ML19339D136

Forwards marked-up Supplemental Matl Submitted in Response to NRC Questions Re Power Sys Branch Issues.Physical Separation & Electrical Isolation,Low or Degraded Grid Voltage,Shared Diesel Generator & Fire Protection Addressed

ML19339D136
Person / Time
Site:	LaSalle
Issue date:	02/10/1981
From:	Delgeorge L COMMONWEALTH EDISON CO.
To:	Youngblood B Office of Nuclear Reactor Regulation
References
LOD-81-40-14, NUDOCS 8102170330
Download: ML19339D136 (29)

Text

Commonwrith Edison One First Natronal Plata. Crucago, Illinois Address Reply to: Post Office Box 767 Chicago, Illinois 60690 February 10, 1981 Mr. B.J. Youngblood, Chief License Branch 1 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C.

20555 Subj ect:

LaSalle County Station Units 1 & 2, Resolution of Power Systems Branch questions, NRC Docket Nos. 50-373/374 LOD 81-40-14

References:

(a) L.0 DelGeorge letter to B.J. Youngblood (LOD 81-40-10 Enclosure 3), dated February 10, 1981.

(b) L.0. DelGeorg'e letter to B.J. Youngblood (LOD 81-40-15, dated February 10, 1981.

Dear Mr. Youngblood:

Attached for your review are supplemental materials submitted in response to NRC Staff questions related to the following Power Systems Branch issues:

1.

Physical Separation and Electrical isolation (see reference (a))

2.

Low or Degraded Grid Voltage - see Enclosure 1 3

Shared Diesel Generator - see Enclosure 2 4

Reactor Containment Electrical Penetrations - see Enclosure 3 5.

RPS MG-Set Power Supplies (see Reference (b))

6.

Fire Protection - see Enclosure 4 7.

DC System Adequacy - see Enclosure 5 Each of these issues with the exception of items 1 and 5 are discussed in the enclosure to this letter as referenced above. The separation issue as previously discussed in Reference (a) should be applied to this Power Systems Branch question as well, inasmuch as that response was prepared to resolve both ISCSB and PSB concerns as discussed with those two branches at the meeting of February 6, 1981.

The additional drawings requested by the Staff on the RPS l'G set were submitted in Reference (b).

In the event you have any further questions on these matters,

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please direct them to this office.

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Very truly yours, L.O. De1 George Nuclear Licensing Administrator -6 p

cc: NRC Resident inspector-LSCS g8817o330

ENCLOSURE 1 LOW OR DEGRADED GRID VOLTAGE in response to NRC Staf f question q040.102 Commonwealth Edison described the second level of degraded grid voltage protection to be implemented on LaSalle County. As was previously committed this second level of protection will be installed prior to the start of the second full cycle on Unit 1.

The protective relay design was discussed with the Staff in depth at the meeting of February 6, 1981. At that time the following information was provided:

1.

The design voltage of equipment connected to the 4160 volt class IE Bus is 4000 V. Therefore, the range over which the operation of this equipment can be operated without jeapordizing long term equipment operability is 3600V to 4400V. As indicated in q040.102 the second level of undervoltage protection will be set at 3744V which is greater that the minimum allowable value of 3600v.

2.

The 5-minute time delay to which reference is made in Section 8.2.3 3 of the FSAR is intended to provide a minumum time period during which, under normal reactor operating conditions, corrective action can be initiated to remedy the situation which leads to the operation of both levels of degraded grid protection.

In the event this degraded voltage condition exists concurrent with a LOCA, the 5-minute timer will be bypassed. Although not discussed on February 6, the undervoltage relays which detect the degraded condition have a built in time deiay adjustment capability 1 to 10 seconds. This time delay will be set at 10 seconds to preclude premature transfer from oft site to on-site power.

i 3

Also discussed at the February 6 meeting was the automatic load shedding logic described in Section 8.113 of the FSAR.

Closer examination by the applicant after the meeting revealed that the planned design of the second level of degraded grid voltage

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protection will not initiate automatic load shedding of emergency buses when the onsite source is supplying power to these buses.

4.

The model verification position delineated in Section 4 of q040.102 was also discussed at the February 6 meeting.

Subseruent' review I

of the existing LaSalle County Initial Tast program confirmed i

that such verification testing is planned. The " Emergency i

Power Redundancy Test" (PT-AP103) discussed in Table 14.2-6 of the FSAR require in Acceptance Criteria 8 that the calculational model used to analyze off-normal grid voltage be confirmed by voltage and current measurements.

In this regard, a minimum i

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Mr. B.J. Youngblood, Chief Page Two February 10, 1981

4. (con't) of two data points will be established, one for light load conditions (i.e. within 15% of no load condition) and one for heavy load conditions (i.e.

50% or greater of maximum load)

The computer model will be run without software change using measured input load and grid state conditions and the results for equipment bus voltages compared with those actually measured in the field.

It is judged that this emperical assessment satisfies the objectives of the testing defined in Q040.102 l

Part 4.

