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{{Adams
#REDIRECT [[2CAN060903, License Amendment Request, Technical Specification Changes to Relocate Pressurizer Heater Requirements to Technical Requirements Manual]]
| number = ML091760204
| issue date = 06/18/2009
| title = License Amendment Request, Technical Specification Changes to Relocate Pressurizer Heater Requirements to Technical Requirements Manual
| author name = Walsh K
| author affiliation = Entergy Operations, Inc
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000368
| license number = NPF-006
| contact person =
| case reference number = 2CAN060903
| document type = Letter, Technical Specification, Bases Change
| page count = 13
| project =
| stage = Other
}}
 
=Text=
{{#Wiki_filter:2CAN060903  
 
June 18, 2009 
 
U.S. Nuclear Regulatory Commission
 
Attn: Document Control Desk
 
Washington, DC  20555
 
==SUBJECT:==
License Amendment Request Technical Specification Changes To Relocate Pressurizer Heater  
 
Requirements to TRM
 
Arkansas Nuclear One, Unit 2
 
Docket No. 50-368
 
License No. NPF-6
 
==Dear Sir or Madam:==
 
Pursuant to 10 CFR 50.90, Entergy Operations, Inc. (Entergy) hereby requests the following
 
amendment for Arkansas Nuclear One, Unit 2 (ANO-2). The proposed change will relocate
 
portions of Technical Specification (TS) 3.4.4, Pressurizer , to the Technical Requirements Manual (TRM). TS 3.4.4 specifies operability requirements for both the water volume in the
 
Pressurizer and the electric heater capacity of the Pressurizer. The proposed change will
 
relocate the heater requirements to the TRM.
 
The heater bank and capacity requirements for the Pressurizer are not credited in the accident
 
analyses and, therefore, are proposed for relocation to the station TRM. This is consistent
 
with the intent of 10 CFR 50.36 in that the heaters do not meet the requirements for inclusion
 
in the TSs. Changes to the TRM are controlled in accordance with the requirements of 10
 
CFR 50.59. The associated TS Bases, controlled in accordance with the TS Bases Control
 
Program of TS 6.5.14, will also be relocated to the TRM. The relocation of the TS Bases is
 
part of the ANO TS change implementation process; therefore, a markup of the TS Bases is
 
not provided in this submittal.
 
In addition to the above, the percent-level described in TS 3.4.4 is relocated to the TS Bases. 
 
This "equivalent" to the 910 ft 3 limit contained in the TS can change over time due to changes in instrument uncertainty calculations or due to instrument replacement. Because the accident
 
analysis is based on the volume limit, relocating the "percent" indication to the TS Bases does
 
not result in a change to license basis or the actual TS limit.
 
The proposed change has been evaluated in accordance with 10 CFR 50.91(a)(1) using
 
criteria in 10 CFR 50.92(c) and it has been determined that the changes involve no significant
 
hazards consideration. The bases for these determinations are included in the attached
 
submittal. Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR  72802
 
Tel  479-858-3110 Kevin T. Walsh Vice President, Operations A rkansas Nuclear One
 
2CAN060903 Page 2 of 2
 
The proposed change does not include any new commitments.
 
Although this request is neither exigent nor emergency, your prompt review is requested.
Once approved, the amendment sha ll be implemented within 90 days.
 
If you have any questions or require additional information, please contact David Bice at
 
479-858-5338.
 
I declare under penalty of perjury that the foregoing is true and correct. Executed on
 
June 18, 2009.
 
Sincerely, Brad Berryman for Kevin Walsh KTW/dbb
 
Attachments:
: 1. Analysis of Proposed Technical Specification Change
: 2. Proposed Technical Specification Changes (mark-up)
 
cc: Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX  76011-4125
 
NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310
 
London, AR  72847 U. S. Nuclear Regulatory Commission
 
Attn: Mr. Kaly Kalyanam
 
MS O-8 B1
 
One White Flint North
 
11555 Rockville Pike
 
Rockville, MD  20852 Mr. Bernard R. Bevill
 
Arkansas Department of Health
 
Radiation Control Section
 
4815 West Markham Street Slot #30 Little Rock, AR 72205 Attachment 1 2CAN060903 Analysis of Proposed Technical Specification Change Attachment to 2CAN060903
 
Page 1 of 8
 
==1.0 DESCRIPTION==
 
This letter is a request to amend Operating License NPF-6 for Arkansas Nuclear One, Unit 2 (ANO-2).
 
