ML121210730
| ML121210730 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 05/25/2012 |
| From: | Technical Specifications Task Force |
| To: | Office of Nuclear Reactor Regulation |
| Honcharik M | |
| Shared Package | |
| ML12121A599 | List: |
| References | |
| Download: ML121210730 (15) | |
Text
TSTF Response to the NRC Staff Position NUREG-1434 Technical Specification (TS) 3.8.1 LCO requires three DGs to be Operable in Modes 1, 2, and 3. The Applicability of Specification 3.8.1 is modified by an Applicability Note which states:
"[Division 3] AC electrical power sources are not required to be OPERABLE when High Pressure Core Spray System [2C Standby Service Water System] is inoperable."
The TS Bases describe the Applicability Note as follows:
A Note has been added taking exception to the Applicability requirements for Division 3 sources, provided the HPCS System is declared inoperable. This exception is intended to allow declaring of the Division 3 inoperable either in lieu of declaring the Division 3 source inoperable, or at any time subsequent to entering ACTIONS for an inoperable Division 3 source. This exception is acceptable since, with the Division 3 inoperable and the associated ACTIONS entered, the Division 3 AC sources provide no additional assurance of meeting the above criteria." (emphasis added)
NRC Points:
The NRC disagrees with the existing Bases statements and believes it is:
- 1) contrary to the use and application of TS,
- 2) compromises safety, and
- 3) is not supported by NUREG-1434 or other NRC Regulation.
TSTF Points:
- 1) The allowance is not contrary to the use and application of TS. Licensees routinely declare Operable equipment inoperable for maintenance or in accordance with TS. See 3.8.1, Required Action B.2, which states, "Declare required feature(s), supported by the inoperable DG, inoperable when the redundant required feature(s) are inoperable." This appears in all five ISTS NUREGS and is directly analogous to the HPCS allowance. See also 3.8.3.F, 3.8.6.F, 3.1.6.A.2, 3.3.5.1, Required Actions B.1, C.1, E.1 and H.1, and 3.3.5.2.E.
- 2) Absent new evidence that the 17 day Completion Time is unacceptable, there is no justification for stating that the provisions compromise safety. The 17 day CT was accepted by the NRC during ITS conversion (see below).
- 3) The industry use of the Note is explicitly allowed in the Bases, making it supported by NUREG-1434.
The staff is treating the 3.8.1 Note as a new or reinterpreted allowance. In fact, it is an allowance explicitly considered and approved by the NRC. The current NRC staff may disagree with the approach that was used, but that does not change the facts:
- 1) It was an approved Action in the pre-ISTS standard Tech Specs and plant Technical Specifications; and
- 2) It was specifically addressed and approved in the ITS conversion for the affected plants.
Any action by the staff to "disallow" use of the provisions must be evaluated under 10 CFR 50.109 and justified based on the safety significance.
Supporting Information:
NUREG-0123, Rev. 0, 1980, BWR/6 LCO 3.5.1, contained the requirements on ECCS Division 3, the High Pressure Core Spray (HPCS). Action c provided 14 days to restore an inoperable HPCS.
LCO 3.8.1 contained the requirements on the Division 3 Diesel Generator (DG). Condition e states:
"With diesel generator (1C) of the above required A.C. electrical power sources inoperable, demonstrate the OPDRABILITY of the remaining A.C. sources by performing Surveillance Requirements 4.8.1.1.1.a and 4.8.1.1.2.a.4 within one hour and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter; restore the inoperable diesel generator (1C) to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or declare the HPCS system inoperable and take the ACTION required by Specification 3.5.1."
Therefore, under the pre-ISTS requirements, the TS explicitly provided a 17 day Completion Time when the Division 3 DG is inoperable.
The BWROG proposed ITS, NEDC-31681, proposed an LCO 3.8.6, "Division 3 Electric Power,"
which required the Division 3 electrical power sources to be Operable when HPCS is required to be Operable. It provided 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore an inoperable Division 3 DG, after which it directed the licensee to declare HPCS inoperable.
