Text

Application for Amend to License NPF-6,modifying Requirements for Pressurizer Code Safety Valve Requirements Specified by TS 3.4.2 & Safety Tank Isolation Requirements Specified in TS 3.4.12
	ML20236G677
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/29/1998
From:	Hutchinson C; ENTERGY OPERATIONS, INC.
To:	; NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20236G680	List: 2CAN069806, Application for Amend to License NPF-6,modifying Requirements for Pressurizer Code Safety Valve Requirements Specified by TS 3.4.2 & Safety Tank Isolation Requirements Specified in TS 3.4.12; ML20236G692;
References
	2CAN069806, 2CAN69806, NUDOCS 9807060334
	Download: ML20236G677 (11)
	v • d • e

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Entergy Operations, Inc.

CNEf { y} 14485R 333 RwdAe. AR 77801 Tel 501 -858-4888 C. Randy Hutchinson We Pmsdent

%atons ANO June 29,1998 2CAN069806 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station OPI-17 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket Nos. 50-368 License Nos. NPF-6 Technical Specification Change Request Regarding Reactor Coolant System Safety Valves and Low Temperature Overpressure Protection Gentlemen:

Attached for your review and approval are proposed changes to the Arkansas Nuclear One Unit 2 Technical Specifications. These proposed changes are in Technical Specification 3.4.2,

" Reactor Coolant System - Safety Valvec - Shutdown," and Technical Specification 3.4.12,

" Reactor Coolant System - Overpressure Protection" regarding the low temperature overpressure protection system. The specific changes are described in the attachment to this letter. They include modifying the requirements for the pressurizer code safety valve requirements specified by Technical Specification 3.4.2 and a modification of the safety injection tank isolation requirements specified in Technical Specification 3.4.12.

l The proposed changes have been evaluated in accordance with 10 CFR 50.91(a)(1) using criteria in 10 CFR 50.92(c). It has been determined that these changes involve no significant /

hazards considerations. The bases for this determination is also included in the attachment to this letter, p 1

(fl Although the circumstances of this amendment request are neither exigent or emergency in nature, Entergy Operations requests the effective date for this change to be 30 days before the next refueling outage, currently scheduled to begin on January 8,1999. This schedule will allow time for the required procedure revisions to be incorporated before the refueling outage.

9807060334 900629 PDR ADOCK 05000368 P PDR

t t U. S. NRC l

June 29,1998 2CAN069806 Page 2 l

! Very truly yo rs, A Ak-CRH/rdc Attachment To the best of my knowledge and belief, the statements contained in this submittal are true.

SUBSCRIBED AND SWORN TO before m a Notary lic in and for @ 7D County and the State of Arkansas, this day of cz ,1998.#

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7' t/ vild & h V N6tary P4blic //

My Commission Expires- 98#v // #d#d g /

y U. S. NRC June 29,1998 2CAN069806 Page 3 )

.cc: Mr. Ellis W. Merschoff Regional Administrator U. S. Nuclear Regulatory Commission i RegionIV l 611 Ryan Plaza Drive, Suite 400 f

Arlington, TX 76011-8064 i NRC Senior Resident Inspector Arkansas Nuclear One 1 P.O. Box 310 I London, AR72847 Mr. William D. Reckley NRR Project Manager Region IV/ANO-1 & 2 U. S. Nuclear Regulatory Commission NRR Mail .Stop 13-H One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. David D. Snellings Director, Division ofRadiation ,

Control and Emergency Management i Arkansas Department ofHealth 4815 West Markham Street

. Little Rock, AR 72205 i

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i ATTACHMENI l t

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i 2CAN069806 PROPOSED TECHNICAL SPECIFICATION i

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f RESPECTIVE SAFETY ANALYSES l

l-IN THE MATTER OF AMENDING l

LICENSE NO. NPF-6 t

i ENTERGY OPERATIONS. INC.

