimal core decay heat generation rate and low 1-1 4
O-a core temperature under present loss-to-ambient cooling con-ditions, the ambient pressure condition of the reactor coolant system with the reactor vessel head removed, and the improved building radiological conditions, many original safeguard system loads on the emergency diesel generators are no longer applicable and existing batteries are suf fi-cient to power remaining vital equipment during the unlikely occurrence of loss-of-of f-site power.
The purpose of this SER is to evaluate the present plant conditions and show that the TMI-2 Technical Specifications can be simplified in these areas without causing undue risk to the health and safety of the public.
1.2 Scope The scope of this SER includes evaluations of, and proposed changes to, the Technical Specification requirements that cover the Class lE diesel generators.
In addition, this SER shows that under loss-of-of f-site power conditions, there is sufficient available station battery power without the emergency diesel generators to provide alternate power sup-port for the few remaining vital loads.
These evaluations are based on the present and anticipated future plant conditions.
Specifically these conditions are:
The plant is in a cold shutdown condition.
The plant is undergoing recovery operations which will include the defueling of the reactor vessel.
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1.3 organization Secticn 2.0 describes the specific functional areas where simplifications of Technical Specification requirements are justified based on the results of the SER.
This section also lists the resulting changes to Technical Specification requirements that are proposed to implement these simpli-fications.
Section 3.0 summarizes the beneficial effects that these Technical Specification changes would have on the allocation of plant resources.
Section 4.0 presents the necessary evaluations to show that current plant safety functions and requirements can be satisfied after the proposed Technical Specification changes are made.
Section 5.0 evaluates the current safety functions, if any, of the plant systems and components affected by the proposed Technical Specification changes.
This evaluation shows that reducing or eliminating requirements for emergency back-up electrical power for these systems and components does not compromise any current plant essential function.
Section 6.0 provides a 10 CFR 50.92 evaluation of these Technical Specification changes.
Section 7.0 gives the con-clusions of this SER, and Section 8.0 lists references.
Section 9.0 contains detailed information about the elec-trical loads evaluated in this SER.
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a 2.0 PROPOSED TECHNICAL SPECIFICATION REVISIONS 2.1 Present Technical Specification Systems Considered This SER shows that the emergency diesel generators can be eliminated from the Technical Specifications.
The basis for this is an evaluation of the TMI-2 Class lE emergency diesel generator and station battery electrical power systems, as discussed below.
This SER also shows that the Nuclear Service River Water System (NSRWS) can be removed from the Technical Specifications.
With the elimination of the emergency diesel generator Technical Specifications, the f
NSRWS no longer serves any Technical Specification equipment.
2.1.1 Emergency Diesel Generator Stand-by Power System Evaluations in Section 4.2 and 5.0 of this SER demonstrate that all present plant safety functions can be supported (1) by off-site AC power, or (2) in the event of loss-of-off-site AC power without use of the emergency diesel gener-ators.
Most of the loads automatically or manually sequenced on emergency diesel generators are for components whose functions are no longer safety-related or whose continuous functioning is no longer required to maintain safe plant conditions.
This SER shows that all loads potentially served by the emergency diesel generators either can be interrupted safely for a length of time conserva-tively assumed necessary to restore off-site power or can be.
supplied with back-up power from the existing station batteries.
Accordingly, Technical Specification require-2-1 4
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e ments for the emergency diesel generators are no longer l
l needed.
l 2.1.2 Station Battery Power System This SER shows that the existing station batteries are capable of supplying power to all loads for equipment whose operation may be needed to maintain current safe plant con-ditions if all off-site power is lost for a conservatively long period of time.
Section 4.3 of this SER defines the required duty cycle for these loads and demonstrates that the available battery capacity is sufficient to meet this need.
As a result, it is concluded that the existing sta-tion batteries are sufficient to maintain safe conditions without the emergency diesel generators.
2.1.3 Nuclear Service River Water System The Nuclear Service River Water System is evaluated in Section 5.3 of this SER.
The evaluation shows that, since the emergency diesel generator Technical Specification requirements can be deleted, the NSRWS no longer serves any Technical Specification equipment.
Accordingly, the Technical Specification requirements for the NSRWS also may be deleted.
2.2 Proposed Technical Specification Revisions The following changes are proposed for the TMI-2 Technical Specifications.
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Section 3.0 Delete paragraphs 3.7.4 and 3.8.1.1.b and all references to the Class lE diesel generators in Tables 3.8-1 and 3.8-2.
Section 4.0 Amend Table 4.3-2 to reflect deletion of Nuclear Service River Water System buses.
Delete paragraphs 4.7.4 and 4.8.1.1.2.
Amend para-graph 4.8.2.1 to delete buses no longer necessary based on this submittal and previous submittals.
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e 3 '. 0 REASONS FOR PROPOSED TECHNICAL SPECIFICATION REVISIONS 3.1 Plant Resource Allocation This SER shows that because of the present configuration of the reactor, some Technical Specification components are no longer needed to assure that the plant remains in a safe and stable condition.
If the proposed Technical Specification changes are enacted, the effort required to maintain and test these systems and components can be more ef fectively concentrated on recovery program activities and other activities which enhance the future safe condition of the plant.
3.2 Critical Function Considerations Elimination of those system requirements no longer necessary for assurance of plant safety simplifies the organization of the Class lE system and permits streamlining of the electrical support for the few remaining plant systems and functions that are important to safety.
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4.0 SAFETY EVALUATION This section presents a safety evaluation of those parts of the Class 1E electrical system related to emergency diesel generators and station batteries.
The purpose of this evaluation is to show that all electrical loads presently provided back up power by emergency diesel generators (1) are no longer needed for safe function of the plant, or (2) are small enough to be backed up by existing on-site battery capacity, or (3) can be safely interrupted for a length of time conservatively assumed necessary to restore off-site power after its loss.
As a result, it is shown here that emergency diesel generators are no longer needed for any plant safety functions and can be removed from the Technical Specifications.
This section includes the technical approach and acceptance criteria for the work, detailed descriptions of the evaluations, and a summary of the results.
4.1 Technical Approach and Criteria The TMI-2 Final Safety Analysis Report (FSAR) describes the original design basis of all plant safety systems and their connections with the plant Class 1E electrical system.
These systems were designed to assure that safe conditions would result from all plant design-basis events.
The plant, however, is no longer capable of producing the potential mass or energy releases discussed in Chapter 15 of the TMI-2 FSAR; consequently, the original design bases are no longer applicable.
Specifically, the condition of the 4-1 l
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plant has changed significantly since the present Technical Specification requirements were established.
Many of the Technical Specification requirements for these systems can be simplified or deleted.
The overall technical approa.ch used in demonstrating that such changes are feasible has been to review the present condition of the plant from the standpoint of all safety functions currently required by regulatory criteria.
In all cases, the,results of this review'$ ave shown that there s n would be no undue risk to the health and safety of the public if Technical Specification requirements for many safety systems were' simplified or eliminated, as proposed.
Two SER's have been prepared and submitted as part of the overall TMI-2 Technical Specification simplification Program, which documented these safety reviews.
One SER contained a review of the TMI-2 safety systems for core cooling, reactor pressure control, reactor coolant inventory control, and reactivity control (Reference 8.1).
A second SER reviewed the TMI-2 safety systems for building
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atmospheric control (Reference S.2).
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The present SER contains a similar review of those TMI-2 Class lE electzi, cal system loads for safety system equipment which are backed up by the emergency diesel generators to q
show that Technical Specification requirements can be simplified in this area, as well.