The NRC staff issued NUREG-1434 for comment in January 1991. The NRC combined all NSSS design Section 3.8 Specifications (labeled "AOG") with notes on which portions are applicable to each plant type. There were many changes for BWR/6 plants. The staff's proposed Bases for Specification 3.8.1, Required Action C.1 stated that the Completion Time for a Division 3 DG may be increased from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days consistent with the HPCS TS provided the sole function of the Division 3 DG is to support the HPCS.
In the BWROG comments on the draft for comment, the industry proposed deleting the staff's discussion of Division 3 DG and proposed an insert that closely resembles the existing LCO 3.8.1 Bases, i.e., "Division 3 systems could be declared inoperable".
The justification for the industry proposed changes follows:
"(GE BWR/6 only) The LCO markup {i.e., the comments made on the draft for comment}, related to BWR 5 and 6 Division 3 requirements, returns the ACTIONS to those previously negotiated (refer to Jose Calvo letter to Warren Hall, March 27, 1990).
Specifically, 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> are allowed with the required offsite circuit or Division 3 DG inoperable .
At the expiration of this time the loads served from the Division 3 bus are declared inoperable and operation continued in accordance with applicable specifications. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> required restoration ("from discovery of two division with no offsite power") is more
conservative than approved Specifications which allow 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for the single circuit that serves Division 1 or 2 in addition to Division 3.
The new Staff position (from the draft NUREG) to shutdown after the allowed Completion Time, is inconsistent with the allowed Completion Time for the system's inoperability of 14 days prior to shutdown (refer to LCO 3.5.1). In the condition of loss of one of the two AC Sources to the system, the system function still remains for one source. It is appropriate with one of two sources inoperable, to allow at least 14 days.
Furthermore, no reason is given to eliminate the previously accepted 3-day extension to this time for the loss of one source. For designs which include systems other than HPCS on the division 3 bus (these additions are minimal - i.e., a Service Water pump), the declaration of these additional system inoperable will provide the appropriate limitations."
In the NRC staff issued "Proof and Review" copy of NUREG-1434 (June 1992), the NRC accepted the industry comments and incorporated the following paragraph in the NUREG-1434, 3.8.1 Applicability Bases:
"A Note has been added taking exception to the Applicability requirements for Division 3 sources, providing the HPCS System is declared inoperable. This exception is intended to allow declaring of the Division 3 inoperable either in lieu of declaring the Division 3 source inoperable, or at any time subsequent to entering ACTIONS for an inoperable Division 3 source. This exception is acceptable since with the Division 3 inoperable and the associated ACTIONS entered, the Division 3 ac sources provide no additional assurance of meeting the above criteria."
Revision 0 of the ISTS (which was the basis for ITS conversion for all the BWR/6 plants) contains this basis as stated in the "Proof and Review" copy.
From the record, it is clear that the NRC thoughtfully and intentionally included the allowance to declare HPCS inoperable in order to extend the Division 3 DG Completion Time to 17 days in order to retain the pre-ISTS allowance while minimizing the AC Sources TS variations between designs.
This intention is also reflected in the Safety Evaluations for ITS conversions. For example:
Grand Gulf (BWR/6)
The Grand Gulf pre-ITS TS action stated, Restore diesel generator 13 to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or declare the HPCS system inoperable and take the ACTION required by Specification 3.5.1. The ITS conversion SE from the NRC (like others) stated, However, the Applicability Note for the improved TS 3.8.1 states that the HPCS DG is not required to be operable when the HPCS is inoperable. The note allows the licensee to continue applying the conditions and RAs for other inoperable AC sources without addressing the HPCS DG inoperability, which is addressed in improved TS 3.5.1. The improved TS Applicability exception is consistent with the existing TS 3.8.1.1, which separates actions for Divisions 1 and 2 from actions for Division 3. The improved TS retain the changes and are therefore acceptable.
