ML20235V925
| ML20235V925 | |
| Person / Time | |
|---|---|
| Site: | Shoreham File:Long Island Lighting Company icon.png |
| Issue date: | 10/13/1987 |
| From: | Boger B Office of Nuclear Reactor Regulation |
| To: | Congel F Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8710150392 | |
| Download: ML20235V925 (2) | |
Text
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October 13, 1987 l
MEMORANDUM FOR:
Frank Congel, Director N~&
Division of Radiation Protection i
& Emergency Preparedness FROM:
Bruce A. Boger, Assistant Director l
For Region I Reactors Division of Reactor Projects I/II
SUBJECT:
REQUEST FOR REVIEW 0F THE PROPOSED SUPPLEMENTAL j
CONTAINMENT SYSTEM FOR SHOREHAM
.t As you are aware. LILC0 has filed a report on its proposed Supplemental Containment System (SCS).
Some background information on this filing is provided as Enclosure A.
We request DREP to perform a safety review and prepare an SER on the~SCS for 1
Shoreham. We request your review to include the following areas:
(1) Potential new accident sequences that could degrade existing plant safety and the radiation dose consequences of those new accident scenarios; and (2) Impact on public risks associated with severe accidents.
Ronnie lo will be coordinating your review with that of DEST, which is performing systems safety reviews.
He will forward to your staff LILC0's response to the staff's questions in the area of risk analysis when received.
/s/
Bruce A. Boger, Assistant Director For Region I Reactors Division of Reactor Projects I/II
Enclosures:
As stated DISTRIBUTION
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October 13,'1987
.....f MEMORANDUM FOR:
Frank Congel, Director Division of Radiation Protection
& Emergency Preparedness FROM:
Bruce A. Boger, Assistant Director For Region'I Reactors Division of Reactor Projects I/II
SUBJECT:
REQUEST FOR REVIEW OF THE PROPOSED SUPPLEMENTAL CONTAINMENT SYSTEM FOR SHOREHAM As you are aware, LILC0 has filed a report on its proposed Supplemental Containment System (SCS).
Some background information on this filing is provided as Enclosure A.
We request DREP to perform a safety review and prepare an SER on the SCS for i
Shoreham. We request your review to include the following areas:
(1) Potential new accident sequences that could degrade existing plant safety and the radiation dose consequences of those new accident scenarios; and (2) Impact on public risks associated with severe accidents.
Ronnie Lo will be coordinating your review with that of DEST, which is performing systems safety reviews.
He will forward to your staff LILCO's response to the staff's questions in the area of risk analysis when received.
Bruce A. Boger, Assistant Director For Region I Reactors Division of Reactor Projects I/II
Enclosures:
As stated O
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WASHINGTON, D. C 20555.
September 15, 1987
,,,g PEMORANDUM TO: Ashok C. Thadani, Assistant Director Assistant Director for Systems l
I FROM:
Bruce A.'Boger, Assistant Director for Region I-Reactors t
Division of Reactor Projects I/II i
SUBJECT:
SAFETY REVIEW 0F THE PROPOSED SUPPLEMENTAL CONTAINMENT SYSTEM (SCS) FOR SHOREHAM As you are aware, the Long Island Lighting Company (LILCo)-is preparing to proceed with contractual comitments for the design and construction of the SCS for Shoreham.
In a meeting which you attended en July 21, 1987, the staff raised a number of safety concerns about the SCS (see Enclosure 1 Meeting Summary). LILCo has reviewed the meeting transcript and wishes to resolve the staff's concerns and obtain the staff's guidance on design and By procedural requirements be' ore proceeding)further on the SCS project.26, 1987 (Encl letter dated August staff's questions. LILCo will supplement this letter in October, 1987 to complete its responses.
We request DEST to perform a safety review and prepare an SER on the SCS for Shoreham. The purpose of the review is to assure that the SCS does not degrade overall safety at the Shoreham Station. The SER will identify the conditions I
under which the staff finds the SCS acceptable.
Finally, the review should also reflect the staff's guidance (which LILCo has requested) on the various design bases for the SCS. The conclusions of the review will form the bases for LILCo's decisions with respect to the SCS.
