ML20217E421
| ML20217E421 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/12/1999 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20217E428 | List: |
| References | |
| NUDOCS 9910190244 | |
| Download: ML20217E421 (10) | |
Text
!
,. J-J y
i Tennessee Valley Authonty. Post Ofhce Box 2000. Soddy-Daisy. Tennessee 31379 l
1 October 12, 1999 Y
l TVA-SON-TS-99-15 10 CFR 50.90 G.S. Nuclear Regulatory Commission ATTN:
Document Control Desk l
Washington, D.
C.
20555 i
Gentlemen:
l l
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 1
SEQUOYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - TECHNICAL SPECIFICATION (TS) CHANGE NO. 99-15, " REVISION OF REQUIREMENTS FOR CONTAINMENT PENETRATIONS DURING REFUELING OPERATIONS" In accordance with'the provisions of 10 CFR 50.4 and 50.90, TVA is submitting a request for an amendment to SON's Licenses DPR-77 and 79 to change the TSs for Units 1 and 2.
The proposed change will provide for unisolation of cor.tainment penetrations under administrative controls.
This revision will add a footnote to Specification 3.9.4.c indicating this allowance and the necessary Bases addition for'this section to clarify the use of this allowance.
TVA has determined that there are no significant hazarda considerations associated with the proposed change and that the change is exempt from environmental review pursuant to the provisions of 10 CFR 51.22 (c) (9).
The SQN Plant Operations Review Committee and the SON Nuclear Safety Review Board have reviewed this proposed change and determined that operation of SON Units 1 and 2, in accordance with the l
l 9910190244 991012
?
PDR ADOCK 05000327 l
P PDR ;f
1
- )
sh
~
'U.S.; Nuclear Regulatory Commission r
Page 2-
' October 12, 1999
' proposed. change, will not' endanger the health and safety of the public.
Additionally, in accordance with 10 CFR 50.91(b)~(1),, TVA is sending a copy of this letter to the Tennessee State Department of.Public Health.
Enclosure.1 to-thisfletter provides the-description and evaluation of the proposed change.
This includes TVA's determination that the proposed change does not involve a significant hazards consideration, and is exempt from environmental review. contains copies of the appropriate-TS pages from Units 1 and 2 marked-up to show the proposed _ change. forwards the revised TS pages for Units'l and'2 which incorporate the proposed change.
'The allowance proposed in this request is needed to enhance outage activities associated with theLUnit 1 Cycle 10 refueling outage as well as future outages.
The Unit 1
~
outage is currently; scheduled to begin in February of 2000, and TVA requests approval of the proposed revision before D'
' February.2000.
TVA also requests that the revised TS be made
. effective within 45-days of NRC approval.. If you have any questions about. this change, please telephone me at. (423) j 843-7170 or J.
D. Smith at (423) 843-6672.
j i
Sjn e
y, d
ro Salas Licensing.and' Industry Affairs Manager
~
hith i
t 4
b Subscribed' apd sworn to bej/M//U ope,ge o'~nNth'is - /O k day of /)o/
.f & k'
.j
/ /D /s)
Notarp'P'ublic
/
^
My Commission Expires October 9, 2002 P
i Enclosures.
.cc:
See page--3.
1 4
l-L
p
., f.
e U.S. Nuclear Regulatory Commission Page 3 c
October 12, 1999 cc (Enclosures) :
Mr.
R. W.
Hernan, Project Manager LNuclear Regulatory Commission One' White-Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Mr. Michael H. Mobley, Director (w/o Enclosures)
Division of Radiological. Health Third Floor L&C Annex 401 Church Street Nashville, Tennessee 37243-1532 NRC Resident Sequoyah Nuclear-Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37384-2000 Regional Administrator U.S.
Nuclear Regulatory Commission Region II l
Atlanta Federal Center 61 ForsythlSt., SW, Suite 23T85 Atlanta, Georgia 30303-3415 1
i 1
i I
l I
l l
1
)
P t
f
\\
o._.
