ML20126D337
| ML20126D337 | |
| Person / Time | |
|---|---|
| Issue date: | 06/26/1979 |
| From: | Thompson D, William Ward NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| Shared Package | |
| ML20126D330 | List: |
| References | |
| REF-QA-99900400 NUDOCS 8004280146 | |
| Download: ML20126D337 (300) | |
Text
'
)o, UNITED STATES
'y' ' e j g ,
NUCLEAR REGULATORY COMMISSION
/~ } )
_E WASHINGTON, D. C. 20555
' A, w ]
'o.** REPORT OF INVESTIGATION JUN 26 nb TITLE: BABCOCK & WILCOX 205 FUEL ASSEMBLY PWR/ Alleged Susceptibility to Small Break LOCAS -
CASE NUMBER: 79-HQ-001 SUPPLEMENTAL: VENDOR NUMBER 99900400 PERIOD OF INVESTIGATION: May 14-May 31, 1979 REPORTING INVESTIGATOR: / [
$Jilliam p. Ward, Senior Investigator, Executive Office for Operations Support, IE:HQ
,y PARTICIPATING PERSONNEL: Arthur Oxfurth Career Management Branch, IE:HQ Executive Office For Management and Analysis STATUS OF INVESTIGATION: Pending REPORT APPROVED BY:
Du'dley Tym'pson, Exec 6tive Officer for Operations Support Office of Inspection and Enforcement
./
800.4280146
l 4
I l
DISTRIBUTION l
)
Victor Stello, IE John G. Davis, IE H.D. Thornburg, IE N.M. Mosley, IE D. Thompson, IE J
l 1
Regional Directors l'
C. Kammerer, OCA l
l J. J. Cummings, OIA H. Denton, NRR M. Carbon, ACRS D. Gamble, TMI Task Force I
(
I l
1 l
l 1
l l l 1
I
SUMMARY
In April, 1979, the Office of Inspection and Enforcement received a copy of a January,1978. Report prepared by a consultant to the Advisory Committee on Reactor Safeguards (ACRS) concerning the,s'usceptability of certain pressurized water reactors designed by Babcock & Wilcox to small pipe break LOCAS.
Because of his concern that the information contained in the Report may fall -
into that category of safety information that must be reported in accordance with 10 CFR 21, the Director, Division of Reactor Construction Inspection requested that an investigation be initiated concerning the Part 21 signifi-cance of the Report. When interviewed, the author of the report, who is employed by TVA as an engineer, indicated that he had written the Report in the Fall of 1977, at which time he provided a copy to a member of the ACRS; he also provided a copy to B&W and asked for their analysis of this issue. He did not hear anything from B&W until January,1979, and had no further contact with NRC until April, 1979. A January 1979, response from B&W was unsatisfac-tory to him so he sent them another request in February,1979, but has not received a response to it. Interviews of seven (7) B&W employees involved with this Report revealed that analysis of the Report received a low priority and that it languished without detailed analysis until Winter, 1978. Inter-viewees claimed that their preliminary evaluation of the Report was that it was technically valid for the most part, but it did not identify any item not already known to or considered by B&W. None of the interviewees felt it was a matter of substantial safety significance, and none felt that it should have been considered as a Part 21 item. Appendix K to a May, 1979, report by B&W
- O represents, according to interviewees, is the formal B&W analysis of the Report's concerns; this B&W Report refutes the contentions of the Consultant's Report. Investigation to date has included the obtaining of copies of both the typed and handwritten drafts of the Consultant's Reports, copies of B&W mail and telephone logs, and copies of B&W Part 21 procedures. Investigation continues pending a NRR determination of the safety significance of the inform-ation in the Consultant's Report as well as the desirability of investigation at TVA.
O
-( ) DETAILS PREDICATION AND BACKGROUND On April 17, 1979, Mr. Darrell Eisenhut, Deputy Director, Division of Oper-ating Reactors, Office of Nuclear Reactor Regulation (NRR) forwarded a copy.
of a 1978 Draft Report (Atch (1)) entitled, " Decay Heat Removal During a Very -
Small Break LOCA for a B&W 205 Fuel Assembly PWR" to the Office of Inspection and Enforcement. This report, hereinafter referred to as the Michelson Rep-ort, was prepared by Mr. Carlyle Michelson, an engineer with the Tennessee Valley Authority (TVA) who is also a consultant to the NRC Advisory Committee on Reactor Safeguards (ACRS). Upon reviewing this report, both the Acting Director, OIE, and the Director, Division of Reactor Construction Inspection expressed concern that the information contained'in the report not only was significant, but that it may fall into the category of information that must be reported expeditiously to the NRC in accordance with 10 CFR 21.