ARKANSAS NUCLEAR ONE -UNIT TWO l

QQCKET NO. 50-368 1

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Attachment to

. 2CAN069806 '

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DESCRIPTION OF PROPOSED CHANGES i , ,

Entergy Operations is proposing to amend the Arkansas Nuclear One, Unit 2 (ANO-2) i Technical Specification (TS) 3.4.2, " Reactor Coolant System - Safety Valves - Shutdown,"

and TS 3.4.12, " Reactor Coolant System - Overpressure Protection" regarding low l temperature overpressure protection (LTOP) and their associated Bases. The specific changes include: l l

l e Index page VI - The proposed change modifies the limiting condition for operation index l page to include the LTOP specification.

Bases index page XII - The proposed change modifies the Bases index page to include

the LTOP specification. '

e TS 3.4.2 - The mode of applicability for one operable pressurizer code safety valve has r

l been modified from " Modes 4 and 5" to " Mode 4 with T. > 220'F." The action l requirement for both pressurizer code safeties being inoperable was also revised to l require the RCS inlet temperature T, to be reduced to 5: 220 F within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . Since l the proposed specification will no longer be applicable in Mode 5, the "#" footnote i associated with Mode 5 applicability was also removed.

e TS 3.4.12 - The proposed change revises the title of this specification for consistency.

This change also modifies the safety injection tank (SIT) isolation requirements to ensure each SIT "that is pressurized 2 300 psig" is isolated. The associated action requirements were also revised to be consistent with the proposed LCO. Minor human factors wording changes were also made to increase the clarity of the specification and for consistency within the actions.

The Bases for TS 3.4.2 and TS 3.4.12 were also modified to reflect the changes made to i the associated specifications. Minor wording changes were also made to these Bases to increase their clarity.

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Attachment to 2CAN069806 l- I Page 2Cf 7 BACKGROUND a e The ANO-2 LTOP system consists of two redundant pressure relief valves which relieve from a single discharge header on the pressurizer. Each valve has an orifice area of 6.38 in' and has an opening setpoint of s 430 psig. Two isolation (or block) valves and corwing piping precede each LTOP relief valve. The LTOP relief valves are operator enabled by opening the block valves during a cooldown when the RCS conditions require the LTOP system to be operable. No other operator action is required to prevent an overpressurization event at low temperatures. The LTOP system has been designed with sufficient relief capacity to prevent an RCS overpressure event under anticipated transient conditions.

.To protect the RCS from overpressurization in Modes 1, 2, and 3, TS 3.4.3 requires both pressurizer code safety valves to be operable. When this limiting condition for operation (LCO) is not met, then the applicable actions are entered.- To protect the RCS from overpressurization in Modes 4 and 5, TS 3.4.2 presently requires a minimum of one pressurizer code safety valve to be operable. When this LCO is not met, the action requires -

an operable shutdown cooling loop to be placed into operation. Although the shutdown l cooling system provides additional RCS overpressure protection, it does not contain sufficient l relief capacity to prevent an RCS overpressurization event under all anticipated transient i conditions. These conditions include inadvertent operation of the high pressure safety L injection (HPSI) or charging pumps.

Entergy Operations has previously notified the staff that the actions associated with TS 3.4.2 for inoperable ' pressurizer code safeties require change to assure sufficient relief capacity exists in Mode 4. This information was provided to the staff'by letter 0CAN129105, dated D-mhar 20,1991. In this letter, Entergy Operations committed to submit the necessary changes to TS 3.4.2 by June 30,1992. By letter 2CAN069206 dated June 30,1992, Entergy

, Operations deferred making the change to TS 3.4.2 until the proposed LTOP specification was approved. As an interim measure, administrative controls were established to ensure adequate RCS overpressure protection in Mode 4 with inoperable pressurizer code safeties.

L - The LTOP system was added to the ANO-2 TS by mir.er.dir.er.t 180 as TS 3.4.12 with an applicability of Mode 4 with T. s 220 F, Mode 5, and Mode 6 with reactor vessel head in place.

