ML20214T846

Proposed Tech Specs Consisting of Tech Spec Change 87-19, Deleting Action Statement for Ice Bed Temp Monitoring Sys

ML20214T846
Person / Time
Site:	Sequoyah
Issue date:	05/29/1987
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20214T832	List: ML20214T829 ML20214T846
References
TAC-R00165, TAC-R00166, TAC-R165, TAC-R166, NUDOCS 8706100448
Download: ML20214T846 (8)

Text

(.

ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-87-19)

PROPOSED CHANGE TO DELETE ICE BED ACTION STATEMENT LIST OF AFFECTED PAGES Unit 1 3/4 6-28 Unit 2 3/4 6-29 8706100448 G70529 PDH ADOCK 05000327 p PDH

r CONTAINMENT SYSTEMS ICE BED TEMPERATURE MONITORING SYSTEM LIMITING CONDITION FOR OPERATION 3.6.5.2 The ice bed temperature monitoring system shall be OPERABLE with at least 2 OPERABLE RTD channels in the ice bed at each of 3 basic elevations (10'6", 30'9" and 55' above the floor of the ice condenser) for each one third of the ice condenser.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

a. With the ice bed temperature indication not available in the main control room, determine the ice bed temperature at the local ice condenser temperature monitoring panel every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> g With the ice bed temperature monitoring system inoperable, and '

iable to determine ice bed temperature at the local panel, POWER OP TION may continue for up to 30 days provided:

nd top d r -

2. The last recorde an ice bed temper re was less than or equal to 20 F and ste  ; and

3. The ice condense

• coolin s >

is OPERABLE with at least:

a) 21 OPERABLE handling units, b) 2 OP LE glycol circulating pumps, an c 3 OPERABLE refrigerant units; erwise, be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHllT00WN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

b. With the ice bed temperature monitoring system inoperable and unable to determine the ice bed temperatures by alternate meansj--d i h R17 t'  % ~: : ! ' . , , ; t :- :t :t !; fy' ;; ' M '- 2 r ::- :-- .tr C "" " I '. ! !" n r. b -"t; c' '.? A;._, POWER OPERATION may continue for up to 6 days provided the ice compartment lower inlet doors, intermediate deck doors, and top deck doors are closed and the last recorded mean ice bed temperature was less than or equal to 15'F and steady; otherwise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTOOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

SURVE!LLANCE REQUIREMENTS 4.6.5.2 The ice bed temperature monitoring system shall be determined OPERABLE by performance of a CHANNEL CHECK at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

u su mn ,

A (QQ SEQUOYAH - UNIT I 3/4 6-28 ^-- " -' "- 9

F CONTAINMENT SYSTEMS ICE BED TEMPERATURE MONITORING SYSTEM LIMITING CONDITION FOR OPERATION 3.6.5.2 The ice bed temperature monitoring system shall be OPERABLE with at least 2 OPERABLE RTO channels in the ice bed at each of 3 basic elevations (10'6", 30'9", and 55' above the floor of the ice condenser) for each one third of the ice condenser.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

a. With the ice bed temperature indication not available in the main control room, determine the ice bed temperature at the local ice condenser temperature moritoring panel every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. R4 t

With the ice bed temperature monitoring system inoperable, and unable to determine ice bed temperature at the local panel, POWER r ATION may continue for up to 30 days provided:

1. The compartm r o ermedi deck doors,

! 2. The last record ,ean ice bed temper re was less than or equal to 20*F and s dy; and l 3. The ice condenser cooling em is OPERABLE with at least:

l

! a) 21 OPERABLE < handling units, b) 2 OPE E glycol circulating pumps, a c) OPERABLE refrigerant units; Terwise, be'in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COL SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

,pd With the ice bed temperature monitoring system inoperable and unable R4 b, to determine the ice bed temperatures by alternate means "' : ' c c-c' * ::: : : _ ' ' , _ j--:^ *- - ^" c t : _' ' ' 1 ' y ' ', ' ~ ' " ' - " - ' ^ ;' ^ ^ - * ' N D -

^3 " ' "' ,_:- 3 :b;;;, POWER OPERATION may continue for up to 6 days provided the ice compartment lower inlet doors, intermediate deck doors, and top deck doors are closed and the last recorded mean i ice bed temperature was less than or equal to 15*F and steady; other-wise, be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

SURVEILLANCE REQUIREMENTS 4.6.5.2 The ice bed temperature monitoring system shall be determined OPERABLE .

by performance of a CHANNEL CHECK at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. ii i u A anno

! C""'^

SEQUOYAH - UNIT 2 3/4 6-29 ^

l

r ENCLOSURE 2 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-87-19)

DESCRIPTION AND JUSTIFICATION FOR PROPOSED CHANGE TO DELETE ICE BED ACTION STATENENT i

i

F i

\

l ENCLOSURE 2 l

1 l

Description of Change l The proposed change will delete action statement b of limiting condition I

for operation (LCO) 3.6.5.2, " Ice Bed Temperature Monitoring System."