This report makes use of the conclusions of the two previous SER's mentioned above to evaluate the need for much of this safety system equipment in light of t'he present plant conditions.
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All of these reviews of the TMI-2 safety systems make use of l
the conservative assumptions listed below.
l 4.1.1 Design Basis Events (DBE's) f iThe following Design Basis Events (DBE' s) are considered is s
applicable to the current TMI-2 configuration.
Most DBE's are taken from the TMI-2 FSAR as discussed in References 8.1 l
and 8.2.
l TMI-2 Loss of
- t. actor coolant system integrity (LOCA)
,1 j TMI-l worst case radiological release - LOCA TMI-2 radiological events Wind and tornados i
Flood I
Aircraft and tornado missiles External hazardous atmospheres These DBE's were considered in all the evaluations of References 8.1 and 8.2 and are also taken into account in the present evaluations.
With regard to the Class lE electrical system equipment itself, all of the equipment reviewed in this SER is existing plant equipment which was qualified to nuclear safety standards under these DBE ponditions when the plant was constructed.
In addition, the necessary functions of the Class lE electrical system during conditions assumed for the latest TMI-2 Fire Protection Program Evaluation (Reference 8.3) are also evaluated in the SER.
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A seismic event is not considered here; it has been considered in a sepa' rate SER (Reference 8.4).
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4.1.2 Loss of AC Power A complete loss of off-site and on-site AC power (i.e.,
j complete unavailability of the Class lE emergency diesel generators) coincident with or after any of the DBE's is assumed in all evaluations.
As part of the safety evalua-l tions in this SER and the two preceding SER's (References 8.1 and 8.2), the maximum permissible duration of this off-site power loss is determined.
The overall results show L
that:.this duration is limited to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> based on a conservative analysis of the capability of the existing l
station batteries to power the remaining safety loads.
(NOTE:
A more realistic analysis suggests that the battery capacity is sufficient to support safety functions for about 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, as discussed in Appendix 9.2 of this SER.)
Accordingly, this SER assumes an 8-hour duration for off-
't site power loss.
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l A study of off-site power reliability (Reference 8.5) shows
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that an off-site power loss longer than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is very unlikely.
This study demonstrates that (1) because there are multiple sources of off-site power available to provide power to the TMI site and - (2) even in the event power is 4.,
lost, it can be restored within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> with a very high probability.
This grid reliability study considered the past historical reliability of the power systems that feed TMI-2 (power has never been lost to the site) and the reli-ability and redundancy of the various transmission paths from the site switchyard to vital TMI-2 buses.
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4.1.3 Detailed Approach for Evaluation of Class lE Electrical Loads The purpose of this SER is to evaluate the consequences to plant essential functions of simplifying the Technical Specification requirements for Class lE electrical power systems by eliminating the emergency diesel generators.
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do this, all present loads on the emergency diesel
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generators are evaluated to determine if their corresponding equipment functions are still considered essential under the present plant conditions.
In cases where the loads cannot be eliminated entirely, a further evaluation is performed to h
show either (1) the load can be safely interrupted for the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conservatively asscued necessary to restore off-site power after its loss, or (2) the load, together with all similar loads, can be powered within the present capacity of the station batteries.
4.2 Evaluation of Class lE Emergency Diesel Generator Loads The emergency diesel generators are described in Section l
8.3.1.1.8 of the TMI-2 FSAR.
In the event of loss of off-site power to auxiliary transformers 2A and 2B, an emergency on-site power system based on these emergency diesel j
generators is automatically activated.
l When loss of either of the auxiliary transformers is sensed, various fast transfers of the feeder breakers to the 4160 volt Class lE buses, the 4160 volt balance-of-plant (BOP) buses, and the 6900 volt reactor coolent pump buses are automatically accomplished to attempt to supply power from the alternate auxiliary transformer.
During this process, the undervoltage condition will cause the operating motor loads powered directly from the 4160 volt Class lE buses 4-5
- (Buses 2-lE, 2-2E, 2-3E, and 2-4E) to trip; and, ultimately, the emergency diesel generators will start.
j Each emergency diesel generator is connected to a 4160 volt Class lE bus through a breaker which is automatically closed when the generator is running and up to speed and voltage.
After this occurs, an automatic loading sequence begins for the bus during which selected safety loads begin receiving power from the generator.
Any other loads powered through this Class lE bus are also available for manual connection l
to the generator provided the total generator load is kept below the generator capacity.
4.2.1.
Loads Considered The loads considered in this evaluation include all loads automatically sequenced and all loads available for manual loading on the emergency diesel generators upon startup of the emergency diesel generators following a loss-of-off-site power.
1 The loads are grouped in tables contained in Appendix 9.1 to aid in this evaluation.
This grouping is explained below.
Loads Automatically Sequenced on the Emergency Diesel Generators The current list of these loads is provided in Section 4.6 of the current TMI-2 operating procedure for the Class 1E electrical system (Reference 8.5).
These loads are evaluated in Table A (for the AC loads) and f
I Table B (for the DC loads).
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Other Class lE Electrical System Loads These loads are obtained from the current plant drawings listed in Appendix 9.1 and include all Class lE loads not automatically sequenced on the diesel generators.
The loads are grouped in the tables of Appendix'9.1 as follows.
Loads on the 4160 volt switchgear buses are in Table C.
Loads on the 480 volt unit substations are in Table D.
Loads on the 480 volt motor control centers are in Table E.
4.2.2 Evaluation Criteria Each of the loads considered is evaluated based on the function provided by its corresponding equipment in relation to the present plant essential functions.
From this evaluation, the loads are categorized as follows.
Category A These loads are no longer needed for the performance of any essential functions considering the present condition of the plant.
In some cases, the plant has already " racked-out" equipment in this category.
Therefore, these loads do not require back-up power from the emergency diesel generators or station batteries.
Category B These loads include those that may be needed in the long term:
(1) to perform current essential plant 4-7
functions, or (2) to perform useful functions which are not safety-related or required by Technical Specifica-tions.
These loads may be interrupted for the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conservatively assumed necessary to restore off-site power after its loss.
Therefore, these loads do not require back-up power from the emergency diesel genera-tors or station batteries.
Category C These loads are necessary for current essential plant functions and may not be interrupted for the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conservatively assumed necessary to restore off-site power after its loss.
These loads, taken together, will be compared to the capacity of the present station batteries, as discussed in Section 4.3 of this SER.
4.2.3 Evaluation Using the load tables and evaluation criteria described above, the following evaluation is made.
First, the plant systems or functions served by the loads are identified by cross-referencing each load in each load table to a particular part of Section 5.0 of this SER (referred to as
" Basis" in the tables.)
Section 5.0 contains safety evaluations based on present plant conditions for all plant systems and functions presently affected by the Class lE electrical system.
Next, the results of the safety evaluations in Section 5.0 are used to categorize the current safety significance of each load and its corresponding dependence on emergency 4-8
diesel generator back-up power, as described in Section 4.2.2 of this SER.
This category selection is designated in
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the tables in the column marked " Category."
Finally, the results of the categorization process are reviewed from the load tables.
The results show that most loads are in Categories A or B and do not require back-up power capability.
Those loads still requiring battery power under conditions of loss-of-of f-site power and unavailability of the emergency diesel generators, i.e.,
in Category C, include switchgear control loads, radiation monitoring, communications, emergency lighting, fire protection, and control room instrumentation loads powered from vital power supply cabinets and DC power panels.
All of these loads are presently connected to the station batteries or local batteries although normally powered through rectifiers from normal off-site power sources.