Columbia (BWR/5 plant)
The Columbia Safety Evaluation for their ITS conversion states:
"In the event DG-3 is inoperable, Action c of CTS 3.B.1.1 requires restoring DG-3 to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or declaring the HPCS inoperable and taking the action specified in CTS 3/4.5.1 for an inoperable HPCS system. This action requirement is retained in applicability note and Action B of ITS 3.8.1. The note states that if the HPCS System is inoperable, the Division 3 AC electrical power sources are not required to be operable. As explained in the associated Bases for the note, in the event HPCS is required and DG-3 is inoperable, HPCS must be declared inoperable (requiring entry into ITS 3.5.1) or DG-3 must be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. "
Similar discussions can be found in the Safety Evaluations for the BWR/6 plants and the affected BWR/5 plants.
As all the affected plants have converted to the ISTS and have an explicit discussion of the allowance, any NRC action to prevent use of the allowance must be evaluated under 10 CFR 50.109.
MUREG-01~3-REV-3 StlnJlrd leehnlcil Speclrle~tlon~ for G4!nerll Electrlc 80111nl Wiler Ruetor, (BVII5)
(u.s.) Nuclear Belulatory Co** ls~lon WIlIhlnlton, DC Ole 8u
(
i.... ----Jf U~\. Ill;WI t " C.... ra No_I 1,,_1 In1onnahon Serrict NIlS.
ELECTRICAL POW£R S,'STatS LIMITING CONDITION FOR UFERATION \Contln~ed)
ACTION (Continued)
,. With two of tlw above required ofhiu c1rcuiu lnoper.ble.
dMonstraUt tile OPEIlA811lTY of ttlrft dluel generlto~ by perfo...inll S...rvelll.nce Ileqvl~nt 4.8.1.1.2 .*. 4 wlttlln one tlo......nd It least once per 8 ha..... ! ttlere~fter. unless the d1esel gener.tors .re ~lready
,I operating; "esto"e .t least one of the lnope..able effs1te ci ..c...its I to OPEIlASLE.st.t...s within 24 ho.....s or be 1n .t least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. With ::",ly or.. ofhiu c1rc...it ~ston-d to ,
OPERABLE s~tus, reste... It le.st two ~ffsite circuits to OPEllASlE stat...s within 12 ho ... rs f..- ti ... of inltl.l loss or be in It lust HOT SIfJlI)(M; within UW next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> alld 1n COLO SHUTOOlo1( witnin the following 24 hou~.
- d. With dje~el generators (IA) anJ (18) of the .bove req ...ired A.C.
eleclric.l power S~llrCeS inoperable. de~nslrate tt.. OPER~ILITY of tile r...1nlng A.C. SOllret! by perfo...ing Sllrveillance Ileqllln.ellts 4.8.1.1.1 .* and 4.8.1.1.2.*. 4 within one hour.nd at lea~t once per 8 hou... thereafter; restore at lust _ of the inoperable diesel gener.tors (IA) and (ll) to OPEIlASL£ st.atu~ within 2 hou~ or be in at least .....T SHlJl1)(MI within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLO SHIITI'lMt within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Restore !loth diesel lIeneralors (l~) and (IB) to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> fra.
( ti~ of Initial loss or be in at leasl HOT SHUTDOWN within til!
ne~t 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> ~nd 1n COLD SHUT~ within the following 24 ho~rs.
t!. With dlut!l ~ner.tor (Ie) ~f tne above ,equlred A.C. electrlu,1 power sources inoperable. desonstrate the OPEKABltirf of the r..aining A.C.
50urct!S by pErfo... i~ Surveillance Ilequir....nts 4.8.1.1. i.a and 4.8.1.1.?a.4 witt.ln one hour ard at lu~t Oll':t! pt!r 8 llours thel'Uftt";
re-tore the inoperablt! diesel gEnerator (IC) to OPERABLE statuf within 72 hour~ or decl,:,!! the HPCS syste_ inoperlble and take the ACTION req"jrell by Specification 3 5.1.