.)
R a
ENCLOSURE 1 l
TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)
UNITS 1 AND 2 DOCKET NOS. 327 AND 328 FROPOSED TECHNICAL SPECIFICATION (TS) CHANGE 99-15 DESCRIPTION AND EVALUATION OF THE PROPOSED CHANGE I.
DESCRIPTION OF THE PROPOSED CHANGE TVA proposes a revision to Specification 3.9.4, "Centainment Building Penetrations," that will add a footnote to Item c of the limiting condition for operation (LCO) statement.
This footnote will allow penetration flow paths that travel outside the containment, but are routed through and terminate within the auxiliary building secondary containment enclosure (ABSCE), to be unisolated provided specific administrative controls are utilized.
The details of the administrative controls are added to the Bases discussion for this specification and include awareness of the open flow path condition, the designation of individuals to isolate the flow path in the event of a fuel handling accident (FHA), and the operability of at least one train of the auxiliary building gas treatment system (ABGTS).
The Bases discussions also delineate the scope of flow-paths that can utilize this allowance and exclude the containment ventilation isolation valves and other flow paths that are routed, isolated, or terminated outside the ABSCE.
II.
REASON FOR THE PROPOSED CHANGE TVA currently has a similar provision at SON for opening penetration flow paths in Modes 1 through 4 but this allowance does not apply in lower modes.
While moving irradiated fuel or during core alterations, the allowance to keep penetrations open with administrative controls in place will support the performance of outage activities.
With the current TS requirements, several outage tasks must be interrupted as a result of required penetration isolation until the completion of fuel handling activities.
The proposed revision will allow for more efficient performance of outage activities while continuing to provide an acceptable barrier against the release of l
radioactivity to the outside atmosphere.
TVA does not propose the inclusion of this allowance for tne containment ventilation isolation valves or other flow paths that communicate with the unfiltered areas ortside the ABSCE.
El-1
E o
This is based on the higher potential for the release of radioactivity associated with flow paths that do not have the ability to be filtered or have a motive force to expel
' radioactivity.
III.
SAFETY ANALYSIS The containment serves to contain fission product radioactivity that may be released from the reactor core following an accident, such that offsite radiation exposures are maintained well within the requirements of 10 CFR 100.
Additionally, the containment provides radiation shielding from the fissica products that may be
)
present in the containment atmosphere following accident conditions.
The requirements for containment penetration
)
closure ensure that a release of fission product radioactivity within containment will be restricted from escaping to the environment.
The closure restrictions are sufficient to restrict fission product radioactivity release from containment due to an FHA during refueling.
During core alterations or movement of irradiated fuel assemblies within containment, a release of fission product radioactivity within containment will be restricted from escaping to the environment when the containment building penetration requirements are met.
In Modes 1, 2,
3, and 4, this is accomplished by maintaining containment operable as described in LCO 3.6.1,
" Primary
' Containment."
During fuel movement, the potential for containment pressurization as a result of an accident is not likely; therefore, requirements to isolate the containment from the outside atmosphere can be less stringent.
The LCO requirements are referred to as
" containment closure" rather than " containment operability."
Containment closure means that all potential escape paths are closed or capable of being closed.
Since there is no potential for containment pressurization, the 10 CFR 50, Appendix J leakage criteria and tests are not required.
" Containment Building Penetrations," limits the consequences of an FHA in containment by limiting the potential escape paths for fission product radioactivity released within containment.
The LCO includes closure requirements or acceptable administrative controls for the equipment door, the containment personnel airlocks, and any penetration providing direct access from the containment atmosphere to the outside atmosphere.
For the
" OPERABLE" containment ventilation penetrations, this LCO ensures that these penetrations are capable of isolation by the containment ventilation isolation system.
l El-2 o
/
TVA currently has a provision in the SQN TSs that allows penetration flow paths to be unisolated under administrative. controls in Modes 1 through 4.
