NSD-NRC-98-5577, Forwards W Responses to FSER Open Items on AP600.Summary of Encl Responses,Including FSER Open Item Number,Associated Oits Number & Status to Be Designated in W Status Column of Oits Provided.Proprietary Revs to WCAP-14727 Withheld
| ML20203B031 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 02/18/1998 |
| From: | Mcintyre B WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | Quay T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19317C929 | List: |
| References | |
| NSD-NRC-98-5577, NUDOCS 9802240189 | |
| Download: ML20203B031 (62) | |
Text
[\
CJ Q-Westinghouse Energy Systems > 355 Patsburgh Pennsylvania 1523}0355 Electric Corporation DCP/NRC1261 NSD NRC-98-5577 Docket No.: 52-003 )
February 18,1998 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: T. R. QUAY
SUBJECT:
AP600 RESPONSE TO FSER OPEN ITEMS
Dear Mr. Quay:
Enclosed wi'h this letter are the Westinghouse responses to FSER open items on the AP600. A summary of the enclosed responses is provided in Table 1. Included in the table is the FSER open item number, the associated OITS number, and the status to be designated in the Westinghouse status column of OITS.
The NRC should review the enclosures and inform Westinghouse of the status to be designated in the "NRC Status" column of OITS.
Please contact me on (412) 374-4334 if you have any questions concerning this traasmittal.
0x fdOA' Brian A. Mclmyre, Manager
)
Advanced Plant Safety and Licensing jml
'e Enclosure ,
cc: W. C. Iluffman, NRC (Enclosure)
J. E. I,yons, NRC (Enclosure) g96k v
T. J. Kenyon. NRC (Enclosure)
J. M. Sebrosky. NRC (Enclosure)
D. C. Scaletti, NRC (Enclosure)
N. J. Liparuto. Westinghouse (w/o Enclosure)
V """ '
- lljilll!!lllj;;;ll 9802240189 980218 PDR ADOCK 05200003 E PDR
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, IX'P/NRCl261 NSD-NRC-98 5577 2 February 18,1998 Table 1 List of FSER Open Items Included in Letter DCP/NRCl261 FSER Open Item OITS Number Westinghouse status in OITS 220.128F (RI) 6315 Confirm W 440.790F 6447 Confirm W 440.799F 6451 Confinn W 440.802F 6454 Action N 3
M$k DN
Enclosure to Westinghouse Letter DCP/ARCl261 February 18,1998 l
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FSER Open item - _ . , , , ,
Open Item 220,128F (OITS # 6315) Response Revision 1 l l
1 Because of the complication of the coupled shield / auxiliary building structures, Westinghouse informed the staff that the completed structural design of this building will not be performed. (The five-story i auxiliary building is structurally connected with 'he cylindrical shell shield building at sin different elevations and formed a coupled structure. He coupled shield / auxiliary building is founded, together with the containment vessel and the containment intemal structures, on a irregular shaped foundation mat.) Instead, the detailed design would be completed only for the critical sections of structures. As
, - descr bed in revision 12 of SSAR Section 3.8.4.5.3, Westinghouse identified 9 critical sections for which Westinghouse completed its structural design. De staff reviewed samples of these critical section designs and raised the following concerns:
e in reviewing the design calculations for the auxiliary building roof slab at Elevation 180 ft (Calculation Nos.1260-SSC 003, Revision 2, and 1260-CCC-003, Revision 3), the staff identified two issues:
4 (1) The design did not account for the effect of global out of-plane seismic moments along the edge of the roof slab.
(2) Reinforcements for the concrete slab in the north-south direction (parallel to floor steel girders) along the roof edge should be designed assuming no composite action of the concrete slab with the steel girder.
The design of the shield building roof structures is not adequate as discussed under Open Item 3.8.4.4 2 above.
. Westinghouse should include the detailed design drawing for each of these critical sections in the SSAR.
Westinghouse needs to revise the design calculation to address the staff's concem discussed above and provide figures describing reinforcement details of critical sections in the SSAR.
Response: Revision 1 The issues related to the design of the auxiliary building roof were addressed in Westinghouse's letter of November 19,1997, DCP/NRCl143.
i Westinghouse had proposed thit the critical sections details be provided in a summary report to be i referenced from the SSAR. As stated in FSER Open item 220.122F, a draft design summary report (Design summary report Auxiliary Building S* ;tures,1200-S3R-001, revision 0 (draft) was available for review during the meeting on Jart 14 through 16,1997. Jn a meeting open item (OITS # 5150) from this meeting (summarizeo . We March 18,1997 letter, Attachment 3), NRC staff identified that Westinghouse should include critical section details in a formal revision of the SSAR.
Westinghouse has prepared information on the critical sections in the auxiliary and shield buildings for inclusion in the SSAR in a new Appendix 3H. This new appendix is substantially the same information as was in the draft summary report already reviewed by the staff. The draft design summary reports that were reviewed by the staff in previous meetings are internal Westinghouse T Mpm 220.128(RI) 1
- FSER Open item a =.
e .
l l quality documents. These design summary reports will be reconciled for as procured or as-built conditions as described in SSAR subsection 3.8.4.5.
SSAR Revision: Response Revision 1 The revisions identified in revision 0 of this response and most of those revisions identified in the notes of the structural meeting on January 17-18,1998 were incorporated in Revision 20 of the SSAR.
Revision I of this response identifies changes to SSAR revision 20 to address the remaining comments from the NRC staff during meetings in January and additional comments in subsequent phone calls.
Revise Table 3.8.4 7 as follows:
i Applicable l Flevation Reinforcement Reinforcement Reinforcement Level or Concrete Reinforcement Required Provided Provided Wall Appli:ab'e Column Elevation Required Vertical Horizontal Vertical lionzontal Thicg) ness Description Lines Level Range (
(in2/ft)(3) (in2/ft)(3) (in2 /ft)") (in2/ft)H)
IShield From intersection of From 160' 6" 3 '-0" 3.94 3.9M 5.644 46M Building column line N to 7
. Cylinder wrapping around 4
freestanding clockwise until portion intersection of column line Q IShield From intersection of From 7 to il 3 '.0" '39M 34M 4.2M 3,5M Building column line N Cylinder wrapping around freestanding c'ockwise until portion intersection of column line Q Revise the first and second bullet of subsection 3H.2 as follows:
- Seismic forces are obtained from '.ne response spectrum analysis of the three-I dimensional finite element analysis models as described in subsection 3H.4. The shear wall and floor slab design also considers out-of-plane bending and shear forces du: to loading, such as live load, dead load, seismic, lateral earth pressure, hydrostatic, ,
hydrodynamic, and wind pressure. l
- De shield building roof and the passive containment cooling water storage tank are analyzed using three-dimensional finite element models with the ANSYS and i GTSTRUDL computer codes as described in subsection 3.8.4.4.1 Loads and load combinations include construction, dead, live, thermal, wind, and seismic. Seismic loads are applied as equivalent static accelerations. He seismic response of the water in the tank is analyzed in a separate finite element response spectrum analysis with seismic input defined by the floor response spectrum.
NOM 220.128(RI) 2
PSER open item ..
Revise the third paragraph of subsection 3H.5.1.3 as follows:
- I- The governing load combination and associated design loads are those due to the i postulated pipe rupture and are shown in Table 3H.5-6.
_ Revise the fourth paragraph of subsection 3H.S.I.3 as follows:
1 Table 3H.5 7 and Figure 3H.512 presents the details of the wall reinforcement. The actual reinforcement provided is compared to the required reinforcement area for each wall
- segment.