Since it is shown in Section 4.3 of this SER that all of the Category C loads can be powered by the station batteries for the duration of the assumed off-site power loss, it is concluded that all plant essential f unctions can be maintained without the emergency diesel generators.
Accordingly, all Technical Specification requirements for the emergency diesel generators may be safely eliminated.
4.3 Evaluation of Station Battery Capacity The TMI-2 station batteries are part of a 125 volt /250 volt DC power system described in Section 8.3.2 of the TMI-2 FSAR.
There are two batteries, each of which can power one 4-9
of two redundant DC buses (2-lDC and 2-2DC) ordinarily powered through rectifiers from normal off-site power sources.
The batteries are fully functional and have been continuously maintained in accordance with Technical Specification surveillance requirements.
The batteries are part of a DC power distribution system whose design meets all applicable original licensing-basis regulatory criteria for power system design, including independence and physical separation of power sources, redundance of load, and use of single failure design criteria.
4.3.1 Battery Duty Cycle The station batteries were originally designed to provide 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of back-up power for the duty cycle described in Section 8.3.2 of the TMI-2 FSAR.
The results of Section 4.2 of this SER show that no new loads need to be added to the
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batteries and several present battery loads no longer require back-up power.
Therefore, a new battery duty cycle has been defined and compared to the battery capacity to determine the length of time the batteries can power all current essential loads.
The magnitudes of the loads in the new duty cycle are determined as follows.
Switchgear Control Loads These loads only exist momentarily when feeder breakers trip and reset upon loss-of-off-site power to either of the auxiliary transformers.
Since the relay logic for this fast transfer sequence is unchanged from the original plant design, the values for these loads given in Tables 8.3-2A and 8.3-2B of the TMI-2 FSAR are still 4-10
valid.
These values are identical for each DC bus and are 50 amperes for 1.0 seconds immediately af ter of f-site power is lost and 75 amperes for 1.0 minutes at the end of the duty cycle.
All Other Loads on DC Buses 2-lDC and 2-2DC As shown in Table B of Appendix 9.1 of this SER, the only remaining essential loads on these buses are powered from the vital power supply cabinets and DC power panels.
As discussed in Sections 5.20 and 5.21 of this SER, these cabinets and panels also provide power routinely to other loads which are not essential.
To conservatively estimate the size of the essential loads on these buses, the present total amperage on each DC bus. was measured and is used.
These measured values are 100 amperes per bus.
To satisfy the assumption that off-site power could be lost for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, a duty cycle is constructed for each battery which assumes the present measured DC bus loads continue for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
The switchgear loads are superimposed on this time interval to create a total duty cycle.
Figure 9.2-1 of Appendix 9.2 of this SER shows the complete duty cycle on each battery.
4.3.2 Evaluation Criteria The current battery sizing criteria recommended by IEEE Standard 308-1980 (Reference 8.7) are used in this evaluation.
These criteria are given in IEEE Standard 485-1978 (Reference 8.8).
As recommended in this Standard, the analysis includes a correction factor which accounts for the 4-11
effect of battery age on reducing end-of-life capacity to 80% of initial rated capacity.
4.3.2 Evaluation Appendix 9.2 of this SER contains the detailed evaluation of the required battery capacity for the essential duty cycle defined cbove.
The results show that a battery with an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> rating of 1100 ampere-hours is required to power the new duty cycle for each DC bus under loss-of-off-site power conditions without use of the emergency diesel generators.
Each TMI-2 battery has an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> rating of 1800 ampere-hours.
Thus, the present TMI-2 batteries are large enough to handle the essential plant loads for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
In fact, it is shown in the Appendix that the batteries have sufficient capacity for about 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of use.
Accordingly, use of the emergency diesel generators is not required to maintain safe plant conditions and Technical Specification requirements for the diesel generators may be eliminated.
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5.0< EVALUATION OF SAFETY FUNCTIONS OF AFFECTED SYSTEMS AND COMPONENTS This section contains safety evaluations of all systems and components capable of being powered by the emergency diesel generators through the Class lE electrical system.
As part of the evaluation of diesel generator loads described in Section 4.2.3 of this SER, the essential functions, if any, of these systems and components are evaluated in this section to determine if back-up power is required.
The evaluation of each system and component follows the evaluation criteria of Section 4.2.2 of this SER.
Specifically, this evaluation determines whether the equipment still performs a safety function, and if so, whether enis function can be adequately supported if the equipment is without power for the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conservatively assumed to be required to restore off-site power after its loss.
The results of the evaluation are expressed in terms of a selected category for each electrical load based on the current safety function performed by the equipment under the present TMI-2 plant conditions.
These results are also documented in the electrical load tables in Appendix 9.1 of this SER to assist in screening the overall results.
The overall conclusion of the evaluations in this section is that safe plant conditions can be maintained for this 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> interval without the functioning of much of this equipment.
The loads requiring back-up power include switchgear controls, radiation monitoring, communications, emergency lighting, fire protection, and control room instrumentation loads powered from vital power supply cabinets and DC power panels.
All of these loads are 5-1 l
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i presently connected to the station batteries although
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powered through rectifiers from normal off-site power sources.
These results are used in the evaluation of the required duty cycle for the station batteries as discussed j
in Section 4.3 of this SER to show that the batteries can j
supply this needed back-up capacity without the emergency diesel generators.
Accordingly, all Technical Specification requirements for the emergency diesel generators may be safely eliminated.
5.1 Decay Heat Removal System (DBRS)
The functions of the DHRS have been reviewed in Reference 8.1 for the present plant condition.
The review shows that most of the original safety functions of the DHRS are no longer required for present or projected plant conditions.
The remaining safety function (gravity feed from the Borated Water Storage Tank) can be accomplished with the manual operation of valves in the gravity feed flow path to the reactor vessel and the BWST (which is not an active component).
i As a result, the DHRS equipment electrical loads no longer j
j require a back-up power source.
The valves in the gravity feed path can be put in Category B2 of Section 4.2.2 of this SER and all other active components can be put in Category A.
5.2 Makeup and Purification System As discussed in Reference 8.1, the plant can be maintained in a safe state under any foreseeable conditions without the i
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core injection capabilities of the Makeup and Purification System.
Accordingly, the corresponding system equipment electrical loads are no longer needed for any plant essential functions and can be put in Category A of Section 4.2.2 of this SER.
5.3 Nuclear Service River Water System (NS RWS)
The Nuclear Service River Water System (NSRWS) supplies cooling to several systems and components listed in the current plant Technical Specifications.
Recent evaluations in References 8.1 and 8.2 have addressed all of these systems and components, except the emergency diesel generators.
As discussed below, the evaluations show that none of these systems and components perform essential 1
functions and all of them are proposed for deletion from the j
Technical Specifications.
The present SER reaches the same l
conclusion about the emergency diesel generators.
Accordingly, the NSRWS no longer serves necessary Technical Specification equipment and may, itself, be deleted from the Technical Specifications.
As a result, NSRWS equipment electrical loads no longer require a back-up power source and can be put in Category A of Section 4.2.2 of this SER.
5.3.1 NSCCWS and DHCCWS Cooling l
The NSRWS supplies cooling water to the Nuclear Service Closed Cooling Water System and the Decay Heat Closed
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Cooling Water System.
It was shown in Reference 8.1 that neither of these systems is required for present and foreseeable plant conditions.
Therefore, these NSRWS l
cooling loads are not required.
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o 5.3.2 control Room Ventilation System Cooling Coils These coils are part of the Control Room Ventilation System which is used to reduce control room air temperature when the control room is isolated following external hazardous events.