The FSAR will be amended to reflect the information discussed in items 2 and 3 above. The proposed text changes are submitted as attachment E-1.

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Mr. B.J. Youngblood, Chief Page Two February 10, 1981

4. (cen't) of two data points will be established, one for light load conditions (i.e. within 15% of no load condition) and one

-for heavy load conditions (i.e.

50% or greater of maximum load)

The computer model will be run without sof tware change using measured input load and grid state conditions and the resui's for equipment bus voltages compared with those actually measured i,. the field.

It is judged that this emperical assessment s

atisfies the objectives of the testing defined in q040.102 Part 4.

The FSAR will be amended to reflect the information discussed in items 2 and 3 above.

The proposed text changes are submitted as attachment E-1.

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$10*i 5$$$ N?c A;d$b70.Y>o@nd level of degraded b

• /~ h In response to the,NRC's request, q]M as yg grid voltage protection is to be added at La Salle A brief f5 i

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discussion of the addit 9nal scheme is as follows.f' i

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M Two undervoltage relays are to be installed on each 4 kV ESF bus; these are connected in a two-out-of-two logic similar 34 V,[3 31 to the existing undervoltage relays.

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1d *D pOrgaum.of both of these added relays initiates an alarm

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4i in the control room and starts a 5-minute timer, via-e+new-

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If the degraded voltage is not corrected within QS the 5-minute period, the bus will automatically be transferred

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from the offsite power source to an on> site diesel

• generator.,

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This second level'undervoltaghotection has a sethoint o#

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~n h.5 90%ofnormalbusvoltagefitpicksupat3744 volts (decreasing) on the buses 5 The minimbs voltage relav orotection from the t'-

existing unde Ro $ elays is set to p'tch T W 2Tf5 volts

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or 65:6% of the normal bus voltage for Divisions 1 and 2 and i

2870 volts c r 71.8% of the normal bus voltage for Division 3 as previously described.

f 8.2.3.4 Conclusion i

i This analysis shows that the auxiliary distribution system at LSCS has the capability to adequately handle worst case

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loading and maintain all voltages well within equipment ratings under the postulated most severe contingency condi-tions.

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LSCS-FSAR AMEUDME:;T 04-(

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T;.e requested voltage profiles are provided in Table

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Q40.82-2.

(5)

The undervoltage relays that sense loss of offsite i

power are located in the following medium voltage switchgear:

151, 152, 251 and 252 (for the 6900-volt buses); 141Y and 241Y (for the Division 1 4160-volt buses); 142Y and 242Y (for the Division 2 4160-volt buses); and 143 and 243 (for the Division 3 4160-volt buses).

The undervoltage trip setpoints are 5220 volts for -

the relays in switt.hgear 151, 152,~251, and 252;

"""y sW volts for the relays in - switchgear 14 lY, 142Y,

,, f 241Y, and 24 2Y ; and 2870 volts for the relays in i

switchgear 143 and 243.

These values were selected to provide m'ximum protection for the. equipment from a

the adverse effects of.austained undervoltage condi-tions while preventing nuisance tripping as a result of system fault clearing or large motor starting.

(6)

The intent of this question i.s not understandable.

It is unclear how a " degradation of the grid system voltage" can be assumed yet "the voltage values...

corresponding to the maximum value of grid voltage" be provided.

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(7)

Response to this portion of the question can not be provided before part (6) above is clarified.

(8)

The bus voltage monitoring equipment available in the control room for Unit 1 includes the follcwing:

Bus Equipment i

151 and 152 Voltmeter and selector swi'tch 141X and 141Y Voltmeter and selector switch d.

14 2X and 142Y Voltmeter and -selector - switch s

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~143 Voltmeter and. selector switch N

131A and B, 133A and B Voltmeter and selector cwitch 132A and B,

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134A and B Voltmeter and selector. switch

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l 131X and Y, 13 7X and Y,

. voltmeter and selector switch 133 Voltmeter and selector switch D**

3 Q40.82-3 wc o

LSCS-FSAR AMENDME T '2s

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.e Bus Equipment 132X and Y, 134X and Y Voltmeter and selector switch 138 Voltmeter and selector switch 13 5X and 13 5Y Voltmeter and selector switch 136X and 136Y Voltneter and selector switch 143-1 Voltmeter Similar equipment is available in the control room for Unit 2.

A bus undervoltage alarm is provided in the e>nossaJ e.asus room for each 6900-volt, 4160-volt and 480-volt switchgear bus.

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040.82-4

r LSCS-FSAR AMENDMENT 26

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in determini,9 5ese conditions and related probabilities b

were very c anservative.

Operating experience on the Edinon system aisc confirms the accuracy and conservatism of the system voltige calculations.

The analysis of degraded system voltage conditions considered x

various cases starting with the loss of one generator to a q*

y case considering the simultaneous loss of four generators x

and six transmission lines.

The worst case studied produ k

i a voltage of 331 kV with probability of occurrence of 10 ged y '*

' ';I)i The above analysis indicates that the Commonwealth Edison Company system voltage, even for severely degraded conditions, e

would remain at a level at which equipment malfunction because k3 of low voltage would not occur.