Ronnie lo will be coordinating your review activities in this area with those of other groups within NRR and Region I.
i Bruce A. Boge, Assistant Director for Region I Reactors Division of Reactor Projects I/II
Enclosures:
As stated 1
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July 28, 1987
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Decket No.: 50-322 LICENSEE: 'Long Island Lighting Company FACILITY: Shoreham huclear Station Unit - 1
SUBJECT:
SUMMaDY OF MEETING WITH L1LCO.ON JULY 21, 1987 REGARDING_THE DESIGN 10F A SUPPLEMENTAL CONTAINMENT SYSTEM (SCS)
At the request of Long Island Lighting Company (LILCo), a meeting between the j
hRC staff and the management of LILCo was held in Bethesda, MD, on July 21, 1927. The purpose of the meeting was for the staff to receive a briefing fror L1LCo nn its plar te design and construct a Supplemental Containment Syster
.(SCS) for the Shorehar. Nuclea-Station. The discussions in the meeting were trerscribed and e copy of the transcript is provided as Enclosure 1.
.The' principal speakers included LILCo's Vice President, Mr. John Leonard and Dr. Thomas Murley who led the' staff in discussing the _ safety aspects of the d
SCS. The meeting was also attended by Mr. Gregory Minor, representing Suffolk Courty, N.Y., which is a party intervening in the licensing proceedings of the Shoreha" plant. A list of attendees, along with the viewgraphs used in LILCo's presentatier are included in Enclosure 1.
The following sumr.ary notes the saliert peints of the discussior. The associated pages of the transcript are-showr, in parentheses.
The primarv pu-oose of the SCS is to provide a mechanism to relieve the pressure in th* wetwell Pirsoace fnr a class of low probability /high t-..
consequence severe accidents which could tha11enge the structural integrity of the containment (91. The Shnreham containment design pressure is 48 psig and-
[
the_ ultimate structural pressure is approximately 130 psig (10). The pressure setpoint o' the rupture disc in the vent path leading to the Filtra Building of i
the SCS will be set at 60 psic. This setpoint-is chosen to ensure the integrity I
of the drywell floor seal (12). The Filtra Building will be similar to the Swedish insta11stier at the Barseback plant. It consists of a steel-lined concrete structure with a volume of 10,000 cubic meters containing about 14,000 kg of quertzite-type gravel material as the filter medium (22). The design basis for the SCS is OA Category I to the Containment Pressure Boundary (CPB) and QA Category !! beyond the CPB. The mechanical design basis is ASME III, Class 2 up to the CPP, and ASME 111, Class 3 beyond the CPB (31,88).
)
The main concerns raised by the staff during the meeting were related to assurance that no potentially unsafe conditions will be introduced by the
-5CS. The following is a highlight of some of the staff's concerns and questions:
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l Wow will the activatier.cf filtered venting be considered in' conjunctier j
i,ith the urfiltered venting procedure in the E0P (18).
)
i Analyses to overtify the reduction of public risk (24).
I Anelyses en the releases from the SCS in new accident sequences where the containment is reenverable (25, 26, 41 43, 50).-
Response nf the SCS to a short duration pressure pulse in the containmer.t (38'.
Analyses of acc4 dent sequences which could lead to pump cavitatier and core danage because of the pressure relief, although the containment integrity is mairteinad (44, 52 54).
Concerns about the petertial of the containment approaching a negative pressure in the ever.t that the containment spray is activated (81 831 LILCo irtends to review the trarscript and respond to the steff's concerns whict -
are net limitec te those highlighted above. LILCo would wish to obtain the resolution of the safet.v concerns and staff guidance or design requirements price te co m itting major design and construction contracts (104). The schedule for project completion is 36 months following the award of the desige Contract.
. G M":
Ronnie Lo, Project Manager Project Directorate PD).2 Division of Reactor Projects 1/11 Enclosura:
As stated cc w/o enclosure:
See next pege
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- I LONG ISLAND LIGHTING CO,MPANY SHoMEHAM NUoLEAR POWER STATION ay,,g.,,e P o. sox etW, NORTM COUNTMV MO AD 6 WACING RNSR, N.Y. Met i
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van Hese0Mf Muc.tM D'I AM10Ns AN 28 M7 BbiRC-1367 U. S. Ncclear Regulatory Commission ATTN Document control Desk Washington, DC 20555 Request for Concurrence with the Proposed Supplemental Containment Systeni (SCS) Plan and f
Res pense to Staff Concerns Sboreiam Nuclear Power Station Docket No. 50-322 Gentlemen:
LILCO has reviewed the ' transcript of the July 21, 1987 meek:ing with the Staff concerning the proposed Supplemental Containment system (BCS) for Shoreham.