As discussed in Reference 8.2, the control room heat loads are now low enough that supplemental cooling is not required during accident conditions.
Therefore, this NSRWS cooling load is not required.
5.3.3 Diesel Generator Coolers Since the results of this SER show that the emergency diesel generators are no longer needed as a back-up power source for plant essential functions, this cooling load is not required.
5.4 Decay Heat Closed Cooling Water System (DHCCWS)
The single safety function of the DHCCWS is to provide cooling to the Decay Heat Removal System (DHRS) when that system is needed for pumped cooling during LOCA conditions.
The evaluation in Reference 8.1 shows that the DHRS is no longer required for pumped cooling for the present plant conditions.
Consequently, the DHCCWS is not needed for any plant essential functions and the equipment electrical loads can be put in Category A as defined in Section 4.2.2 of this SER.
5.5 Nuclear Service Closed Cooling Water System (NSCCWS)
All of the original essential functions of this system have been evaluated in Reference 8.1 for the present TMI-2 plant 5-4
o conditions.
It is shown in the Reference that these functions are not needed now to maintain the plant in a safe condition.
As a result, NSCCWS equipment electrical loads are no longer required for any plant essential functions and can be put in Category A as discussed in Section 4.2.2 of this SER.
5.6 Intermediate Closed Cooling Water System (ICCWS)
According to Section 9.2.2.4 of the TMI-2 FSAR, the Intermediate Closed Cooling Water System is a closed loop system that provides cooling for various components in the reactor building that handle reactor coolant.
These components include the reactor coolant pump cooling jackets, the letdown coolers, and the control rod drive coolers.
The evaluation in Reference 8.1 shows that removal of the small remaining core decay heat load at TMI-2 can be accomplished without any of these coolers in service.
Therefore, the ICCWS is no longer needed for any plant essential functions and the equipment electrical loads can be put in Category A as discussed in Section 4.2.2 of this SER.
5.7 Spent Fuel Pool Cooling System This system is designed to remove decay heat from spent fuel stored in the spent fuel pool.
There is no spent fuel being stored at TMI-2 and, as discussed in Reference 8.1, separate analysis of pool temperature during recovery program operations will be performed for approval of fuel canister i
design and storage.
Therefore, this system is not needed for any present plant safety functions and its electrical loads may be put in Category A as defined in Section 4.2.2 of this SER.
5-5 t
5.8 Reactor Building Sump Recirculation System The recent safety evaluation report of Reference 8.1 shows that long term reactor vessel water inventory control, core cooling, and boron concentration requirements can be provided during the worst credible postulated vessel incore nozzle leak rate scenario by a simple dedicated sump recirculation system.
This system, consisting of redundant portable. ump pumps and hoses, can be activated to make up water to the reactor vessel from the reactor building basement in order to maintain an acceptable water level.
This system may be out of service for periods of time after it is activated since water inventory in the reactor vessel above the minimum required level and gravity flow from the borated water storage tank can be used to compensate for the leak rate.
Recent analyses of the maximum credible leak rate scenarios discussed in References 8.1 and 8.9 show that operation of this system could cease for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, which is the maximum expected duration of off-site power loss, without reaching the minimum acceptable reactor vessel level.
Accordingly, this system does not require back-up power and can be put in Category B1 of Section 4.2.2 of this SER.
5.9 Reactor Building Cooling Systems As described in Section 9.4.15 of the TMI-2 FSAR, there are two systems available for cooling the reactor building area:
the Reactor Building Cooling System and the Reactor Building Penetrations Forced Air Cooling System.
Both of these systems are designed to remove heat from the building 5-6 I
(
S during normal operations and the building cooling system also functions for post-LOCA containment heat removal.
Recent evaluations in Reference 8.1 have shown that the plant can remain in a safe condition without this cooling.
The reactor coolant temperature will not exceed acceptable limits if the present " loss-to-ambient" decay heat removal method is used without any building atmosphere cooling.
Therefore, none of these building cooling systas are needed for any plant safety functions and their electrical loads can be put in Category A as defined in Section 4.2.2 of this SER.
5.10 Control Room Ventilation and Emergency Air Cleanup System The need for the Control Room Ventilation and Emergency Air Cleanup System under present plant conditions was evaluated in Reference 8.2.
The results show that conditions in the Control Room are acceptable if the system is not in use for at least the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the most limiting external hazardous release.
Therefore, the system equipment electrical loads no longer require a back-up power source and can be put in Category B1 of Section 4.2.2 of this SER.
5.11 Control Building and Control Building Area Ventilation Systems These systems include the ventilation systems for the Cable, Battery, Switchgear and Mechanical Equipment Rooms in the Control Building as well as the ventilation system for the Control Building Area.
The purpose of these systems is to j
provide cooling to maintain ambient temperatures below 104*F to avoid equipment degradation in severe summer conditions 5-7 1
5 m
.__ _ _ _ _ _ _ _. _, _ _. - +..-,.. --.
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7
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with full operating heat loads created by mechanical and electrical equipment.
Since the'present plant condition does not require full operation of all this equipment, lower heat loads are generated.
Also, the short-term exposure of this equipment to slighly higher temperatures for the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> conservatively assumed necessary to restore off-site power is not likely to result in any significant equipment thermal aging.
Therefore, this cooling function may be safely interrupted during loss-of-off-site power events.
As a result of the above evaluation, it is concluded that equipment electrical loads for these systems no longer require a back-up power source and can be put in Category B2 as discussed in Section 4.2.2 of this SER.
5.12 Reactor Coolant System and Auxiliaries Reference 8.1 shows that active functioning of the reactor coolant system or its auxiliary systems are not required for maintaining a safe and stable condition in the reactor Specifically, equipment such as drain and vent core.
systems, core flood tank valves, chemical addition lines, and reactor coolant pump auxiliaries are no longer essential.
This equipment can be put in Category A of Section 4.2.2 of this SER.
5.13 Steam, Feed and Condensate and Secondary Systems As part of the evaluations in Reference 8.1, the core decay heat generation rate is shown to be small enough that the current passive " loss-to-ambient" cooling method is adequate to maintain the plant in a safe condition No heat removal systems other than gravity feed BWST flow and reactor 5-8 i
,,,,.n.
,_,,---,--,_.---_,.---,,.,.._n._.
t building sump recirculation would be needed under any fore-seeable conditions.
Accordingly, no elements of the Steam, Feed and Condensate or other secondary systems are required i
for any plant essential functions and all equipment elec-trical loads can be put in Category 'A as discussed in Section 4.2.2 of this SER.
5.14 Instrument Air System -
According to Sections 7.4.2.3.a and 9.3.1.3 of the TMI-2 FSAR, the instrument air system is not required for a LOCA emergency or safe shutdown.
Therefore, the system elec-trical loads are not needed for any plant essential functions and can be put in Category A as defined in Section 4.2.2 of this SER.
4 5.15 Radiation Monitoring Airborne radioactivity monitors are used at building release points to monitor plant releases.
When electrical power is lost to the site, the building ventilation systems auto-matically isolate these release points so that monitoring is not needed.
Also, portable battery-powered radioactivity monitors are available on-site.
Therefore, the airborne monitors can be put in Category B1 as discussed in Section 4.2.2 of this SER.
5.16 Plant Lighting The TMI-2 plant lighting can be evaluated as follows.
5.16.1 Building Internal Lighting As discussed in the fire protection program evaluation, l
Reference 8.3, adequate emergency lighting is available in i
5-9 es+.e--,---..-
m---., -.,-,,.
m,-w-
---mmw,moyw-w,--e,
,w,-
y-
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-,-----.,r, r---,--
e all areas of the plant.