Accordingly, the question of the applicability of Part 21 was referred to the Office of the Executive Legal Director (0 ELD). On May 4, 1979, an attorney with OELD advised OIE that information such as that contained in the Michelson Report could be encompassed within the ambit of Part 21, but that additional information would be needed in order to make.a specific determination. Based on the foregoing, on May 14, 1979, Mr. Harold Thornburg, Director, Division of Reactor Construction Inspection requested that an investigation be initiated regarding the Part 21 implications of the Michelson Report.
I i
l i
1 1
I l
1 l
l l
l
($)
u l
1
--,--w O
INVESTIGATION AT NUCIIAR REGULATORY COMMISSION HEADQUARTERS O
n v
i 1
I
\
1 1
I INTERVIEW WITH CARLYLE (NMN) MICHELSON )
i Michelson when interviewd in the ACRS Offices, Washington, D.C. by Investigator I W.J. Ward on May 21, 1979, indicated that he first became concerned about small pipe break LOCAs in 1974, and that this interest, which was independent -
of his consultant relationship with the ACRS, grew over the years. Stimulated by a 1975 report regarding the susceptibility of certain Combustion Engineering (CE) reactors to this phenomenon, he said he first wrote a report regarding those reactors. Later, after deciding that B&W reactors were even more vulner-able than CE's, he wrote a report in September, 1977 documenting his concerns.
He related that he provided a handwritten copy of that report to Mr. Jesse Ebersole, his former supervisor at TVA, then and now a member of the ACRS.
According to Michelson, Ebersole advised him to " harden up" the report in that it was too speculative. He did so, and prepared a typed draft in January, 1978.
Michelson said he did not know if Ebersole had shown his draft report to anyone else in NRC, but commented that certain questions asked by the ACRS during the Fall,1977 Pebble Springs hearings were apparently based on his
. report. Michelson denied having any other contact with NRC regarding the l report during that period.
Michelson stated that he had several discussions concerning his report within TVA during the Winter of 1978 that eventually resulted in a letter to B&W O
V dated April 27,1978, (Attachment 1) forwarding a copy of his report and asking for a B&W response to it. Michelson during this time indicated that the highest level of TVA management with whom he discussed his concerns was his immediate supervisor, Mr. E. G. Beasley, Head Nuclear Engineering Group. Michelson advised that he did discuss whether his concerns may fall within the ambit of 10 CFR 21 with Mr. E. J. Walker, TVA Licensing. According to Michelson, it was decided that neither Part 21 nor 10 CFR 50:55(e) applied to his concerns, the former because of TVA's perception that it applied only to vendors, and the latter because it did not fit the rigid criteria developed by TVA to determine whether an issue was encompassed by that regulation.
Michelson related that between April, 1978 and December, 1978, he asked TVA Contracts to contact B&W on at least six different occasions to stimulate a response to his questions, and that he participated in a telephone conference in December after which he transmitted a one page summary of his concerns to B&W via facsimile. Michelson went on to say that, nonetheless, he did not receive a written reply until January 23, 1979. Feeling that this reply (Attach-ment 2) was not entirely responsive to his concerns, he authored a second letter which was mailed to B&W on February 8, 1979 (Attachment 3). He claimed that B&W has yet to respond to that letter.
In conclusion, Michelson emphasized that the thrust of his concern was not that he was certain that the small pipe break LOCA's that he postulated pre-seated a significant safety hazard, but rather he felt that they had not been sufficiently analyzed. Michelson conceded that it was possible that a,more
]* rigorous analysis of his concerns might well demonstrate that there is not a problem. A detailed results of interview with Mr. Michelson is (Attachment 4).