SCRYElllAHtE REQUIREMENTS 4.8.1. 1.1 ~~ch of the ~ve required I~end.nt clrc~its bt!tween the offsit.
trans.ission net~rk and the on~ite Cl~s~ IE distribution syst... shall be:
- Oete...lned OPERA~LE at l~,st ~nce ~.r 7 d'YS by verifying correct br.ak~r allgnmrrLs ano i~icat.d,pOWt!r av,il~biI1ly, ~nd
- b. ONOnstr'ted OP£lWll£ at l.. ~st ote. per 18 _nths d",ring s~tOOwn b) tr.nsf.rri ....~. :..nu.lly ~nd .:.t_tlcally, ""it power supply frca ~he nor... l clr<",it to the ~It.r... t. clr<uit.
GE-STS
NEOC*31681 Class I April 1989 Improved BWR Technical Specifications Volwne 5 BWR/6 Technical Specifications
Dhlsion 3 EJectrlCJ.l Power 3.B.6 3.8 El[CTRlCAl POW[R SYSTOIS 3.8.6 Oiyislon 3 £llCtrlcal Power LCD 3.8.6 The following Division 3 [lectrlcil Power Sources shill be OP[RABLE:
A. One circuit between the off*slte tran smission network ind the on -Site Division 3 Class IE distribution system, B. Dluel Generator [ 13 1, C. D.C. Electr ical Power Sources, D. A.C. power distribution system, E. D.C. power distribution system.
APPLICABILITY: When HPCS Is req uired to be OPERABLE.
ACTIONS CONDITION REQUIRED ACTiON COMPLET ION TiM£ A. Diesel GenerJ.tor [ 13 J A.l Perfonl SR 3.B .6. 1 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> inoperible. for circuit from off-site.
Once per
[ B 1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> thereafter (continued)
BWR/6 3.B-28 4/2B/89
Division 3 Electrical Power 3.8.6 Icontinued)
CONDITiON REQUIRED ACTiON COMPLETION TIME A. (continued) A.1 ----------NOTE-------- ---
- l. Only required 1f diesel generator became Inoperable for any cause other tha n prephnned lI1a intenance or testing.
- 1. Not required if condition which caused the diesel generator to be decl ared inoperabl e does not impact OPERABILITY of OPERABLE diesel generators.
Perform SR 3.8 . 1.4 for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
( Diesel Generator [ II I
,,' [ 12 ) .
ANIl A. 3 Restore Diesel Generator 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
[ 13 I to OPERABL E status .
B. Requ I red circuit from B. I Restore Inoperable 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> off -site Inoperable. circ ui t from off-site to OPERABLE status.
(. Required Actions and t.l Declare HPCS and Invnediat el y associated Complet ion {Emergency Serv ice Wat er Ti~es of Cond ition A Pump] inoperable .
or 6 not met .
Dh i sion 3 inoperabl e for reason s other than Cond i tion A or B.
BWRl 6 3 . 8-29 4/ 28/ 89
STAFF POSITION ON USE AND APPLICATOION OF TS 3.8.1, AC SOURCES OPERATING, APPLICABILITY NOTE RELATING TO INOPERABILITY OF THE DIVISION 3 DIESEL AND HPCS NUREG 1434 TS 3.8.1 states:
Technical Specification (TS) 3.8.1 (limiting Condition for Operation (LCO) requires three DGs to be Operable in Modes 1, 2, and 3. The Applicability of Specification 3.8.1 is modified by an Applicability Note which states:
"[Division 3] AC electrical power sources are not required to be OPERABLE when High Pressure Core Spray System [2C Standby Service Water System] is inoperable."
Industry Position - Applicability and Use of TS 3.8.1 Note Note: The following statement is taken from a white paper attached to an email sent to Michele Honcharik, NRC, from Brian Mann, Excel Services Corporation, on October 12, 2011.
The existing Technical Specification Completion Time of 72 or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for an inoperable Division 3 DG followed by declaring the HPCS inoperable and following the Actions for that system is an appropriate action, explicitly considered and accepted by the NRC during development of the ISTS [NUREG-1434].