If voltages much lower than 0 0 y the probability is great that those indicated were to occur, the system would collapse completely, i.e., a no-voltage condition )v N

would result.

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More specifically:

1.

Based on the above analysis of system voltages, the proba-g bility of a system voltage level occurring low g ough u

to result in equipment failure is very low (10 or less).

gk It is also Commonwealth Edison Company's opinion that N

lower system voltages would result in a complete collapse

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of the system, i.e.,

a no-voltage condition.

\\ hi, au tic load shed of 8

The present system design allows [dwe source is supplying 2.

the emergency buses when the omed ij power to the sequenced loads on 'the emergency bus.

The d{

design & wee-includesload shedding if the onsite source supply breakers are W=4 cyhd cAdde8<. 44 N bhe uses re bei suppilsd from\\the/'gsita

.er do/emer encypre entio' gof loa' shedojyig f ro;a' thaf6me rg.efic'y W

urce p s'\\f r al nde torta co;tdi ons (loss \\of v61tage\\senping)

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/ent. '\\p'w vol.t$ge\\applie,d

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.oa'd sh (ding i's ref ain'ed hen,in 'tiatdd On h

e;aerkency/ bus, b m t d loss-#f-vo'1.ta)ge sensor be,ca,use.-equip,; tent ma>1func'bsion g

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ure c-Nccu/'at thes\\ voltage I'evels.

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ble,,gsens4ble t',o/shed ' load tk proteht s

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r p sr#4 eq 1pmeg 3.

Onsite power source testing is addressed in chapter 16.0,'

" Technical Specifications".

4.

Voltage levels of safety-related. buses will.be measured f.

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and documented before initial reactor power operation.

~,f The data are to be recorded ii. i.ne'LSCS Emergency Power

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Redundancy Preoperaticnal Test (PT-AP103).

i 040.102-6 0**D D

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LSCS-FSAR AMEN 1'. MENT 59 e

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Asecondlevelofdegradedgridvoltageprotectionrelaydd{yy s

are to be installed at LSCS as a result of NRC's i-hoW that the above analysis is non-conclusive.

See Subsection 8.2.3.3 for the revised description of the dual undervoltage protection of ESF buses.

I Installation of these second level relays and timer will occur during the first scheduled refueling outage after delivery of the required equipment to.the site.

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ENCLOSURE 2 SHARED DIESEL GENERATOR Although the shared diesel design at LaSalle County has been judged acceptable by the NRC Staff for Unit 1 operation, a question has been raised relative to the conformance of the design to the regulatory position of RG 1.81.

This issue has been discussed with the Staff, and the focus of the remaining concern is the situation attendant to a loss of off-site power and a coincident accident signal from Unit 2.

The shared diesel would automatically supply Unit 2 safety loads and (1) the diesel support systems do not have an alternating current source nd (2) the alternating current source to the nit 1 250v d.c.

and 125v d.c.

system is unavailable.

The app ~Icant's response to Q040.111 has been revised as discussed with the Staff on February 6, 1981 to resolve the remaining questions.

A copy of the proposed revision to Q040.111 is attached to this enclosure, and will be formally documented in a future amendment to the FSAR.

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LSCS-FSAR AMENDMENT 'XD gggr, 1o93 swing diesel generator will a'atomatically trip from the bus where the testing is l'9ir g done and automatically close onto the bus receiving the w cident signal.

(4)

No coordination is required between the unit operators in order to accomplish item (3).

However, some degree of coordination is required to accomplish the operator action discussed in item (1).

(5)

The auxiliary systems associated with, and required for, the operation of the shared diesel generator are:

s a.

engine control system; b.

air start system; c.

lube oil system; d.

fuel oil system; e.

cooling water system; and f.

HVAC system.

These auxiliary systems are powered as follows:

4 a.

The engine control system is powered by 125-Vdc from either the Unit 1 or the Unit 2 ESF Division 1 125-Vdc battery.

If the d-c feed from one unit should fail, an alarm sounds in the main control room and the control power is switched to the other unit.

b.

The air start system has two air compressors; one powered from Unit 2, both of which are capable of supplying the total' air receiver requirements.

c.

The lube oil system has engine-driven pumps for use during normal operation.

During standby con-dition, the soak back pump is operated continuously and is powered by a 125-Vdc motor.

The power for this motor is from control power which, as discussed in item a, can be from either Unit 1 or Unit 2.

d.

The fuel oil system has an engine' driven fuel pump for use'during normal operation.

During' starting, the primary pump is used.

This pump is powered by 125-Vdc control power which, as discussed in-item a previous 1v, can be powgred from either Unit 1'or Unit 2_.Fxe n ei il tv - r se r m a c.

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G adMeggyySN' d The cooling water system has one motor driven pump.

s e.

This 125-horsepower motor has the capability to be powered from either Unit 1 or Unit 2 and will auto-matically be fed from the unit that has power available, i.e.,

the unit to which the swing diesel generator furnishes pwer when all of fsit.e_.gnger has_bs3n_ lost.