The proposed change will relocate portions of Technical Specification (TS) 3.4.4, Pressurizer , to the ANO-2 Technical Requirements Manual (TRM). This TS specifies operability
 
requirements for both the water volume in the Pressurizer and the electric heater capacity of
 
the Pressurizer. The proposed change will relocate the heater requirements to the TRM. 
 
Changes to the TRM are controlled in accordance with 10 CFR 50.59.
 
In addition to the above, the percent-level described in TS 3.4.4 is relocated to the TS Bases. 
 
Because the safety analysis is based on the volume limit, relocating the "percent" indication to
 
the TS Bases does not result in a change to license basis or the actual TS limit.
 
==2.0 PROPOSED CHANGE==
 
The electric heater portion of ANO-2 TS 3.4.4, Pressurizer , is proposed for relocation to the ANO-2 TRM. During relocation, the current TS Actions may be modified. Such modification, if performed, will be in accordance with the requirements of 10 CFR 50.59. A markup of the
 
affected TS page is included in Attachment 2 of this submittal.
 
In addition to the above, the percent-level described in TS 3.4.4 is relocated to the TS Bases. 
 
This "equivalent" to the 910 ft 3 limit contained in the TS can change over time due to changes in instrument uncertainty calculations or due to instrument replacement. Because the
 
accident analysis is based on the volume limit, relocating the "percent" indication to the
 
TS Bases does not result in a change to license basis or the actual TS limit.
 
==3.0 BACKGROUND==
 
TS 3.4.4 requires two proportional heater banks to be operable in Modes 1, 2, and 3 with a
 
capacity of  150 Kilowatts (kW) each. These heater banks are powered from vital AC buses backed by a respective TS-required Emergency Diesel Generator (EDG). In addition to the
 
two proportional heater banks, non-vital back-up heater banks are also installed to help
 
accommodate significant transients during normal power operation.
 
The pressure in the Reactor Coolant System (RCS) is controlled by regulating the
 
temperature of the coolant in the Pressurizer, where steam and water are held in thermal
 
equilibrium. Steam is formed by the Pressu rizer heaters or condensed by the Pressurizer spray to reduce variations caused by expansion and contraction of the reactor coolant due to
 
system temperature changes.
 
The Pressurizer heaters are single unit, direct immersion heaters which protrude vertically
 
into the Pressurizer through sleeves welded in the lower head. Approximately one-third of the
 
heaters are connected to proportional controllers which adjust the heat input as required to
 
compensate for steady state losses and to maintain the desired steam pressure in the
 
Pressurizer. The remaining backup heaters are connected to on-off controllers. These
 
heaters are normally de-energized, but will automatically energize on a low Pressurizer Attachment to 2CAN060903
 
Page 2 of 8
 
pressure signal or high level error signal. This latter feature is provided since load increases result in an in-surge of relatively cold coolant into the Pressurizer, thereby decreasing the bulk
 
water temperature. The Chemical and Volume Cont rol System (CVCS) acts to restore level, resulting in a transient pressure below normal operating pressure. To minimize the extent of
 
this transient, the backup heaters are energized, contributing more heat to the water. A low-
 
low Pressurizer level signal de-energizes all heaters to protect the heaters should they
 
uncover.
 
The Pressurizer proportional heater feeders are furnished with power (watt) transducers
 
providing an analog value of the circuit power to the Safety Parameter Display System (SPDS). The magnitude of the power indicates the operational status and integrity of the
 
heater bank.
 
The 150 kW of Pressurizer heater capacity powered from an assured power source will
 
ensure that RCS subcooling margin will be maintained  20 °F for a period of 45 hours following loss of off-site power. This time period includes a period of one-half hour at the
 
beginning of the transient in which the heaters are unavailable.
 