Revise the second paragraph of subsection 3H.5.1.5 as follows The wall is designed for the applicable loads described in subsection 3H.3-3. A detailed
, finite element analysis is performed to determine the design forces, he amount of-reinforcement in horizontal and vertical directions provided on each face is same.- Typical reinforcement from elevation 200'0" to 160'-6", above the auxiliary building roof, on each face, is as follows:
1 E, lavation 200'-0" to 180'-6"-
l Required horizontal reinforcement = M53.43 inch 2frg, I Provided horizontal rainforcement u M13.51 inch2/ft.
I Required venical reinforcement = 3-743.90 inch2 /ft.
I Provided vertical reinforcement = ME4.20 inch2 /ft.
i Elevation 180'-6" to 160'-6":
1 Required horizontal reinforcement = h.95 inch2/ft.
1- Pcovided horizontal reinforcement = M44.68 inch2 /ft.
I Required vertical reinforcement = 4-003.95 inch2 ft,
-I Provided vertical- reinforcement = 4-505.59 inch frg,.
2 Revise the third paragraph of subsection 3H.5.1.5 as follows I ne reinforcement is shown on Figure 3H.5 7. The design of the shield building roof is described in 3H.5.6.
Revise the fourth paragraph of subsection 3H.5.2.1 as follows:-
A typical connection of the roof slab to the shield building is shown in d::: 2 cf Figure 1 3H.5-7. The figure shows the arrangement of reinf :ement at the connection in the fuel I
building roof, the shield building cylindrical wall, an.d the walls of the auxiliary building 1- just below the roof.
DM 220.128(RI)-3
s FSER Open item 4- ,,j, Revise subsection 3H.5.6 as foiiows:
3H.5.6 Shield bul. ding roof The shield building roof is a reinforced concrete shell supporting the passive containment I cooling system tank and air diffuser. The structural configuration is shown on sheets 7. 8 I and 9 of Figure 3.7.2-12. Air intakes are located at the top of tive cylindrical portion of the shield building. The conical roof supports the passive containment cooling system I_ tank as shown in Figure 3.8.4 7. The conical roof is constmeted using double tee precast I concrete panels with temporary support during erection on the containment vessel. The I location of the precast panels and double tee webs are shown on rU 1 of Figure 3H.5-1 i1. De precast panels are six inches thick and the remaining 18 s M 4 of concrete is cast i in place after erection of the precast panels. The design of critical areas is discussed below. These areas include the tension ring at the connection of the conical roof to the cylindrical wall, the columns between the air inlets just below the air inlets, and the connection of the exteiior wall of the passive containment cooling system tank to the conical roof.
Revise subsection 3H.S.6.3 as fo!!ows:
3H.54.3 Exterior wall of the passive containment cooling system tank The exterior wall of the passive containment cooling system tank is two feet thick, The wall starts at the tank floor elevation of 276' 6". Here is a stainless steel liner on the inside surface of the tank. The wall liner consists of a plate with stiffeners and welded studs on the concrete side of the plate. Leak chase channels are provided over the liner welds. The reinforcement in the concrete wall is designed without taking credit for the strength provided by the liner. The goveming loads for design of the exterior wall are the hydrostatic pressure of the water, the in plane and out of-plane seismic response, and the I temperature gradient across the wall. The reinforcement is shown in sheet 8 of i Figure 3H.5-121. The reinforcement required and provided is summarized in sheet 3 of Table 3H.5 il.
Revise the heading for Shu: acinforcement for Table 3H.5-7 as follows:
Shear Reinforcement:
i I Wall Segment Type Reinforcement, sq.in/sq.ft.
Revise the title for figure 3H.5 il as follows:
1 I Shield Building Roof: Typical Reinforcement a: Rocf to *aP. Cen ;ction hM W65tiflgh00S8 220.128(RI)-4
FSER Open item i
Revise the title for figure 3H.5-12 as follows:
I Shield-Building Reef: Reinforeement-at-htenor-Tenk-Welf-GenneenenTypical i Reinforcement in Wall L Revise Figure 3H.5-6 as shown ;n the attached page to add reinforcement details.
Revise Figure 3H.5 7 as shown in the attached page to show additional reinforcement details in connection between shield building wall and auxiliary building roof and wall.
Revise Figure 3H.5 8 as shown in the attached page to show typical auxiliary building ceiling stab.
Revise Figure 3H.51I as shown in the attached pages to show plan views of shield building roof and ine'ude external wall of tank.
Revise Figure 3H.512 as shown in the attached page to show reinforcement for auxiliary building wall.
ITAAC Revisions Revise Certified Design Table 3.3.1 as follows:
Applicable Reinforcement Applicable Ebvation Level Concrete Reinforcement Required Radiation Applicable Wall Applicable Column or Elevation Thickness Required Vertical florizontal Shielding Wall Dimension Desenption Lines Level Range (2 @ (in2 /ft)(3' (in2/ft)(3) (Yes/No)
- Shield From intersection of From 160'.6" to 3 '-0" 3 94-0 3W Yes -
Building column line N wrapping 7 Cylinder around clockwise until freestanding intersection of column portion line Q Shield From intersection of From 7 to 8 3 '-0" 3.9 M 34M Yes Building column line N wrappmg Cylinder around clockwise until frecuanding intersection of column pomon line Q 3 Westingh00S8 220.128(RI) 5
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FSER Open item 440,790F (a) and (b) Partial Response (OITS #447)
The scope, organization, and content of the "AP600 Scaling and PIRT Closure Report," WCAP 14727 was also discussed at the December 9-10,1997, meeting between the staff, Westinghouse, and the ACRS Subcommittee on Thermal Hydraulic Phenomena. Westinghouse should revise the report to address ACRS comments, including:
(a) correctior. of errors in equations; (b) correction (if necessary), complete discussion, and justification of assumptions and/or specific models used in data assessment, determination of scaling parameters, and "pi" group evaluations.
(c) in the specific case of OSU/ APEX scaling, performance of a multi loop scaling analysis, or an alternative quantitative assessment, to demonstrate that the facility is appropriately scaled for the thermal hydraulic phenomena and system behavior occurring during the transition from tae end of the ADS blowdown period to the inception of IRWST injection (e.g., flow split between ADS 1/2/3 and ADS 4 valves, pressurizer draining behavior, CCFL in the pressurizer surge line, overall system depressurization behavior), to provide confidence that these data can be used to assess design basis accident analysis computer codes used fer the AP600 plant.
Revision of WCAP 14727 to address these issues is an Open Item.
Response
Responses are provided to items (a) and (b) only, Item (c) will be incorporated in Revision 2 of I
I WCAP 14272. Revision 2 will include 1) the changes made in response to FSER Open item -
440.747F previously submitted to the staff in letter DCP/NRCl257 dated February 13,1998, 2) the changes described in items a) and b) below,3) future changes made as a result of the scaling analysis performed in response to item (c) of this FSER open item and 4) responses to OSU RAls submitted to the staff since Revision I was issued.
(a) Equation 3-63 on page 3 33 of WCAP-14727, Revision 1, has been modified to incorporate the comments from the ACRS Subcommittee on Thermal Hydraulic Phenomena meeting held on December 910,1997 regarding the correctness of this equation. Equation 3 33 has been corrected to include all the terms in the denominator as derived by Wallis and the appropriate reference to Wallis (? 16) has been added.
In addition, Tabic 3.2-4a has been added to evaluate the terms in the denominator of equation 3 33 over the appropriate range of qualities and pressures for the AP600 and the SPES 2 and OSU test facilities. For this range of qualities and pressures, equation 3-64a, which neglects the less importai,: terms in the denominator of equation 3-33, can be justified. However, this approximation (equation 3 64a) is only valid for the ADSl time period. For the ADSI 2 time period, the flow mixture is of a low quality, equation 3-64b is appropriate.
ygg 440.747-1
\ .. .