RE-CONTACT WITH CARLYLE MICHELSON At 1635 hrs., May 30, 1979, Michelson telephoned the reporting investigator and provided the following information in substance: Michelson had recently had a
- conversation with Jesse Ebersole who told him that he had found a copy.of an -
October 21, 1979 note from an NRR Staff member which had returned the hand-written draft reports prepared by Michelson that had been given NRR by Ebersole at an earlier date. Michelson said he could not recall the identity of the signer of the Note. Michelson, when asked, recalled that he had also given Ebersole a copy of the typed draft report, but could not remember exactly when it was. He estimated that it was sometime in January or February,1978.
Michelson indicated that he had legible copies of his handwritten reports concerning both CE and B&W reactors that he would forward to the reporting investigator. These copies were subsequently received and are appended as (Attachment 5 and 6), respectively.
O i
O
1 l
l EXTRACT OF NRC REGULATIONS A copy of 10 CFR Part 21, the question of ' compliance with which forms the basis of this investigation, is appended as (Attachment 7) Additionally, a copy of 10 CFR Part 50:55(e) which was alluded to during Michelson's interview as -
setting forth criteria against which the safety significance of his report was )
measured is (Attachment 8). '
l 1
l l
l l
l l
1 I
f l
l I
1 1
1 l
r c
l l
1
l INVESTIGATION AT LYNCHBURG, VIRGINIA
!O I
i ,
's*
l i
l0 1
- .. . - _ ._ . . - - . ~ . . , - . - - , . . - - , - - . . , . . _ - - . .
l l
] INTERVIEW OF ROBERT E. LIGHTLE Lightle, Associate Project Manager at the B&W Nuclear Power Generation Division, when interviewed by Mr. Arthur Oxfurth, NRC and the reporting investigator on May 29, 1979, provided the following information in substance: According to -
his mail logs, the Michelson Report was received by B&W on May 3, 1979. He made copies of it and provided them routinely to his supervisor, James McFarland ,
and another employee in his group, Scott Delicate. He does not recall spe-i cifically discussing the report at that time with either person. Upon reading l the report, he felt that any action to be taken regarding it should be taken l by the ECCS Analysis Group who he understood assigned it to one of his engineers, Robert Jones. He recalled discussing the matter shortly afterwards with Jones who indicated to him that the report contained a lot of good points but that he was busy conducting a small break analysis which encompassed breaks of the size described within the Michelson Report. '
Nothing further was done regarding the Report until he recieved a call from TVA on June 9, 1978, inquiring about the status of the B&W reply. Several other calls were received from TVA on this same subject. These calls were all entered into Lightle's telephone log. A one and one half hour conference call was held between several TVA personnel including Michelson, and several B&W employees including Jones on December 4, 1979. In response to yet another O telephone call, Michelson provided a one page summary of his concerns to B&W via facsimile (Attachment 9). The response was finally written on January 19, 1979, l
and mailed to TVA on January 23, 1979. On February 9, 1979, TVA advised that l
a letter was enroute to B&W asking for additional information. On March 5, 1979, B&W promised a response by mid-May, and on April 2, 1979, TVA called to state that they had to have an answer as soon as possible. In summary, the l Michelson Report was the subject of at least thirteen (13) telephone conver-sations between B&W and TVA during the period between May 3, 1978, and April 2,1979.
Lightle indicated that he had frequently asked Jones the status of the Report, but that he did not see the issue as requiring referral to any higher level within B&W. He felt that the Report basically was a valid technical comment, but that he did not perceive it as having safety significance. He also in-dicated that he had not discussed the issue with any other B&W officials prior to the Three Mile Island Accident at a higher management level than Dunn or McFarland. Lightle provided copies of the B&W Mail Log (Attachment 9), the telaxed copy of Michelson's one page summary (Attachment 10), and copies of his telephone logs covering this period (Attachment 11).
l V
br' INTERVIEW WITH JAMES (NMN) MCFARLAND McFarland, Senior Project Manager, B&W Nuclear Power Generation Division, interviewed May 29, 1979, by Arthur Oxfurth, NRC, and the reporting inves-tigator provided the following information in substance: He recalled seeing -
the Michelson Report when it first came into the B&W system. He understood that his assidGat, Robert Lightle, was handling it and was confident that Lightle was competent to do so. Nothing then or since led him to believe that the Report dealt wi.a a significant safety hazard. For that reason, he saw no particular reason to put any extraordinary pressure upon the ECCS Group to expedite their analysis of it. He noted that the Group was especially busy during this period.