This lighting is powered by local batteries and is supplemented by battery powered portable hand lights.
No back-up power from the emergency diesel generators or station batteries is required under emergency conditions.
Therefore, this load.is considered to be Category A as discussed in Section 4.2.2 of this SER.
5.16.2 Cooling Tower Aircraft Warning Lights i
The two natural draft cooling towers have aircraft warning lights which activate automatically if ambient lighting conditions require them.
If off-site power is lost when these lights would otherwise be functioning, the nearby airport will be notified to assure that any necessary precautions are taken.
Accordingly, this electrical load can be put in Category B2 of Section 4.2.2 of this SER.
5.17 Heat Tracing s
Heat tracing panels are located throughout the plant to provide supplemental heating of equipment and piping.
Many of the panels powered from the Class lE electrical system serve process equipment no longer needed for plant essential functions.
Also, during the relatively short period of time that of f-site power could be lost, it is unlikely that any adverse effects would occur due to temperature changes in equipment.
To insure that the BWST would be capable of performing its intended function with a loss.of off-site power during sub-freezing weather, potential damage to small bore piping has been evaluated and bounded.
An hourly surveillance of the BWST enclosure during sub-freezing weather coincident with the loss of off-site power will be added to emergency response procedures.
This will assure 5-10
J that any potential leakage from frozen pipes will be identified before it can significantly affect make-up cap-ability from the BWST.
As a result, it is concluded that these loads do not require back-up power and can be put in Category B2 of Section 4.2.2 of this SER.
5.18 Communications As discussed in the fire protection program evaluation, Ref erence 8.3, adequate emergency communications are available at TMI-2.
Three emergency communications systems:
the page party, the emergency page party, and the maintenance communication jack systems are powered from vital power supply cabinets backed-up by station battery power.
Accordingly, these loads are classified in Category C of Section 4.2.2 of this SER.
5.19 Fire Protection System The current TMI-2 fire protection system is described in Reference 8.3.
The system remains operational during periods when off-site power is lost since needed active equipment is backed-up by battery power or other means.
An evaluation of major portions of the system is given below.
The yard main water supply system is pressurized by an elevated storage tank and can be fed by on-site diesel-driven fire pumps.
All detectors and alarms in the zone detection system are powered from power panels backed-up by the station batteries.
5-11
0-D s
The Halon systems in the air intake tunnel and cable room have local battery back-up with a capacity of at least 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />.
Local water delivery systems such as hydrants, hoses, and wet pipe sprinkler systems do not require electric power or can be operated manually.
Accordingly, the portions of the fire protection system backed-up by the station batteries are classified as Category C of Section 4.2.2 of this SER.
The remainder of the system can function without Class lE electrical system power during the period of time when off-site power-is not available.
5.20 Vital Power Supply Cabinets All of these cabinets contain loads that are designed to be powered by uninterrupted power supplies.
Power can be provided directly from AC buses but is routinely supplied through inverters f rom the two DC buses backed-up by the station batteries.
These cabinets include communications system loads, radiation monitor loads and other essential loads as well as several loads no longer considered essential.
For purposes of this evaluation, it will be conservatively assumed that all loads currently powered by these cabinets are in Category C of Section 4.2.2 of this SER.
5-12
i 5.21 DC Power Panels These power panels are powered directly from the 2 DC buses backed-up by the station batteries.
Power is normally supplied from off-site sources through rectifiers connected to the buses.
These panels supply power for switchgear control loads such as the breaker trip and reset loads caused by the f ast transfer relay logic when off-site power is lost to eith'er auxiliary transformer.
Many other loads are also connected to the panels including essential fire protection system loads, and various non-essential loads.
For purposes of this evaluation, it will be conservatively assumed that all loads currently powered by these panels are in Category C of Section 4.2.2 of this SER.
5.22 Emergency Diesel Generator Auxiliaries and Related Equipment Several items of equipment directly related to operation of the emergency diesel generators are provided with back-up l
power from the emergency diesel generators and station batteries.
Since this SER shows that these generators are no longer required for plant essential functions, these j
equipment electrical loads are no longer needed and can be l
put in Category A as discussed in Section 4.2.2 of this SER.
t' 5.23 Reactor Building Spray System As discussed in Reference 8.1, this system is not needed to maintain safe thermal or radiological conditions inside the containment building.
As a result, the system electrical l
loads are no longer needed and can be put in Category A of 1
Section 4. 2. 2 of this SER.
i 5-13 l
a f
5.24 Regulated Voltage Power Supplies The regulated voltage power supply cabinets contain miscellaneous non-essential original plant loads as well as recent connections to recovery program systems.
These recent connections are controls for the Standby Pressure Control (SPC) and Mini-Decay Heat Removal Systems (MDHRS) and a power panel for the chemistry laboratory.
The evaluations in Reference 8.1 show that the SPC and MDHR systems no longer perform essential functions.
The chemistry laboratory power connection is also for non-essential equipment.
Accordingly, there are no essential loads on these power supplies and they can be assigned to Category A of Section 4.2.2 of this SER.
5.25 Hydrogen Purge Cleanup System The containment hydrogen purge cleanup system is no longer essential and has been deleted f rom the TMI-2 Technical Specifications.
It can be classified in Category A of Section 4'. 2. 2 of this SER.
5.26 Miscellaneous Power Panels Miscellaneous power panels MP2-llEB and MP2-21EB contain loads no longer considered essential.
These loads include l
diesel generator building ventilation damper controls, secondary system equipment such as feedwater latching relays, isolation valves for reactor coolant pump cooling water f rom the NSCCWS, and other balance-of-plant equipment.
This equipment can be classified in Category A l
of Section 4.2.2 of this SER.
5-14
5.27 Nuclear System Monitoring Instrumentation Adequate monitoring can be maintained for the few remaining nuclear system functions during conditions when off-site power is lost and emergency diesel generators are not available.
Water levels in the reactor vessel, steam generators, and reactor building can be monitored within the required surveillance frequency if power is lost for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
Intermediate range and source range neutron monitors are powered with back-up station battery power along with BWST water level instrumentation.
Although incore thermocouples are currently powered from a Class lE plug receptacle not backed up by station batteries, thermocouple readings can be taken manually using a portable battery-powered unit.
Thus, it is concluded that emergency diesel i
generators are not required to meet current monitoring requirements.
1 i
r l
5-15
\\
4 i
6.0 10 CFR 50.92 EVALUATION Section 50.91 of 10 CFR 50, entitled " Notice for Public Comment; State Consultation", requires the licensee to sub-mit an analysis concerning the issue of "no significant hazards consideration" applying the standards in Section 50.92 of 10 CFR 50.
10 CFR 50.92 states than an issue involves "no significant hazard consideration" if it would not:
a)
Involve a significant increase in the probability or consequences of an accident previously evaluated.
b)
Create the possibility of a new or different kind of accident from any accident previously evaluated, or c)
Involve a significant reduction in a margin of safety.
The conclusions of this Safety Evaluation Report (SER) sup-port selected changes to the TMI-2 Technical Specifications; in addition, this Section demonstrates the proposed Tech-nical Specification changes involve "no significant hazard consideration".
The changes proposed by this SER do not increase the prob-ability or the consequences of an accident previously eval-uated in the safety analysis report.
Under present plant conditions, the requirements for Class lE electrical system support for the few remaining essential plant systems and components are much less than those required for the conditions evaluated in the Final Safety Analysis Report 4
(FSAR).