NRC Staff Position - Applicability and Use of TS 3.8.1 Note The TSTF position regarding declaring the Emergency Core Cooling HPCS system inoperable for the sole purpose of gaining additional TS Required Action Completion Time for an inoperable onsite or offsite power source (i.e., HPCS is otherwise Operable) is contrary to the use and application of TS, compromises safety, and is not supported by NUREG-1434 or other NRC Regulation. Licensees who can justify acceptable alternatives to a plant shutdown, due to an inoperable Division 3 electrical system, should pursue an acceptable regulatory alternative.
HPCS System Description The initial conditions of DBA and transient analyses in the FSAR, Chapter [6] and Chapter [15],
assume ESF systems are OPERABLE. The AC electrical power sources are designed to provide sufficient capacity, capability, redundancy, and reliability to ensure the availability of necessary power to ESF systems so that the fuel, Reactor Coolant System (RCS), and containment design limits are not exceeded.
The high pressure core spray (HPCS) system provides and maintains an adequate coolant inventory inside the reactor vessel to limit fuel cladding temperatures in the event of breaks in the reactor coolant pressure boundary as required by 10 CFR 50.46. The system is initiated by either high pressure in the drywell or low water level in the vessel. It operates independently of all other systems over the entire range of pressure differences from greater than normal
operating pressure to zero. The HPCS cooling decreases vessel pressure to enable the low pressure cooling systems to function. The HPCS system pump motor is powered by a diesel generator (Division 3) if normal offsite power is not available; the system may also be used as a backup for the RCIC system.
The HPCS system, utilized at all GE BWR/6 plants and some GE BWR/5 plants, consists of a single motor driven pump and dedicated (Division 3) diesel generator, system piping, valves, controls, and instrumentation. The HPCS system is provided to assure that the reactor core is adequately cooled to prevent excessive fuel clad temperatures for breaks in the nuclear system that do not result in rapid depressurization of the reactor vessel. The HPCS continues to operate when reactor vessel pressure is below the pressure at which LPCI operation or LPCS system operation maintains core cooling.
NUREG 1434 TS 3.8 and TS Bases NUREG-1434, Standard Technical Specifications General Electric Plants, BWR/6, specification 3.8.1, AC Sources Operating, describes the typical offsite power requirements (two qualified circuits) and a three diesel generator (DG) onsite electrical system. Two DGs power independent and redundant 4.16 kV Engineered Safety Feature (ESF) busses. The Division 3 DG supports the 4.16 kV bus which provides the electrical power for the High Pressure Core Spray (HPCS) System. The normal power source for the Division 3, 4.16 kV bus (HPCS system), is provided by the offsite power system.
Technical Specification (TS) 3.8.1 LCO requires three DGs to be Operable in Modes 1, 2, and 3.
The Applicability of Specification 3.8.1 is modified by an Applicability Note which states:
"[Division 3] AC electrical power sources are not required to be OPERABLE when High Pressure Core Spray System [2C Standby Service Water System] is inoperable."
The TS Bases describe the Applicability Note as follows:
The AC sources and sequencers are required to be OPERABLE in MODES 1, 2, and 3 to ensure that:
- a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOOs or abnormal transients and,
- b. Adequate core cooling is provided and containment OPERABILITY and other vital functions are maintained in the event of a postulated DBA.
A Note has been added taking exception to the Applicability requirements for Division 3 sources, provided the HPCS System is declared inoperable. This exception is intended to allow declaring of the Division 3 inoperable either in lieu of declaring the Division 3 source inoperable, or at any time subsequent to entering ACTIONS for an inoperable Division 3 source. This exception is acceptable since, with the Division 3 inoperable and the associated ACTIONS entered, the Division 3 AC sources provide no additional assurance of meeting the above criteria."
The requirements for TS limiting conditions for operation (LCOs) are established in
10 CFR 50.36, which states:
Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met.