This calculation is conservative in that the actual heat losses would decrease during the
 
transient as RCS pressure and temperature decreases, thereby prolonging the time to reach
 
20 °F margin-to-saturation.
 
The TS limit on Pressurizer volume exists to ensure the system is not operated under water-
 
solid conditions. Such operation would preclude appropriate pressure control and could
 
challenge the RCS pressure boundary. The percent-level indication provided in the TS was
 
intended only as an operator aid and is not used in the accident analysis. This operator aid
 
can change over time due to instrument replacem ent or calculation adjustment of instrument uncertainty. Therefore, it is proposed that this operator aid be relocated to the TS Bases.
 
The Pressurizer is discussed throughout the ANO-2 Safety Analysis Report (SAR), including
 
Sections 5.5.10 and 7.7.1.1.2 (Reference 1). Note that the Pressurizer heaters are not
 
discussed in SAR Chapter 15, Accident Analysis , nor credited in the accident analysis, except to state their loss on low Pressurizer level in Table 15.1.18-2.
 
Natural Circulation
 
Accident analyses presented in the SAR do not take credit for Pressurizer heater operation;
 
however, an implicit initial condition assumption of the safety analyses is that the RCS is
 
operating at normal pressure.
 
Although the heaters are not specifically used in accident analysis, the desire to maintain
 
subcooled margin over the long term during a loss of offsite power, as indicated in
 
NUREG 0737, Clarification of TMI Action Plan Requirements (Reference 2), is the reason for their original inclusion in the TSs. The requirement for emergency power supplies is also
 
based on NUREG 0737. The intent is to keep the reactor coolant in a subcooled condition
 
with natural circulation cooling at hot, high pressure conditions for an undefined, but extended
 
time period after a loss of offsite power. While loss of offsite power is a coincident occurrence
 
assumed in the accident analyses, maintaining hot, high pressure conditions over an
 
extended time period is not evaluated in the accident analyses.
 
Attachment to 2CAN060903
 
Page 3 of 8
 
Following the accident at Three Mile Island in 1979, NUREG 0737 was developed by the NRC to address a wide array of needed safety enhancements at commercial nuclear power
 
plants. As mentioned above, the Pressurizer heaters were included in NUREG 0737 to
 
support natural circulation (i.e., loss of forced flow) conditions following a loss of off-site
 
power. Reactor coolant pumps are lost when off-site power is lost and the RCS begins to
 
transition to natural circulation as the hot water from the reactor core rises through the RCS
 
hot leg piping to the Steam Generators (SGs) where it is cooled as it passes through the SG
 
tubes and descends back through the RCS cold leg piping to the bottom of the core where it
 
again absorbs heat from the core as it rises through the fuel region. This natural convection
 
flow continues as long as a minimum water level is maintained in the SGs and
 
thermohydraulic communication is maintained throughout the RCS hot and cold leg piping.
 
Following the TMI accident, it was believed that a plant cooldown via natural circulation could
 
result in a steam bubble being formed in the reactor vessel head region. This is because the
 
head region is a low or stagnant flow area of the vessel and would not be readily cooled by
 
natural circulation flow. A slow cooldown would permit time for ambient heat losses from the
 
reactor vessel head to afford necessary head-area cooling to inhibit steam bubble formation. 
 
However, a more rapid cooldown may not permit sufficient time for adequate vessel head
 
cooldown and subsequently, formation of a steam bubble in the head region may occur. If
 
this postulated condition were to continue uninhibited, it was thought the bubble could
 
increase in size until it entered the hot leg piping, creating an adverse impact on the
 
thermohydraulic communication needed to maintain natural circulation flow. Therefore, Pressurizer heaters were adopted as a means of increasing the RCS pressure to either
 
maintain adequate subcooled margin with respect to vessel head conditions during natural
 
circulation cooldown or to collapse any steam bubble in the vessel head should one develop.
 
