ML20077J074

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Proposed Tech Spec Section 3.1 & Table 3.1.1 Increasing High Drywell Pressure Trip Setpoint
ML20077J074
Person / Time
Site: Oyster Creek
Issue date: 08/04/1983
From:
GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20077J067 List:
References
NUDOCS 8308120227
Download: ML20077J074 (5)
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3.1-32

~ The manual scram associated with moving the mode switch i

to shutdown is used merely to provide a mechanism whereby the

! reactor protection system scram logic channels.and the reactor manual control system can be energized. The ability to reset a scram twenty (20) seconds after going into the shutdown mode

- provides the beneficial function of relieving scram pressure from the control rod drives which will increase their expected J

4 lifetime. .

To permit plant operation to generate adequate steam and pressure to establish turbine seals and condenser vacuum at relatively -

low reactor power, the main condenser vacuum trip is bypassed until 600 psig. This bypass also applies to the main steam

. isolation valves for the same reason.

i The action required when the minimum instrument logic condi-

} tions are not met is chosen so as to bring plant operation i ' promptly to such a condition that the particular protection in-

' strument is not required; or the plant is placed in the protec-tion or safe condition that the instrument initiates. This is i

accomplished in a normal manner without subjecting the plant to abnormal operating conditions. The action and out-of-1 service requirements apply to all instrumentation within a particular function, e.g., if the requirements on any one of i the ten scram functions cannot be met then control rods shall be inserted. ,

The trip level settings not specified in Specification 2.3 have been included in this specification. The bases for these a

l settings are discussed below.

l The high drywell pressure trip is set at 2.4 psig. This trip l

vill scram the reactor, initiate reactor isolation, initiate containment spray in conjunction with low low reactor water level, initiate core spray,, initiate primary containment

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8308120227 830804 PDR ADOCK 05000219 p PDR Amendment No. '

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I 3.1 4 W - isolation, initiate automatic depressurization in conjunction I

with low-low-low reactor water level, initiate the standby gas treatment system and isolate the reactor building. The scram function shuts the core down during the loss-of-coolant accidents. A steen leak of about 15 gpa and a liquid leak of about 35 gym from the primary system will cause drywell pressure to reach the scram point; and, therefore, the scram provides protection for breaks greater than the above.

High drywell pressure provides a second means of initiating the core spray to mitigate the consequences of a loss-of-coolant accident. Its set point of 2.4 psig initiates the core spray in time to provide adequate core cooling. The break-size l coverage of high drywell pressure was discussed above. Low-low water level and high drywell pressure in addition to initiating core spray also causes isolation valve closure.

These settings are adequate to cause isolation to minimize the offsite dose within required limits.

It is permissible to make the drywell pressure instrument channels inoperable during performance of the integrated primary containment leakage rate test provided the reactor is in the cold shutdown condition. The reason for this is that the Engineered Safety Features, which are effective in case of a LOCA under these conditions, will still be effective because they will be activated by low-low reactor water level.

The high water level in the scram discharge volume setting is based on the design that 37 gallons of water in the scram dis-charge volume will permit the 137 control rods to scram with a pressure in the volume 165 peig. To provide further margin, one gallon of water collecting in the volume will cause an alarm. A escond high level slarm is set at two gallons.

Detailed analyses of transients have shown that sufficient protection is provided by other scrams below 45% power to permit bypassing of the turbine trip and generator load rejection scrams. However, for operational convenience, 40% of rated power has been chosen as the setpoint below which these trips are bypassed. This setpoint is coincident with bypass valve capacity.

7 A low condenser vacuum scram trip of 23" Hg has been provided to protect the main condenser in the event that vacuum is lost.

A loss of condenser vacuum would cause the turbine stop valves to close, resulting in a turbine trip transient. The low condenser vacuum trip anticipates this transient and scrams the reactor. The condenser is capable of receiving bypass steam until 7" Hg vacuum theraby mitigating the transient and providing a margin.

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3'1'7 TABLE 3.1.1 PROTECTIVE INSTRL?tENTATICM. REQUIREMENTS

, , , .. .I HLn, No. et- .

Reactor Modes Hin. No. of Operable. .

in which Function Operable or instruoent

. Hust Be Operable Operating. Cliannels Per Function (Tripped) Trip Operable ,

Trip Setting Shutdown Refuel Startup Run Systems Trip Systems Action Required

  • A. _S_ cram

. Insert control

1. Hanual Scrps X rods X X X 2 1
2. High Reactpr **

. X(s) X X 2 2 Pressure .

3. Illgh Drywell 3 2.4 psig . Xfu) X(u) X 2 2 Pressure **

-l 4 Low Reactor **

~

X - X 1 2 2 Water Level ,, .