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n The HVAC system / Tone"Q Q eh<1bthTcn th~e swing alesel-e he

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generator is Tocated has one motor-driven vent f anelv This f an motor Mum the capability to be powered from either Unit 1 or nit 2 and will automatically be.*

fed from the unit that has power available, i.e.,

the unit to which the swing diesel generator _ furnishes power when all offsite _ oowe_r _ has,._b eLlosp(See Rep i

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/ A concern relative to maintaining the 250V DC and 125V DC batteries I

from becoming discharged over an extended period of time on the non i

.k accident Unit when offsite power is not available is alleviated by the

\\followingdiscussion:

l, 1

The Unit 1 and Unit 2 DC Systems have a cross connection l

between units uhich would allow one bar.tery charger to supply both DC Systems.

This cross c.onnection can be i

1 seen in Figure 8.3-11.

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Since the Unit 2 125V DC battery charger rating is j

already more than two times greater than required (This q

situation came about in order to make use of existing I

qualified equipment), the Unit 1 125V DC battery charger will be replaced with a battery charger rated more than two times the presently installed battery charger.

Thus, this would allow either the Unit 1 or the Unit 2, 125V DC battery charger to be adegaately sizedsto feed both DC Systems simultaneously.

The 250V DC battery loads are shown in Table 8.3-11.

The RCIC pump loads shown on this table are energized by an accident signal and will not start during Unit 3 shutdown.

The emergency bearing oil pump and the emergency seal oil pump have AC backup pumps powered from the Di~ vision 2 diesel generator.

The UPS 120V AC panelboard has a Unit 2 alternate power source.

Thus the emergency bearing oil pump, the emergency seal oil pump and the UPS may be tripped off rhe 250V DC distribution bus, lesving virtually no further drain on the 250V DC battery.

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i Therefore, based on the above thare is no need to automatically or manually iransfer the AC source of power to the 250V DC and 125V DC battery chargers.

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Q40.111-5

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ENCLOSURE 3 REACTOR CONTAINMENT ELECTRICAL PENETRATIONS Although this issue is the subject of a technical appeal, additional information is submitted as Attachment E-3 regarding the coordination of the primary breaker protection for the containment electrical penetrations.

Three plots are provided each representative of a class of circuit design:

1.

Case 1-Typical MCC Load Of the 24 containment electrical loads, 17 are represented by this case, i.e.

primary breaker setpoint at 10 amps.

2.

Case 2-MCC Load Of the 24 containment electrical loads, 2 are represented by this case which includes a thermal overload bypass, i.e primary breaker setpoint at 70 amps. L 3 other circuits have p r i ma ry breaker setpoints at or near 70 amps but do not require a thermal overload bypass.

The efore, the case shown bounds these 3 circuits 3

Case 3-Largest MCC C.B.

Setting Of the 24 containment electrical loads, 2 are represented by this case, i.e.

primary breaker setpoint at 175 amps.

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ENCLOSURE 4 FIRE PROTECTION A comprehensive fire protection review of LaSalle County Station was conducted in 1979 and 1980 at which time with limited exception all outstanding issues were resolved to the satisfaction of the NRC Staff.

With the promulgation of 10CFR50 Appendix R,

certain additional questions were informally posed by the Power Systems Branch on the following subjects:

1.

Adequacy of (VAC system design in cubicles relied uoon to mai.itain hot shutdown.

This issue was addressed in Secticas H.4.3 and H.4.1.5.e of the FSAR and, it is judged, was resolved.

2.

The potential for inter-system LOCA resulting from a single fire effecting the controls of redundant isolation valves.

In general this potential problem is precluded in the LaSalle County design by the existence of check valves in each line of sufficient size for which a system overpressurization could occur if the redundant electrically operated valves failed simultaneously.

These check valves have been classified A/C in' Table 6.2-21 of the FS AR and are thereby tested as system isolation valves.

In addition, an augmented leakage test program, described in response to Qlll.86 has been implemented to assure the leak tightness of the check valves.

Therefore, in the extremely remote case of the single fire in the control room which is necessary to cause the simultaneous opening of the redundant electrically operated isolation valves, the tested check valve will protect the pressure boundary.

This justification is documented in the attached proposed revision to Sections H.4.2.17 and H.4.2.21.2 of the FSAR.

These changes will be formally documented in a future amendment to the FSAR.

Also discussed in this package is the only piping subsystem modified to resolve the same concern.

That modification is discussed in the revision to Section H.4.2.21.2 of the FSAR.

3. The design of Class lE or non-Class lE cables that are associated with the essential shutdown systems and the remote method of shutdown, it is judged that the cable separation design employed at LaSalle County as described in Reference (a) as well as the coordinated short circuit provisions provided for all associated cable of the design in question assures the protection of any safe shutdown systems with which these cables are associated.

The discussion in Section H.4.2 has been revised to document the fact of this circuit protection.

The proposed revision to Section H.4.2 is attached, and will be formally documented in a future amendment to the FSAR.

