ML19347D027

Slide Presentation Re Final Design Review Presentation at 810326 Meeting of Util Design Review Board.Responses to NRC Questions Encl

ML19347D027
Person / Time
Site:	Midland
Issue date:	03/05/1981
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML19347D022	List: ML19347D021 ML19347D023 ML19347D027
References
NUDOCS 8103100563
Download: ML19347D027 (43)

Text

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FICLTES 4

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! COLD

, HOT STANDBY . , HOT SHUTOOWN . ,

SHUTDOWN .

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i l

l I

i l i REACTOR OPERATIONAL MODES 1

l l 6

l REACTOR COOLANT SYSTEM RELIEF VALVE NOZZLES i

j SPRAY LINE PRESSURIZER - -

i CO FLOODING 2 Q REACTOR COOLANT v

O FLOOOING TANK PUMP TANK l

! REACTOR j JECTION

, NOME X ,

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{q U SURGE LINE f, v f RLSCTOR XI IARY FEEbWATER -"' ( # C O ANT l ,

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STEAM OUTLET ^ -D' l . [1 ,

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i l MAKEUP

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j HEAT REJECTION (TEMPERATURE CONTROL) G 1508 06

SHUTDOWN SYSTEMS OPERATIONAL RANGE '

SHUTDOWN FUNCTIONS SHUTDOWN STAGE AND SYSTEMS 4--- HOT STANOSY  : l 4-HOT SHUTDOWN-> 4 D I I I I i I l l 1

PRESSURE CONTROL I I l l 1 Pressurizer Heaters (5&6) -W '

Auxiliary Pressurizer Spray

[Y i tt Lotdown isolation Valves X l I

I l

l l l l Pressurizer Safety Valves l l (Set at 2,500 psig) i i POfiV (Set at 2,260 psig) l j l PORV Block Valve (Set at i i

! 2,100 psig Coincident With l l l PORV not Shut) i i

} t t a f l t l ._

600 579 532 500 400 325 300 250 200 4

(POWER (HOT (EMERGENCY (NORMAL D9R l OPERATIONS) ZERO POWER) DHR CUT-IN) CUT-IN)

{mM NORMAL OPERATING RANGE RCS TEMPERATURE (*F) h AUTOMATIC ACTUATION q,,,,

y MANUAL ACTION "

i l-

SHUTDOWN SYSTEMS OPERATIONAL RANGE l ,

l SHUTDOWN FUNCTIONS SHUTDOWN STAGE

AND SYSTEMS l ,

O HOT STANOSY O l 4-HOT SHUTDOWN-> 4 D 1 _

l I 1 i l I I l l I

i REACTIVITY CONTROL I I I l

! Control Rods X I

1 I l EBS nummme l l l9y Makeup from BWST Makeup from CAS I I

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l I l I

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y MANUAL ACTION

l SHUTDOWN SYSTEMS OPERATIONAL RANGE i SHUTDOWN FUNCTIONS SHUTDOWN STAGE AND SYSTEMS 4 HOT STAND 8Y I 4--HOT SHUTDOWN + ,. D .

I I  !

I I l' l l HEAT REJECTION I I i l i i Steam Generator I I MSIV & MFWlV (Automatic Isolation at 585 psig) l l 9

.g AFW M

Main Steam Relief Valves I I (Set at 1,050 psig) l l POAV i '

Decay Heat Removal PM System I I i I ,

I I I I i i i i l i l  !

600 579 531 500 400 325 300 280 200 (POWER (10T (EMERGENCY (NORM AL DHR OPERATIONS) ZC.*O POWER) DHR CUT-IN) CUT-IN)  !

m NORMAL OPERATING RANGE RCS TEMPERATURE (*F) h AUTOMATIC ACTUATION

)( MANUAL ACTION '-

l i

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i I' CHEMICAL STEAM ADDITION GENERATOR g TANK I l

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SUCTION CONFIGURATION G 1508 to I i

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l e NRC POSITION l Provide DHR Dropline Design to Accommodate a Single Failure i s i e REFERENCES l BTP RSB 5-1, Q211.35, PSB-11, RSB-20 e MIDLAND DESIGN Complies: ParallellSeries Motor-Operated Valves Provided Inside Containment Ml0 LAND UNIIS 1 AND 2 G-1510 06 i