Benefit of Proposed Change
 
On several occasions since initial startup, ANO-2 has experienced conditions where a
 
proportional heater bank was found to narrowly meet the 150 kW TS requirement or found to
 
have a capacity slightly below the TS requiremen
: t. Such conditions could prevent unit startup if discovered during a plant outage or could result in an unnecessary plant shutdown if
 
discovered in Mode 1, 2, or 3. In addition, since the TS requirement for the proportional
 
heaters is based on natural circulation cooldown support and therefore, a loss of offsite power
 
event, the heater bank must be declared inoperable anytime its respective emergency power
 
supply is removed for maintenance (i.e., the respective EDG or necessary
 
switchgear/breakers). These conditions place an undue hardship on the plant and plant
 
personnel in requiring significant prompt action or plant shutdown for an inoperable
 
component that is not credited in the safety analysis and is not the only means of ensuring
 
safe plant cooldown using the natural circulation method. Therefore, Entergy requests these
 
non-credited heater bank requirements be relocated from the TSs to the TRM.
 
Because heaters provide necessary pressure control during power operation and can be an
 
effective tool in supporting natural circulation cooldown, Entergy will continue to maintain
 
appropriate functionality of the heater banks. Any future changes to the TRM heater
 
requirements will be controlled in accordance with 10 CFR 50.59.
 
Attachment to 2CAN060903
 
Page 4 of 8
 
==4.0 TECHNICAL ANALYSIS==
 
TS 3.4.4 requires two groups of Pressurizer heaters, each with a capacity  150 kW and capable of being powered from an emergency power supply. The minimum heater capacity
 
required is sufficient to maintain the RCS near normal operating pressure when accounting
 
for heat losses through the Pressurizer insulation. By maintaining the pressure near normal
 
operating conditions, a substantial subcooling margin can be maintained in the RCS loops
 
during a natural circulation cooldown. The amount of heater capacity needed to maintain
 
pressure is dependent on the ambient heat losses (see background information in preceding
 
section).
As discussed in the Background section above, the post-TMI concern was the formation of a
 
steam bubble in the reactor vessel head region during natural circulation cooldown of the
 
plant. However, experience gained since the 1979 TMI accident indicates that there are other
 
means of controlling head bubble formation and growth.
 
Note that the following discussions assume a natural circulation cooldown is required without
 
a loss of RCS inventory that would result in loss of thermohydraulic communication in the RCS. Natural circulation cooldown is not relevant to such scenarios since the injection of
 
borated water via high and/or low pressure safety injection pumps will be required to maintain
 
inventory and support the necessary cooldown of the reactor core.
 
The most significant bubble prevention method is to control the rate of natural circulation
 
cooldown while monitoring reactor vessel head temperatures. Besides Pressurizer heaters, NUREG 0737 also required a means of monitoring reactor vessel head temperature and
 
reactor vessel reactor coolant level. ANO-2 has multiple Core Exit Thermocouples (CETs) for
 
use in monitoring temperature in the upper regions of the reactor vessel. At least 2 CETs are
 
required per core quadrant in accordance with TS 3.3.3.6, Post-Accident Instrumentation , in Modes 1, 2, and 3. ANO-2 also has a Reacto r Vessel Level Monitoring System (RVLMS) that will indicate when steam bubble formation begins and monitor bubble growth during natural
 
circulation conditions. Two channels of RVLMS are required to be operable in accordance
 
with TS 3.3.3.6. The Plant Monitoring System (PMS) and SPDS computer also provide real-time display of RCS pressure-temperature relationships to plant operators for monitoring
 
subcooled margin, the rate of cooldown, and the driving force effectiveness (core delta-
 
temperature), among other things. Operations procedures contain in-depth discussion and
 
guidance with regard to head bubble formation, prevention, and mitigation during natural
 
circulation cooldown conditions. In the years since the TMI accident, operators have
 
continuously practiced plant cooldowns under natural circulation conditions using plant simulators. Based on current plant capabilities and extensive operator knowledge and
 
experience, the uncontrolled formation and growth of a steam bubble in the reactor vessel
 
head is extremely unlikely.
 
In addition to the above, RCS pressure can be increased by normal inventory makeup
 
sources. RCS level slowly decreases as the RCS temperature is lowered during the
 
cooldown. A charging pump or high pressure injection pump is used at ANO-2 to makeup for
 
this "shrink" in RCS level due to density changes. However, level can be raised in the
 
Pressurizer beyond that needed to account for the density changes which will result in an
 
additional increase in RCS pressure. This method of pressure control is proceduralized and
 
well understood by plant operators.
 