LSCS-FSAR AMENDMENT 47 OCTOBER 1979 m

the reacror can be brought to a hot shutdown condition frcm

(

the remote shutdown panel in the auxiliary electric equipment cot.{. 03 gygi: ff{~li room as discussed in Subsection 7.1.4.1.4.

However, a fire

.aL I6,

affecting the operational capability of the auxiliary control panel IPM0lJ which contains controls and logic for the Divi-STf[il sion 1 and Division 2 diesel-generators (DG's), the asscciated DG output breaker, and the Division 1 and Division 2 ESF suitchgear}

feed breakers for 480 volt substations could affect the safe shotdown of the reactor frou the remote shutdown panel due to a loss of a-c power.

Therefore, local control capability independent of the control room will be provided for the electricab cquipment on this panel nccessary to support safe shutdown i

of the reactor from the remote shutdown panel.

H.4.2.18 Fire Zone 4C2 (Unit 1 Auxiliarv Building, Elevation 768 feet 0 inch, Main Floor)

The safe shutdown equipment and cabling locared in fire zone 4C2 are listed in Table H.4-31.

A fire in this zone could affect only components and cables of the basic shutdown method.

Therefore, the alternate method, which ir independent of this fire zone can be used to bring the reactor to a hot shut-down condition.

H.4.2.19 Fire Zone 4D1 (Unit 1 Auxiliarv Building, Elevation 749 feet 0 inch, Cable Screadinc Room)

Fire zone 4D1 was divided into two subzones.

Fire subzone 4Dl-1 is the cable riser aisle and fire subzone 4Dl-2 is the cable spreading area.

These two subzones are separated by a 3-hour fire rated (concrete block) wall so that a fire' in one subzone does not affect the other.

H.4.2.19.1 Fire Subzone 4Dl-1 The safe shutdown equipment and cabling located in fire subzone 4Dl-1 are listed in Table H.4-32.

A fire in this subzone could affect only the RCIC system, RHR Loop A, and ADS Division 1.

Therefore, HPCS and ADS Division 2 are available for decay heat removal and reactor water makeup.

RHR Loop B is available

(

for suppression pool cooling to assist in getting the reactor to a hot shutdown condition.

H.4.2.19.2 Fire Subzone 4Dl-2 The safe shutdown equipment and cabling locate ~d in fire subzone 4Dl-2 are listed in Table H.4-33.

A fire in this subzone could i

only affect the RCIC system, RHR Loop B, and ADS Division 2.

)

Therefore, HPCS and ADS Division 1 are available for decay heat removal and reactor water makeup; RHR Loop A is avail-i able for suppression pool cooling in order to bring the reactor to a hot shutdown condition.

(

l H.4-13 i

INSERT FOR SUBSECTION H.4.2.17 See Subsection 11. 4. 2. 2 1. 2 for a discussion of a fire causing the spurious opening of redundant values used to separate the primary coolant boundary and any low pressure piping system.

t

AMENDMENT 49 LSCS-FSAR MAY 1980 H.4.2.20 Fire Zone 4D3 (Unit 1 Auxiliary Building', Elevation

~~

(')

749 feet 0 inch, Electrical Equipment Room)

The safe shutdown equipment and cabling located in fire zone A fire in.this zone could 4D3 are listed in Table H.4-34.

Therefore, both affect only RHR Loop B and ADS Division 2.and ADS Division 1 are available HPCS and RCIC, RHR Loop A is avail ~

heat removal and reactor water makeup.

able for suppression pool cooling to assist in getting the reactor to a hot shutdown condition.

j H.4.2.21 Fire Zone 4El (Unit 1 Auxiliary Building, Elevation _

Room)

• 731 feet 0 inch, Auxiliary Electric Ecuipment Fire zone 4El will be divided into two subcones by a 3-hour fire rated barrier so that a fire in one subzone does not The location of this barrier 'is shown on affect the other. Fire subcone 4El-1 is located to the lef t Figure H.4-1.of this barrier and fire subzone 4El-2 is located to the

~

right of this barrier H.4.2.21.1 Fire Subzone 4El-1

~

The safe shutdown eqU'i ment and cabling located in fire A fire in this subzone 4El-1 are listed in Table H.4-35.

and subzone could only affect the RCIC system, RHR Loop B, Therefore, HPCS and ADS Division 1 are ADS Division 2.

I

available for decay heat removal and reactor water makeup.

RHR Loop A is available for sunpression pool cooling to assist in getting the reactor to a hot shutdown condition...

H.4.2.21.2 Fire Subcone 4El-2 The safe shutdown equipment and cabling located in fire sub-The remote shutdown zone 4El-2 are listed in Table H.4-35a. Equipment and cables panel is located in this fire subzone.for the remote shutdown panel are The isolation of these circuits and H.4-39 by the letters RSP.

from the control room is illustrated on the electricalA fire in t l

schematics in Section 1.7 and RHR Loop B.

the RCIC system, ADS Division 1, RHR Loop A, l

Therefore, HPCS and ADS Division 2 are available for decayBoth modes of cooling heat removal and reactor water makeup.

