ML20214V378
| ML20214V378 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 09/19/1986 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20214V356 | List: |
| References | |
| 2130K, NUDOCS 8610020263 | |
| Download: ML20214V378 (8) | |
Text
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LIMITING CONDITION FOR OPERATION SURVEILLANCE REQUIREMENTS 3.15.2 (Continued) 4.15.2. (Continued)
I F. From and after the date that a 125-volt F. During the period when a battery charger is i battery charger is made or found inoperable and the battery charge is being I inoperable,* reactor operation on that unit maintained by a battery charger of the other is permissible only during the succeeding 14 unit, the output voltage and current of the days. During this period the tie breakers cross-tied charger shall be checked and from the battery charger's bus to the recorder immediately and daily thereaf ter.
corresponding battery bus of the other unit In addition the testing specified in section shall be closed and the battery charger of 4.15.1.E.1 shall be performed immediately that battery shall be OPERABLE. and daily thereafter:on the two batteries 1 that are cross-tied.
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- One battery charger assigned to a 125-volt d.c. bus of a unit in the COLD SHUTDOWN MODE I lor REFUELING MODE may be used to fulfill the 4 operability requirement of a battery charger assigned to the 125-volt d.c. bus of an 1 operating unit by utilizing the cross-tie
] breakers.
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ATTACHIENT 2 DRSCRIPTION OF THE PROPOSED CHANGE Technical Specification Section 4.15.1.E.4.C requires that a capacity performance discharge test be conducted each refueling outage. In 1975, Section 3.15.2.e required that a unit be placed in cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the inoperability of a battery and/or distribution system. In March of 1975, commonwealth Edison Company recognized that the performance of the required discharge test for the 011 battery would require that 011 be inoperable for longer than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This would evidently require the shutdown of the opposite, operating unit.
In response to this concern, commonwealth Edison Company requested
] an amendment to the technical specifications to allow the use of the i
installed cross-tie breakers to allow one D.C. bus on the shutdown unit to fulfill the operability requirements for a D.C. bus on the operating unit for an indefinite time period. For example, if Unit I were in a refueling outage and Unit 2 was operating, this 1975 change allowed D.C. Bus 111 to carry D.C. Bus 011-2 during the time period that battery 011 was undergoing its performance discharge tests This would prevent a Unit 2 shutdown after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. (See attached schematic of Zion's D.C. Power System.)
This provision for the extended use of the D.C. buses dedicated to j a shutdown unit was only applied to Section 3.15.2.e. It was not extended
. to Section 3.15.2.f. It is currently believed that the reason for over-looking paragraph f was that the discharge tests and subsequent recharging is easily completed within approximately 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br />. Thus, there was no need, in 1975, to extend the proposed change to the 14 day limitation of paragraph
, f. Therefore,'the amendment request granted by the referenced letter only i addressed paragraph e.
Now, in 1986, Commonwealth Edison Company is undertaking the replacement of the Zion Station batteries. The act of replacing 011 battery requires in excess of 14 days. D.C. Bus 011-2 will be crosstied to Bus 111 immediately. A strict reading of Section 3.15.2.f would require a Unit 2
( shutdown after 14 days of crosstied operation. Thus, the need now exists to extend the logic currently contained in paragraph e to the requirements listed in paragraph-f.
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! The logic that formed the basis of the approval transmitted in the referenced letter is precisely the same as the logic that Commonwealth Edison is currently proposing to justify this proposed change. As discussed in the referenced letter, when a unit is in cold shutdown or refueling modes three batteries are not required. Therefore, using one of the batteries for a i
shutdown unit to supply power to a bus of the other unit is acceptable. The l
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shared bus is still available to the shutdown unit. This provides three buses for the operating unit and two buses for the shutdown unit. It was not the intent of the original Technical Specifications to require shutdown of both units under these conditions. Therefore, this proposed change is in effect a clarification and does not reduce the margin of safety defined in the basis for the Technical Specifications.
The acceptability of this proposed change is further justified by the fact that it is extremely. difficult to remove a battery from service, while leaving the charger carrying the D.C. bus. As can be seen,from the attached diagram, there is no battery output breaker. That is, the physical battery leads would have to be lifted in order to remove the battery from service while leaving the charger connected to the D.C. bus. Thus, if a battery were to be inoperable, it is extremely likely that the charger would be inoperable also. This means that there would be no reason to differen-tiate between the applicability of paragraph e and the applicability of paragraph f with one unit in cold shutdown and the other unit operating.
Based upon the above discussion, the proposed change is a clarification of the pre-existing intent of the Technical Specifications.
That is,'the existing technical specifications allow for the use of a D.C.
bus from a unit in cold shutdown or refueling modes to be utilized to fulfill the operability requirements for the opposite operating, unit through the use of the cross-tie breakers.
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DESIGN FEATURES I
2 5.6 FUEL STORAGE CRITICALITY -
- 5. 6.1.1 The spent fuel storage racks are designed and shall be maintained with:
- a. A k,ff equivalent to < 0.95 when flooded with unborated water, including all calculational uncertainties and biases, as described in Section 9.1 of the FSAR.
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- b. A nominals ("-inch center-to-center distance between fuel assemblies placed in the storage racks.
5.6.1.2 The k for new fuel for the first core ' loading stored dry in the spent fuel,[(orage racks shall not exceed 10.95 when flooded with water.
DRAINAGE 5.6.2 The spent fuel storage pool is designed and shall b'e maintained to prevent inadvertent draining of the pool below elevation 819 feet.
CAPACITY 5.6.3 The spent fuel storage pool is designed and shall be maintained with a storage capacity limited to no more than 444WL fuel assemblies.