This
' provision is found in Specification 3.6.3 for containment isolation valves and includes an operator it. constant communication with the control room, closure of the valve in the event of an accident, and suitable environmental conditions to complete the isolation action.
This allowance has been determined to be an acceptable means to allow the opening of flow paths in consideration of the administrative controls that minimize the impact of an accident.
In these modes, the reactor has the potential to provide a significant motive force for the expulsion of radioactivity.
The same allowance is acceptable for penetrations that are open during fuel movement or core alterations provided appropriate administrative controls are utilized.
In this case, since there is no potential motive force to expel radioactivity from containment, the necessary administrative controls can be more flexible.
In place of constant communication with an operator, the awareness of the open condition by appropriate operation persvanel ensures knowledge of the condition such that isolation can be implemented as needed.
The designation of individuals to isolate the penetration ensures that closure can be accomplished in a reasonable length of time.
This isolation provision is necessary to support mitigation and long-term recovery from an FHA in containment similar to the closure provision for the airlock doors in Item b of Specification 3.9.4.
The additional requirement to have one train of ABGTS operable ensures the ability to process radioactivity in the ABSCE through filters before being released to the outside atmosphere.
The ABGTS is fully capable of mitigating the radiological consequences of an FHA in the ABSCE or any releases to the ABSCZ from an FHA in containment.
ABGTS operation may not be necessary because of the unlikely transmission of radiation resulting from an FHA in containment to the ABSCE.
While unlikely that radiation would enter the ABSCE, should this occur, the ABGTS automatic actuation cannot be guaranteed.
Thic l
is based on the potential that the dispersion of radiation l
from affected penetrations may not communicate with the j
spent fuel pit radiation monitors that are assumed to l
initiate ABGTS operation for a FHA in the auxiliary building.
Therefore, manual initiation may be required to ninimize the release of radioactivity for the FHA in containment event.
f Analysis of the postulated FHA in containment has determined that an operating containment purge system is the most significant contributor to offsite dose.
This is El-3
s.
based on the conservative assumption that the purge system i
and the associated components for containment ventilation isolation will be in service at the time of the accident.
j The purge system provides a motive force to expel the atmosphere from the containment to the outside environment.
The short-time delay associated with the detection of radioactivity and the associated isolation of the purge l
. system results in the release of radioactivity.
The j
release amounts are well within the 10 CFR 100 limits and are calculated without any credit for the clean-up filtration in the exhaust path as described in l
Section 9.4.7 of the Updated Final Safety Analysis Report.
l It is for this reason that the containment ventilation j
isolation valves, which limit the release from the containment purge system flow path, have not been included in the proposed allowance.
For other containment l
penetrations, the motive force that is provided by the purge system is not applicable and would not support tho transport of radioactivity that results from an FHA in containment.
1 While the motive force to transport radioactivity is highly unlikely during movement of fuel, the proposed allowance will also be excluded from those penetration flow paths that communicate with the atmosphere outside the containment and ABSCE.
This would include flow paths from j
the containment that terminate outside the ABSCE or are routed through piping outside the ABSCE that does not meet 4
the criteria for an ABSCE boundary.
Flow paths from containment that are routed through qualified ABSCE piping and structures and either terminate or are able to be isolated within the ABSCE are within the scope of the l
proposed allowance to be unisolated under administrative l
controls.
The basis for these limitations considers the effect of an FHA in containment being no more significant than an FHA in the ABSCE where the ABGTS can perform the l
same mitigation functions.
Flow paths from containment j
that are not totally within the ABSCE could contribute to the unfiltered release of radioactivity even though the potential is very low and the radiological significance of i
such a release is expected to be negligible.
l Based on the administrative controls required for the l
proposed' allowance to unisolate specific penetration flow paths, the proposed revision to specification 3.9.4 is acceptable from a nuclear safety standpoint.
The proposed allowance is consistent with and provides an equivalent j
level of protection as the personnel airlock door
]
provisions that were approved by NRC in Amendments 209 and 199'for Units 1 and 2, respectively.