Therefore, the suppression pool would be affected, however.

controls will be provided for the RHR B Pump and the RHR 1C and 1D service water pumps that will be independent of fire subzone 4El-2 so that RHR Loop B will be available for suppression pool cooling.

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H.4-14

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INSERT FOR THE END OF SUBSECTION H.4;2.21.2 l

(BOTTOM OF PAGE H.4-14)

To prevent the possibility of a fire at the remote shutdown panel or the main control room (

Subsection H.4.2.17) from causing spurious opening of both RHR suction cooling line 1

isolation valves lE12-F008 and lE-12-F009 while the reactor is at operating pressure and thereby exposing low pressure RHR piping to reactor pressure, the motor control center circuit breaker furnishing both motive and control power for valve lE12-F008 will be racked out and locked in that position when the reactor is at operating pressure and temperature.

A separate power supply will be furnished for the indicating lights of valve 1E12-F008.

Note that since these two isolation valves (lE12-F008 & lE12-F009) are directly in series only one of the two valves must have its associated power supply removed to eliminate the possibility of a fire causing both valves to open and expose the low pressure RHR piping to reactor pressure.

The primary safety objective of this modification is to prevent intersystem LOCA; wherein leakage through valves isolating the reactor coolant pressure boundary (RCPB) may overpressurize a low pressure system.

This concern has been addressed in greater detail in the response to Q111.86, and a satisfactory basis for resolving this issue on LaSalle has been established with the Mechanical Engineering Branch (MEB).

The LaSalle design provisions for preventing adverse effects from intersystem leakages, and the methods for detecting and testing for these leakages have been thoroughly reviewed with the NRC-MEB.

Therefore, further NRC concern with the intersystem leakage issue :chcuWMMhtestsd*

.Ma, has b e?/A res,wed ca h baSb cf gw c-rea ched as A PeSvLt o f %8 MB rev'aw.

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J LSCS-FSAR NfENDMENT 47 i

OC'rOBER 1979 l

IS.

H.4.2 Fire Area / Zone Hot Shutdown Analysis i

%)

l The fire areas / zones which contain essential components of l

both shutdown methods indicated in Subsection H.4.1.3 are analyzed in Subsections H.4.2.1 through H.4.2.4.1.

Those fire zones associated with La Salle Unit 1 which do not contain components or cables for either of the shutdown methods are listed in Table H.4-8 and, as discussed in Subsection H.4.1.3 i

item b, no analysis was performed for these areas.

Tables H.4-9 through H.4-56 list the mechanical equipment i

I including ventilation equipment, electrical equipment, and i

cables within a specific fire zone which may affect the safe

[C ' *D *8

• shutdown of the reactor.

These tables include the shutdown

' U-D P" ".

'# "' D"#

mode 'to shich each item is associated.

" Alt." indicates the 4

and "Both" "F3 alternate method, " Bas." indicates the basic method, indicates equipment common to both shutdown methods.

In the fire zone hot shutdown analysis the systems o'E concern I

are the high pressure core spray (HPCS) system, the reactor core isolation cooling -(RCIC) system, the residual heat removal (RHR) system Loops A and B and the automatic depressurization system (ADS) Divisions 1 and 2.

The evaluation determines s

shich of - these systems may be af fected by the fire directly or indirectly such as a fire in a diesel-generator room which could affect onsite power to particular systems.

Also discussed am

(..)

are the alternate systems which could be used for safe shutdown.

Each analysis shows that either HPCS or RCIC and either ADS Division 1 or ADS Division 2 are available respectively for depressurization reactor water makeup, and decay heat removal and that either RHR Loop A or RHR Loop.B, is available for suppression pool cooling.

i Each of these systems must interact with other systems in order to achieve a safe shutdown.

Such interaction 'uses the following logic:

a.

RCIC and HPCS maintain reactor' water level and aid in removing decay heat initially.

+

b.

ADS depressurizers the reactor and transfers the decay heat to the suppre.sion pool thus causing e

the suppression pool to heat up.

c.

The RHR system cools the suppression pool and transfers the heat to the RHR service water system __

i via the RHR heat exchanger.

i l

~~

d.

The RHR service water system transfers heat to l

the cooling lake..

i e.

ESP switchgear and. batteries supply electrical" l-f,])

power to these-systems.

H.4-6 I

. - ~, _,,.. -,., _ _.....,. _ _

1 INSERT FOR SUBSECTION H.4.2 It should be pointed out that cables which are not needed for either the basic or alternate shutdown modes but which have a co:=on power source or a cormon raceway with cables needed for safe shutdown have coordinated short circuit protection such that the open, ground or hot short of these cables will not af fect the shutdown system for which a common power source or corr.on raceway is shared.

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i ENCLOSURE 5 DC SYSTEM ADEQUACY Several Issues relative to the DC System at LaSalle County Station were discussed with the NRC Staff on February j

6, 1981.

Those issues are:

1.

Charging capacity of the battery chargers on the Division i 250v system.

The issue relates to the l

basis for determining the steady state load for which i

the battery charger was sized.