40 f t 5.7 COMPONENT' CYCLIC OR TRANSIENT LIMIT 5.7.1 The components identified in Table 5.7.1-1 are designed and shall be maintained within the cyclic or transient limits of Table 5.7.1-1.
LA SALLE - UNIT 2 5-5
,a . , , . , _ - , - -, , ,-
D.C. BUS 212 480 V, 480 V D.C. BUS 112 D. C. B U S Ill D.C. BUS 2ll BUS BUS 238 239 139 13 8 V BATT. 212 D.C BUS B ATT. 211 BATT.112 B ATT. Ill D.C. BUS FD.BKR.
Ill BUS 211 BUS FD.BKR.
(Y TO FD.DCBKR. ( D.C. BUS BUS l12 112 BUS l FD.
TO DC BKR.(
BUS Ill BUS 0112 )
TIE TO DC DC BUS )
TIE TO TO DC (
) DC
) BUS 2ll (l (TODC BUS 212 l l
TIE TO DC 111 BUSl I BUS lli n 211
( D.C. BUS n 212 l12 n BUS 212 lli n CHGR. 212 BUS BATT. CHE CHGR.
CHGR BATT. CHGR. CHGR. BATT.CHGR, TIE TO DC D.C. BUS BATT.CHGE BUS 211 TIE TO DC 212 FD. BKR.
til FD. BKR. 211 BUS 211 FD. BKR.
112 FD. BKR. BUS 112 TO BATT. 212 TO BATT.111 TIE TO DC TO BATT.211 TO BATT.112 '
f ~f BUS Oll-1 f ~f BATT, BATT.
BATT. BATT.
112 111 X 211 212 D.C. BUS D.C. BUS 011-1 BUS 011-2 BUSf
D.C. BUS 011-1 BUS 211 BUSIll D.C BUS 011-2 BATT. Oil
( FD.BKR.
BATT. Oil (
l FD.BKR.
J TO DC TO DC BUS Oll-l BUS Oll-2 1
^
- BATT. CHGR. Oil FD. Oli
( 137 v ^
BKR. TO BATT. Oil CHGR (237 .
~5 BATT.
Oli 125 VDC DISTRIBUTION SYSTEM
ATTACHMENT 3 EVALUATION OF SIGNIFICANT HAZARDS CONSIDEhATION PROPOSED CHANGES TO ZION TECHNICAL SPECIFICATION APPENDIX A - SECTION 3.15 f AUXTLTARY ELECTRICAL POWER SYSTEMS DESCRIPTION OF AMENDMENT REOUEST I
An amendment to the Zion Facility Operating License is proposed to allow the use of the battery charger assigned to a 125V D.C. bus of a shutdown unit to be utilized to fulfill the operability requirement of a battery charger assigned to a D.C. bus of che opposite, operating unit.
BACKGROUND 10 CFR 50.92 states that a proposed amendment will involve a no significant hazards consideration if the proposed amendment does not:
(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.
I In addition, the commission has provided guidance in the practical applica-tion of these criteria by publishing eight examples in 48 FR 14870.
l The discussion below addresses each of these three criteria and demonstrates that the proposed amendment involves a no significant hazards consideration.
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BASIS FOR NO SIGNIFICANT HAZARDS CONSIDERATION DETERMTNATION l
Does the proposed amendment l (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or
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(2) Create the possibility of a new or different kind of accident from any accident previously. evaluated; or (3) Involve a significant reduction in a margin of safety?
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s' DISCUSSION - ITEM #1 The operating unit will have three batteries and three operable 125 V.D.C. buses available to it at all times. Thus, there has been no change in the availability or quality of the D.C. control power available to the operating Zion reactor.
Since there has been no degradation in the integrity of Zion's electrical system, then all safety-related systems will operate as previously evaluated. Thus, there will be no change in the consequences of any accident previously evaluated.
The extension of the intended flexibility to allow a battery charger assigned to a shutdown unit to be utilized to fulfill the operability requirements of an operating unit has no effect on any of Zion's systems.
In addition, none of the operating parameters of the Zion reactors will be altered. Thus, there will be no change in the probability of any accidents previously evaluated.
Based upon the above discussion this proposed amendment does not involve a significant increase in the probability or consequences of any accident previously evaluated.
DISCUSSION - ITEM #2 As discussed above, the use of the crosstie breakers to allow the battery charger assigned to a shutdown unit to be utilized to fulfill the operability requirements of the opposite, operating unit has no effect on any of Zion's systems nor on the operating conditions of the Zion reactors.
In addition, the reliability and integrity of the Zion electrical system will be unaltered. Thus, the possibility of a new or different kind of
' internally generated accident cannot be created.
The use of the 125 V.D.C. bus crossties has no conceivable effect on the generation of any external event. That is, there is no connection between the alignment of the D.C. system and the susceptibility of Zion Station to such external events as earthquakes, tornadoes, and floods.
Based upon the above discussion, this proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
DISCUSSION ITEM #3 As discussed above in Attachment 2 and in the referenced letter, there will be three D.C. buses continuously available for the operating unit and two buses available for the shutdown unit. Thus, the operating unit remains capable of withstanding a postulated single failure at all times.
Therefore, this proposed change does not reduce the margin of safety.
r It should be noted that the proposed Technical Specifications are an administrative change. That is, this change will achieve consistency between the intent of paragraph section 3.15.2.e and Section 3.15.2.f. Thus, example (i) is applicable to the proposed change. Example (i) reads as follows:
(1) A purely administrative change to technical specifications: for excmple, a change to achieve consistency throughout the technical specifications, correction of an 'stror, or a change in nomenclature.
Therefore, since the application for amendment satisfies the criteria specified in 10.CFR 50.92 and is similar to examples for which no significant hazards consideration exists, Commonwealth Edison Company has made a determination that the application involves no significant hazards consideration.
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