FSER Cpen It:m As a result, the Pi Group (l'13 y) evaluated based on equation 3 33 in Revision I of WCAP 14727 {
is not appropriate for ADSl 2 and has been removed from the System Level Single-Loop Pi Group evaluation and Table E 5. In addition, this Pi Group was developed based on applying the momentum equation developed by Wallis to the ADS system only, and is more appropriate as a Bottom Up Pi Group.
An alternative evaluation has been performed and added to Appendix C. section C.I.7 md is referenced in subsection 3.3.2.7, ADSI. This evaluation is applicable for ADSl and ADSl-2 and i< based on the rate of pressure change equation. The scaling groups and depressurization system time constant ratios resulting f;om this evaluation are presented in Appendix C, section C.2.4.1.
The scaling ratios show that the SPES facility is very well scaled for the ADS critical flow. OSU is distorted during the ADSl blowdown, but is better scaled for the ADSI 2 blowdewr..
(b Corrections and additions have been made to WCAP 14727, Revision i to address staff and ACRS comments discussed at the December 910,1997 meeting. The transcript of the meeting was reviewed to identify the comments and a thorough review of the document was performed to verify and correct equations, definitions, internal references and text. As a result, the following modifications have been made to WCAP 1472:
l l o Updates and corrections to the Nomenclature descriptions o Addition of a plot the transient phases used in the scaling approach (Figure E-4) o Corrections to the Pi Group Ratio definitions. e.g., sensible heat rate / core power ratio, in Tables E 5 and E 9 and Tables 3.2-7 through 3.2-12.
o Addition of a reference to the appendices in Tables E-6 and E-7 I
o Correction to the appendix references in Tables E 10 through E-16 o A clarification note is added to Appendix B.2.1 ti,at the Pi groups are for the multi-loop scaling analysis o Equation variable definitions at initial conditions were modified in Append!* C, Subsection C.2.1.1, Critical Flow, and Ib is defined for clarification o Pi 10 in Appendix C, section C.2.6, IRWST, has been i tvaluated using a temperature difference instead of absolute temperature and l'imws7 3 in To ble E-15 has been revised WCAP 14727 Revisions:
The proposed revisions to WCAP-I4727. Revision 1 are attached to this RAI respont 4
W westinghouse 440.747-2
,n- - - -
I dii l!!!
NRC FSER OPEN ITEM m Question 440,799F (OITS 6451) REVISION 1 TO RESPONSE The ERGS do not rely on containment sump level, hydrogen concentration or core exit temperature to monitor the integrity or performance of containment. In addition, the ERGS do not have guidance for initiating hydrogen igniters and cavity flooding system. Wutinghouse should explain why monitoring containment radiation is sufficient to monitor the performanca of the containment during shutdown and should explain why these other parameters are not required to be monitored.
Response: REVISION 1 A rapid containment overpressur: during modes 5 and 6 cannot occur due to the initial low energy condition of the primary system. During the shutdown conditions of modes 5 and 6, the containment building may be open to allow easy access for maintenance activitiesthowever een:ainmen: !cw::
l espability-is-fequired per :he Technical Specifications. Thus, the main objective for the
! containment function during modes 5 and 6 is to prevent radiation releases during a challenge, The-contaimr.ce function preven:s eadia:ica rele=es during a challenge ne intent of the containment function can be maintained if containment closure is initiated upon indication of abnormal radiation in containment. High containment radiation would be detected well before any core damage would occur or large quantities of hydrogen are released into the containment. Thus adequate time is available for determining if additional actions are necessary, as stated in the guidel;ne for a response to a high radiation in containment, SDG 3 RESPONSE TO HIGH CONTAINMENT RADIATION DURING SHUTDOWN. Herefore only contamment radiation is monitored on '.he shutde,vn LRG status tree. Abnormal radiation will require prompt operator 'ction to establish containment closure.
Nottaha: .; discussed in :he : spe= :c RA! 4 !0 798F, con:rinmen: !csure upcn c. !cz cf RNS-is also-add: s ed in SDO 2.-
Use of the hydrogen igniters or cavity flooding was is not specified in the shutdown ERGS. It-it intended-that-these-aetic= Se ecvered under :he si: sewe-eeeident-m=agemen: guidelines and-tmder the-Step 20 cf SDO 1, Evalua:: Long Te= P!=: S:a:=, =d under S: p 2 cf SDO ?, D :::mine4f Additional,\etions at: N:: za j. Tc :=ure : hat :his-informa:ica ai!! no: be fcqc::en, the fc!!cwing s:a:emen: .il! be added :c Sectica 3.2, Key-Uti!!:y Decisica Pein:- in :he-beekgrom daloeuments for SDG-h-AP609-RESPONSE TO LOSS OP RGS INVENTORY DURING SHL"DOWF =d SDC 2 AP600-RESPONSE TO LOSS OF RNE DURING SHL"DO= These actions wih be included by revising Steps 14 and 30 of SDG 1, AP600 RESPONSE TO LOSS OF RCS INVENTORY DURING SHUTDOWN to read as follows:
W Westinghouse 440.799F(R1)-1
[i "jj{
NRC FSER OPEN ITEM i Evaluate 1,ong Term Plant Status
- a. Determine if additional accident management actions are necessary
o Hydrogen igniter operation l o Cavity Gooding i o PCCS operation I
! o implementation of Severe Accident Management Guidelines i
i o
[ Include additional AP600 details in EOPs]
i b. Return To Step 3 j Section 3.2, Key Utility Decision Points in the background for SDG 1 AP600 RESPONSE TO l LOSS OF RCS INVENTORY DURING SHUTDOWN will also be modified by inserting the i following:
"If cooling of the core cannot be reestab;ished and plant conditions continue to degrade, the opere:or
! will have to decide whether to initiate the Severe Accident Management Guidelines. Additional I actions possible would include the use of hydrogen igniters, cavity nooding, PCCS operation and
} implementation of the Severe Accident Management Guidelines. The Se.;re Aesh Management Guideliner. cheuld contain-additionabeeticas :c mi:ign:: :he acciden: nd pretee+-tb eentainmeneueh+1-duse+eMydrogen-igniter . nd cav; y Scoding "
The following statement will also be added to Section 3.2, Key Utility Decision Points in the background document for SDG 3, AP600 RESPONSE TO HIGH CONTAINMENT RADIATION DURING SHUTDOWN:
" Examples of additional actions would be use of hydrogen igniters, cavity Gooding and initiation of the Severe Accident Management Guidelines.
In addition, steps 12 and 28 in SDG 1 and steps 11 and 20 in SDG 2 will be modified to include
" Instrument air to containment," in the example checklist for containment closure, Markup of the SDG and background document changes are attached.
SSAR Revision: -
None. ,
440.799F(R1)-2 W Westir.ghouse W
N aber Ittle Rey,/Date 50G-1 RESPONSE T0-LOSS OF RCS INVENTORY OURING SHUT 00WN Rev. 4 !
7/1/97 A. PURPOSE The purpose of this guideline is to provide the actions necessary for maintaining core cooling and protecting the reactor core in the event that PRZR level is lost during shutdown operations wher the RCS is intact or RCS level is too low to support operation of th* RNS pumps during operation in reduced inventory conditions in the RCS.
l B. SYMPTOMS OR ENTRY CONDITIONS l
This guideline is entered from SDF-0.1, SHUTOOWN SAFETY Critical Safety Function Status Tree on an ORANGE condition.
"*S' l ' I2 Wo.H9 Fkt)- 3
Neber ittle hv./Date SDG-1 RESPONSE TO LOSS OF RCS INVENTORY DURING SHUTOOWN Rev. 4 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 1 Check If RNS Pumps Should Be Stopped;
- a. RNS pumps - ANY RUNNING a. Go to Step 2.
