ML20207H933

SPDS Status Trees Development Summary Package,Catawba Nuclear Station

ML20207H933
Person / Time
Site:	Catawba
Issue date:	03/14/1986
From:	Lee H DUKE POWER CO.
To:
Shared Package
ML20207H868	List: ML20207H863 ML20207H890 ML20207H921 ML20207H933 ML20207H950 ML20207H954 ML20207H960 ML20207H965 ML20207H970
References
NUDOCS 8607250137
Download: ML20207H933 (13)

Text

Attachment 3 SPDS STATUS TREES DEVEIDPIENT SUIEEARY PACKAGE CATAWBA NUCLEAR STATION Section I: Description of Development Process Section II: Summary of Results Section III: Listing of Applicable Documentation H. J. Lee, Jr.

Nuclear Engineering Design Engineering Department March 14, 1986 Page 1 of 5 e607230137 e60715 14 PDR ADOCK 0500 P

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Attachment 3 I. Description of Develotmoent Process Parts 1 and 2 of the following have been condensed from the Westinghouse Owners Group Emergency Response Guidelines Background information.

Status Tree Format The plant parameters that define the state of each Critical Safety Function are identified on the associated Status Tree.

Typically, only a few parameters are required to identify the status of a Critical Safety Function. This limited set of parameters must be evaluated in a systematic manner to determine the Critical Safety Function status. A branching structure inherent in a decision or event tree is the logical vehicle to structure the systematic evaluation of plant parameters that determine the status of a Critical Safety Function. Each Status Tree has a single entry point and several exit points (termini) depending on the parameters that define the Critical Safety Function status. Each pass through a Status Tree can produce only one exit point based on the values of the parameters in the Status Tree.

The basic format for the Catawba SPDS Status Trees is referred to as the block version. In the block version, each question is simply stated once in a positive sense, and the decision options "YES" or "NO" provide the branching.

The block version has been found easy to evaluate since a question only needs to be answered once and the branching follows from the decision. This form closely approximates the logic which would be programmed for a computer evaluation of a " branch point".

Definition of Priorities In addition to identifying the safety state of the plant, the Status Trees also provide an ideal vehicle to prioritize operator response to Critical Safety Function challenges.

When Critical Safety Functions are challenged, multiple challenges may exist requiring additional guidance to structure operator function-related restoration. This additional guidance is provided by prioritizing all potential challenges to Critical Safety Functions. This predefined prioritization is accomplished by prioritizing the Critical Safety Function" (i.e., specifying the order in which the Status Trees are monitored) and prioritizing the termini of

! the Status Trees.

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J Attachment 3 6

Challenges must be prioritized within each critical Safety i Function and between Critical Safety Functions. Since each

! pass through a Status Tree produces a single terminus (exit)

}

based on the status of the Critical Safety Function, the j termini can be prioritized based on the severity of the

challenge. Four status conditions (i.e., extreme challenge, j severe challenge, off- normal and satisfied) are defined to permit each condition to be prioritized with respect to other j Critical Safety Function conditions. Furthermore, for each j Status Tree the parameter decision points are arranged so i that parameter decisions that indicate extreme challenges are i generally situated early in the Status Tree followed success-ively by decision points that indicate severe challenges, J off-normal and satisfied conditions. This permits relatively j comparable conditions (e.g.; two severe challenge conditions)

! within a Status Tree to be prioritized by the arrangement of I decision points in the tree structure.

) As indicated previously, the prioritization discussed above is expressed by colored line codings and terminus symbols.

l The color coding is used as a mechanism to immediately inform 4

the operator that a Critical Safety Function is in jeopardy and to indicate the relative severity of the challenge. The priorities of each Status Tree terminus (representing some i

l plant condition) have been evaluated against each other so that all internal priorities are consistent.

The action which an operator takes in response to a Critical Safety Function challenge is related to the severity of that i challenge. Each terminus symbol which is not green (satis- ,

! fied) is annotated with the instruction "GO TO l EP/2/A/5000/2XY," the appropriate Function Restoration l Procedure. "X" is the alphabetical code for the respective l Critical Safety Function and "Y" is the subprocedure number.

Each of the RED priorities is assigned the first subprocedure i number; for example, the Function Restoration Procedure or an

! inadequate core cooling condition (RED priority on Core Cooling (B) Status Tree) is depicted as EP/2/A/5000/2Bl.

f In summary, the priority of operator action is fixed by the physical arrangement of the trees. Each tree contains d multiple termini, each of which represents possible current status of that critical Safety Function. Each terminus (and

preceding branch) is color coded, reflecting the urgency of that condition regarding operator action, and each also l

j refers to the appropriate guidelines to be used.