Tbs purpose of our review was to j
identify and respond to those concerns raised by the staff during the presentation, that were over and above those specifically highlighted in the Staff's letter to LILCO dated July 28, 1987.
In accordance with the results of the review, attached are formalised LILCO responses to the Staff's questions.
The pages of transcript associated with each Staff question are shown in Currently, it is our intent to respond to those parentheses '
coditional questions highlighted in the July 28 letter in The October submittal date is governed b the scheduled October.
completion date of the currently on-going PRA anal sisi the results of which will be used to respond to the hi blighted questions.
In order for LILCO to proceed in a deliberate manner with the design and construction of the Supplemental Containment System, it la necessary to determine the appropriate criteria to which it should be built.
We have determined that that portion from the primary containment to the two containment isolation valves, rupture disk, and associated controls, should be treate6 as cafety related and built in accordance with Shoreham's Category I otandards.
We have also determined that the part of the
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.'ALL 31 '87 11:30 P.3 SNRC-1367 PCge 2 l
e Supplemental' Containment System which is downstream'of the luolation valves and rupture disk should be built to standards appropriate with a category II designation.
This has a significant impact on the cost of this system.
For LILCO to proceed on a deliberate basis with the engineering of the Supplemental Containment System, we request your ogneurrence in these two broad, general categories, with the understanding that the Staff reserves the right to review and comment upon the' detailed design submittal which will be forwarded to you as the design is finalized.
Should you desire to discuss our request further, or require any additional information, please do not hesitate to contact my office.
P Vary truly yours,
),
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on r, Jr.
Vi o President - N c1 ar Operations
" --.JpL/ lac Enclosures
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l cca W. RusseII - Region I Administrator R. Lo l
C. Warren i
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Attachment.
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.NRC Staff Concerns-f that will not Why does Shoreham need a vent (FILTRA) 1.
accomplish the same purpose as venting? (10)
The purpose of the supplemental containment System le to improve upon the venting capability
Response
i (SCS)
The SCB provides an already installed at Shoreham.
engingered passive primary containment wetvell 4
airspace vent with the ability to control rtleases fer post accident mainagement.
Existing venting j
capabilities, including.those currently available through the implementation of the RP", Revision 4 gruidelines, have -limitations in their ability to What mitigate certain types of severe accidents, the SCS does is to increase the venting capability to cope with those accidents currently within the existing venting abilities plus additional severe The 808 has the added benefit accident scenarios.
of also being able to filter the releases, signiti-cantly reducing the extent of radioactive particua late that could be r'eleased to the atmosphere during a esvere accident.
Mas.LILCO looked at the possibility of the drywell bead remaining intact at 130 psig, the ultimate capacity? (10)
,'/
-2.
In support of the 1983 Shoreham Probabilistic Risk Assessment (PRA), the drywell head was analysed to
Response
determine its ultimate structural espacity along with other structural elements of the primary The results of this analysis showed containment.
that the drywell head. reaches a general yield state At this pressure, at approximately 130 psig. relaxation of the 0-ring seal between t
.Contain-head flanges was found to be negligible.
ment structural integrity is being consiotred in the current PRA efforts, the results of which will be.provided in the October submittal, tias the omega osal (connecting the drywell floor with the containment wall) been analysed for failure at high 3.
temperature? (12) has been Responsee The omega seal (drywell floor seal) analysed to ensur The the DBA-LocA conditions of 48 psig and 340 F.
functional and environmental material testing programs for the drywell floor seal are detailed in subsection 3.8.1.7.2 of the USAR.
The drywell floor seal has not been specifically analysed at the higher temperatures associated with those
Attschment VENRC-1361 Pcgo 2 accidents outside of the design basis of the plant, Wowever, the design basis for. the SCS has been established assuming that drywell to wetwell bypass exists.
Is LILCo. planning to contract with a Swedish company for the SCS project or simply planning to buy the rights to the 4
design, including the calculations 7 (22,23)
LILCO is presently eng ged in contract negotiations Responses WM will provide us with the with SwedPower,ign documents, research data and technology, des licensing support for the FILTRA structure and the auxiliary building, The balance of plant (BOP) engineering, which represents.the scope of work from the primary containment penetration out to the auxiliary building, will be competitively bid to an architect-engineer.