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j e NRC POSITION

! Provide Safety-Grade Steam Dump Valves G

I4 eREFERENCE I

. BTP RSB 5-1, Q211.35, ASB-8, RG 1.139 -

l l

l

! e MIDLAND DESIGN l Complies: Two POAV Valves Provided per Steam Generator MIOLAND UNIS 1 AND 2 G 1510 07 i

I i

l e NRC POSITION

Provide Auxiliary Pressurizer Spray or Show A9ceptable Manual Actions i s 6

L e REFERENCES BTP RSP 5-1, Q211.35

e MIDLAND DESIGN Complies

Auxiliary Pressurizer Spray Provided MtOLAND UNITS 1 AND 2 G-1510-08 i

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. NRC POSITION Provide Safety-Grade Boration Capability or Show Acceptable Manual Actions ,

l s ,

i eREFERENCES BTP RSB 5-1, Q211.35, RG 1.139 I

i e MIDLAND DESIGN i

Complies: EBS and Other Safety-Grade '

! Borated Water Sources Provide Sufficient Boration MifR AND ONifS I ANO 2

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! e NRC POSITION l Conduct Natural Circulation.Cooldown and l Borated Water Mixing Test i

! eREFERENCES BTP RSB 5-1, Q211.35, RG 1.139 e MIDLAND DESIGN Partial Compliance: 50F Natural Circulation Cooldown Test Will Be Conducted or Referenced; No Separate Boron Mixing Test Planned; Safe Boron Mixing Test infeasible MIDLAND UNITS 1 AND 2 G- 1510- 12

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e NRC POSITION l Provide Adequate Seismic Category I AFW l Supply i

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! eREFERENCES l BTP RSB 5-1, Q211.35, RG 1.139

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l e MIDLAND DESIGN Complies: Normal Supply is Nonsafety-Grade Condensate; Automatic Switchover Provided l to Safety-Grade Service Water l MIDLANDUNITS I ANO 2 G 151014 l

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i i e NRC POSITION

! Provide Safety-Grade Steam Generator Water Level Indication and Alarm i

l l

9 eREFERENCES 5 RG 1.139 i

l e MIDLAND DESIGN l Complies with Clarification: Safety-Grade i Water Level Indication and l Nonsafety-Grade Alarms Provided MIDLAND UNITS 1 At40 2 G-1510- 16

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e NRC POSITION l Achieve Cold Shutdown with Safety-Grade Systems l e REFERENCES l BTP RSB 5-1. 0211.35, RG 1.139 Open items i%8-11, RSB-10, ASB-8, RSB-7 l

! e MIDLAND DESIGN Complies with Clarifications:

i

. s,

• Boration accomplished without letdown

% = Boration monitorad and sampled by nonsafety-grade i

systems

• No separate boron mixing test planned

• Steam generator water level alarms are nonsafety-grade l

!

• One steam generator cooldown will take longer than 36 l hours

= Upgraded nonseismic CAS can provide contraction volume

after tornado i

MIDLAND UNITS 1 AND 2 G 1510-19 i

0

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e 4

I i CONTROL CAPABILITIES l,

OUTSIDE THE CONTROL ROOM l AUXILIARY SHUTDOWN PANEL

, MONITORS

! EBS Tank Level Pressurizer Level T-Hot, T-Cold AFW Flow OTSG Pressure & Level RCS Flow & Pressure LOCAL CONTROL PANELS, POAV Position MCC, & SWGR 6 .

g CONTROLS SYSTEMS  !