Attachment to 2CAN060903
 
Page 5 of 8
 
Notwithstanding the above, if a bubble were to form and grow to the point of reaching the top of the vessel flow region, the cooler temperature of the water in the flow region would
 
immediately collapse the steam attempting to enter the hot leg. This is enhanced by the fact
 
that natural circulation flow is relatively low and the transport time from the reactor vessel to
 
the SG does not permit rapid entrainment of steam that could reach the top of the SG tubes
 
and inhibit natural circulation flow. Therefore, even in the event the natural circulation
 
cooldown is not as controlled as desired, the steam bubble should not be capable of
 
preventing natural circulation flow. To project the improbable and assume that steam is
 
transported from the upper region of the vessel to the top of the steam generator tubes and
 
interrupt thermohydraulic communication, the coolant would then enter a state of reflux boiling
 
where the hot water travels through the hot leg and up one side of the SG tubes, cools, and
 
returns through the lower portion of the hot leg back into the reactor vessel. This is a well
 
defined phenomenon that is discussed in Combustion Engineering (CE) topical CEN-114-P, Amendment 1-P (Reference 3). In summary, the ov erriding safety function of core cooling is maintained regardless of the methods used, or not used, to control a natural circulation
 
cooldown.
 
If core cooling could be lost due to bubble formation in the reactor vessel head, procedures
 
provide for re-establishment of core cooling by either collapsing the bubble or depressurize
 
the RCS to permit high pressure safety injection. With regard to the former and as discussed
 
above, Pressurizer heaters are not required for bubble collapse, but can be used to support
 
bubble collapse if available.
 
During development of this proposed TS change, a natural circulation cooldown was
 
performed on the simulator. The ANO-2 simulator remains updated with respect to physical
 
changes to the plant, including heat production and heat losses. During the entire event, all
 
Pressurizer heaters (both the proportional banks and backup banks) were maintained in OFF. 
 
An attempt was also made to place the plant in a condition of greatest challenge in that
 
following a simulated reactor trip caused by a loss of offsite power, the plant was permitted to
 
operate automatically until a head bubble was formed (saturated RCS conditions). Operator
 
intervention following head bubble formation required a very slight cooldown over time using
 
the upstream atmospheric steam dump valves and minimal feedwater supplied to the SGs. 
 
The cooldown was not required to be commenced until approximately 10 hours after event
 
initiation. The cooldown was required to be adjusted slightly approximately once every
 
===1.5 hours===
due to decay heat load decreasing over time. Twenty-four hours following event
 
initiation, RCS temperature had only been reduced to 500 °F (normal cold-leg temperature is
 
545 °F) indicating that the plant can be maintained in Hot Standby (RCS temperature 300 °F) conditions for a significant period of time without excessive bubble formation and without the use of Pressurizer heaters. The simulated natural circulation cooldown was
 
uneventful and presented no challenge to operators.
 
With regard to the simulated cooldown above, if a more rapid cooldown were desired, pressure reduction may be delayed due to the need to makeup to the Pressurizer water
 
volume (volume shrinks as temperature decreases). In addition, normal post-trip Pressurizer
 
level (41%) may be raised to approximately 80% level to assist in maintaining RCS pressure
 
above saturated conditions. Nevertheless, the above simulated scenario provides evidence
 
that permitting the RCS to enter a saturated state under controlled conditions does not
 
present a challenge to operators nor does it present a challenge to safe reactor operation.
 