The proposed l
revision, considering the associated administrative controls, will maintain acceptable offsite dose levels i
l El-4 l
w
I o
associated with an FHA in containment and will support the ability to complete long-term recovery activities.
IV.
NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION TVA has concluded that operation of SON Units 1 and 2, in accordance with_the proposed change to the technical specificatior.a, does not involve a significant hazards consideration.
TVA's conclusion is based on its evaluation, in accordance with 10 CFR 50. 91 (a) (1), of the three standards set forth in 10 CFR 50.92 (c).
A.
The prop sed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed revision will allow the orening of specific containment penetrations during the movement of irradiated fuel cr core alterations provided administrative controls are implenented.
These controls will establish the proper awareness of the unisolated penetration condition, designate individuals to isolate the penetration in the event of an FHA, and ensure the auxiliary building gas treatment system (ABGTS) is available.
The status of containment penetrations does not impact the generation of an accident nor does the ability to unisolate penetrations affect this potential.
The I
proposed revision does not alter any plant equipment or operating practices other than penetration isolation such that the probability of an accident is increased.
The administrative controls provide adequate requirements to provide timely identification and closure of penetrations opened under this allowance should a fuel handling event occur.
Designated individuals ensure that adequate resources are available to isolate the penetration such that the offsite dose consequences are not significantly impacted.
The lack of motive force in containment during fuel movement to expel the radioactive material allows a more flexible isolation interval.
The exception for the containment ventilation isolation valves is based on being exposed to a motive force and the flow paths outside the auxiliary building secondary containment enclosure (ABSCE) is based on being exposed to an unfiltered atmosphere.
Timely isolation of the specified flow paths is required to ensure that the unlikely transmission of radioactive material does not occur.
Interactions that may occur during the period of time before isolation will be El-5 l
o controlled by operation of the ABGTS and will not significantly increase the consequences of an accident as previously evaluated.
Completion of penetration isolation and operation of the ABGTS, as required by the administrative controls, will maintain the offsite dose consequences well within the 10 CFR 100 limits.
B.
The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed allowance to open penetrations in Mode 6 will not alter plant functions or equipment operating practices other than penetration isolation.
Containment penetration status is not considered to be the source of an accident.
Therefore, since the plant functions and equipment are not altered and the isolation status of containment penetrations do not contribute to the initiation of postulated accidents, the proposed revision will not create a nea or different kind of accident.
C.
The proposed amendment does not involve a significant reduction in a margin of safety.
The isolation requirements for containment penetrations ensure that the release of radioactivity is minimized to maintain the 10 CFR 100 limits for offsite dose consequences in the event of an FHA.
The proposed change to allow penetrations to be unisolated does not significantly affect the expected dose consequence because of the absence of containment pressurization potential during fuel movement or core alterations.
The most significant offsite dose contributor to the fuel handling event is the containment purge system that generates a motive force for the radioactive material.
This flow path is excluded from the proposed allowance because of this motive force potential along with flow paths outside the ABSCE.
Without this motive force, as is the case with other penetrations during fuel movement or core alterations, the potential for additional offsite dose consequence is unlj_;1y.
As an additional measure, this allowance applies to flow paths that can be filtered by the ABGTS.
Therefore, the margin of safety provided by the containment building penetration requirements is not significantly impacted by the proposed allowance to open penetrations under administrative controls.
With the timely provision to identify and isolate affected penetrations and the provision for ABGTS operability, the margin of safety is maintained without a significant reduction.
El-6
V.
ENVIRONMENTAL IMPACT CONSIDERATION The proposed change does not involve a significant hazards consideration, a significant change in the types of or significant increase in the amounts of any effluents that may be released offsite, or a significant increase in individual or cumulative occupational radiation exposure.
Therefore, the proposed change meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22 (c) (9).
Therefore, pursuant to 10 CFR 51.22 (b), an environmental assessment of the proposed change is not required.
i I
l l
l i
l El-7 j
l