NUREG 1434, Section 1.1, defines OPERABLE-OPERABILITY as follows:
A system, subsystem, division, component, or device shall be OPERABLE or have OPERABILITY when it is capable of performing its specified safety function(s) and when all necessary attendant instrumentation, controls, normal or emergency electrical power, cooling and seal water, lubrication, and other auxiliary equipment that are required for the system, subsystem, division, component, or device to perform its specified safety function(s) are also capable of performing their related support function(s).
The definition of remedial actions is defined in the Standard Technical Specifications (NUREG-1434) states as follows:
ACTIONS shall be that part of a Specification that prescribes Required Actions to be taken under designated Conditions within specified Completion Times.
NUREG 1434 Limiting Condition for Operation (LCO) 3.0.2 Bases, states, in part:
The Completion Times of the Required Actions are also applicable when a system or component is removed from service intentionally. The reasons for intentionally relying on the ACTIONS include, but are not limited to, performance of Surveillances, preventive maintenance, corrective maintenance, or investigation of operational problems. Entering ACTIONS for these reasons must be done in a manner that does not compromise safety. Intentional entry into ACTIONS should not be made for operational convenience. Additionally, if intentional entry into ACTIONS would result in redundant equipment being inoperable, alternatives should be used instead.
Discussion At the August 5, 2011 Technical Specification Task Force (TSTF)/Nuclear Regulatory Commission (NRC) Public Meeting, NRC staff stated that that it is inappropriate to declare a TS required system inoperable solely for the purpose of extending the time allowed to operate in non-compliance of a TS Limiting Condition for Operation (LCO).
The TSTF position stating that the existing Technical Specification Completion Time of 72 or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for an inoperable Division 3 DG followed by declaring the HPCS inoperable and following the Actions for that system (HPCS) is an appropriate action, explicitly considered and accepted by the NRC during development of the ISTS is not supported by the current revision (3) of
Standard Technical Specifications (STS/NUREG-1434) for GE BWR/6 Plants. NRC staff disagrees with the TSTF position for the following reasons:
- 1. As described above and in the UFSAR Chapters 6 and 15 for BWR/5-6 plants with high pressure core spray (HPCS), the system provides and maintains an adequate coolant inventory inside the reactor vessel to limit fuel cladding temperatures in the event of breaks in the reactor coolant pressure boundary as required by 10 CFR 50.46. The 4.16 kV bus that supplies power to the HPCS system is normally powered by the offsite power source and can be powered from an onsitef dedicated diesel generator. The 4.16 kV bus and electrical sources associated with the HPCS system are known and referred to as Division 3.
Because the Division 3 power sources only safety related (Emergency core cooling system or ECCS) load is the HPCS system, the TS 3.8.1 NOTE recognizes that if the HPCS system is inoperable, the TS Action requirements for concurrently inoperable Division 3 electrical power sources provides no ECCS benefit and, therefore, the TS Actions for the inoperable HPCS system provide the appropriate remedial actions to either return the HPCS system to Operable or to shutdown the reactor. This is supported by the final sentence in the STS Bases which states that: This exception is acceptable since, with the Division 3 inoperable and the associated ACTIONS entered, the Division 3 AC sources provide no additional assurance of meeting the above criteria
( i.e., criteria a, Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOOs or abnormal transients and, criteria b.,
Adequate core cooling is provided and containment OPERABILITY and other vital functions are maintained in the event of a postulated DBA).
- 2. The TS definition of Operable states that: A system, subsystem, division, component, or device shall be OPERABLE or have OPERABILITY when it is capable of performing its specified safety function(s) and when all necessary attendant instrumentation, controls, normal or emergency electrical power [emphasis added], cooling and seal water, lubrication, and other auxiliary equipment that are required for the system, subsystem, division, component, or device to perform its specified safety function(s) are also capable of performing their related support function(s).
The TSTF position appears to ignore the fact that the HPCS system has an offsite power supply and is TS Operable and capable of performing its specified safety function when the Division 3 diesel is inoperable but the Div 3 offsite power source is Operable.