Do the dissimilarities of Barseback and Shoreham make a big 5,
difference in terms of oopying the desige? (32)
Through design discussions with swedPower, LILCO has evaluated the ability to utilise the Barseback Responset We have y
design to meet Shoreham's design criteria.
concluded it is feasible to adapt the Darseback 1
,FILTRA' design to Shoreham.
6.
What is the pressure at the vent top? (35)
^
Pressure relief capabilities located at the top of the Shoreham vent structure are comprised of two
Response
l The high capacity (large l
discharge lines.
diameter) discherge line is equippd with relief and a ruptura l
valves set at approximately 45 psig,here and pro-disc to maintain the nitrogen atmosp teot the relief valves from the outside environ-It should bel 3
pont.
the relief valves le still under consideration.
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The low capacity discharge line (anall diameter) l ogaipped with a remote manual valve and rupturaThis dise which actuates at approximately 4 psig.
l low capacity line is normally valved of f (locked) l and is only used in long term recovery to i
l depressurite the FILTRA.
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TOG 31 87 14i42 P.2 3,
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'SNRC-1367 Page 3 7,..
,e 7.
What is the seismic design category of_the 8087 (45)
Response
The SCS is an added safety measure which is neither required nor relied upon to meet the plant design basis.
Accordingly, LILCO has classified.the SCS as QA Category I typ to the containment interface (i.e.,-the two safety-related isolation valvas and rupture disk) and QA category II for the balance of the system.
However, in view of the significance of the ses in mitigating severe accidents beyond the design basis of the plant, the main process system of the sc5 (i.e., passive filtering and venting) will be designed to the seismic loading j
criteria established for the licensing basis of the Shoreham plant, 7
Thus, those structures,. systems, and components whese failure may affect the critical functions of the SCS will, in general, be designed to seismic Category I loads and criteria as specified in the Shoreham USAR and other applicable documents. Using this definition, Seismic category I requirements will be followed as a guide for the design of the
~p FILTRA structure, auxiliary building, and oli structures and components directly associated with the primary vent path.
In addition, the main process system and, in prticular, the FILTRA and auxiliary building shall be designed for the effects of tornado loading.
8.
Discuss inspection and testing requirements for the SCS (46, 94)
Responses An appropriate preoperational test program will be
- ~
developed for the BCs.
Testing vill include routine equipment checkout and various power and I
logic circuit checks, special tests beyond these requirements will be formulated at a later date.
l-9.
Discuss the isolation valves with respect to operator l
actions. (48) l Response: The design philosophy of the SC8 is that the acti-vation is a passive function requiring no p'the rator i
action.
Accordingly, the normal position ef containment isolation valves in the main process piping is the open position.
System logic is such that if flow is detected in the discharge line with pressure less than the containment design pressure, l
the containment isolation valves will close.
In the other case where the containment pressure rises to a point beyonc a 55 psig permissive and flow l
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AUG 31 '87 11 3
' P. 7 I
- Attachment
.SFRC-1367 l
Page 4-1s detected, system logic will cause the The containment isolation valves to remain open l
s logic will be sealed in such a way that the valves will not close should the pressure subsequently fall below the 55 psig permissive.
The isoistion.
valves upstream of the rupture disc can be operated.
Pro-by remote manual control in the control room.
cedures will be developed to instruct the operator when to open or close the valves.
The containment isolation valves in the smaller j
i drywell vent lies leading to the FILTRA structure are normally closed and can be manually activated from the control room operator for long term Procedures will also be developed to venting.
instruct the operator in the use of these valves, o
- 10. Could the step to lower the water level in ATWs procedures be eliminated? (56)
The Scs will allow (reater flexibility for the
Response
operator to cope with higher power levels in en With this additional benefit, ATWS situation.
there is no need to eliminate the step'in the ATWS
?
procedures that directs the operator to lower water level.
At this tLme, LILCO anticipates that the basio philosophy in dealing with an ATws will remsin the same.
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- 11. Mas LTLCO looked at the radial displacement of the I
oenteinment at 60 psig? (58)
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Responsen Radial displacement considerations have currently not been evaluated since only a conceptual piping i
layout has been developed.
50 wever,.as part of the detailed piping design, stress analyses will be performed to evaluate the effects of radialThis process will displacement of the containment.
ensure that the scs piping system will accommodate any displacement and prevent excess stress on both the pipe and containment.
l
- 12. Provide a clarification of the valves in the FILTRA building, including controls on the valves. (62) (87)
The FILTRA is designed to accommodsta flow through a high capacity discharge line (30 inch diameter),
Response
but is also equipped with a low capacity discharge line (12 inch diameter).