- THAN (SL02) level decreases to less than (SLO 2) and RNS pumps start to cavitate, IliEH stop RNS pumps,
- c. RNS pumps - CAVITATING c. Continue with Step 2. 1E RNS 4
pumps start to cavitate, IliEN stop RNS pumps.
- d. Stop RNS pumps i
2 Verify RCS Drain Path Isolation Manually close valves as e RNS IRWST return valve e letdown
, NOTE The RCS is considered open when an opening exists that cannot be closed from the control room such as a SG manway.
3 Check RCS Status - OPEN 1E reduced inventory operations were in. progress, IllEh go to Step
- 4. IE 801, IllEH go to Step 15, i
4 Verify Stage'1, 2 and 3 ADS Manually open valves as Valves - OPEN necessary.
Page 2 of 12 fio.7?9 F bl.h- 9
Neber title
- Rev./Cate
$00 1 RESPONSE TO LOSS OF RCS INVENTORY DURING SHUTOOWN Rev. 4
, 7/1/97 5(EP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED CAUTION
- l'ersonnel working in ccMainment should be warned before reftlling the RCS to avoid Inadvertent contamination of personnel working near RCS open1ngs.
- Only borated water should be added to the RCS to 1 maintain adequate thutdown margin.
e if RCS hot leg level remains less than (Sl02) for greater than 30 minutes, automatic alignment for IRWS1 Injection should be verified.
5 Reffil RCS
, a. Refill RCS using CVS makeup e. IE CVS makeup can NOI be pumps as necessary established, IRIN refill the RCS using any of the e (includeadditionalAP600 following:
details n E0Ps]
e CMTs.
t
-0R-e Gravity feed using the IRWST to RNS suction line.
-0R-e Gravi *.y feed using the IRWS1 injection line,
- b. Refill RCS until RCS hot leg level greater than (SLO 2) 6 Identify ind Isolate Any RCS Leakage 1 Check RCS Hot leg Level - GREATER Continue with Step 9. WHEN RCS THAN(SLO 2) hot leg 1* el greater than (SLO?) d do Step 8.
Page 3 of 12 4%.H f F (Al)- r
N M er 1it14 Rev./Date SDG 1 RESPONSE TO LOSS OF kCS INVENTORY DURING SHUT 00WN Rev. 4 7/1/97 STEP ACil0N/ EXPECTED RESPONSE RESPONSE NOT OBTAINED CAUUCN Starting an RNS pump may result in an RCS level decrease due to shrink or void evilapse.
8 Try To Restore RNS Flcw:
- a. Start one RNS pump e (includi additional AP600 .
detailsinE0Ps]
- b. Maintain RCS hot leg level - '
GREATER THAN (SLO 2)
- c. RNS flow RESTORED c. Go to Step 9.
- d. Estabiish desired RCS cooldown rate
- e. Go to appropriate plant procedure 9 Check If Fourth Stage ADS Shnuld Be Actuated:
- a. CMT level - LESS THAN (SLOS) a. Perform the following:
1)1ECMTleveldecreasesto less than (SLOS) IllEN do Steps 9b and c.
2)IfRCShosleglevel indication decreases to less than (SLO 4), IhEN manually actuate fourth stage ADS and do Steps 9b and c.
3)ContinuewithStep10.
- b. Verify fourth stage ADS b. Manually open valves as isolation valves - OPEN necessary.
- c. Verify IRWST injection c. Manually open valves as isolation valves . OPEN necessary.
=_
Page 4 of 12 No,199 F (A.I)- f.
N,s't e r Title noe./0cte 50G-1 RESPONSE TO LOSS OF RCS INVENTORY DURING SHUTDOWN Rev. 4 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 10 Check IRWST Levels
- a. IRWST level - LESS THAN a. Perfom the following:
(SLO 6) i 1)W11EliIRWSTlevelless )
than (SLO 6). IBL1 do Step 10b.
2)GotoStep11.
- b. Verify containment sump b. Manually align ,alves as
- recirculation valves OPEN necessary.
11 Initiate Actions To Frotect Personnel Working In Containment:
- a. Evacuate non essential personnel in containment
- b. Periodically monitor containment radiation conditions 12 Initiate Actions To Establish Containment Closure:
- Equipment hatch
- Personnel hatch
- $ #** * * %Y
- Containment purge and exhaust system #
- [IncludeaddftfonalAP600 E4!
- N' b'"3 '
f S. boksem;w II additI*wl ne 8l84'i detailsinE0Ps) mmpms.4 wtiem are. Atwthy
- Nd)4 '$
' d u *P' d *"
U t Available Containment Fan
,LaMg Fl**M 3 a f4.t 5 a pa,( dien Jg 14 se +nen r7 g y M44*t MWpmed Guilotiota s
[ h. b. ben to $fa.p 3 4
Pa0e 5 of 12 (N o.791 F @0 - 7
1 Noter fitte
- tev. m te
$0G 1 RESPONSE TO LOSS OF RCS INVENTORY DURING SHUTOOWN Rev. 4 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 15 Check If CMis $hould Be Actuated:
- a. PRZR level - LESS THAN a. Go to Step 22.
(SLOl)
- b. CMT injection valves - OPEN b. Manually open valves as necessary.
16 Verify PRHR Actuated: Actuate PRHR initiation. 1E valves will tiOI open, M e Verify PRilR isolation valves - manually open valves as OPEN necessary, 17 Check If ADS Should Be Actuated:
- a. CMT level - LESS THAN (SLO 3) a. If RCS hot leg level indication greater than (SLO 4), M 90 to Step 22.
IE tiQI, M manually actuate ADS.
- b. Verify first stage ADS b. Manually open valves as isolation valves - OPEN necessary.
- c. Check second stage ADS c. M (ST01) seconds have valves - OPEN elapsed from first stage ADS signal, M verify second stage ADS valves open. If it0I, M manually open second stage ADS valves as necessary.
- d. Check third stage ADS d. M (ST02) seconds have valves '0 PEN elapsed from second stage ADS signal, M verify third stage ADS valves open.
1E ff01, M manually open third stage ADS valves as necessary.
Align RNS to inject into RCE e.
Page d of 12 p97 g
, N#bef IltIt pgy,/Qggg 50G 1 RESPONSE TO LOSS OF RCS INVENTORY OURING SHUTOOWN Rev. 4 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 18 Check If Fourth Stage ADS Should Be Actuatedt i
- a. CMT level - LESS THAN (SLOS) a. Perfom the following:
- 1) 11 CMT level decreases to less than (SLOS),1118 do Steps 18b and c.
tuate fourth stage ADS and do Steps 18b and c.
3)ContinuewithStep19.
- b. Verify fourth stage ADS b. Manually open valves as isolation valves - OPEN necessary,
- c. Verify IRWST injection c. Manually open valves as isolation valves - OPEN necessary.
19 Check IRWST Level
- a. IRWST level - LESS THAN a. Perfom the following:
(SLO 6)
2)GotoStep27.
- b. Verify ctntainment sump b. Manually align valves as recirculation valves - OPEN necessary.
20 Evaluate Long Tem Plant Status 21 Go To Appropriate Plant Procedure
\
Page 7 of 12 g , 3 9 F $1) -' i
l y -
.Ai title an itete
? 5 '- 1 RESPONSE TO LOSS OF RCS INVENTORY DURING SHUTDOWN Rev 4 4
1 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED CAufl0N e Personnel working in containment should be warned before refilling the RCS to avoid inadvertent contamination of personnel working near RCS openings.
- Cnly borated water should be added to the RCS to ;
matrtain adequate shutdown margin.