He did not discuss this report or its substance with B&W management, nor did he discuss it with the B&W Licensing Manager, James Taylor, who has overall responsibility for the B&W Part 21 Program. He did not discuss either the Report or its substance with the NRC during this period. He noted that TVA Engineering aperiodically generates a list of TVA projects awaiting action called the TOIL (TVA Outstanding Item List). As the Michelson Report and transmittal letter did not ever appear on the TOIL, he assumed that TVA itself did not consider the letter to be especially.important. McFarland was unable to provide any additional information.
O l
l i
l l
l i
V
l ,
INTERVIEW OF ROBERT JONES Jones, a Senior Engineer with B&W, when interviewed May 29, 1979, at Lynchburg, Virginia by the reporting investigator, stated that he had received the Michelson Report in early May, 1978, and been assigned responsibility for -
responding to the questions raised by it. He related that a cursory review of the Report led him to conclude that it appeared to be technically valid, but did not bring to light any new information. On the other hand, according to Jones, he felt that Michelson used the wrong calculational approach
(" energy balance") in arriving at his answers, and he did not agree with all of Michelson's Report as raising a substantial safety issue, and that it most cer-tainly did not meet the reporting criteria of 10 CFR 21. For that reason he denied having informed higher management or discussing the issue with NRC. He indicated that during the period until the Fall of 1978, he was too busy on other projects to reply to TVA notwithstanding many reminders from Robert Lightle, Project Management Group. He claimed that he finally prepared a response in December,1978, that formed the basis of B&W's January 23, 1979, letter to TVA. Jones recounted that he was also assigned the action to respond to the resulting February 8, 1979, TVA letter, that he assigned it a low priority, but never answered it due to the Three Mile Island Accident. Jones asserted, however, that Appendix K to a May 7, 1979, B&W report to the NRC entitled, " Evaluation of Transient Behavior and Small Reactor Coolant System Breaks" in the 177 Fuel Assembly Plant adequately addressed and resolved
'O Michelson's concerns. The Conclusions section of that Appendix is (Attachment 12) to this report. The interview was concluded with Jones averring his belief that the Michelson report did not meet the reportin'g criteria of Part 21 and did not represent data new to B&W or not already encompassed by previous studies. A detailed Results of Interview with Jones is (Attachment 13).
9 l
l
..=_ . .-
INTERVIEW OF BERT DUNN Dunn, Manager, ECCS Analysis Group, B&W Nuclear Power Generation Division, when interviewed May 29, 1979, by the reporting investigator provided the following information in substance: He recalled that the Michelson Report -
had been received by his group in early May 1978, and that he had assigned it to Robert Jones who was at that time engaged in an extensive small pipe break analysis. Jones told him that in Jones's opinion detailed analysis of the Report could wait. Dunn concurred with this, and the intervening period of May-September was spent with Jones devoting his effort to higher priority p roj ects . Duan subsequently became aware of the increasing pressure from TVA for an answer at the time Jones became involved in drafting a formal reply to TVA. Dunn stated that he did not discuss the Michelson Report with any person in the B&W management of a higher level than himself.
Dunn indicated that he had not noted anything about the Michelson Report that would have led him to overrule Jones's decision to work on projects that Jones felt deserving of higher priority. In conclusion, Dunn stated that he disagreed with Michelson's concerns and pointed out that he had been personally involved in the preparation of the May 7, 1979, Report mentioned by Jones during his interview that refuted Michelson's tentative conclusions.
O 2
O i !
l .-, , .,. -m--
O INTERVIEWS OF B&W SENIOR MANAGEMENT OFFICIALS -
The following senior level management officials of the B&W Nuclear Power Generation Group were interviewed May 29, 1979, by the reporting investigator:
E. Allen Womack, Manager, Plant Design Department James C. Dedden, Manager, Project Management Department James H. Taylor, Manager, Licensing Womack is the immediate supervisor of Bert Dunn. Dedden is the immediate supervisor of James McFarland. Both persons when interviewed stated that they did not learn of the existence of the Michelson Report until after the Three Mile Island Incident. Neither could recall any conversations with their staff regarding it prior to that time. Taylor, who is responsible for administration of the Part 21 program at B&W, asserted that he did not hear of the existence of the Michelson Report until Congressional hearings subsequent to the Three Mile Island Incident. He stated that he was certain that no Part 21 action was initiated regarding this Report as he would have been involved in any Part 21 reports made by the B&W Nuclear Power Generation l Division. He indicated that he knew of no management official at a level
! higher than he who was aware of the Report during the period in question.