6-1
._..,..._.-__._.,,.__.,m__
The possibility of a new or different type of accident is not created by the proposed Technical Specification changes.
This conclusion is based on having demonstrated that the envelope of essential Class lE electrical system loads is now smaller and simpler than considered in the FSAR.
In addition, the margin of safety would not be reduced by the proposed Technical Specification changes.
It has been shown in this SER that the performance of the Class lE electrical system under the proposed simplified Technical Specification requirements would meet all licensing-basis safety design criteria such as loss-of-power requirements, which remain applicable based on the current plant status.
Therefore, it is concluded that the Technical Specification changes proposed in this SER involve "no significant hazards consideration" as defined in 10 CFR 50.92.
t A
l 6-2
7.0 CONCLUSION
S i
It has been shown in this SER that the TMI-2 Technical Spe-cification revis' ions listed in Section 2.0 of this SER can be accomplished without causing undue risk to the health and safety of the public.
Furthermore, the proposed revisions would permit more effective use of plant resources on recovery program activities.
L i
i i
I i
7-1
.i
8.0 REFERENCES
{
l 8.1 GPU Nuclear Letter 4410-84-L-0154. Technical Speci-fication Change Request No. 46, Safety Evaluation l
Report for Simplification of Technical Specifications for Water Injection, Core Cooling and Reactor Pressure Control Systems, Three Mile Island Unit 2, Revision 0, November 6, 1984.
8.2 GPU Nuclear Letter 4410-85-L-0110, Technical Speci-fication Change Request No. 49, Safety Evaluation Report for Simplification of Technical Specifications for Building Atmospheric Control Systems, Revision 0, June 18, 1985.
8.3 GPU Nuclear Letter 4410-84-L-0196, TMI-2 Operating License No. DPR-73, Docket No. 50-320, Fire Hazards Analysis, November 2, 1984.
~
8.4 GPU Nuclear Letter 4410-85-L-0077, GPU Nuclear Corporation seismic Design Criteria, April 16, 1985.
f 8.5 GPU Nuclear Report, Probability of Loss of Offsite Power at TMI-2, Risk Assessment Section, Licensing and Nuclear Saf ety Depar tment, Revision 1.
8.6 GPU Nuclear TMI-2 Operating Procedure 4210-OPS-3750.01, Class lE Electrical System, Revision 0, April 20, 1985.
t 8.7 IEEE Standard 308-1980, IEEE Standard Criteria for Class lE Power Systems for Nuclear Power Generating Stations.
8.8 IEEE Standard 485-1978, IEEE Recommended Practice for l
Sizing Large Lead Acid Storage Batteries for Generating Stations and Substations.
8.9 GPU Nuclear Letter 4410-85-L-0089, TMI-2 Safety Evaluation Report for Heavy Load Handling Over the TMI-2 Reactor Vessel, April 19, 1985.
8 10 Burns & Roe Drawing 3009, Vital Power Supply System Regulated Voltage System, Revision 16.
8-1 4
~
ll n
l e
8.11 Burns & Roe Drawing 3010, D.C. One Line Diagram and D.C. Power Panel Schedules, Sheet 1, Revision 7; Sheet 2, Revision 9.
J l
f 8.12 Burns 5 Roe Drawing 3004, 4160 v..Switchgear One Line
}
Diagram, Sheet 2, Revision 12.
8.13 Burns & Roe Drawing 3005, 480 v. Unit Substations one Line Diagram, Sheet 2,. Revision 16; Sheet 4, f
Revisiori 14.
(
8.14 Durns & Roe Drawing 3006, 480 V. Motor Control Center f
Auxiliary One Line Diagram, Sheet 3, Revision 14; f.
, Sheet 4, Revision 15; Sheet 5, Revision 7.
1 a
F f
a d
8-2
(
i
l 9.0 APPENDICES This section contains the following two appendices.
)
9.1 Emergency Diesel Generator Load Tables.
9.2 Evaluation of Existing Station Batteries.
f 9-1
o Appendix 9.1 Emergency Diesel Generator Load Tables This appendix contains tables of all loads automatically sequenced and all loads available for manual loading on the emergency diesel generators following a los's-of-off-site power.
The tables are organized as discussed in Section 4.2.1 of this SER.
In particular, the tables show how each load is categorized using the evaluation criteria of Section 4.2.2 (referred to as " Category" in the tables) and the l
safety evaluations of Section 5.0 of this SER (referred to as " Basis" in the tables).
A list of these tables and the l
references used to identify the loads in them is given below.
9.1.1 Loads Automatically Sequenced on the Emergency Diesel Generators Table A - AC Loads on Loading Sequence for Buses 2-lE and 2-2E These loads are obtained f rom GPUN THI-2 Operating Procedure 4210-OPS-3750.01 (Reference 8.6).
Table B - Loads on Station Battery Buses 2-lDC and 2-2DC These loads are obtained from Burns & Roe Drawing j
3009 and 3010 (References 8.10 and 8.11).
9-2
9.1.2 Other Class lE Electrical System Loads Table C - 4160 Volt Loads on Buses 2-lE, 2-2E, 2-3E and 2-4E These loads are obtained from Burns & Roe Drawing 3004 (Reference 8.12).
Table D - 480 Volt Unit Substation Loads on Buses 2-llE, 2-21E, 2-12E, 2-22E, 2-31E, and 2-41E These loads are obtained from Burns & Roe Drawing 3005 (Reference 8.13).
Table E - 480 Volt Motor Control Center Loads on Buses 2-llEA, 2-21EA, 2-llEB, 2-21EB, 2-llEC, 2-21EC, 2-12XD, and 2-22XD These loads are obtained from Burns & Roe Drawing 3006 (Reference 8.14).