Attachment to 2CAN060903
 
Page 6 of 8
 
Although it is preferable to maintain the Pressurizer heaters to enhance operation during natural circulation cooldown, the associated limits and surveillance requirements do not meet the intent of 10 CFR 50.36 for inclusion in the TSs in that they are not installed
 
instrumentation that is used to detect, and indicate in the control room, a significant abnormal
 
degradation of the reactor coolant pressure boundary, they are not a process variable, design
 
feature, or operating restriction that is an initial condition of a Design Basis Accident (DBA) or
 
transient analysis that either assumes the failure of or presents a challenge to the integrity of
 
a fission product barrier, and they are not a structure, system or component that is part of the
 
primary success path and which functions or actuates to mitigate a DBA or transient that
 
either assumes the failure of or presents a challenge to the integrity of a fission product
 
barrier. In addition, the Pressurizer heaters are not a structure, system, or component which
 
operating experience or probabilistic risk assessment has shown to be significant to public
 
health and safety. As discussed above, the Pressurizer heaters are not required to prevent or
 
mitigate any DBA, nor are they required to successfully complete a natural circulation
 
cooldown through Mode 3. In Mode 4 (RCS temperature < 300 &deg;F), Shutdown Cooling (SDC)
 
may be placed in service as desired to exit natural circulation cooldown conditions.
The Pressurizer heaters are not critical to nuclear or public safety for any scenarios modeled
 
in the ANO-2 safety analyses. Therefore, consistent with the intent of 10 CFR 50.36, the
 
Pressurizer heater operability requirements, applicability, actions, and surveillance
 
requirements may be relocated from the TSs to the TRM. Changes to the TRM will continue
 
to be controlled under the provisions of 10 CFR 50.59.
In addition to the above, the percent-level described in TS 3.4.4 is relocated to the TS Bases. 
 
This "equivalent" to the 910 ft 3 limit contained in the TS can change over time due to changes in instrument uncertainty calculations or due to instrument replacement. Because the
 
accident analysis is based on the volume limit, relocating the "percent" indication to the TS
 
Bases does not result in a change to the license basis or the actual TS limit. The percent-
 
level was originally intended as an operator aid. As such, this information is more
 
appropriately controlled within the TS Bases. The TS Bases are controlled in accordance
 
with TS 6.5.14, Technical Specification (TS) Bases Control Program. 
 
==5.0 REGULATORY ANALYSIS==
 
===5.1 Applicable===
Regulatory Requirements/Criteria The proposed change has been evaluated to determine whether applicable regulations and
 
requirements continue to be met.
There are no specific General Design Criteria (GDC) associated with Pressurizer heaters or
 
the use of operator aids within the TSs (i.e., the current percent-level denoted in Technical
 
Specification (TS) 3.4.4, Pressurizer
). Pressurizer heaters are discussed in various documents, such as NUREG 0737. However, the proposed change does not eliminate
 
maintaining Pressurizer heaters, but only acts to relocate the requirements from the TSs to
 
the TRM. Additionally, the relocation of the percent-level denoted in the TS to the TS Bases
 
does not change any TS limit or operating requirement. Based on the considerations
 
discussed above, (1) there is reasonable assurance that the health and safety of the public
 
will not be endangered by operation in the proposed manner, (2) such activities will continue
 
to be conducted in accordance with the site licensing basis, and (3) the approval of the
 
proposed change will not be inimical to the common defense and security or to the health and
 
safety of the public.
 
Attachment to 2CAN060903
 
Page 7 of 8
 
In conclusion, Entergy has determined that the proposed change does not require any exemptions or relief from regulatory requirements, other than the TS, and does not affect
 
conformance with any GDC differently than descr ibed in the Safety Analysis Report (SAR).
 
5.2 No Significant Hazards Consideration
 
A change is proposed to the Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specifications (TSs) to relocate portions of TS 3.4.4, Pressurizer , relating to the Pressurizer heater banks to the Technical Requirements Manual (TRM) and to relocate the percent-level information denoted in the TS to the TS Bases.
 
Entergy Operations, Inc. (Entergy) has evaluated whether or not a significant hazards
 
consideration is involved with the proposed amendment by focusing on the three standards
 
set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
: 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response:  No.
The proposed change acts to relocate current Pressurizer heater requirements from
 
the TSs to the TRM and percent-level information to the TS Bases. The heaters serve
 
only a support role in maintaining normal operating pressure in the Reactor Coolant
 
System (RCS) and in can be used to support maintenance of subcooled conditions
 
during a natural circulation (loss of forced flow) cooldown of the plant. The heaters
 
are not credited in any accident analysis for accident prevention or mitigation. The
 
percent-level information is an operator aid and is not associated with any accident or
 
safety analysis limit. Neither of these items are related to accident initiators.
Therefore, the proposed change does not involve a significant increase in the
 
probability or consequences of an accident previously evaluated.
: 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response:  No.
The proposed change does not result in any plant modifications or changes in the way
 
the plant is operated. The proposed change only acts to relocate current Pressurizer
 
heater requirements from the TSs to the TRM and to relocate the percent-level
 
information denoted in the TS to the TS Bases. The proposed change is unrelated to
 
any accident initiator.
 