Taylor said that B&W has written procedures regarding the review of potential
'(( ) Part 21 matters and provided copies of both the B&W Corporate and Nuclear Power Generation Division procedures. (Attachment 14 and 15 respectively).
Investigators Note: Examination of Official Bulletin Boards revealed that the written notice required by 10 CFR 21-6 was posted.
t l
r i
__.m.. . , __,,. -_ _ ,w ,
. _.. . . .. .. _ ,_ _ .. _ _ _ . . . ._ _ _ _.~ . _ .._..
. O .
STATUS OF INVESTIGATION ,
This investigation continues in a PENDING status awaiting an official evaluation from NRR as to whether the info'rmation in the Michelson Report meets the reporting criteria of 10 CFR Part 21, and whether further investiga-tive effort is warranted in view of the information gathered to date. -
l l
O )
1 l
l l
4 O
l' L l I - .,, _ . .
_, , . . . ,, . _ . _ _ , . . , . , _ m ,. .. ,, ,.
l i
e ATTACHMENTS Item Dissemination I
- 4) Results of Interview of Michelson Orig. (XOOS), Copy All
- 5) Draft C-E Rpt by Michelson Copy All *
- 6) Draft B&W Rpt by Michelson Copy All !
- 7) 10 CFR 21 Copy All
- 8) 10 CFR 50:55(e) Copy All
- 9) B&W Mail Log Copy All '
l l 10) Telafax to B&W Copy All
- 11) Lightle telephone Copy All
- 12) Appendix K Conclusion Copy All
- 13) Results of Interview of Jones Orig. (XOOS), Copy All ,
- 14) B&W Corp Procedures Copy All
- 15) B&W NPGD Procedures Copy All l
l l
l l
t l
e 1
l-l l ., -, - - -
c
' 70: n'asn.tngtan u,,n.c ,
/
' W10La6, 400 Concerce Avenua []/[," , /
FROM: Mike But) cr, E.12D4 7 C- K (27 8. ) .'
2fMO DISTRIBUTED TO ACRs Mggggag 7 pril 27,1978
'I C/ N kt /
Babcock snw Jilcox Post Office Box 1260 gEB 780427 13 ,2 ,~
Y' 1.ynchburg, Virginia 24505 R L 3 t ',0 m.:3 ,; ce g.i m t u-Attention: Mr. James McFarland CEACTLR 5/.C:.' /..CJ ', 5 h .. .
Centlemen! -
ry g h8% 1 DELI.IF0HTE NUCLEAR FIMT UNITS 1 AND 2 .go H0 CLEAR STEAM SUPPLY SYSTEMS O"
- CONTP,ACT 71C62-54114-2 YtOOM I.ETTER NO. K-S020 Et1ERCEFCV CORE COOLING SYSTEM - SMALL BHEAK I.0CA ANALYSIS N4 An increase of interest and questioning by ACRS in the area of very small The break 10CA's has prorepted TVA to take a closer look at this problem.
ettached preliminary draf t study reflect.s some of our initial thoughts We believemed concerns. Please review thin work and give us your views.
-. that a small break I.0CA question similar to that asked by ACRS for Pcbble
~j Spring (Question 6) might be asked in greater depth by HRC for Dellefonte.
- be assured that B&W is preparing for a timely reply. Perhaps We cust the ot.tached draft will help.
After you have reviewed.this study,'we would like to discuss it with you by tc)cphone. HowcVer, we also propose that a meeting be held in Knoxville in the near, future to examine the entire question of very srnall break 10CA'6 in suf ficient depth to develcp an adequate niutual understanding and assure TVA that B&W is working toward a timely resolution of s11 concerns. We believe that the following outline of observations and conditions should be used at a preliminary basis for the proposed meeting.