Pressurizer Heaters Diesel Generator Portions of MU&PS Service Water CCW Pumps Component Cooling Water POAV Valves Chilled Water Pressurizer PORV VARIOUS Plant HVAC Auxillary FeedWater ACTIONS Auxiliary Pressurizer Spray i INDICATED (e.g , EBS DHR)

LOCAL AT EOUIPMENT

! HOT STANDBY  :

HOT SHUTDOWN  :

COLD SHUTDOWN

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l SHUTDOWN SYSTEMS OPERATIONAL RANGE -

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! SHUTDOWN FUNCTIONS SHUTDOWN STAGE l AND SYSTEMS SHUTDOWN MONITORING INSTRUMENTATION j . . . ,

4 HOT STANDSY  : 14-HOT SHUTDOWN 4 4. COLD

! I I

I l l l l REACTIVITY CONTROL l I 1 I l

i Control Rods X I I

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,3 Makeup from BWST ummum 0

a Makeup from CAS l l I I CRD BREAKER POSITION SOURCE RANGE NEUTRON POWER EBS TANK LEVEL PRESSURIZER LEVEL I I I I I I i l i I I i i i i I i I 600 579 532 500 400 325 300 280 200 1 (POWER (HOT (EMERGENCY (NORMAL DHR >

OPERAYlONS) ZERO POWER) DHR CUT-IN) CUT 4N) m NORMAL OPERATING RANGE RCS TEMPERATURE (*F) h AUTOMATIC ACTUATION ,,,,, ,

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! SHUTDOWN FUNCTIONS

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SHUTDOWN STAGE l AND SYSTEMS SHUTDOWN MONITORING INSTRUMENTATION O HOT STANDSY O I eHOT SHUTDOWed+ 4.C D

! I I l l l

I I

HEAT REJECTION I I i i I Steam Gensrator I i l MSIV & MFWlV (Automatic M

l Isolation at 585 psiO) l I

!s AFW -

!$; Main Steam Relief Valves M I I

!" (Set at 1,050 psig) l l

l POAV l Decay Heat Removal -

munuun System T-HOT T-COLD AFW FLOW OTSG LEVEL & PRESSURE RCS FLOW POAV VALVE POSITION DHR FLOW l DHR HX OUTLET TEMP i i i i l i l l 600 579 532 500 400 325 300 280 200 (POWER (HOT (EMERGENCY (NORM AL DHR OPERATIONS) ZERO POWER) DHR CUT-IN) CUT-IN) m NORMAL OPERATING RANGE RCS TEMPERATURE (*F) h ALTTOMATIC ACTUATION

)( MANUAL ACTION i

s e?

u oe t

APPEDIX l

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Razronsco to NRC Questions i Midland 1&2 Question 211.35 (5.4.7) .

Should the Midland plants experience an event that will require eventual cooldown to permit either long-term cooling with the DHR system or going to cold shutdown for inspection and 'apairs (extended loss of offsite power, steam generator taoe rupture, failure of steam generater relief valves te reclose, etc), it is desirable that qualified systems be available to perform the operation safely and in an orderly manner. Discuss the capability of the Midland plants to be taken to a cold shutdown condition using only safety-grade equipment, assuming only onsite l or offsite power is available, and considering a single failure.

Address each of the following areas of concern in your response:

1. Discuss the capability of the single DER drop line to '

provide for the cooldown of the plant assuming a single active failure, including manual actions inside or outside o' containment or the return to hot standby until manual actions or maintenance can be performed to correct the failure.

With regard to the "idland shutdown capability, we note that manual operation outside the control room is i required for normal shutdown, and containment entry is 9 required for a failure of a motor-operated DHR suction valve. With regard to reducing the need for such manual actions, address tne following areas: .

l

a. Discuss the modifications required to provide the capability to conduct a normal shutdown from the control room.

b. Justify the viability of the manual actions required after a suction valve failure gi.e.,

opening cross-connects 093, 094). Addrehs times required, doses expected, and potential fc -

inadvertent opening of crcss-connects during high primary side pressure conditions. Compare the Midland cross-connect design to Davis-Besse Unit 1.

Provide a reliability analysis for the manual action outside the control. room and discuss the incremental increase in reliability expected for various selected design modifications.

2. Provide safety-grade steam generator dump valves, operators, air, and power supplies which meet the single failure criterion.

3. Provide the capability to cool down to cold shutdown assuming the most limiting single failure in less than 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> or show that 12;ual actions inside or outside containment or return to hot standby until the manual ,

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Responses to NRC Questions Midland 1&2

( actions or maintenance can be performed provides an acceptable alternative.

4. Provide the capability to depressurize the reactor coolant system with only safety grade systems assuming a single failure, or show that manual actions inside or outside containment or remaining at hot standby until manual actions or repairs are complete provides an acceptable alternative.