- 3. The TSTF white paper states:
NUREG-1434 has many instances of directing that a component be declared inoperable. See Specification 3.1.5, Required Action a.2, Specification 3.3.5.1, Required Action B.2, and Specification 3.7.2, Required Action A.1, for a few examples.
A search of NUREG-1434, Revision 3, could not identify any instance where the TS directed that a TS Operable system, subsystem, division, component, or device be declared inoperable. Where TS does direct a system, subsystem, division, component, or device to be declared inoperable, including the above TSTF white paper cited examples, the reason for the declared inoperable Required Action is because the system, subsystem, division, component, or
device is inoperable per the TS definition of Operable/Operability. Additionally, rendering the Operable HPCS system inoperable solely to exit a TS Condition (inoperable Division 3 DG) without completing the Required Actions is contrary to 10 CFR 50.36 which states, Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met.
However, the distinction between Divisions 1& 2 and Division 3 was retained through the inclusion of the LCO 3.5.1 APPLICABILITY NOTE (the NOTE was used instead of adding extra, separate Conditions that applied to Division 3 only). The 3.5.1 NOTE allows licensees to do exactly what they were originally licensed to do, which is administratively declare HPCS inoperable and limit plant operation using the HPCS system Actions.
A search of NUREG-1434, Revision 3, for the above referenced LCO 3.5.1 Applicability Note cannot be found. Regarding the statement that The Note allows licensees to do exactly what they were originally licensed to do, which is administratively declare HPCS inoperable and limit plant operation using the HPCS system Actions, is not supported by NUREG-1434, Revision 3. A search of the NUREG could not identify any reference or definition of TS administrative inoperability. The TS definition of Operable/Operability is very clear and a licensee can, for example, make the determination that a system, subsystem, division, component, or device is Operable but degraded using the Operability Determination Process. However, this process does not address a declared administrative inoperable status. Finally, RIS 2005-20 addresses Operability as follows:
It should be noted that the stand of Reasonable Expectation is a high standard, and there is no such thing as an indeterminate state of Operability; an SSC is either Operable or Inoperable [Emphasis added].
Therefore, lacking an established NRC approved definition or NRC guidance for determining that a TS required SSC is administratively inoperable, a licensee would, in effect, be falsifying the status of a TS Operable system, subsystem, division, component, or device if it is stated to be inoperable when it is actually Operable as understood and defined by TS.
Staff agrees that the Division 3 electrical power sources (onsite and/or offsite) are not required to be Operable if the HPCS is Inoperable. The reasons for intentionally relying on the HPCS LCO ACTIONS include, but are not limited to, performance of Surveillances, preventive maintenance, corrective maintenance, or investigation of operational problems. Entering ACTIONS for these reasons
must be done in a manner that does not compromise safety. Therefore, the HPCS system cannot be declared inoperable for the sole purpose of extending the Division 3 onsite or offsite power Division 3 TS Required Action Completion Time if one of the two HPCS power sources remains Operable. Other acceptable alternative means to avoid a plant shutdown by requesting additional Required Action Completion Time (CT) for an inoperable Division 3 power source exist.
Some of the acceptable alternative means include requesting:
- Staff Notice of Enforcement Discretion
- Exigent or Emergency TS Amendment NUREG 1434 Required Action Completion Time for an Inoperable Division 3 DG is 72-hours. It is contrary to TS Section 1.0, Use and Application, to arbitrarily extend this CT for operational convenience (i.e., avoid a plant shutdown, or compliance with the LCO Required Actions) when other, safer, alternatives exist.
Summary Provided that normal (offsite) power is available to power the HPCS, the stated TSTF position that if the Division 3 Diesel Generator (DG) is declared for 72 or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> the Operable HPCS system can subsequently be declared inoperable, for the sole purpose of exiting the Applicability of the inoperable Division 3 DG TS Required Action and Completion Time, is contrary to safety, defense-in-depth, and conservative-decision-making.