2 )
The ,elass of very small break 1.0CA's of int. crest. probably range up to 0.05 ft .'~
(e cIlaivalent to the single ended circiunferential break of a 3- to 4-inch * -
pipe). For brcsks in this range, the steam generators must zernove * ,
significant portion of the decay heat during the initial phase of blowdowh; , , .
l ot he rvin e , reactor cuolsnt system repressurization occurs since the break is too small to remove a)I of the decay heat. Repressurization or even prolonged high pressure operation could seriously limit high pressure injection makeup during blowdown and thereby adversely influence the peak clad temperature f or those cases wherein the core uncovers during the blowddwn. ,
. ~
s
- C b ,* *' l (
m .,
$k k; k agp
- - s x ^_ < =
w w w f t '} in$ p. n.
- f 5" # #l un wsTfMW . -- . .
~. h( q9 QQp vu c . v .
j
2 Bsbenck and Wilcox April 27,1978 l
In order to tske credit, for decay hest. removal through thc steam generators and thereby deter prolonged pressuript. ion or repressurizstion, it is .
necessary t.o assure either (a) continustinn of natural circulation through the react.or core and steam generat. ors or (b) establislunent of pool {3 .,
boiling in the react.or core region and a steam flow path to the condensing ;?"
(cooled) portion of t.he steam generstor tubing. There appears to be a ~q nurnber of possible sit.uations that might icipede decay beat, remuval through the steam generat. ors during the natural circulation phase or during the' transition from natural circulst. ion to pool boiling / condensing or back again. For example:
- 1. Since there is no significant temperature loss between the reactor ,
core exit. and the steam generators, a st.eam bubble is likely to form in the high point. (U-bend) at the t.op of each steam genurator after system overpressure is lost. This would interrupt natural circulation I and dec.y heat removal. At best, so intermittent natural circulation reight be re-established for decay heat removal.
- 2. The transit. ion from natt.rsl circulation t.o pool boiling /enndensing could be troublesome because of t.he time delay while wsiting for the stcom generator t.ubes to drain down to the secondary side water level and thereby establish a condensing surface. Unless the break can already remove all decsy heat., system repressurization will occur while the E condensing surface is being established for decay heat removal.
- 3. Reactor vessel )cvel turnaround will occur when the makeup rat.e exceeds the fluid leaving the break. Decay hest removal by condensation will I I
cease when the water level inside the steam generator tubec exceeds t.he secondary side water level. Itepressurintion will occur unicss the break can remove all decay hest. Natural circulation esonut. he re-established unt.11 the tubes have been filled and the steam bubble at. the high point (U-bend) has collapsed. If suf ficient. noncondensable gases are present., natural circulation may not be achieved.
l Associsted with operation in cach of these conditions is a concern that. the (
l opdator might be able t.o identify and isolate the breah sud thereby interrupt I the, blowdown and Jecay heat removal processes. If natural circulation has
- been lost. and the pool boiling / condensing mode has not been cst.ablished, this int.crruption could cause full repressusizat. ion and a subst.antial passage of liquid and/or two phase fluid through the pressurizer safety valves. The {
valves have not, been qualified for t.his severe service. Also associated vith operation in each of the above ennditions is a concern that the pressuriser level is not a correct iodicator of wst.er level over the reactor core. . Decouse of the loop scal on the pressurizer, it may be possible to hav,e a full pressurizer while the core is partially uncovered. This .
could lead to incorrect operst.or actions.
l'\ ,
J l
- a
- j l
Babcock and Wilcox -
l April 27,1978 I l
I -
. l k'e assume that the situations and concerns which have benn identified above and in the sttached draft study have been considered in your own in-house _
LOCA analysis work. Your reote detailed' transient calculationt based on {;?
r realistic system and core thermal-hydraulic models would be a.n appropriate :',.-
verification that no serious problem exists. Please let us know. '
Very truly yours, ,
TEFHESSEE VALLEY AUTHORITY '
Origin.51 nirned'b~y D. )t. P.uterson D. R. Patter:on, Chief -
Hechanical Engineering Branch Enclosures In triplicate ,
.c e: Mr. J. L. Atchison D .
S 4
~ i SENT. t!.AY 011978 O , s,um nre a
,,m-- y ,,,y
VEEY SF.LL
, DECAY iCAT
= REI~ OVAL .D.11RIEG A --
g3 3x 7.o:A roa A scu 2,ps-7n_q-jgs_rdgLY Pd3
~'T C. Michels en r -~_/
Jahuarv. r 1978 .