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Attachment 3 For the entire set of trees, priority of operator action is given by the following:

1. REDS (Extreme challenges), in tree order

2. ORANGES (Severe challenges), in tree order

3. YELLOWS (Off-normal) in tree order As an example, a RED condition for Core Cooling is of higher priority than a RED condition for Containment (order of trees). However, the RED condition for Containment is of higher priority than any ORANGE condition (order of colors).

Incorporation of NRC Comments In the NRC SER on the BASIC version of the WOG ERGS, page 4-9, Item (12), it is recommended that ice condenser plants should incorporate an additional branch on the containment status tree to check for a high containment hydrogen concentration. This change, although not done on a generic basis, has been made to the Catawba Status Trees.

Technical Chances by Duke Power Company The WOG ERG Integrity statue tree treats pressurized thermal shock and cold overpressurization as the only challenges to RCS integrity. Overpressuriation due to a partial or complete failure of the RCS pressure control mechanisms is also a valid challenge. To address this, additional branches were added to the Catawba Status Trees.

' Setpoint Development All of the setpoints used in the Catawba Status Trees have

been calculated, reviewed, and documented by Duke Power Company. Appropriate consideration was given to the differences between Catawba and the generic plant. e.g. the UHI RVLIS, and to differences between units at Catawba, the steam generator level setpoints. The Catawba Status Trees use dual setpoints for normal and adverse containment conditions where appropriate.

Format Chances to Facilitate SPDS Usage The WOG ERG Subcriticality Status Tree was modified by adding a branch at the beginning to decide whether a reactor trip is required. If not, the safety function is satisfied. This allows usage of this Status Tree when the unit is at power.

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Attachment 3 II. Sununary of Results The enclosed Catawba Unit 2 Critical Safety Function Status Trees are reprinted from EP/2/A/5000/02 III. Listing of Applicable Doctamentation Date From M Subject 06/01/83 DG Eisenhut (NRC) JJ Sheppard (WOG) BASIC ERG SER 06/18/84 HB Tucker HR Denton (NRC) Deviations (Duke Power) Between Catawba EPGs and Revision 1 ERGS.

06/01/84. Duke Power Company Catawba Nuclear Station Emergency Procedure Guidelines Reference Document, Chapter 5, "Setpoints".

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PAGE NO.

CNS SUBCRITICALITY 1 EP/2/A/5000/2A RETYPE #0 GO TO EP/2/A/5000/2A1 GO TO EP/2/A/5000/2A1 gMMMMMMMMMMMMM NO g POWER E RANGE g

< 5%

g ,.

GO TO

• ' ;EP/2/A/$000/2A2 YES E E

N0 INTERMEDIATE

^"

INTERMEDIATE YES M0RE RANGE SUR NEGATIVE REACTOR ZEROOR

~ THAN -0 2DPM

+ TRIP NEGATIVE YES REQUIRED YES NO l CSF i

SAT NO SOURCE RANGE ENERGlZED YES GO TO EP/2/A/5000/2A2 l

l l NO SOURCE l RANGE l SUR ZERO OR r NEGATIVE YES i CSF SAT l

CSF i SAT PAGE 10F 1

4 CNS PAGE NO.

CORE COOLING 1 EP/2/A/5000/2B RETYPE #0 P/2 A/5000/2B1 GO TO EP/2/A/5000/2B1 NO CORE EXIT

'$ RX VESSEL f'H AN l200*F LOWER RANGE LEVEL GREATER YES THAN 43%

- NO CORE EXIT T/Cs LeSS g THAN 700*F GO TO NO EP/2/A/5000/282 YES ONE NC GO TO PUMP RUNNING EP/2/A/5000/282 NO RX VESSEL LOWER RANGE LEVEL GRE ATER THAN 43%

NO NC SYSTEM YES SUBC00 LING GREATER THAN0*F YES GO TO EP/2/A/5000/283 GO T0 l

1 EP/2/A/5000/282 RX VESSEL D/P LEVEL NO GRE ATER THAN REQUIRED j LEVEL FOR PUMP COMBIN (REFER TO YES EP/28 PG 2)

GO TO EP/2/Ai5000/283 CSF i

SAT PAGE 10F 2

A2(H21 PAca NO.

r , CNS 2 CORE COOLING Retype #0 EP/2/A/!M)00/2B ,

p' DYNAMIC HEAD RANGE RVLIS I SETPOINTS FOR DEGRAOED CORE COOLING  !

Channel B f Number of Channel A with NC Pump C l NC Pumps with NC Pump A ~

' Not Running Running Not Running Running

-- 80%

4 80%

60% 32%

60% 32%

3 45% 20%

45% 20%

2 35% 14%

35% 14%

1

. 0 Page 2 of 2

CNS PAGE NO.