It was indicated by the applicant that the steady state load was established approximately 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after the accident, and loss of offsite power was assumed to occur.

At this point in time, the loads on the DC system in question are such that the charger can take the full load and at the the same time recharge the system battery, if the on-site AC emergency source is assumed to operate properly, loads norme11y carried by the battery such as emergency lighting, sirens, etc. would be supplied by the AC system allowing for the. chargers to carry the remaining DC loads and recharge the batteries much earlier in the accident scenario.

These numbers were reviewed in detail with the Staff on February 6 and i

resolved the stated concern.

2.

Information relative to the 24V system was Judged to be inadequate because it was assumed based on certain references in the FSAR that the 24V DC system was Class IE.

I This observation by the NRC Staff was corrected upon verification that the 24V DC system is in fact non-Class IE.

Proposed revisions to Sections 8.3.2.1 and RGl.32 in Appendix B of the FSAR are attached which clarify this point.

These' revisions will be documented in a future amendment to the FSAR.

1

3. Confirmation of the completeness _g[,the DC system loads was requested in order that the Storf review could be comoteted.

Tables 8.3-11 through 14 do in fact list all safety and non-safety loads on the DC system.

This fact was communicated to the Staff in the meeting of February 6,

1981 and is documonted in proposed revisions to Section 8.3.2.1.1 of the FSAR.

A copy of this revision l

is attached, and will be formally submitted in a future amendment to the FSAR.

Also to be proposed as a revision I

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to the requirements in Section 4.8.2.3.2 of the l

Technical Specification is an appropriate revision to the battery charger surveillance.

This proposed revision is also attached for incorporation by the NRC in the LaSalle County Specification.

4. The adequacy of the LaSalle County battery system monitoring instrumentation was also reviewed and based on the existence of a battery breakers open alarm, DC i

bus voltage, DC bus ground alarm, DC bus overvoltage trip and alarm, battery charger low DC voltage alarm and battery charger breaker open alarm, along with the required local alarms, was judged acceptable by the NRC Staff on February 6, 1981.

This judgment was based on j

the ability to use the DC bus voltage meter and battery l

charger surveillance to resolve the lack battery current input and output and charger output voltage meters in the control room.

Based on this discussion no further information was required of the applicant.

t.

LSCS-FSAR

8. 3. 2 D-C Power systems 8.3.2.1 Descriotion The d-c power-distribution system and batteries are designed to provide control pcwer for switchgear groups, diesel generators, relays, solenoid valves, and other electric devices and components.

Batteries are provided as a source of power for vital loads in case of emergencies such as loss of a-c power.

The d-c system and batteries are designed to provide control power for both normal and emergency operation of plant equipment and to provide power for auecmatic operation of the engineered safety feature nrotection__nystems dur.ino ab_nqtnaLand W he conditicn3 (LCCh).

Md t4.,TCf. n Pd _ 2.4 vdr 4 -c. c.er ut 4 e 7

gmy The d-c power system of 1Gich unit includes the unit Class 12 d-c pcwer system CN=s, system is s.acun in single-line form in Figure 0.3-7 and Figures 8.3-10 through 8.3-13.

8.3.2.1.1 Unit class 1E D-C Power System Each unit has one 250-volt power battery and three 125-volt control batteries located in ventilated rooms having concrete walls.

The 250-volt battery is adequately sized to supply its loads until a-c power sources to redundant loads are restored (Figure 8.3-10).

Each 125-volt battery is sized to supply control power requirements of the switchgear and logic circuitry of one of the three engineered safety features divisions (Figure 8.3-11).

The reuundancy and independence of these load groups is the same as that described for the 4160-volt and 480-Vac class 1E load groups.

Each battery has its own charger with a capacity for restoring it to full charge under normal load in a time commensurate with the recommendations of the battery vendcr.

One spare charger is available as a replacement for the two power battery chargers, l

and one spare charger is provided for the six control batteries.

l Battery chargers are powered from a-c sources, and in case of l

loss of normal a-c power from both cnsite and of fsite sources, can be supplied from the standby diesel generators associated with their respective engineered safeguards divisions.

~

Each battery subsystem is complete with its main distribution center, battery charger, and accessory equipment.

Each battery subsystem is physically separated f rom its redundant system so that any failure involving one system cannot jeopardize the other system.

('

Curing an actual failure of normal i er, the diesel-generator power supply establishes battery 7he

.er. input and thereby reduces the drain on the battery 7 tem.

The ampere-hour l

l 8.3-30 i

L

LSCS-FSAR AMENDMENT 44 MARCH 1979 REGULATORY GUIDE 1.32 Initial Issue:

Revision 0, August 11, 1972 Current Issue:

Revision 0, August 11, 1972 La Salle C.P.