The moraal flow path is through the high capacity line with its corres r l
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, AUG 31 787 21:46 -
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. Attachment
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SNRC-1367 Pcgo 5 e
pending main isolation AOV maintained in the open The low capacity discharge line is position.
primarily used for the depressurisation of the FILTRA during post accident recovery activities.
Monce, the main isolation A0V infthis line is However, since these valves are normally closed.
remotely operable, the operator.does have the capability of manipulating these valves to alter the flow path through the low flow capacity line should conditions necessitate such action.
Procedures will be developed to instruct the operator in the use of these valves.
- 13. Will the BCS have a flow element on the system for normal I
type operation?.(64) l g
Flow measuring devices will be incorporated in the The current design configur-
Response
design of the SC8.
ation incorporates flow measuring devices in the l
vicinity.of the containment isolation valves that interplay with the talve logic as previouslyAdditional flow measuring discussed in question 9.
devices will be included in both the high and low capacity discharge lines to monitor any rolesses to mg.
the environment.
- 14. Are there provisions for sakeup water to the suppression pool in ATWS sequences?
(67)
Responser The volume of water in the suppression pool, reactor, and condensate storage tank are significantly larger than the FILTRA itself can In any seoident, many hours of steam co.ndense.
production would have to occur h fore experiencing any significant depletion of water inventory.needed to make up inventor There is no new system as a result of the SCS installation.
- 15. Was any evaluation been done on the possibility of a wate containment sprays? (70)
Two phase flow in the vant line due to containment spray operation is not ooneidered to beThe containment sprays a
Response
significant.the drywell, which is sealed off from the wetwell airspace, where the vent opening is located.
Therefore, contribution from these sprays is not of 7
6' significanos.
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,.7 ALM 31 '87 11:50 P.9
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Attachment
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SNRC-1367 I
90ge-6 The wetwell airspace sprays operate at a low flow (about 500 gpm).
This will create some rate suspended liquid in the wetwell airspace, but notThe of the proportions as from the drywell sprays.
possibility of a steam / water mirture flowing through the vent line consistent with the above design conditions will be evaluated in the design of the 30P system.~
16, Eas LILco evaluated ATWS sequences above 8 percent, especially 20 percent power leve17 (70)
The PRA currently being performed by LILCO will Response: evaluate the full spectrum of ATWs power levels and Realistically, the ultimate their consequenose.
steam flow capacity of the FILTRA is significantly above St.
- 17. Does the amount of steam condhneed determine when the vent relief valves would. lift? (76)
~
Responses As previously discussed, the FILTRA is maintained
~
in a mitrogen inerted environment.
As a result, the initial relief valve lift will depend upon the volume available to accomodate non-condenseles The amount (primarily nitrogen) within the system.
of steam alone cannot be used to make the The FRA determination when or if they will lift.
will develop a timeframe for this phenomena in more detail and will be provided in the october submitts1.
- 18. What are the chances of activating tha system and not activating the vents? (78)
It is anticipated that there are some severe accident scenarios in which the event is terminated
Response
quickly, resulting in negligible releases from the FILTRA vent.
For these scenarios, initial pressurization and releasa from the FILTRA is due As a to the nitrogen atmosphere within the FILTRA.
result, it is anticipated that the nitrogen and only a small fraction of concondensibles would beSubsagdent ej
~
released to the atmosphere.
setion of the FILTRA structure would be long term I
and probably not sufficient to reactivate the These events are discharge line relief valves.
currently being assessed in the FRA, the results of which will be discussed in the October submittal.
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P.10
,,. -s Attachment CNBC-1367 Page 7
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- 19. Discuss the testability and surveillance of the FILTRA system. (89)
Response
' developed, however, appropriate equipmentThe minimum. preventative maintenance will be performed as a
- 20. Now will the relief valve logic handle a steam spike where the pressure drops off rapidly?
(87)
Response
There is no logic currently anticipated to control.
the activation of the relief valves within the SCS.
T Operation of these valves is due entirely to the pressurization rate of the FILTRA structure, f
Operation of the containment isolation valves is
. controlled by the system logic previously discussed in question number 9.
the safety related logie, consideration ofDuring the development potential steam spikes will be evaluated against the accurney and response times of the logic T~
instrumentation.
the logie will be considered.The inclusion of time delays in
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