22 Maintain PRZR Level - GREATER THAN (SLO 1)
- a. Maintain PRZR level using a. IE CVS makeup can fl01 be CVS makeup pumps as established, IBEN maintain necessary PRZR level using any of the
- following:
e [ Include additional AP600 detailsinE0Ps] e CMis.
-0R-e Gravity feed using the IRWST to RNS suction
- i. line.
-0R-i e Gravity feed using the IRWST injection line.
23 Check If CMT Injection Should B4 Isolated
- a. PRZR level - GREATER THAN a. Continue with Step 24. WHEN (SLO 1) PRZR level greater than (SLOl),IBENdoStep23b.
- b. Close CMT injection valves Page 8 of 12 g ,g
NJmbOP fItle Rev./Date 50G.1 RESPONSL' TO LOSS OF RCS INVENTORY DURING SHUTOOWN Rev. 4 i 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED i
CAUT/GN Starting an RNS pump may rewlt in an RCS level j decrease due to shrink or void collapse.
24 Try To Restore RNS Flows
- a. RCS hot leg level - GREATER a. Go to Step 25.
THAN (SLO 2)
- b. Start one RNS pump e (IncludeadditionalAP600 '
detailsinE0Ps)
- c. Try to maintain PRZR level -
GREATERTHAN(SL0l)
- d. RNS flow - RESTORED d. Go to Step 25.
- e. CMTs - ISOLATED e. Return to Step 22.
- g. Establish desired RCS cooldown rate
- a. SGs - ANY AVAILABLE a. Perform the following:
- 1) Try to restore SGs to service.
- 2) Go to Step 26.
( c. Open respective SG PORVs Page 9 of 12 g g 799p
N xer fitte eee./Nie 500-1 RESPONSE TO LOSS OF RCS INVENTORY OURING SHUTDOWN Rev. 4 j7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 26 Establish RCS Heat $1nk Using PRHR:
- a. PRHR - AVAILABLE a. Continue with Step 27. Try to restore PRHR. W118 PRHR available, IEG do Steps 26b and c.
- c. PRHR cooling - IN SERVICE c. IE RCS temperature increases to greater than (ST03)*F before a heat sink :s established, Ilih oN n all ADS valves.
27 Initiate Actions To Protect Personnel Working In Containment
- a. Evacuate non-essential personnel in containment b.. Periodically monitor containment radiation conditions 28 Initiate Actions To Establish Containment Closure:
- Equipment, hatch e Personnel hatch
- -
- T mi/o w T Sie te ConiM n%%4 e Containment purge and exhaust system ,
e [includeadditionalAP600 detailsinE0Ps]'
i 29 Start Available Containment Fan Coolers Page 10 of 12 g g g g g ,, g
Neber fille des./Cato SDG-1 RESPONSE T0 1.0$$ OF RCS INVENTORY DURING SHUTDOWN Rev. 4 7/1/97 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 30 %**~a Ya Wa ?
M - END -
- Ev>lus.te. Les Te.< m Plant 54aiu3
- 3. behu%;,. ; adat% nst ac_d M t
> <.& n3 hea- 6 tee-ssn<j m> nag % e,d
- Wg de,ge.n ig n'.t u o p u a.fie n
- kWy $ \oa A:~3
- 9c.Ls opu>% n fuue,
- Imp lemutation .8 GrutdeMoe,s Sujded M>,nsgesne g+
- b. RaAuen to 5+ep 15' a
Page 11 of 12 qqo,791 F(ty - l3
f I
Naber fitte .
ne,/ cat, 50G 1 -RESPONSE TO LOS$ 0F RC5 INVENTORY DURING 5HUTOOWN Rev. 4 !
7/1/97 +
FOOTNOTES i
Refer to 50 GUIDELINE F001 NOTE DEFINITION Document for a description of all footnoted parameters used in this guideline, i
l l
t t
i i.
k t,
Page 12 of 12 4 40,'799 F (,4,1)- 19 i
,..-.--,--..-,,,..,,--.---,--,-.r-- , - - - , , , - -
3 I
Manbe r title
$DG-2 tev./Date RESPONSE TO LO$$ OF RN$ DURING SHUTDOWN Rev. 2 7/31/96 ;
l' I A. PURPOSE The purpose of this guideline is to provide the actions necessary for maintaining core cooling and protecting the reactor core in the event that RNS cooling is i lost.
B. SYMPT 0MS OR ENTRY CONDITIONS 4
This guideline is entered from SDF.0.1, SHUTOOWN SAFETY Critical Safety Function
, Status Tree on an ORANGE condition.
i
't i.
4 l
1
\
Page 1 of 8 440.Tt97(a.d-tr
Neer title 50G 2 nov./0.te RESPONSE TO LOS$ OF RNS DURING SHUTDOWN Rev. 2 7/31/96 Sir,P ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 1 Check Reactor Cavity Level - Go to Step 4. OBSERVE NOTE PRIOR FLOODED d TO STEP 4.
2 Try To Restore RNS Flow
- a. [ Include additional AP600 detailsinE0Ps]
- b. RNS flow - RESTORED b. Align fuel pool cooling
- system to cool reactor cavity.
(include additional AP600 detailsinE0Ps]
JE fuel pool cooling can HQI be aligned to cool reactor cavity IBEN perfom the following:
- 1) Establish containment integrity.
- 2) Establish a long tern makeu) source of water
> for tie reactor cavity.
3 Go To Appropriate Plant Procedure NOTE The RCS is considered open when an opening exists that cannot manway.
be closed from the control roca such as a SG 4 Check RCS Status - OPEN Go to Step 14.
S Check RCS Hot leg Level - GREATER Go to SDG-1, RESPONSE TO LOSS OF THAN(SLO 2) RCS INVENTORY DURING SHUTDOWN, STEP 1.
6 Verify Stage 1, 2 and 3 ADS Manually open valves as Valves OPEN necessary.
Q40. h9 F (ll)- /b
.- . ~_. - ... - . -. - -_ -_ .- . - - . . - - - . ~ . - . . - - - . . - . - - - . - - . - . - . - . - . - - . . - - . - .
Nat,et ittle 500 2 Rev./hte RESPONSE TO LOSS OF RNS DJRING SHUTDOWN Rev. 2 7/31/96 r
STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED
^
- r. union
- Personnel working in containment should be warned before refilling the RCS to avoid inadvertent contamination of personnel Working near RCS openings, e Only borated water should be added to the RCS to maintain adequate shutdown margin.
7 Maintain RCS Hot Leg Level -
GREATERTHAN(SLO 2)
- a. Maintain RCS hot leg levcl a. If CVS makeup can 1101 be using CVS makeup pumps os used JEG maintain 05 hot necessary leg level using any of the following:
e include additional AP600 etails in E0Ps) e CMT!.
-0R-e Gravity f'eed using the IRWST to RNS suction line.
-OR.
e Gravity feed using the IRWST injection line.
8 Identify And Isolate Any RCS Leakage S
$0.111 F (,RJ)- I?
l
_ _ . _ m-_. . _ . _ _ _ _ _ _ _ _ _ . _ . _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _
Numbor Title Rey,/Date 50G-2 RESPONSE TO LOSS OF RNS DURING SHUTDOWN Rev. 2 7/31/96 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED
'l CAUT10N Starting an RNS pump may result in an RCS level decrease due to shrink or vold collapse.
9 Try To Restore RNS Flows
- a. Start one RNS pump e
(includeadditionalAP600 details in E0Ps)
- b. Maintain RCS hot leg level -
GREATER THAN (St02)
- c. RNS flow - RESTORED c. Go to Step 10.