5. Discuss the capability for boration with only safety-grade systems assuming a single failure or show that manual actions inside or outside containment or remaining at hot standby until manual action or repairs are completed provides an acceptable alternative.

6. Discuss the capability for the collection and containment of DER system pressure relief valve discharge.

, '. Conduct tests to study the air.ing of the added borated 9

, water and cooldown under natr.ral circulation conditions with and without a single failure of a steam generator

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atmospheric dump valve.

8. Commit to providing specific procedures for cooling down

> using natural circulation and submit a summary of these

(, procedures.

9. Provide a Seismic Category I AWF [ SIC] supply for at l

least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> at hot shutdown plus cooldown to the DHR system cut-in based on the longest time (for only onsite or offsite power and assuming the worst single failure),

l or show that an adequate alternate seismic category I source is available.

Response

The Midland design basis provides f.i the . ility to achieve and 30 maintain, by safety grade means, the not shutdown condition as '

l described in Section 7.4 of the FSAR. As discussed in the response to Question 110.16,. hot shutdown provides for an 14 extremely stable and safe condition at which the plant can be -

maintained until an eventual cooldown can proceed. Although not a design basis, the Midland design does incorporate the ability 30 ,

to be taken to the cold shutdown condition using only safety 3g grade equipment, assuming only onsite cn: offsite power is available and considering a single failure. Therefore, in the unlikely event that a design basis earthquake occurs which 30 results in the need to achieve cold shutdowr expeditiously, design features exist to accomplish this evolution. This 3

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v s Responses to NRC Questions Midland 1&2 capability is discussed in the following point-by-point response 3g keyed to the item numbers of NRC Question 211.35:

1. The suction side of the decay heat removal (DER) system inside containment has beea upgraded to incorporate motor operators for the proeviously manual bypass valves.

These bypass valves are supplied with redundant Class 1E power (channel E) through manual transfer switches operated outside containment. Therefore, operator l action inside containment is not required assuming a 30 single active failure. In addition, the isolation valve outside containment (IMO-1010 or 2MO-1110) is mechanically locked open. Therefore, this valve is not susceptible to an active failure.

To align the DHR system for cooldown will require '

limited operator action outside the control room. The operator actions required are:

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a. The operator must open the DHR pump suction cross-connect manual valves (Unit 1 valves 009 and 016 or Unit 2 valves 003 and 008) to establish the suction flowpath.

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b. The operator must reestablish power to the DHE cooler bypass valve (IMO-1014A, B or 2MO-1114A, B).

This valve is electrically locked closed during normal reactor operation. '

To reduce the need for manual actions outside the control room for initiating the normal DHR system cooldown, the DER system would require:

, a. Replacement of the DHR pump suction cross-connect manual valves with power operated valves

b. Removal of the electrical lock on the DHR cooler bypass valves. These valves would be ensured 14 closed during normal reactor operation by administrative control.

The M.!.ltiple purposes of the DER system pump suction

_ cross-connect manual isolation valves are given below:

a. DuriLJ power operation (DBR system aligned for standby low-pressure injection (LPI) mode), the l valves function to separate the suction of the LPI pumps.

I b. During the DHR mode of operation, the valves

, provide the capability to isolate one DHR train while providing DER with the other train.

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t ./ t Responses to NJC Questions Midland 1&2

( This combination of functions requires manua valves and l operator actions outside the control room, or power in operated valves controlled from the control room, to align the system for decay heat removal operations. 130 Because ample time is available for operator action to i align the system for DER operation (approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />), and because of the cost of equipment 14 considerations, manual valves were selected for the appplication.