9-3
TABLE A AC LOADS ON LOADING SEQUENCE PAGE 1 OF 2 FOR BUSES 2-lE AND 2-2E LOAD EQUIPMENT ID CATEGORY B AS IS DC Bus Rectifiers See Table B NDCT Aircraft Warning Lights 2A, 2B B2 5.16 Emergency Diesel Auxiliaries various A
5.22 Control Building lighting PDP-lE, RPC-1AE, B2 5.16 LPC-3AE, LPC-5AE, PDP-2E, LPC-2BE, RPC-4BE, LPC-6BE Radiation Monitoring RMP-EA, RMP-EB B1 5.15 Nuclear Services Closed NS-P-1 A
5.5 Ccoling Water Pumps Diesel Generator Building AH-E-24 A
5.22 Vent Fans Nuclear Services River NR-S-1 A
5.3 Water Strainers Diesel Fuel Transfer Pumps DF-P-1 A
5.22 Diesel Generator Building SD-P-10 A
5.22 Sump Pumps Diesel Generator Air DF-P-2 A
5.22 Compressors Suction Valve From BWST DH-VSA B2 5.1 Makeup Pumps MU-P-1 A
5.2 Control Room Supply Fans AH-C-16 B1 5.10 Motor Driven Emergency EF-P-2 A
5.13 Feedwater Pumps Nuclear Services River NR-P-1 A
5.3 Water Pumps
TABLE A (Continued)
PAGE 2 of 2 LOAD EQUIPMENT ID CATEGORY BASIS Cable Room Supply Fans AH-C-17 B2 5.11 Mechanical Equipment Room AH-C-19 B2 5.11 Coil Fans River Water Pump House Coil AH-C-20 A
5.3 Fans Control Building Area Coil AH-C-50 B2 5.11 Fans Diesel Generator Cooling Fans AH-E-50 A
5.22 Diesel Generator Swgr. Room AH-E-51 A
5.22 Cooling Fans Intermediate Closed Cooling IC-P-1 A
5.6 Pumps i
TABLE B LOADS ON STATION BATTERY PAGE 1 OF 1 BUSES 2-lDC AND 2-2DC LOAD EQUIPMENT ID CATEGORY BASIS DC Emergency Bearing Oil FW-P-1 A
5.13 Pumps for Turbine Driven Feedwater Pumps DC High Pressure Oil Lift RC-P-1, RC-P-2 A
5.12 i
Pumps for Reactor Coolant Pumps Generator Air Side Hydrogen SO-P-2 A
5.13 Seal Oil Backup Pump Turbine Generator Emergency M/EOP A
5.13 Auxiliary Oil Pump Control Building DC Panels DCC-1, DCC-2 C
5.21 Auxiliary Building DC Panels DCA-1, DCA-2 C
5.21 River Water Pump House DC DCW-1, DCW-2 C
5.21 Panels Turbine Generator Building DCT-1, DCT-2 C
5.21 DC Panels Diesel Generator DC Panels DF-X-1 A
5.22 Vital Power Supplies 2-IV, 2-2V, 2-3V, C
5.20 2-4V, 2-5V
A TABLE C 4160 VOLT LOADS ON BUSES 2-lE, PAGE 1 OF 1 2-2E, 2-3E, 2-4E LOAD EQUIPMENT ID CATEGORY BASIS Decay Heat Removal Pumps DE-P-1 A
5.1 Reactor Building Spray Pumps BS-P-1 A
5.23
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i TABLE D 480 VOLT UNIT SUBSTATION LOADS ON PAGE 1 OF 2 BUSES 2-llE, 2-21E, 2-12E, 2-22E, 2-31E, AND 2-41E LOAD EQUIPMENT ID CATEGORY BASIS Reactor Building Emergency RR-P-1 A
5.9 Cooling Booster Pumps Reactor Building Penetration AH-E-48 A
5.9 Cooling Fans Reactor Building Air Cooling AH-E-ll A
5.9 Fans Control Room Bypass Supply AH-E-4 B1 5.10 Fans Control Building Liquid AH-C-8 B2 5.11 Chillers Control Building Liquid AH-P-1 B2 5.11 Cooler Pumps Control Building River Water NR-P-2 A
5.3 Booster Pumps Cable and Battery Room AH-E-20 B2 5.11 Exhaust Fans Control Room Exhaust Fan AH-E-35 B1 5.10 Instrument Air Dryer IA-Q-1 A
5.14 Instrument Ai,r Compressors IA-P-1 A
5.14 Secondary Service Water SR-V74 A
5.13 Coolers to Mechanical Draft Cooling Tower Valve Heat Trace Panels HT-P-12B, B2 5.17 HT-P-13B Regulated Voltage Power 2-12R, 2-22R A
5.24 Supplies Traveling Screens SW-S-2 A
5.3
TABLE D (Continued)
PAGE 2 of 2 LOAD EQUIPMENT ID CATEGORY BASIS Nuclear Service Cooling Pump NR-V2 A
5.3
' Discharge Valves Nuclear Service Water Systems NR-V3, NR-V197 A
5.3 Cross Tie Valves Nuclear Service Cooling Pump NR-V4 A
5.3 Discharge Header Valves A
5.3 Trash Room Door Mechanical Trash Rakes SW-S-1 A
5.3 Screen Wash Pumps SW-P-1 A
5.3 Nuclear Services Rake SW-S-1A A
5.3 Screen Wash Pump Discharge SW-S-3 A
5.3 Strainer Miscellaneous Power Panels MP2-31E, A
5.3 MP2-41E
e TABLE E 480 VOLT MOTOR CONTROL CENTER PAGE 1 OF 6 LOADS ON BUSES 2-llEA, 2-21EA, 2-llEB, 2-21EB, 2-llEC, 2-21EC, 2-12XD, 2-22XD LOAD EQUIPMENT ID CATEGORY BASIS Decay Heat to Makeup Pump DH-V7 B2 5.2 Valves Reactor Building Spray Pump BS-V1 A
5.23 to Spray Header Valves Reactor Building Emergency RR-V2 A
5.9 Cooling Coil Booster Pump Discharge valves Decay Heat to Reactor BS-V3 A
5.23 Building Spray Pump Valves Seal Injection Isolation MU-V439 A
5.2 Valves Decay Heat Valves Upstream DH-V4 B2 5.1 of Reactor Vessel Letdown Cooler to Block MU-V2 A
5.2 Orifice Valves Reactor Building Normal RR-V26, v79 A
5.9 Cooling coil valves Makeup Pump Discharge to MU-V-16 A
5.2 Primary Loop Valves Decay Heat Valves DH-V-102 A
5.1 Chemical Addition Valves CA-V1, V3, V4, A
5.13 and V6 Decay Heat Service Cooler NR-V40 A
5.4 Inlet Valves 1
Nuclear Services Cooler NR-V6 A
5.5 Inlet Valves
e TABLE E (Continued)
PAGE 2 of 6 LOAD EQUIPMENT ID CATEGORY BASIS Nuclear Services River Water NR-V51 A
5.6 Pump to Intermediate Cooler Valves Nuclear Services Cooling Pump NR-V5 A
5.3 Discharge Header Valves Upstream of Reactor Building RR-VS, V6 A
5.9 Normal Cooling Coil Valves Primary Loop to Decay Heat DH-V1, V2, V3 B2 5.1 Removal Pump Valves V171 Reactor Building Normal RB-P-1 A
5.9 Cooling Water Pumps Feedwater to Steam Generator EF-V12 A
5.13 Valves Steam Generator Main Steam MS-V4, V7 A
5.13 Isolating valves Intermediate Cooling Valves IC-V1, V2 A
5.6 Reactor Coolant Drain WDL-V22 A
5.13 Isolation Valve Emergency Feedwater Header EF-V32 A
5.13 Valves Sodium Hydroxide Supply to DH-V8 A
5.1 Borated Water Supply Valves Primary. Loop to Letdown MU-V1 A
5.2 Cooler Valves A
5.2 Auxiliary Gear Lube Oil Pumps for Makeup Pumps A
5.2 Main Bearing Lube Oil Pumps for Makeup Pumps f
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TABLE E (Continued)
PAGE 3 of 6 t
LOAD EQUIPMENT ID CATEGORY BASIS A
5.2 Auxiliary Bearing Lube Oil Pumps for Makeup Pumps Emergency Feed Pump EF-V4 A
5.13 Discharge Valves Steam Generator Main Steam MS-V-15 A
5.13 Bypass Block Valves Intermediate Cooling Pumps IC-P-1 A
5.6 Decay Heat Pump Suction DH-V100 A
5.1 Valves Decay Heat Removal Cooler DR-V128 A
5.1 Valves Emergency Feedwater Bypass EF-V33 A
5.13 Valves Makeup Pumps to Seal Return MU-V36, V37 A
5.2 Cooler Valves Nuclear Service Cooler NR-V7, V8 A
5.5 Backwash Valves Reactor Building Sump to DH-V6 A
5.1 Decay Heat Removal Pump Valves Reactor Coolant Drain Pump WDL-Vil26 A
5.13 Discharge valve Reactor Coolant Drain Tank WDL-V1092, V1095 A
5.13 Containment Isolation Valves Pressure Steam Generator and WDG-Vl99 A
5.13 1
Core Flood Tanks Vent Valve Steam Generator Vents SV-V54,V55 A
5.13 Containment Isolation Valves