To assure sufficient pressure relief capability exists for all modes, TS 3.4.2 has been revised by this proposed amendment request to require the RCS temperature to be reduced to s 220 F within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months when both pressurizer code safeties are inoperable. This reduction in RCS temperature will require the LTOP system to be placed in service in accordance with TS 3.4.12. TS 3.4.12 ensures the RCS is protected from overpressurization events at low temperature by requiring the operability of the LTOP system. These changes are consistent with the associated requirements in Revision 1 of NUREG-1432, " Standard Technical Specifications for Combustion Engineering Plants" (CE-STS).

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l The LTOP specification (TS 3.4.12) presently requires the SITS to be isolated when the SIT l pressure is greater than or equal to the RCS pressure. According to the Bases of the 1

, . Attachment to 2CAN069806 I Page 3 of 7 specification, the LTOP analysis assumes that the SITS are either isolated or are depressurized and ' the RCS is. water solid. This requirement was added to preclude the rapid overpressurization of the RCS due to an inadvertent SIT actuation. The proposed change modifies the SIT isolation requirements to ensure each SIT that is pressurized to 2 300 psig is isolated. As indicated in the proposed LTOP specification Bases, the associated instrumentation uncertainty is not included in the 300 psig vr.lue. The 300 psig limit will continue to ensure the mass of water contained in the SITS will not challenge the LTOP relief valves and potentially overpressurize the RCS due to an inadvertent SIT injection.

ANO-2 is required by the American Society of Mechanical Engineers (ASME) Code,Section XI, to perform an inservice test of each SIT discharge check valve (2SI-15A through D and 2SI-16A through D). These check valves can be tested by either intrusive testing (visually l inspecting the disc swing) or non-intrusive (performing an acoustic check of the valve's

movement under an established flow) methods. It is ANO's desire to perform this test using the non-intrusive method. This test would typically be performed in Mode 5 during a cooldown.

In order to perform a non-intrusive test of the 2SI-16 valves, a positive head from SIT pressure is necessary to lift these valves off their seats. Without installation of a separate pressurization scheme, the positive head can only be provided when the SITS pressure is above that of the RCS. The allowance proposed by this change permits non-intrusive check valve testing using flow from the associated SITS. ANO also desires to have the SITS available as a backup source of borated water for use in the lower mode emergency cperating procedures. This change will allow the SITS to be used as additional makeup sources to refill

!. the RCS, if needed.

By letter 2CAN069804 dated June 29,1998, Entergy Operations submitted a separate ANO-2 TS change request to revise the "as found" lift setting tolerance for the safety valves listed in

-TS 3.4.2. Should that change be approved before this amendment request, changes to the affected pages will be made and sent to the staff.

DISCUSSION OF CHANGE e Index pages VI and XII have been modified to include the LTOP specification 3.4.12.

The LTOP specification was added to the ANO-2 TS by amendment 180 and did not include the necessary index page changes. These index page changes are considered administrative in nature.

TS 3.4.2 - The mode of applicability was modified for this specification from " Modes 4

! and 5" to " Mode 4 with T > 220*F". RCS overpressure protection is provided by specification 3.4.12 with a mode of applicability of Mode 4 with T. s 220*F, Mode 5, and Mode 6 with reactor vessel head in place. Since the LTOP system provides adequate RCS overpressure protection during the remainder of Mode 4 and all of Mode 5, the requirement to maintain one pressurizer code r,afety operable by TS 3.4.2 during this same l-L__________-_____________________-________________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . _ . _____ _

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At*=chment to

, 2CAN069806 4

Page 4 of 7 period of time was no longer necessary and was therefore removed. With the Mode 5 requirements removed from TS 3.4.2, the # footnote associated with the Mode 5 applicability was also removed from this specification.