A d. Establish desired RCS l cooldown rate
- e. Go to appropriate plant procedure 10 Initiate Actions To Protect Personnel Working In Containment:
- a. Evacuate non-essential persennel in containment
- b. Periodically monitor containment radiation conditions 11 Initiate Actions To Establish Containment Closures e Eqrvment hatch e Personnel h ch , ggg @c 4, (oghimd o Containment purge and exhaust system e (Include additional AP600 detailsinE0Ps)
'*** * *' * %c,111 F (D)- I t'
(
l NJther 91110 SDG 2 ROV./Dett RESPONSE TO LOSS OF RNS DURING SHUTDOWN Rev. 2 i
7/31/96 STEP ACTION / EXPECTED RESPONSE
, RESPONSE NOT OBTAINED 12 Start Available Containment Fan Coolers 13 Return To Step 4 14 Check PRZR Level GREATER THAN Go to SDG-1 RESPONSE TO LOSS OF
(!' M) RCS INVENTORY DURING SHUTDOWN, STEP 1.
CAUT10N
- Personnel working in containment should be warned before refilling the RCS to avoid inadvertent contamination of personnel working near RCS openings.
- Only borated water should be added to the RCS to maintain adequate shutdown margin.
15 Maintain PRZR Level Greater Than (SLO 1) Using CVS Makeup Pumps As Necessary CAUTION Starting an RNS pump may result in an RCS level decrease due to shrink or void collapse.
16 Try To Restore RNS Flow
- a. Start one RNS pump
. [ Include additional AP600 details in E0Ps)
- b. Maintain PRZR level -
GREATERTHAN(SLO 1)
- c. RNS flow - RESTORED c. Go to Step 17.
- d. Establish desired RCS cooldown rate
- e. Go to appropriate plant procedure Page 5 of 8 do.7 t t F @l)- li
- .-- _.._. . -_ - . - - . _ _.- _- - _ - _ _ . . . . - . - . ~ . . - - - .
[
Nnber 11tle 50G 2 Rev./Date I RESPONSE TO LOSS OF RNS DURING SHUTDOWN Rev. 2 1 7/31/96 STEP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 17 Establish RCS Heat $1nk Using SGs j a. SGs . ANY AVAILABLE a. Perfom the following:
- 1) Try to restore SGs to service. ,
- 2) Go to Step 18.
. b. Feed SGs as necessary to establish and maintain SG level
- a. PRHR - AVAILABLE a.
Continue with Step 17. Try to restore PRHR. WHEN PRHR available, IBEN do Steps
, 18b c and d.
(includeadditionalAP600 detailsinE0Ps)
- c. PRHR cooling - IN SERVICE c. Perfom the following:
- 1) 1E RCS temperature increases to greater than sinki )s established (ST03 open all ADS valves., IHEN
- F befo 2)GotoStep19.
- d. Check PRZR level - GREATER d. Continue with Step 19. WiiE8
' THAN - (SLO 1) PRZR level greater than (SLO 1), IllEB do Step 18e.
- e. Close all ADS valves Page 6 of 8
% MFMu
Naber Title SDG 2 P.ev./Date RESPONSE TO LOSS OF RN$ DURING SHU100WN Rev. 2 7/31/96 51EP ACTION / EXPECTED RESPONSE RESPONSE NOT OBTAINED 19 Initiate Actions To Protect Personnel Working In Containment
- a. Evacuate non-essential personnel in containment
- b. Periodically montior containment radiation conditions 20 Initiate Actions To Establish Containment Closuret e Equipment hatch e Personnel ha .
g g g gg g
- Containment purge and exhaust system e (includeadditionalAP600 details in E0Ps]
21 Start Available Containment Fan Coolers 22 Return To Step 14
- END -
Page 7 of 8 ggy9f(gy..Ag
Nu4er 11tle
$DG-2 ' "
RCSPONSE TO LOS$ 0F RN$ DURING $HUTDOWN ReI. '2 7/31/96 FOOTNOTEE 1
Refer to SD GUIDELINE FOOTNOTE DEFINITION Document fo_r a description of all footnoted patameters used in this guideline.
9 5
4 muieN d
~
'aara
1.9 INTRODUCTION
The Status Tree SDF 0.1, SHUTDOWN SAFETY STATUS 11EE. provides a systemauc method to explicitly detennine the status of the plant during shutdown conditions after entering Mode 5. This tree requires no operator action other than monitoring a limited ret of plant parameters and comparing them to reference values within the tree.
This tu represents the Critical Safety Functions that are of concem during plant shutdown and, as such, is always monitored anytime the plant is in a shutdown condition after entering Mode 5. Tiw tree can direct operators to either of six Shutdown Guidelines (SDGs).
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I, 1 I l 3.2 Key Utility Decisloe Points f , , ,,, ;3 m tw9 3 There% key utility de ,ision poinfin this guideline, ' hen the operator must initi, ate actions to protec ,
penonnel laside containme it. In Steps 11 and 27. the operator is instructed to evacuate non. essential !
perr.ornel inside conteinmem. The opuntor will have to determine wl.ich personnel must be evacuated l
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STEP DESCRIPTION TABLE FOR SDGot STEP 12 v
SIgr. Initiate Actions To Establish Containment Closure i
PURPOSE:
To establish a boundary to prevent the release of fission products R6111:
Since kNS cooling has been lost and initial attempts to restore RNS cooling have been unsuccessful, actions must be taken to address the possibility of core uncovery ard subsequent fuel damage due to RCS inventory loss. Sirce two of the three radiological barrier! may be open (the RCS and containment), actions must be taken to close containment and provide a barrier to the telease of radioactive materials should the event proceed to core damage. Contaltunent closure must I be secomplished before the onset of core damage. Once containment closure is indtiated, closure should continue until controlled and stable decay heat removal has been restored (either RNS coolingi or stable heat removal via the secondary plant) and the RCS is retumed to a controlled ard stable l M.edBcondition.
- 4 AC110NS:
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Initiate actions to establish conta.runent closure ;
j INSTRUMENTATION:
I N/A '
CONI 1tOUEOUIPMENT:
N/A KNOWLEDGE: -
Means to establish containment closure ADDfT10NAL INFORMATION: -
Specific guidelless for establishing containment closure during typical shutdown conditions.
Containmers cisam as 'HmM in this step includes establishing the desired position of available containment isoleden valves to mirdmize release outside containment.
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STEP DESCRFnON TABLE FOR SDGil STEP 14 Evdnte l ess Ttt 4 T laar b'A Ty "'
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3 ACTIONS:
- Retum to Step 3 INSTRUMEPGATION:
N/A l CON 11tOLAOUIPMENT: '
N/A
- KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
N/A
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4 STEP DESCRIPt10N TABLE FOR SDG 1 STEP 28 32y2: Initiate Actions To Estabil6h Contaltunent Closure PURPOSE: To establish a boundary to prevere the release of fission products D.6111:
Since RNS cooling has been lost, and initial anempts to restore RNS cooling have been unsuccessful, acdons must be taken to aJd ses the possibuity of core uncovery and subsequent fuel damage due to RCS inventory loss. Slnm two of the three radiological barrieg may be open (the RCS and contalruners), actions must be taken to close containment and provide a barrier to the release of radioactive materials should the evert proceed to core damage. Containment closure must i
be accomplished before the onset of core damage. Once containment closure is inidated, closure '
l should continue undl controlled and stable decay heat removal has been restored (either RNS cooling or stable heat removal via the secondary plant) and the RCS is returned to a controlled and stable condidon.