HEAT SINK 1 EP/2/A/5000/2C RETYPE #0 P/2 A/5000/2C1 TOTAL NO FEEDWATER FLOW TO INTACT S/Gs GREATER THAN 450 GPM YES ~~

" ' ' ' * ~ __ -. ,,

" " c "

2 GO TO

'EP/2/A/5000/2C2 NO NO NR LEVEL IN PRESSURE IN AT LEAST ONE ALL S/Gs S LESS THAN

• ( >,18%G FOR

> 5% 1230 PSIG ACC)

! yg YES GO TO

, 0 0; EP/2/A/5000/2C3 NARROW NO RANGE LEVEL IN ALL S/Gs LESS THAN 781%

( < 631% FOR YES ACC)

' ~ ' ' ' GO TO

'.\

I

. _ 'EP/2/A/5000/2C4 I

NO PRESSURE IN ALL S/Gs LESS THAN l 1175 PSIG YES GO TO EP/2/A/5000/2C5 NR LEVEL IN NO ALL S/Gs

> 5%

( > 18% FOR ACC)

YES l

CSF PAGEt0F1 SAT

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CNS PAGE NO.

REACTOR COOLANT INTEGRITY 1 EP/2/A/5000/2D RETYPE #0 P/ A/5000/201 ALL NC NO PRESSURE /

COLD LEG

_ TEMPERATURE POINTS TO RIGHT OF LIMIT A YES EBE R R E m m m m m m m ag n g333 0T fp/2A!5000/201 ALL NC SYSTEM NO EPJPERATURES . EEEEEEEEE P/2 A!5000/203 GREATER E THAN 350*F YES PZR N0 "'

GO T0 SuR G<

g hR gA ( a EP/2/A/5000/202 2400 PSIG TEMPERATURE { < 2250 FOR NC ACC) YES DECREASE IN ALL COLD M

t gg

' ^

HA 1 "F IN GR ATER THE LAST 60 THAN MINUTES YES 457'F YES CSF l SAT EEI B LEI M E3 M E3 E E E E M M E G EI N E E M E EE EE C2 . , GO TO EP/2/A/5000/203 g f .,

" ~

GO TO Ell EP/2/A/5000/201 PZR NO PRESSURE LESS THAN NO

• ALL NC 2400 PSIG COLD LEG

( < 2250 FOR l ACC) TEMPERATURES YEe' GREATER NO THAN 250*F NC PRESSN'S LESS THAN N0 400 PSIG GO TO ALL NC SYSTEM ype' COLD LEG EP/2/A/5000/202 TEMPERATURES

- GREATER THAN 300 F YES f

CSF SAT I . CSF PAGE 1 OF 2 \

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CNS PAGE NO.

REACTOR COOLANT INTEGRITY 2 EP/2/A/5000/2D RETYPE #0 PTS LIMIT CURVE 2600

)

2400

[

2200 2050 FSIG /

/

muF 'A /

wy 2000 1800 1600 en i

b w 1400 -

( g

?n

@ 1200 j 49 &

m C RFn 4 M ORAblGE

$ 6

~

ALARM ALARM d E 1000 h

800 600 400 200 l

0 100 200 300 400 TEMPERATURE ( F)

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CNS PAGE NO.

CONTAINMENT 1 EP/2/A/5000/2E RETYPE #0 P/2 A/5000/2E1 NO CONTAINMENT PRESSURE LESS THAN 15 n rSIG YES GO T0 g4 E E IB E E E E IB Idi M E E E K3 E E E E E E EP/2/A/5000/2E1 m

CONTAINMENT PRESSURE LESS THAN 3 0 PSIG YES (EEEEEEEEEEEEEE P/2 A/5000/2E1 B

CONTAINMENT N0 HYDROGEN CONCEN-TRATION LESS THAN YES

( GO TO gEEDEEEEEE EP/2/A/5000/2E2 I e l

NO CONTAINMENT SUMP LEVEL LESS THAN 13 FT YES l GO TO EP/2/A!5000/2E3 EMF 53A(B) l CONTAINMENT R ADI ATION LESS THAN 3R HR YES PAGE 10F 1 l 'O.

i CSF g / SAT

CNS PAGE NO.

REACTOR COOLANT INVENTORY 1 EP/2/A/5000/2F RETYPE #0 Gd TO 9

EP/2/A/5000/2F3 NO RX VESSEL UPPER RANGE LEVEL > 97%

& STABLE 1

YES GO TO EP/2/A/5000/2F1 NO PRESSURIZER LEVEL GO TO

=

LESS THAN EP/2/A/5000/2F2 92% ( < 80% -

FOR ACC)

YES PRESSURIZER LEVEL N0 GREATER THAN 17%

( > 45% FOR GO TO ACC)

EP/2/A/5000/2F3 NO RX VESSEL UPPER RANGE LEVEL > 97%

& STABLE YES l3 , CSF SAT l PAGE10F1 l

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