Issued:

September 10, 1973 USE OF IEEE STANDARD 308-1971, "CRITERI A FOR CLASS 1E ELECTRIC SYSTEMS FOR NUCLEAR POWER GENERATING STATIONS" Regulatory Guide 1. 32 states that IEEE 308-1971 provides criteria that may be used in establishing scme of the bases for the design of electric power systems, except that conflicts with General Design Criterion 17 should be resolved by:

a.

provision of two immediate access circuits from the transmission network; and b.

the capacity of the battery charger supply shculd be based on:

the largest combined demands of the various steady-state loads and enough charging capacity to restore the battery from the minimum design charge state to a fully charged state, irrespective of the states of the plant.

Two physically independent 345-kV transmission circuits (four transmission lines) occupying separate rights-of-way are available to each of the two LSCS reactor units so that each unit l

has an immediate access to a seccnd offsite power source.

offsite power is available to each unit from the systems l

auxiliary transformer of the opposite unit via nonredundant bus ties between emergency 4-kV buses.

Switchyard power is available

(

to both units as long as one of the four 345-kV transmission lineyDm stw 2.n d a o a + pei n avai 1 abl e___fwH nn 8 2)..#

l Q

r'corgea-o.s w e D A2 8 0 : q l

I Eachk.HPCS (Divisich$25 battery charger has sufficient capacity to restore its battery o full charge under the maximum steady-state cad.

(Section 8. 3. )fh_ cape *y%nn-vrifi+u..

A. aqs. - -

-ci u -c d,222essed,4ne.:SubsectioG82;322Pl?iv -

.s' We believe that we comply with the guidance set forth in this regulatory guide.

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B.1-39 l

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LSCS-FSAR AMENCFEMT 42 FEBRUARY 1979 capacity of each batt?"v is sized to supply all essential loads until a-c pcuer is restored to power its battery chargers (Tables 8.3-11, 8.3-12, 8.3-13, and 8.3-14).

The battery charger associated with each Divisior.1 or 2 battery is rated to supply the normal plant d-c loads while its battery is returned to or maintained in a fully charged state.

The tattery equiprent is designed and rated for operation for a 40-year plant life with reasonable maintenance and replacement of parts.

The ESF portion of the equipment covered by this design criterien is designed (Seismic category I) to withstand all postulated design-basis accidents without loss of operating capability under seismic and accident environmental conditions.

The d-c loads served by the battery subsystems include all the 125-vdc and 250-vde loads of the station, both Class 1E and non-Class 1E.

The system-connected loads are identified in Table 8. 3-1 and Figure 8.1-

/

g i

The d-c' loa M cf ESF Divisions 1, 2, and 3 are suppJi_g/ f rcm lcads(.cfDivision1.three independent d-c systems.

Table 8.3-11listststhe250-Vd{c{])

8.3-13,and8.3-14 list (.

Tables 8.3-12, the 125-Vdc loads'of Division 1, 2, and 3 respectively.

Cemconents

-ik Cf 2: Lot en CLCI C)

Each battery has its cwn independent instrumentation.

The follcwing monitoring features are provided for continucus supervision of each 125-Vdc and 250-Vdc subsysten except for Division 3 a.

d-c voltmeter with a selector switch to measure the d-c output voltage of the battery charger and the bus voltage; b.

d-c ammeter to measure the d-c output current of the battery charger to the tattery; c.

power failure alarm relay which indicates a loss of a-c power to the tattery charger; l

d.

d-c dmmeter to neasure the output current of each i

battery; e.

charger 1cw d-c voltage alarm relay; f.

charger high d-c voltage shutdcwn relay; g.

recording ground-detector voltmeter and alarm; k

8.3-31

ELECTRICAL P0'.lER SYSTEtiS AMEflDMEtlT 49 MAY 1980 1

i SURVEILLAf!CE REQUIREMEtiTS (Continued)

$ ?, $,0, D u ?. { C h.wr )

At least once per 18 months by verifying that:

c.

1.

The cells, cell plates and battery racks show no visual indication of physical damage or abnormal deterioration.

2.

The cell-to-cell and terminal connections are clean, tight, free of corrosion and coated with anti-corrosion material.

GE.@idsion 1 or 2 battery charger will supply at least 3.

D amperes at 130 volts for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

4.

Division 3 battery charger will supply at least amperes at 130 volts for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> d.

At least once per 18 months, during shutdown, by verifying that either:

1.

The battery capacity is adequate to supply and maintain in OPERABLE status all of the actual emergency loads when the battery is subjected to a battery service test, f,,

or 2.

The battery capacity is adequate to supply a durny load of the following profile while maintaining the uttery terminal voltage > 103 volts.

a)

Div'ision 1 i

> 466.6 amperes for the first 60 seconds, I 215.7 amperes for the next 29 minutes, s 199.7 amperes for the next 30 minutes, I

s 109.3 amperes for the next 120 minutes, and

[

44.7 amperes for the last 60 minutes.

9 b)

Division 2 422.2 amperes for the first 60 seconds,

>s 183.5 amperes for the next 59 minutes, i

[

93.1 amperes for the next'120 minutes, and 45.5 amperes for the next 60 minutes.

l c)

Division 3 70 amperes for the first 60 seconds, and i 13 amperes for the next 239 minutes.

l LSCS-1 3/4 8-12 May 1980

_