ML20236W075

Proposed Tech Specs Supporting Text Changes to Bases of Tech Specs Section 2.3 & 3.1

ML20236W075
Person / Time
Site:	Oyster Creek
Issue date:	11/30/1987
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20236W069	List: ML20236W067 ML20236W075
References
NUDOCS 8712070260
Download: ML20236W075 (2)

Text

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\ The react'or [oolant system safety Vdves offer h another protective feature I for the rtac'pr, coolant system presAre safety ljrit since these valves are g sted assumiiC no credit for other p&spre relid/ing devicev. In compliance 5

with Section I of the ASME Boiler and 6wsure $nel Code, tha safety valve must beAet to open at a pressurg.A no hig2er (t5an l03% of desi'9a pressure, and theJ W w limit the reactor pressure to no more than 110% of design pressure.

,, The sm".ty valves are sizedWccrdhig to the Cods for a condition of turtine stoobalve,'c sasure phile operating at 1930 MWt, followed by [1] a deloj of all sckmsi DJ,fillure of' the turbine bypass valves to open, and [3] f allera of the @ ot @ qconde Under these i condition 3, a\'otalnsers and relief valks,to operate. fof,ld/afety valses gri transient. The ASME B&W Ade alN af..% of working pressure (1250 psig) variat ton,in the lif t p'uint of the / lyes. Thisvariationisrecogfuedin SpecificQ ion 4.3. s ,

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- I' The low pressure isolation nf the main steam lines at 825 psig was provided to 5 give protection against fasti reactor depressurization and the resulting rapid cool-down of the vessel. Advantage was taken of the scram feature which occurs when the main steam line isolation valves are closed, to provide for reactor shutdown sc,; that high poder operational low reactor pressun does not ,

occur, thus providifq protection for the fuel cladding integrity safety l

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limit. Operelon (: thereactoraj/,p%ureslowerthan825psigreuuires i that the reactor mode switch be in av ShiUP position and be IRhs be in the  !

range 9, or lower, where protection 'of'the fuel cladding integrity safety limit is provided by the IRM high neutron flux scram. Thus, the combinatjan

• of main steam line low pressure isolation and isolation valves closure scram.

assures the availability of neutron flux strary protection over the entire range (l' applicability of the fuel chfling tuNgrity safety lim!t. .in addition the isolation valve closure spam 4nticJpates the pressure and flux f ransients which occur during normal'cq inadvertent isolation valve closure.

c The low (hter level trip set ting w(N N7 5" above the im of the active fuel has been established to assure Ibr '.hQ3 actor is not operated at a water level below that f or wp1G the fuel 'cl/Mng k'y,Lity safety liAtt is applicabb.

.8 he gM. ion of steam, and th.:5 the lois With the scram setht this ofinventory,isithp#.1 For/ x. point,41e6 @ a loss of feedwater flow a reactor

, scram at the value jndj.rc ad,an$ isolatior valve closure at the low-Ic1 water

level set point resultVr mordan M Tret of water remaining above the core

,yj after isolation (6). ) ,

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" During periods when thc. b rt06 is shut down, decay h p. is present and adequate water level must be maintained to provide core cooling. Thus, the low-low level trip point of 7'2" above the core is provided to actuate the

' core spray system (when the core spray system is required as identified in Section 3.4) to provide cooling water should the level drop to this point.*

The turbine s'op valve (s) scram is providb lo anticipate the pressure, neutron flux, and heat flux increase cged oy the rapid closure of the turbir. stop valve (s) ad i"dilure of tW turbine bypass systen.

The generator load rejectic) scram is provided to anticipate the rapid hcrew in pressure and neutroh flux result ing from f ast closure of the turbl,;o c etrol

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• Correctton:

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particular ~prcNctjon instrument is not required; or the plant 'is placed. in the 1  : protection or tsafe condition that the instrument initiates. This is accomplished

'in a normal manner without, subjecting the' plant to abnormal operations conditions.

The action and st-of-service requirements- apply to all instrumentation within a O particular function, e.g., if the requirements on any one of the. ten scram-m

• functions cannob be met then control rodsa shall be-inserted.

The trip level settidqs not specified in. Specification 2.3 have been included in' this specification. The bases for these settings are discussed below.

The high drywell pressure trip setting is < 3.5 psig. This trip will scram the reactor, initiate reacur isolation, initiate containment spray in conjunction with low lcw reactor water level, initiate. core spray, initiate primary containment isolation, initiate automatic depressurization.in conjunction.with low-low-low-reactor water luel, 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 steam leak of about 15 gpm and a liquid leak of about 35.gpm 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. . .Itstrip'settingof(3.5 l psig in_itiates. the core spray in time to provide adequate core cooling. The break-size (4verage of high drywell pressure was discussed above. Low-low water level and high dryvelt pressure in addition to initiating core spray also causes idolation valve closure. These settings are adequate to cause isolation to mfojmin the offsite does within required limits.

It-Permissible to cate the drywell pressure instrument channels inoperable during perf ormance of the integratid primary containment leakage rate test provided the reactor is in the cold shutdown condition. The reason for this is that the Engineered Safety Feat W es, which are effective in case of a LOCA under these conditions, will stilY be effective because they will be activated (when the Engir.aered Safety Features system is required as identified in the technical specification of the system) by low-low reacter water level.*

The scram dWch:rge volume has two separate instrument volumes utilized to detect water accumulation. The high water level is based on the design that the water in the SDH's, as detected by pf tWset of level instruments, shall not be allowed to exceed 29.0 gallons; theciby, permitting 137 control rods to scram. To provide further margin, an accumulation of not more than 14.0 gallons of water, as detected by either instrument volume, will result in a rod block and an alarm. The accumulation of not more than 7.0 gallons of water, as detected in either instrument volume will result in an alarm.

Detailed awlyses of transients have shown that sufficient protection is provided

= by othw scrams below 45% power tc permi bypassing of the turbine trip and generatcr' load mjection scrams. However, for operational convenience, 40% of rated power has been chosen as the ietpoint below which these trips are bypassed.

This setpoint is coincident with bypass valve capacity.

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 Oyster Creek 3.1 -4 Amendment No: 20, 73, 79, 112

• Correction:

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