. s SUP.:G.RY This report gives an account of :some initial consideratiens Ef a c ' > .". .a o ' v a_ - v. s . .:.d '_ b-=..=.>..
. _ m ~^ m".s is ( .o.-cs" = .M. v-< 0 . 0 s~
- e_ . 2 ) _# c . a =- sm..
205-Tuel-Assembly IWR which may have an associated decay heat removal p:cblem. The results indicate that one or more impedirents to decay' hea t removal appea r to exist which need to
-- . e , "- " . 4: -
.. .. s'.o cd i ' . c: a- w --=.. . a ' c'.
= s--
- .. s = a n d a c' e -"
. , a .=.
mitigation are to be assured. of particular concern' is the a ceptabilitv. of intermittent . natural circulation f ollowine the -
f
,- .ecstulated LOCA, and sys tem re.:ressurization f ollowing the icss s
of natural circulation. Also of cc icern is the possibility of
.,.. .. a .i. 4. s o .'. .=. - - . . '-4 ' .o c . a '.c a . o n _ .a s " .' ' 4. . . . . .- =.y.- e s s-'. . a . . n and slug c: two . chase flou through a presuriner saf ety valve.
These uncertainties mav. reflect on the adec.uaev. cf croc.esed .
e.,ergency c .o. e r a t . ng p:cce:ures anc cr.erator tra nine .cr a verv.
s ..m.. ). . . -O
.-..S... O Cn.
,E.sl*n=i;env*
r C l: 4
--- y- .
- , ,, (* c.e.- 4 e -
g,=..n ., . p .i .
- . _ . . . . --oa c.
1 g
e h 6
d
1.O INT?.O. DUCTION .
2.O LOCA CEARACTIRISTICS .
- 2. .t Mass Flow Ra.te Thrdugh 3rea.k - ---
- 2. 2 Decay' Heat Removed Through 'Sreak
- 2. 3, Reacto ~. Vessel Top Plenum Drain Time 2.4 . Steam Generator Drain Time 2.5 Steam Genera' tor Refill Time 3.O MODIS OF PCST-LOCA DICAY HIAT RIMOVAL 0
3.1 1:atural Circulation 3.2 Iransition froh itatural Circulation to Foci ?ciling
- 3. 3 Pool Boiling ,
3.4 Transition from Pool S iling to 1:atural circula .io,n 3.5 Shutdown Cooling 4.O WO?.ST CASI LOCA'COMS!DIRTAIONS .
4.1 Discharge Coef ficient and 3:e'ah Location Decay Heat Removal 4.2 .
4.3 Level Turnaround and I .e:gy I: ilibrium 4.4 1;SSS Vendo: Calculations 4.5 3:eak Isola-ion and Pung Shutoff Iffects -
c.6 Pressuriter Level Indication ,
' i
- 5. O Coli:LUSIONS
~.~
A % --v v FIGURIS M
4 4
,: s L
, , . There appears to be a class of very small break Lo A'a 3 (probably $ 0 0. 05 f tz) for'a BLW 205-Fuel-Assembly FWR which ma, o i associated decay heat removal problem. For this, have ' .n a
c'i s cus sion, a vs..y small break Loci.is one for which the steam i
generato'r must remove a significant portion of the, decay heat during the initial phase of blewdown; othe:: ise, reactor co.clant system re.:ressuri:ation occurs since the break is' toc small to fa ;ilitate the transport of all decay heat to the envirens. For this -lass of 10.CAis, depres surization rates are relativelv slew 4 (when ecmpared to these normally analyzed as small breaks) a..d s e - i o " s .'. .y ' 4. . . 4. - th. a. ... = '. . e o a .' a ' '. a '--- ' a. 3_ e .
- k. a.n_,..
- 4 w
.w. .- . s ..."f
-=-.s" . e
- = "; ~~
_ ~. . )' . - - c . . ~em . ..~es. n' n o . . c. o _'
- .~. ~ . ' '- - - - v a -
o'..s_** e - a~--'- ..
es- ...s -. c-okie... n-"
. - y edi.c s
_ b.a_ .A.
=. ". a. _' o ...=...
- o#- c.'- . =- o- . ..-__
m 3
in.c e d i: .e nt s to d e c av. haat re=cval durin: a very small break .
~_oc'-
This has become a concern that needs to be understood.