1 L The proposed action requirement when both code safeties are inoperable requires the

, reduction in the reactor coolant temperature (RCS T.) to s 220*F within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . The present requirement to place a shutdown cooling loop in service was removed. The LTOP ,

design basis event is the simultaneous injection of two HPSI pumps and all three charging j pumps to a water-solid RCS. A shutdown cooling loop does not contain adequate relief capacity to ensure RCS overpressure protection. Therefore, the proposed action requirements in TS 3.4.2 are revised to lower the RCS temperature to s 220'F such that the operability of the LTOP system is required by TS 3.4.12 to provide RCS overpressure protection.

The action requirement to immediately suspend all operations involving positive reactivity changes was also removed from the TS 3.4.2. This stipulation was removed because it conflicts with the requirement to reduce the RCS T. to s 220'F. A temperature reduction in the RCS under most conditions is classified as a positive reactivity addition. TS 3.1.1.1

! requires the shutdown margin to be maintained greater than or equal to that specified in the core operating limits report (COLR) during Mode 4. Therefore, any reactivity changes performed while all pressurizer safeties are inoperable will be made in accordance with TS 3.1.1.1 and will therefore ensure the associated minimum shutdown margin requirements are met. Since the minimum shutdown margin requirements are ensured by TS 3.1.1.1, this change eliminates a duplicate requirement and is considered administrative in nature.

The 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months allowance to reduce RCS temperature to bring the unit to less than or equal to 220 F is reasonable without challenging plant systems. The RCS contains lower energy levels (reduced pressures and temperatures) in Mode 4, which reduces the potential for large pressurizer insurges, where the overpressure protection systems would be challenged.

l The present action for TS 3.4.2 does not contain a specified completion time and therefore requires interpreting the length of time allowed for the completion of the action. The proposed TS 3.4.2 action requirement to reduce RCS temperature to where the LTOP l system is required to be operable is consistent with the similar requirements of the CE- !

STS.

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, AHdment to 2CAN069806 4

Page S of 7 TS 3.4.12 - The proposed change revises the title of the LTOP specification for consistency between the index pages, the LTOP specification, and its Bases. Minor human factors wording changes were also made to this specification to increase its clarity j and for consistency within the specification. These changes are considered administrative i in nature and are therefore considered acceptable.

l The remaining changes to this specification modify the safety injection tank (SIT) isolation requirements. These changes allow the SITS to be unisolated when LTOP system is operable and the SIT pressure is less than 300 psig. This pressure does not pose any additional overpressurization concerns for the RCS because it is significantly less than the lift setpoint (s 430 psig) for the LTOP.

The pressure limitation of 300 psig is based on the design of the autoclosure interlocks on the shutdown cooling system. In Mode 5 when the check valve testing would normally be performed, the shutdown cooling system will be aligned. There are two valves in series that are used to isolate the lower pressure shutdown cooling system from the RCS. These valves have an interlock system associated with them. When the RCS pressure is increasing these valves will automatically close when the pressure reaches 300 psig. By l limiting the SIT pressure to < 300 psig (minus instrument uncertainties), the risk of closing these valves and losing shutdown cooling during the SIT check valve testing is significantly reduced.

The CE-STS contains an applicable LTOP system standard specification. The applicable standard specification contains the requirement that " SIT isolation is only required when SIT pressure is greater than or equal to the maximum RCS pressure for the existing RCS j cold leg temperature allowed by the P/r limit curve provided in the PTLR." Therefore, !

the proposed wording for TS 3.4.12 for SIT isolation is a more restrictive requirement ;

than the similar requirement contained in the CE-STS.

e The Bases for TS 3.4.2 and TS 3.4.12 were also modified to reflect the changes made to the associated specifications. Minor wording changes were al:,o made to these Bases to increase their clarity on the associated LTOP specification requirements. These changes are considered administrative in nature.

Attachment to

, 2CAN069806 i

Page 6 of 7 DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION An evaluation of the proposed change has been performed in accordance with 10 CFR 50.91(a)(1) regarding no significant hazards considerations using the standards in 10CFR 50.92(c). A discussion of these standards as they relate to this amendment request i

follows:

Criterion 1 - Does Not Involve a Significant Increase in the Probability or Consequences of an Accident Previously Evaluated.