ACTIONS: kej pg b -
Inidase acdons to establish containment closure INSIRUMENTATION:
N/A CON'IROUEOUIPMENT:
N/A
{ KNOWLEDGE:
- Means to establish corsainment closuse ADDITIONAL INFORMATION:
Specific guidellmes for establishing containment closure during shutdown condidons and using the
- passive core costig systems (i.e PXSPRhR and PCC). Containment closme as discussed in this step includes % the desired position of available containment isolation valves to minialse release outside annantamant.
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STEP EESCRIFrION rASLE FOR SDG 1 STEP 30 ktI'ln s 't hug hm lhwf hT'h $ b JIgt: J,.mnsulwr45*
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' Steps 15 to 29 fonn a loop of recovery actions with closed RCS conditions. Since RNS cooling has not been re established, as evaluated in Step 24. the operator is sent back to the beginning of this loop to re evaluate the status of RCS cooling and restoration of RNS cooling of the RCS.
l ACTIONS:
1 Retum to Step 15 IN!mtOMENTATION:
N/A COfffROLAOUIPMENT:
N/A KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
N/A
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STEP SEQUENCE FOR SDG.1 SHf. SEOUENCE
- 1. Check If RNS Pumps Should Be Stopped 1
- 2. Verify RCS Drain Path isolation 2
- 3. Check RCS Status . OPEN 3
l 4 Verify Stage 1,2 and 3 ADS Valves OPEN . 4
- 5. Refill RCS
- 6. Identify And Isolate Any RCS Leakage 6
- 7. Check RCS Hot Leg Level - GREATER THAN (SLD2)) 7
- 8. Try To Report RNS Flow 8
- 9. Check if Fourth Stage ADS Should Be Actuased 9
- 10. Check tRW5T Level 10
- 11. Initiate Actions To Protect Personnel Working in Containment 11 1' In!tiate Actions To 2s'ablish Containment Closure 11 ,
- 13. Start Available Containment Fan Coolers 11 p\
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- 15. Check if Sfft should Be Actuated
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- 16. Verify PRNR Acenated 14
- 19. Check tRW5T Level 17 440.79 9 F [.4) 11 SD0!OnIw 4 47 RNSION: 2
- 20. Evaluate Long Tenn Plant Status is '-
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- 21. Go To Appropriate Plant Procedure 19
- 22. Maintain PRZR Level . GREATER THAN (SLO 2) 20
- 23. Check if CMT Injection Should Be Isolated 21
- 24. Try To Restore RNS Flow 22
- 23
- 27. Initiate Actions To Protect Personnel Working in Containn w 24 l 28. Initiate Actions To Establish Containment Closwa 24 -
- 29. Start Available Containment Fan Coolers 24
- 30. L.... To a.,17 -
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I STEP CE5CRimON TABLE FOR SDG:2 STEP 11 SJZE: Initiate Actions To Establish Containment Closure PURPOSE: To establish a boundary to prevent the release of fission products BASIS
- Since RNS cooling has been lost, and initial anempts to restore RNS cooling have been unsuccessful, actions must be taken to address the possibility of core uncovery and subscouent fuel damage due to RCS inventory loss. Since two of the three radiological banters may be open (the RCS and contairrnent), actions must be taken to close contrinment and provide a barrier to the release of radioactive materials should the event proceed to core damagt Containment closure must be accomplished before the onset of core damage. Once containment closure is initiated, closure should continue undl controllW and stable decay heat removal has been restored (either RNS cooling or stable heat removal via the secondary plant) and the RCS is returned to a controlled and stable condition.
- ACTIONS
- INNb .
Irdtlate actions to establish containment closure INSTRUMENTATION: -
N/A CONTROLAOUIPMENT:
N/A KNOWLEDGE: .
Means to establish containment closure ADDrrIONAL INFORMA110N:
Specific guidelimme for establishing containment closuit during typical statdown condidens.
Containment clogue as discussed in this step includes establishing the desired posidon of available containment isotuon valves to minimize release outside containerwrit.
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STEP CESCRFrl0N TABLE FOR SDG 2 STEP 20 SIEP: Initiate Actior.s To Establish Containment Closure PURPOSE: To estabilsh a boundary to prevent the release of fission products EAS.lS.:
Since RNS cooling has been lost, and initial anempts to resto.e RNS cooling have been unsuccessful, actions must be taken to addreas the possibility of core uncovery and subsequent fuel damage due to RCS inventory loss, Since two of the three radiological barriert may be open (the RCS and containmers), actions must be taken to close containment and provide a barrier to the releue of radioactive materials should the event procecd to core damage. Containment closure must be accomplished before the onset of core damage. Once containment closure is initiated, closure should continue until controlled and stable decay heat removal has been restored (either RNS cooling or stable heat removal via the secondary plant) and the RCS is returred to a ec:urolled and stable condition.
ACTIONS:
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Initiate actions to establish containment closure INSTRUMElfrATION:
N/A CONTROlJEOUIPMENT:
N/A KNOWLEDGE:
Means to establish corsainment closure
- ADDrrioNAL INPCdLMAHON:
Specinc guidelles hr establishing containment closure during shutdown conditions and using the passive core costs systems (i.e., PXSSRHR and PCC). Containment closure as discussed in this step includes establishing the desired position of available containmera isoladon valves to minimize release outside cones.8nment. .
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3.2 Key Ut9ity Decision Points There is one key utility decision pokit in this guidellt'e when the operator must determine an appropriate course of action, in Step 4, the operator is instructed to detennine if any additional actions are necessary to address the containment high radiation level. 'the operator will determine b any additional actions are to be taken at this time in the guideline,
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STEPCESCRFTION TABI.E FOR SDG 3
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STEP 4 SJ1E: Determine if Any Additional Actions Are Necessary E1EEQ3E: To determine if any additional actions are necessary to address the containment high radiation level 1631-TUs step instructs the operator to determine if any additional actions are necessary to address the radiadon level inside containment. The operator is responsible for providing any further actions to address the radiation level, if appropriate.
, ACTIONS: I 6)
Determine if any additional actions are necessary INSTRUMENTATION:
N/A CONTROUEOUIPMENT:
N/A KNOWLEDGE:
N/A ADDITIONAL INFORMATION:
N/A 981o. 799 F(RI) - H soclastw 4-5 REVISION: 2
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INSERT A-he AP600 shutdown emergency response guidelines (ERGS) were developed using the same philosophy 2 and methodology _ that was used for developing the at power EROS for the AP600. Since there was no corresponding generic guidance for shutdown conditions for operating plants, the shutdown guidelines for AP600 are first of a kind guidance and focus on protecting the general public by monitoring and protecting
- the plant critical safety functions. De same barriers (fuel cladding, reactor coolant system and containment building) protect the pubUc whether the plant is at power or is shutdown. _%us the critical safety functions which are used to monitor plant conditions during accidents for at power conditions -
(operating modes 1,2,3, and 4) were used as the basis for developing a monitoring tool to detect
- challenges to the plant safety state for the remaining shutdown conditions (modes 5 and 6). Each symptom (question in the status tree) for each at-power critical safety function status tree and the underlying intent of that safety function was evaluated with respect to shutdown conditions. De resultant was a single status tree for shutdown operations during modes 5 and 6 that represents all six of the critical safety functions.
Additional attention was given to the prevention of bolling in the reactor core and establishing containment closure early if boiling in the reactor core cannot be prevented because these are the prime issues being addressed by the USNRC and operating plants for shutdown operations. %e following thought process was used for arriving at the single shutdown status tree and the symptoms used to determine if there is a challenge to shutdown plant safety, I. Review of the at power subcriticality status tree for shutdown conditionshowed that since the reactor is already shutdown, only decay heat is generated. (Note that the check that the reactor is below 5 % -
power in the at-power ERGS is to assure that only decay heat is generated by the reactor since safety -
systems are designed for decay heat removal only.) Rus, the only concem applicable during modes 5 and 6 is inadvertent criticality. A flux doubling alarm is provided for the AP600 design to identify a loss of shutdown margin which precedes an inadvertent criticality while nuclear flux is well below the point of adding heat into the system An orange path is designated for this condition since prompt -
l operator action should be initiated to reestablish shutdown margin and prevent the retum to criticality.
