ML20076L836

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Proposed Tech Spec Change Request 119 Revising Section 3.1, Scram Sys Reliability
ML20076L836
Person / Time
Site: Oyster Creek
Issue date: 07/13/1983
From:
GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20076L835 List:
References
NUDOCS 8307200007
Download: ML20076L836 (5)
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Text

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OYSTER CREEK NUCLEAR GENERATING STATION PROVISIONAL OPERATING LICENSE-NO. DPR-16 DOCKET No. 50-219 .

TECHNICAL SPECIFICATION CHANGE REQUEST No. 119 Pursuant to 10CFR50.91, an analysis concerning significant hazards considerations is provided below:

1. Section to be changed: -

3.1 2.

Extent of change: ,

Scram Dump Volume (SDV) modifications were performed at the Oyster Creek Nuclear Generating Station in accordance with the BWR Owner's Group recommendations in response to IE Bulletin 80-17 and its supplements.

As a result of providing two SDV instrument volumes to monitor water accumulation, the high water level scram and rod block set points have been changed. Section 3.1 has been modified to reflect these changes.

3. Changes requested:

Per the attached Technical Specification pages 3.1-4, 3.1-7 and 3.1-11.

4. Discussion:

The NRC presented their criteria for the modification of the scram discharge system in their letter of December 1, 1980. Our letters to the NRC dated December 17, 1980, March 4, 1981 and April 30, 1981 confirm that the SDV modification at the Oyster Creek Nuclear Generating Station will be in compliance with the NRC criteria.

The modification will ensure that there is suf ficient volume available in the SDV to allow all 137 control rods to scram in the event that plant

-conditions warrant this action. The subject modification will enhance the safety of the plant, thereby, providing a greater degree of protection for the health and safety of the public. .

5. Determination:

We have determined that the subject change request involves no significant hazards in that operation of the Oyster Creek Nuclear Generating Station in accordance with Technical Specification Change Request No. 119 would not:

1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or
2) Creat'e the possib'ility of a new or dif f erent kind of accident from any accident previously evaluated; or
3) Involve a significant reduction in a margin of safety.

8307200007 830713 PDR ADOCK 05000219 p PM

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a' 0YSTER CREEK NUCLEAR GENERATING STATION

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(DOCKET NO. 50-219i ,

PROVISIONAL OPERATING LICENSE NO. DPR-16 Applicant hereby requests the Comission to change Appendix A to the above captioned license as follows: ,

1. Section to be changed:

3.1

2. Extent of change:

Scram Dump Volume (SDV) modifications were performed at the Oyster Creek Nuclear Generating Station in accordance with the BWR Owner's Group recomendations in response to IE Bulletin 80-17 and its supplements.

As a result of providing two SDV instrument volumes to monitFr water accumulation, the high water level scram and' rod block set points have been changed. Section 3.1 has been modified to reflect these changes.

3. Changes Requested: ,

Per the attached Technical Specification pages 3.1-4, 3.1-7 and 3.1-11.

4. Discussion:

The NRC presented their criteria for the modification of the scram discharge system in their letter of December 1, 1980. Our letters to the.NRC dated December 17, 1980, March 4, 1981 and April 30, 1981 confinn that the SDV modification at the Oyster Creek Nuclear Generating Station will be in -

compliance with the NRC criteria.

The modification will ensure that there is suf ficient volume available in the SDV to allow all 137 control rods to scram in the event that plant conditions warrant this action. The subject modification will enhance the safety of the plant, thereby, providing a greater degree of protection for the health and safety of the public. l 1

m _ _ _ _ _ . _

3.1-4

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isolation, initiate automatic depressurization in conjunction with 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 lo s s-o f-coolant accidents. A steam leak of about 15 gpc 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. Its set point o f 2 psig initiates the core spray in time to provide adequate core cooling. The break-size coverage of high d rywell 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 sinimize 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 conditiens , will still be ef fective because they will be activated by low-low reactor water level.

The scram discharge volune has two separate instrument volumes utilized to detect water accumulation. The high water level setting is based on the design that 18.36 gallons (60 inches) of water de tec ted by either set of level instruments will permit the 137 control rods to scram. To provide further cargin, an accumulation of 9 gallons (30 inches) of water in either instrument volume will result

! in a rod block and an alar =, while an accumulation of 3.76 gallons (12.75 inches) in either instrument volume results in an alarm.

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 4 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.

A low condenser vacuus scram trip of 23" Hg has been provided to protect the =ain 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 un t il 7" Hg vacuum thereby citigating the transient and.providing a cargin.

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3.1-7: .

TABLE 3.1.1 PROTECTIVE INSTRUMENTATION REQUIREMENTS Min. No. of Reactor Modes Min. No. of Operable '

in which Function Operable or Instrument Must Be Operable Operating Channels Per (Tripped) Trip Operable Function Trip Setting Shutdown Refuel Startup Run Systems Trip Systems Action Required A. Scram Insert control rods

1. Manual Scram X X X X 2 1
    • 2
2. liigh Re..ctor X(s) X X 2 Pressure
3. liigh Drywell 5 2 psig X(u) X(u) X 2 2 Pressure
    • 2 2
4. Low Reactor , X X X Water 1.cVel

,S. liigh Water s 18.36. gal. X(a) X X 2 4

1. eve l in Scram Discharge Volume

'6. Low Condenser > 23" lig. X(b) X(b) X 2 2 Vacuum

7. Iligh Itadiation 5 10.x normal bach- X(s) ' X X 2 2 in Main Stcam ground ,

l.ine Tunnel

8. Average l'ower ** X(c,s) X(c) , X(c) 2 3 Itany.e Monitor (APRM)
    • X(d) 2- 3
9. Int e nne<l i zit e X(d)

Range Monitor -

( TitM)

Azeitdment No. 2$, 44

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3.l-11 '.

TABLE 3.1.1 PROTECTIVE INSTRUMENTATION REQUIREMENTS (CONTD)

- Min. No. of i Min. No. of Operable Reactor Modes Operable or Instrument in which Function Operating Channels Per Must be Operable -

(Tripped) Trip Operable Action

, Function Trip Setting Shutdown Refuel Startup Run Systems Trip Systems Required

X X(1) 1 3(y) permitted

2. SRM Downscale 100 cps (f) X X(1) 1 3(y)
3. IRM Downscale 5/125 fu11 scale (g) X X 2 3
4. 'APRM Upscale ** X(s) X X 2 3(c) 5'.[ APRM Downscale 2/150 fu11 scale X 2 3(c) 6.- IRM Upscale 108/125 fu11 scale X X 2 3 7., Scram Discharge Volume a) Water Icvel high 9 gallons X(z) X(z) X(z) 1 1 per.

instru. volume Condenser Vacuum Pump Insert Isolation - ,

control rods

1. Iligh Radiation in Main 10 x Normal Ddring Startup and Run 2 2 Steam Tunnel Background ,

when vacuum pump 1 operating

, Diesel Generator 1.oad Time delay after Consider Sequence Timers energiz. of relay containment ~

spray loop

1. Containment Spray Pump 40 see t 15% X X X X 2(m) 1(n) inoperabic and

. comply with spec.

3.l.C (see Note q)

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