TABLE E (Continued)
PAGE 4 of 6 LOAD EQUIPMENT ID CATEGORY BASIS Decay Heat Closed Cooling NR-V42 A
5.4 Water Cooler Discharge Water Valves Nuclear Services River Water NR-V9 A
5.5 Cooler Discharge Valves Reactor Coolant Pump Seal MU-V377, V378 A
5.2 Water Supply and Return Valves Leakage Closed Cooling DC-V103, V114, A
5.4 Containment Isolation V115 Valves Leakage Closed Cooling DC-V96 A
5.4 Isolation Valves Core Flood Tank Bleed and CF-V144 A
5.13 Sample Valve Pressurizer Steam and Water CA-V10 A
5.13 Space Sample Line Valve Steam Generator Sample Line CA-V8, V9 A
5.13 i
Valves Nuclear Services Cooling NR-V55 A
5.3 Water Deicing Valve Reactor Building Sump Pump WDL-Vil25, V271 A
5.13 Discharge valve Reactor Coolant Pumps NS-V100 A
5.5 Coolant Inlet Valve Reactor Building Pressuriza-AH-V80 A
5.9 tion Valve l
Pressurizer Relief Tank Vent WDG-V2 A
5.13 Valve r
--~ - -e
TABLE E (Continued)
PAGE 5 of 6 4
LOAD EQUIPMENT ID CATEGORY BASIS Core Flood Tank to Bleed CF-Vil5 A
5.13 Holdup Tank Valve Reactor Coolant Pump Outlet MU-V25 A
5.2 to Seal Coolant Valve Heat Trace Panels HT-P-1A to 14A, B2 5.17 HT-P-1B to llB, 14B, 15, 16 Spent Fuel Cooling Pumps SF-P-1 A
5.7 Decay Heat Closed Cooling DC-P-1 A
5.4 Water Pumps Nuclear Service Closed NS-P-1 A
5.5 Cooling Water Pumps Core Flood Tank Valves CF-V1 A
5.13 Condensate to Emergency CO-V-78 A
5.13 Feed Pump Valve Nuclear Services Closed NS-V-84A A
5.5 Cooler Outlet Valve Reactor Building Hydrogen AH-V-25 A
5.25 Control System Valve Reactor Building Hydrogen AH-E-34 A
5.25 Pump Fan i
Nitrogen to Reactor Building NM-V-104 A
5.13 Isolation Valve Emergency Diesel Generator LP2-llEC, 21EC, A
5.22 Building Lighting Panels LPD-llEC Evaporator Cooler Fans RB-Z-1A, 1B A
5.9 Spray Water Circulating Pumps RB-Z-1A, 1B A
5.9 Spray Water Immersion Heaters RB-Z-1A, 1B A
5.9 i
l
TABLE E (Continued)
PAGE 6 of 6 LOAD EQUIPMENT ID CATEGORY BASIS Reactor Building Evaporator RB-P-2 A' '
5.9 Blowdown Pumps Miscellaneous Power Panels MP2-12XD, 22XD A
5.9 Letdown Line to Purification MU-V376 A
5.2 Domineralizer Valve Miscellaneous Power Panels MP2-llEB, 21EB A
5.26 9
Appendix 9.2 Evaluation of Existing Station Datteries This appendix documents a detailed evaluation of the required battery capacity necessary to power the remaining TMI-2 essential loads on each DC bus for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
The discharge characteristics of the existing TMI-2 station batteries are obtained from the PSAR and used for comparison in this evaluation.
The present battery sizing criteria of IEEE Standard 485-1978 (Reference 8.8) are used as the basis for the evaluation.
9.2.1 Required Battery Duty Cycle The required duty cycle for each DC bus (2-lDC and 2-2DC) is determined in Section 4.3.2 of this SER.
Momentary switchgear loads combine with a continuous bus load to create the total duty cycle shown in Figure 9.2-1.
The one second duration for the 50 ampere breaker trip load is rounded up to one minute in accordance with the IEEE S tandard.
Also, the Figure shows the terminology used by the IEEE Standard:
the individual loads (L), the periods when the load is constant (P), and the sections of the duty cycle (S).
The total load during period P1 is(Al = 150 amperes), the load during period P2 is(A2 = 100 amperes),
and the load during period P3 is(A3 = 175 amperes).
9.2.2 Battery Discharge Characteristics Figure 9.2-2 shows the ampere-hour ratings of the TMI-2 station battery for various discharge times, as given in the TMI-2 FSAR.
From this data, the capacity rating factor (K )
T curve is developed using the IEEE Standard criterion.
9-4
c 9.2.3 Evaluation Table 9.2-1 shows the evaluation of the required 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> battery duty cycle for a TMI-2 DC Bus, using the method of the IEEE Standard and the capacity rating factor curve for the TMI-2 battery.
A factor of 1.25 is used to account for the effect of battery age on reducing end-of-life capacity to 80% of the initial rated capacity.
The results show that a battery with an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> rating of at least 1100 ampere-hours is needed to power the 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> duty cycle for each DC bus.
Each TMI-2 battery has an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> rating of 1800 ampere-hours.
Thus, the present TMI-2 batteries are large enough to handle the essential plant loads for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
A separate evaluation not included in the table shows that an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> rating of 1565 ampere-hours is necessary to accomodate a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> duty cycle.
Therefore, the TMI-2 batteries.are capable of sustaining a duty cycle up to about 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, even when considering the 15% capacity design margin recommended by the IEEE Standard, Reference 8.8.
4 9-5
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3 LOAD DESCRIPTION AMPERES PER BUS L
DC PANELS AND 100 I
VITAL POWER SUPPLIES L
BREAKER TRIPS 50 2
1 L
BREAKER RESETS 75 3
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TMI-2 STATION BATTERY ESSENTIAL LOAD DUTY CYCLE BASED ON AN 8 HOUR LOSS OF OFF-SITE POWER FIGURE 9.2-I
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i AMPERE HOUR R ATING FOR 8 HOUR DISCH ARGE 1
K
=
T AMPERES AVAILABLE FOR "T" MINUTE DISCHARGE j
l DISCH ARGE FSt.R TOTAL l
K TIME AMPERE -HOUR AVAllABLE T
("T" MINUTES)
R ATING AMPERES l
1.0 28 1680 1.07 60.0 900 900 2.0 i
120.0 1200 600 3.0 480.0 1800 225 8.
i DISCHARGE CHARACTERISTICS OF TMI-2 STATION R ATTERY j
FIGURE 9.2-2
=
7 i
- ,o (P)
(T)
REQUIRED l
(A)
CHANGE PERIOD END CAPACITY 8 HOUR LOAD IN LOAD DURATION SECTION AT "T"
RATING PERIOD
( AMPE RES)
(AMPERES)
(MINUTES)
TIME RATE (K )
( AMPE RE-HOURS) 7 i
SECTION S1 1
A1 = 150 150 1
1 1.07 160.5 SECTION S2 150 1
479 8
1200 1
A1 = 150 Al-0
=
2 A2 = 100 A2-Al = -50 478 478 8
-400 800 SECTION S3 150 1
480 8
1200 1
A1 = 150 Al-0
=
2 A2 = 100 A2-Al = -50 478 479 8
-400 3
A3 = 175 A3-A2 =
75 1
1 1.07 80 880 (UNCORRECTED SIZE) X (AGING FACTOR) = REQUIRED RATING (880 A-H) X (1.25)
= 1100 AMPERE-HOURS 4
i EVALUATION OF 8 HOUR TMI-2 BATTERY DUTY CYCLE TABLE 9.2-1 4