Therefore, the proposed change does not create the possibility of a new or different
 
kind of accident from any previously evaluated.
 
Attachment to 2CAN060903
 
Page 8 of 8
: 3. Does the proposed change involve a significant reduction in a margin of safety?
Response:  No.
 
The proposed change relocates current Pressurizer heater requirements from the TSs
 
to the TRM and relocates the percent-level information denoted in the TS to the TS
 
Bases. The heaters serve only a support role in maintaining normal operating
 
pressure in the Reactor Coolant System (RCS) and can be used to support
 
maintenance of subcooled conditions during a natural circulation (loss of forced flow)
 
cooldown of the plant. The current TS-required capacity of each heater bank is well
 
beyond that required to maintain RCS pressure during normal operations. Non-TS
 
back-up heaters are also installed to support pressure control during anticipated
 
transients. The heaters are not credited in any accident analysis for accident
 
prevention or mitigation. Because the Pressurizer heaters will continue to be
 
monitored and controlled, relocating the current TS requirements to the TRM will not
 
present an adverse impact to plant operation. In addition, the Pressurizer heaters are
 
not a structure, system, or component wh ich operating experience or probabilistic risk assessment has shown to be significant to public health and safety. The percent-level
 
information currently contained in the TS is an operator aid and is not associated with
 
any accident or safety analysis limit.
 
Therefore, the proposed change does not involve a significant reduction in a margin of
 
safety.
Based on the above, Entergy concludes that the proposed amendment presents no significant
 
hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a
 
finding of "no significant hazards consideration" is justified.
 
===5.3 Environmental===
Considerations 
 
The proposed amendment does not involve (i) a significant hazards consideration, (ii) a
 
significant change in the types or significant increase in the amounts of any effluent that may
 
be released offsite, or (iii) a significant increase in individual or cumulative occupational
 
radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for
 
categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to
 
10 CFR 51.22(b), no environmental impact stat ement or environmental assessment need be prepared in connection with the proposed amendment.
 
==6.0 REFERENCES==
: 1. ANO-2 SAR
: 2. NUREG 0737, November 1980
: 3. CEN-114-P, Amendment 1-P, "Review of Small Break Transients in CE's Nuclear Steam Supply System," July 1979 Attachment 2 2CAN060903 Proposed Technical Specification Changes (mark-up)
ARKANSAS - UNIT 2 3/4 4-5 Amendment No. 20
,234 , REACTOR COOLANT SYSTEM
 
PRESSURIZER
 
LIMITING CONDITION FOR OPERATION 3.4.4 The pressurizer shall be OPERABLE with a water volume of  910 cubic feet (equivalent to  82% of wide range indicated level) and both pressurizer proportional heater groups shall be OPERABLE. APPLICABILITY: MODES 1, 2 and 3.
 
ACTION:  (a) With the pressurizer inoperable due to water volume  910 cubic feet, be in at least HOT SHUTDOWN with the reactor trip breakers open within 12 hours.
(b) With the pressurizer inoperable due to an inoperable emergency power supply to the pressurizer heaters, either restore the inoperable emergency power supply as required by TS 3.8.1.1 action b.3 or be in at least HOT SHUTDOWN within 12 hours.
 
SURVEILLANCE REQUIREMENTS
 
4.4.4.1 The pressurizer water volume shall be determined to be within its limits at least once per 12 hours.
 
4.4.4.2 The pressurizer proportional heater groups shall be determined to be OPERABLE.
  (a) At least once per 12 hours by verifying emergency power is available to the heater groups, and (b) At least once per 18 months by verifying that the summed power consumption of the two proportional heater groups is  150 KW.}}

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