- 2. Review of the at-power core cooling status tree showed that the core cooling safety function is
_ applicable but due to the initial energy levels, elevated core exit temperatures are not expected for a !
long period of time. As long as water level is maintained above the reactor core, heat can be removed to prevent core heatup to temperatures that could possibly damage the core. Adequate water level to -
maintain core cooling can be determined by either pressurizer level (if the RCS is c!med) or hot leg level (if the RCS is at reduced inventory operations). Since the primary system is at a low temperature
_ (and saturation pressure) condition, the prime recovery strategy would be to restore water level over the reactor core by any means possible. No higher prioritization symptoms are necessary (such as core exit temperature symptoms that prioritize FR-C.1 and FR C.2 in the at-power ERGS) since primary pressure at saturated conditions is low enough for all possible injection paths to physically inject. An orange path is designated for this condition since prompt operator action should be initiated. To - -
prevent heat up and possible high saturation pressures, the core cooling safety function challenged was prioritized first on the shutdown status tree. Injection of borated water is desired to prevent and/or mitigate a simultaneous loss of shutdown margin as discussed in item i earlier.
- 3. Review of the at-power heat sink status tree showed that the main heat sink during shutdown conditions in modes 5 and 6 is the normal residual heat removal system (RNS). If the RNS is lost, piumpt mitigating actions must be taken by the operator. An orange path is designated for this condition since
_ prompt operator action should be initiated to reestablish RNS cooling or provide altemate ways of 4W1HF OLD- M i
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removing core decay heat. This symptom is checked just after the shutdown core cooling status check since primary system inventory is needed for the operation of the RNS pumps. It is also prioritized just behind the challenge to the core cooling function since the primary system will start to heat up on the loss of RNS while more time is available to the operator for addressing a loss of shutdown margin and containment closure (containment closure actions are also in the guideline for addressing the loss of RNS). Loss of the ability for RNS to remove heat from the primary system is addressed as its own symptom by means of a check on RCS temperature being maintained within a small band when no heatup or cooldown is in progress.
- 4. Review of the at-power integrity status tree showed that the only challenge to primary system integrity during operating modes 5 and 6 is system overpressurization. Since the primary system is already at a low temperature, a significant rapid cooldown cannot occur, he cold overpressure limits are checked and if exceeded, prompt operator action is required.
- 5. Review of the at power containment status tree showed that rapid containment overpressure during modes 5 and 6 cannot occur due to the iretlal low energy condition of the primary system. He main function for containment is to prevent radiation releases during an accident. During the shutdown conditions of modes 5 and 6 the containment building may be open to allow easy access for maintenance activities. De intent of the containment function can be maintained if containment closure is initiated upon indication of abnormal radiation in containment (Note that containment closure is initiated in the guidelines for loss of inventory and loss of RNS in anticipation of the possible release
! of radiation into containment). Derefore only containment radiation is monitored on the shutdown
- ERG status tree. Abnormal radiation will require prompt operator action to establish containment
! closure.
- 6. Review of the at-power inentory status tree showed that normal primary system inventory could vary during modes 5 and 6 depending on whether or not the plant is in reduced inventory operations. He inventory status tree for the al-power ERGS checks if pressurizer level is normal during operation is modes 1, 2, 3 or 4. Normal water level for operation in modes 5 and 6 is either pressurizer level (if the RCS is closed) or hot leg level (if the RCS is at reduced inventory operations. Since departure from the normal primary inventory is check already in the shutdown status tree to verify adequate core cooling capability, no additional checks are made to specifically address the inventcry function.
i Since the plant is in a shutdown and low energy state in modes 5 or 6, the symptoms for determining a challenge to the plant safety state are different because they are tailored to the shutdown plant conditions.
he priority between functions is also different. The top priority is given to core cooling (inventory on the core) since loss of inventory can result in core boiling in a short pericJ of time since there is less water to absorb core heat and the subsequent loss of RNS due to inadequate water level in the reactor coolant system. Second priority is given to heat sink (loss of RNS) which will also result in a heatup of the primary water. Third priority is given to containment (abnormal radiation) so that prompt closure of containment will be achieved prior to any prolonged releases to the environment. Fourth priority is given to subcriticality (loss of shutdown margin) since more time is available before a reactivity accident causes either boiling in the core or releases to containment than in the previous accidents. The fifth priority is given to integrity (cold overpressurization) since it is less likely to result in core boiling or quick radiation releases outside the containment. De sixth priority is given to the loss of heat sink due to support system failures (unexpected heatup of the RCS) since the expected heatup rate of the primary system would be small. All six of the functional challenges require prompt operator action to mitigate them.
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INSERTB Instrument air to containment is also closed since it is a potential relief path that is open during outages.
INSERT C This step instructs the operator to determine if any additional actions are necessary to protect the core and prevent releases. If core cooling can not be restored, the operator should consider additional actions such as operation of the hydrogen igniters, flooding the cavity, using the PCCS for containment protection and even implementation of the Severe Accident Management Guidelines.
INSERT D Steps 13 and 3 form a loop of recovery actions with open RCS conditions. Since RNS cooling has not been re-established, as evaluated in Step 8, the operator is sent back to the beginning of this loop to re-evaluate the status of RCS cooling and restoration of RNS cooling of the RCS,
-INSERT E If cooling of the core cannot be reestablished and plant conditions continue to degrade, the operator will have to decide whether to initiate additional actions. Additional actions possible would include the use of hydrogen igniters, cavity flooding, PCCS operation and implementation of the Severe Accident Management Guidelines.
INSERT F Examples of additional actions would be use of hydrogen igniters, cavity flooding and initiation of the Severe Accident Management Guidelines.
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iitt iij NRC FSER OPEN ITEM Question 440.802F (OITS 6454) REVISION 1 TO RESPONSE The shutdown safety status tree, SDF-0.1, implies that operator actions are to be taken in a particular sequence for all shutdown alanns. For example, the " Nuclear Flux doubling alarm", has the operator verify whether the normal residual heat removal system (RNS) is in service or not before any action associated with the flux doubling alarm is taken. The seff does not understand the precedence for action in the shutdown safety status tree. Westinghouse should clearly explain how this status tree would be used to develop the plant specific shutdown emergency operating procedures.
Responset REVISION I The priority of monitoring symptoms in the shutdowr status tree is addressed in the response to RAI l 440.798F. The rules of usage for the AP600 ERGS are the same as the rules of usage in the j Westinghouse Owners Group (WOG) ERGS, which are used by the Westinghouse operating l plants to prepare plant specific emergency procedures. If multiple challenges exist, the higher i priority condition should be addressed first. Since all priorities on the shutdown status tree are 1 orange, the order in which the questions are asked determines the order of priority. For l example, if RNS is not in service and containment radiation is greater than (SR01), SDG 2 l would be the appropriate guideline, since it is asked first on the status tree. For more l Information on status tree usage, refer to the WOG ERG Executive Volume under Users Guide I in the section " Control Room Usage of Status Trees."
l The actual method of monitoring the status tree will be determined through the MMI process. (The i man machine interface process will select the displays and the presentation of the information i for the operator using human factors principles.) Since the shutdown status tree was developed to apply at all times during shutdown conditions, it can be monitored by the plant computer and when a challenge occurs, the operator would be alerted to the challenge so that prompt action could be taken to mitigate the challenge.
i SSAR Revision:
j None 4
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