The reactor coolant system (RCS) is designed with overpressure protection devices to be ur,ed in all modes of operation. The changes to Technical Specification (TS) 3.4.2 will ensure that, ifno pressurizer code safety valves are operable, the RCS will be cooled down to the mode of applicability of the low temperature overpressure protection (LTOP) system (TS 3.4.12) within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months . The LTOP relief valves provide suflicient relief capacity to protect the RCS from overpressurization when the RCS inlet temperature (T. ) s 220 F. Therefore, this change will ensure the proper actions will be taken that will ensure adequate overpressure protection of the RCS. These actions are not accident initiators, and therefore do not involve a significant increase in the probability of any accident previously evaluated.

The proposed change to TS 3.4.12 provides additional operational flexibility for the use of the safety injection tanks (SITS) as an additional inventory source during Modes 4, 5, and 6 when the RCS is in LTOP conditions. The ability to use the SITS, with a pressure less than 300 psig is within the existing LTOP analysis. The LTOP analysis ensures that under the analyzed worst case overpressurization event, the RCS is protected. The 300 psig SIT pressure limit, correc. A for instrument uncertainty, will prevent a challenge to the LTOP relief valves and therefore the RCS will be assured of overpressure protection. The SIT pressure limit will also be low enough to prevent an inadvertent isolation of the shutdown cooling system and thus prevent a loss of shutdown cooling due to placing an SIT in service. The remaining changes included in this amendment request are considered administrative in nature and are therefore considered acceptable.

Based on the above discussions, these changes do nol involve a significant increase in the probability or consequences of any accident previously evaluated.

. Attachment to 2CAN069806 4

Page 7 cf 7 j Criterion 2 - Does Not Create the Possibility of a New or Different Kind of Accident from any Previously Evaluated.

The proposed changes included in this amendment request provide additional operational flexibility for the use of the SITS and specify the proper actions to be taken that will ensure adequate overpressure protection of the RCS. The LTOP relief valves have already been evaluated for operation below 220 F. The changes do not introduce any new plant configurations. No new accident possibilities are being introduced by these changes.

Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated. i Criterion 3 - Does Not Involve a Significant Reduction in the Margin of Safety.

The proposed change to the TS 3.4.2 action statement requires the T. s 220 F when no pressurizer code safety valves are available. When T. s 220*F, the LTOP system operability is required by TS 3.4.12. This action will provide assurance that the RCS will be protected from an overpressurization event and therefore incicases the margin of safety.

The requirements to maintain one pressurizer code safety valve in Mode 4 when T. s 220*F ,

and in Mode 5 has been removed by the proposed revision to TS 3.4.2. The LTOPs provide )

adequate RCS over pressure protection during these modes without reliance on the )

pressurizer code safeties. Maintaining the requirement to require one pressurizer code safety ,

to be operable at the same time as the LTOP system is required to be operable, provides no I additional plant safety. An operable LTOP system prevents RCS pressure from increasing high enough to challenge the preswrizer code safety lift setpoints. l l

The current TS 3.4.12 LTOP limits are based on an analysis that uses the methodology outlined in the ASME Code Case N-514. This code case defines the margin of safety for the l current LTOP limits. This code case was utilized in the development of TS 3.4.12. The )'

safety factor utilized by the code case provides a reasonable vessel overpressure allowance for conditions expected during a low temperature transient. The margin of safety is not reduced with SITS in service and pressurized to less than 300 psig because this condition is bounded by the existing LTOP analysis. Therefore, this change does net involve a significant reduction in the margin ofsafety.

Therefore, based upon the reasoning presented above and the previous discussion of the amendment request, Entergy Operations has determined that the requested change does not involve a significant hazards consideration.

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2CAN069806, Application for Amend to License NPF-6,modifying Requirements for Pressurizer Code Safety Valve Requirements Specified by TS 3.4.2 & Safety Tank Isolation Requirements Specified in TS 3.4.12

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