Reason for Change l Action statement b of LCO 3.6.5.2 allows continued power operation for up to 30 days when the ice bed monitoring system is inoperable, provided that required air handling units (AHUs), glycol circulating pumps, and refrigerant units are operable. Ice condenser preoperational testing and refrigerant unit heat load testing identified deficiencies in the ice condenser cooling system performance. The test data did not meet operating criteria stated in the final safety analysis report (FSAR) and, thus, the action statement operating requirements could not guarantee that an ice bed temperature of less than or equal to 27 degrees Fahrenheit i would be maintained as required by LCO 3.6.5.1.c. The proposed change i will remove the option to use action statement b when the ice bed l temperature monitoring system is inoperable. Instead, compliance with action statement c will be required.

, Justification for Change l

The function of an ice condensor system is to provide pressure suppression capability to primary containment in the event of a loss of coolant accident (LOCA). The system consists of a completely enclosed annular compartment formed between the crane wall and the crane shell within which a large inventory of borated ice is maintained at 15 to 20 degrees Fahrenheit throughout a 300-degree arc of the compartment. The compartment walls are lined with thermal insulation and cooling ducts which are supplied with refrigerated air from 30 pairs of AHUs located in the compartment above the ice inventory. The ice condenser floor is also insulated and cooled. A circulating system of 50-percent ethylene glycol solution carries heat from the AHUs and embedded floor cooling coils to a number of glycol chillers located in the additional equipment building.

The technical specifications require that a maximum ice bed temperature of less than or equal to 27 degrees Fahrenheit be maintained in order to ensure ice bed operability. The ice bed temperature monitoring system provides assurance of meeting this temperature limit by verification at least once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. In the event the monitoring system is inoperable, the action requirements provide assurance that the ice bed heat capacity will be retained within the specified time limits. Action statement b allows continued power operation provided the ice condenser cooling system is operable. Thirty AHUs make up part of the ice condenser cooling system. During normal operation, the AHus serve to cool the air and to circulate the cooled air through the ice condenser wall panels to keep the ice subcooled in the ice beds. During an accident, the AHUs are designed to resist additional induced loads.

The preoperational test data for the AHUs showed several performance deficiencies in meeting design criteria. Specifically, design calculations do not support the technical specification requirements for the number of operating units required to ensure that an ice bed temperature of less than or equal to 27_ degrees Fahrenheit is maintained.

However, the ice condenser cooling system as a whole provides adequate system performance to maintain ice bed temperature.

In the event the monitoring system is inoperable and local panel readings could not be made, there is no method for temperature indication. Under worst case conditions, there is no guarantee that ice bed temperature would be maintained less than or equal to 27 degrees Fahrenheit. Deletion of action statement b removes this concern by requiring compliance with action statement c.

n t

1

r e

. r ENCLOSURE 3 PROPOSED TECHNICAL SPECIFICATION CHANGES SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (IVA-SQN-TS-87-19) s DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATIONS FOR PROPOSED CHANGE TO DELETE ICE BED ACTION STATEMENT I

l l

1 i

r o

1 i

ENCLOSURE 3 {

SIGNIFICANT HAZARDS CONSIDERATIONS i

1. Is the probability of an occurrence or the consequences of an accident previously evaluated in the ssfety analysis report i significantly increased?

No. The operability of the ice bed temperature monitoring system ensures that the capability is available for monitoring the ice temperature. In the event the monitoring system is inoperable, the action requirements provide assurance that the ice bed heat removal capacity will be retained withia the specified time limits. The function of the ice condenser system is to provide pressure suppression capability to primary containment in the event of a loss I of coolant accident. It is necessary to delete the proposed action I statement because operating requirements cannot be met and thus ensure that adequate pressure suppression capability will be )

available. The proposed change will enforce more stringent shutdown requirements if unable to monitor ice bed temperature. The possibility of accidents previously evaluated has been decreased.

2. Is the possibility for an accident of a new or different type than evaluated previously in the safety analysis report created?  !

l No. Deletion of the action statement removes an option to continue power operation for a specified time, while trying to restore the ice ,

bed temperature monitoring system to an operable condition.

Compliance with the remaining action statement must still be met.

The possibility for a new or different type of accident has not been created.

L

3. Is the margin of safety significantly reduced!

No. The same shutdown requirements still apply if unable to monitor ice bed temperature, and the same surveillance testing is applicable to detect any problems with the monitoring system. Thus, the margin of safety has not been changed.

l

\

v s

O 4