5 Illah Water 1 37 gal. , X(s) X(z). X(zl 2 2 Level in .

~

. Scram Ills- - '

  • charge Volyse g i 6. Low Condenper > 23" Hg 8 X(b) X(b)
  • Vacuum X, e 2 2

~-

7. lilah Radiation in Hein Stpam- '

ig4gormalback- X(s) X X. 2 2 line Tunnel

  • s
8. Average Power **

X(c,s) ' '

Range Honikor ' X(c)' X(cf 2 . 3 (Al'RM) '

9. Intermediate **

t Range llonitor *

, X(d) X(d) 2 3 (lit:1) -

i i - .. . .

Anesfanent No 5 '

t ' -

(

I I 3.1-9

~

TABl.E 3.1.1 PROTECflVE INSTRUMENTATION RF.QUIRENDITS (CONTD)

Hin. No. of

.! in Which Function Operating

' Channela Per Hust be Operable (Tripped) Trip Operable Action Function Trip Setting Shutdown Refuel Startup Run Systems

  • Trip Systems RequiredA
h. Core Spray Consider the respective core
1. 1.w-l.am Ro nc to r **

X(t) X(t) X(t) X 2 2 apray ioop in-Water I.evel operable, I com-

,2. liinh Drywell i 2.4 psig X(t) X(t) X(t) X 2(k) 2(k)

P reneure
3. l.ow Reactor - > 285 psig X(t) X(t) X(t) X 2 2 4

Paessure (valve permissive) .

, E. r.on t a inaien t Spray l 1. Illgh prywell -< 2.4 psig X(u) X(u) X(u) X 2(k) 2(k)

Pressure Considerthecon-l tainment spray

2. I.w-I.ow Reactor loop inoperable

> 7'2" above X(u) X(u) X(n) X 2 2 and comply witti Water I.evel _ top of Spec. 3.4 i

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active fuel

! 'F. rr'llan"a~yj~ $'IItalsumeiit-luotation Isolate contain-j2.4psig

l. liigh Drywell X(u) X(u) X(u) X 2(k) 2(k) ment or place in l Pressure cold shutdown condition
2. l.ow-l.w licactor [7'2"above X(u) X(u) X(n) X 2 2 Water f.evel top of active fuel -

C. 'AutomntIc Dep.reneurization i

See note li

1. 181g1: lirywell < 2.4 psig X(v) X(v) X(v) X  ?(k) 2(k)

Prennuro l Cleange flo.

Y Anendment No.

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3.1-10 ~

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TABIE 3.1.1 Pil0TECTIVE INSTRtlHENTATIflN REQllIREMENTS (DINTD)

Hin. No. of Reactor Modes Hin. No. of Operable

i. in Which Fianction Operable or Instrument Hust Be Operable Operating Qiannele Fer

,_,, Junction (Tripped) Trip Operable Action Trip Setting Shutdown Refuel Startup Run Systems Trip Systems' RettuiredA

2. I.ow-l.uw-inu > 4'8" above X(v) ,X(y) X(y)

See note h X 2 2 Reactor Water top of 8.evel active fuel

3. AC Voltage NA X(V) X 2 2 Prevent auto depressurization on loss of AC

'II . Inolation Canalesiner Isolation power. See note i i

1. Iltgh Flow Steam 1 20 peig A P Isolate Affectest l X(s) X(s) X X 2 2 isolation con-1.ine I denser, cosaply
2. Bligh Flow Con- [27"A P 11 0 X(s) with Spec. 3.8 X(s) X

' X 2

, densate Line 2

! 1. O_f f fgas System isolation i, 1. liigli Radiation <10 x Stack Xfs) X (5) X X 1 Isolate reactor 1i 2 '

in Offans I.tne Release limit or trip the

_ , , (c) _

(Sen "l.6-A.1) inoperable in-atrument chnunnt

! J. Henctor hullding Isolation and S,tandby Cas Treatment System Isolate Reactor InitIntIon Bldg.l. Initiate I . H i gh linill a s l oei Standby Can Trent-

< 100 Hr/ilt

' X(w) X fwl  : X i 1 ment Synteri, or Renctor nullding H""""I 3"fV"III" l Operation Floor 1 2. Henet.o r fililg. ance for not more

' -< 17 Hr/Ilr M w) X (W) X X 1 1 than 21s lionorn ventitalInn Ex haien t Doral for all in-struments uneler I. tilgli saa vuni t <

2.4 psig M ul X(ul X 'X f(k) -

2(k) .1) sei any M-.Iny

( Pressure l g- Is . I.eu 1.su Reactor 7,, 7'2" nhova X X X X 1 4 2 llater f.evel top of V act.tve fuel 4 .. __

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