The Davis-Besse Unit 1 DER suction cross-connect design is similar to the Midland design. The outstanding differences are that the Davis-Besse DER pump suction valves are provided with motor operators, no containment isolation v:'ve is provided, and the bypass valves inside ca .ainment are not motorized. Incorporation of pump suc' .on valve motor operators for Midland would reduce une of the manual actions outside the control room required to align the DHR system for plant cooldowns. However, the operator has at least 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to perform this action. Tne valves should be opened after plant cooldown commences with the steam generator, but before cooldown commences with the DHR system. Due to the magnitude of the time available to perform the action, the modification is not deemed necessary. 30

.. 2,3. To remove heat after a postulated design basis

( earthquake, two class 1E power operated atmospheric vent

%' (POAV) valves are provided on each steam line between the once-through steam generator (OTSG) outlet nozzle and the main steam isolation valve. These valves and their actuators are qualified as seismic active components. The POAV valves are capable of being jogged to any position between full open and full closed by operator action from the main control room or the auxiliary shutdown panel. Each valve has individual manual isolation provisions. The existence of four POAV valves per unit (two per steam generator) ensures the capability of conducting a balanced cooldown regardless of the occurrence of a single active failure. This cooldown will proceed until the emergency DER cut-in temperature of 325F is achieved. Operation of the DHR system at this temperature is described in subsection 5.4.7.1.1.1. A detailed description of the POAV valves and their associated controls can be found in Subsections 10.3.2 and 7.4.1.2.1.

Water is added to the steam generators by a safety grade, seismically qualified auxiliary feedwater system.

This system will provide adequate water assuming a loss 14 l of offsite power and a single active failure. The steam produced in the steam generators will be relieved by the POAV valves as discussed above. 130 l .

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4. During normal plant cooldown, the reactor coolant system i

(RCS) is depressurized through normal pressurizer spray. '

The driving force for this spray flow is derived from the reactor coolant pump head. Assuming loss of offsite power, reactor coolant pumps stop and are unavailable to provide normal pressurizer spray flow. Under these circumstances, RCS deprc'surization can be achieved through the operation of the high-pressure auxiliary pressurizer spray system. This system utilizes the discharge of the high-pressure injection (HPI)/ makeup pumps to supply spray flow to the pressurizer. Two Class IE, parallel, motor operated valves are provided

that can be jogged by the operator to control the rate l of depressurization. The desion of this system incorporates a seismic Category I connection from the j makeup pump discharge to the auxiliary pressurizer spray line.- The system can perform its function assuming a i-single active failure. A detailed description of this system and its associated controls is presented in FSAR Subsection 9.3.4.2.3,9.

5. The chemical addition system provides the means to borate the RCS to the required shutdown levels during 30 normal plant cooldown. Using this method, boron is added to~ the RCS while simultaneously creating ';olume for_this addition through primary letdown. Neither the chemical addition nor the letdown systems are qualified e*N to operate after a design basis earthquake and therefore I may not be available after this postulated event. Under these circumstances, coincident with a stuck rod, boration to the cold shutdown concentration can be achieved through use of the emergency boration system (EBS). This system stores 6 weight percent boric acid which can be injected into the RCS by the HPI/ makeup pumps. If necessary, the operator can add the contents i

of this system through pump and valve manipulations from the ' control room af ter initial manual system alignment.

. The concentration and storage volume of the EBS, coupled

! with available' excess volume in the pressurizer, ensures that the necessary boric acid required to maintain hot shutdown and achieve cold shutdown concentrations can be

injected into the RCS without letdown.

l The EBS is a safety grade system capable of performing its design function assuming a single active failure. A l detailed description of this system is provided in FSAR Subsection 9.3.10.

6. DHR pressure relief capacity is described in F3AR Subsection 5.4.7.1.1.3. The discharge fluid is directed ja to the reactor- building sump. A further description of J

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v .f L R2cptn:ca to NRC Quastions Midland 1&2 relief valve design is contained in the revised FSAR ;g Table 5.4-10.

7. A natural circulation cooldown test will be referenced if it has been conducted on a plant similar to Midland. 18 If such a test is not available, a test will be conducted to verify that operation of the POAV valves 130 under natural circulation will satisfactorily remove heat required to cool down the plant. This test will demonstrate the ability to cool down approximately 50F 18 under naturel circulation conditions and compare the temperature versus time plot developed with an analytical plot derived for the entire cooldown process. I 30 The test will therefore be used to verify the analytical results.

8. Operating procedures for natural circulation cooldown 18 will be written and made available to the operators before initial criticality.

9. As detailed in our response to Question 010.34 and i14 revised Subsection 10.4.9.2.3, an adequate seismic Category I feedwater source is available. 30

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