. .u.
- , .. ,_. . s.
. ,. _:- - a _ . a . . : e . .. =. . . o -' -h.e
- ea *...-.
v -
a..~. s .vs _ e... #
c a tv. e. ical 20 5-Fu el- Ass embly c. la.n.t' such a s t. he WA Eellefonte
- u: lear plant is shown in Figure 1. Plant elevations cc responc.1.ng to various poin'is :=.n tqe r ea c:c: coo.3 ant systen a-in dic ate d. Decay heat ramoval considerations during the post-
_C A' period are based on the usual ICO3 rules such as loss of effsi'te p:wer, inimum core cooling (en's train) respense, a n d -.:
.'. . .~. . . . =. . . . .- =. ~. ~ ' - =. =. c . =- a ' o ' = c 4 - w. . s. .
M 1
J 4
> . - -. e s .- ..: . . :. . .J
- 2. 0 LOCA CEAMCTERISTICSi '.T.. -
.-% '}- jf ~..; .,5,..:,. :.c. g *-T.W - .
.J.3 : l j
z ... ;- . _ . .
.)
. ,. . a . u .: . . . _ . .: _.a . . .- . . ..- ~ =..: .- - .: _ . .m g =.-=,.:. .. w_ r r.;;: _i .....
- n. . =- -... .r_.:. .:.,. . . m. =n w.t.. : . -r.~.s,, m_ . .:w.;::
. .:: -r. .u .:.. - .. . ~ -.r.
. .. ... .-,~:._..
- _: ..~:.: .n._
.w~_q..._.._,.. - . ..
l
.. A f e.v ele =anta ry. calcula ti.on. s , can b e. :. =. . . . .- .=. .~... . .- _ .. helpful : ::=~~;.::..
- _.._ . . ~ ;
, -: _. - . . . . l w)- .
.. ... . ;. . .% ..;.y:. ..
.; ; %_ Q- .-: .. z ~ .,. - . . . .:..: ~.= i., ? = ~ ~E.~ r . _ : .
betted underst'andi'n'9.o.f '.the.various
...x.
= odes .of pos.t-LOCA ....
decav. he..s.t
. - . , . . \
. .,... . .; . ..- . . . c .. . . . . - . '
removal an.d .the' role. which 's. team generators must play during ~a. .- ~ '- ..
.? .. .. .. ..,-..~;.... .
s n.
.....-...s..r..
., ,. w. ... .. .. . ..
..=....
..O ve..y 'sma11 break. LocAf of.Jparticular interest...:.... is' the mass flow. ._. . ,
. . .- .. ~. .. - - .: . , - - .
- e . v:. :=. . . .; ~
rate through a' postulate.d break, it.s capability. to remove dec;y ' ~
. - haat, and the' makeup rate to the , reactor coolant systen required .
. I Also of interest is the time j
to .compe.nsate f or' any lost mas s. . ,
required to drain the reactor vessel top plenum and steam .
qanerator tubes during a transition to pool boiling, and the ,
l, I
i minimum time r.equired to refill the steam generators if a level .
l turnaround occurs.
For most. calculations it is assum'ed that a quasi-steady-state U
i condition exists with .the reactor coolant system at,1270 .
.~._
psia (5 7 0. y o?) .and the secondary side of the steam generators 1 1
relievin:, steam to at=cspher e .hrough* a saf e:v talve. rha ....a ,
l atelicable," it is assumed that a.. sufficient temperature
.c
. dj.f ferential exists across the steam generator tubes to transfer .
all decay 5 eat not removed by the break. The decay heat is base i
l en the AES ' decay heat cu-peet using a 2 0 perc'ent margin.
':he fluid upstream of the breaX l Th e , reactor power is 3672 Int.
. ~
The flew areas
, is as sumed .to Se.. ; . .. saturated vat.e: .. o r str e am.
{ potential single-ended ficw break areas) corresponding to a .
number of nominal pipe sizes of interest are listed in Table ;.
r
/
- u_/
. . .' a s .c-: -.----: a-.. - c~,
- -..= ~= =- s - n ~w e- . ,. ..
. . - =. . :
.-. .. a... . ---
.e . . . . a. . . ,. . . c: yg.... . l
.. , . u. . .....:... . . . . . . . - -.
. . . .e
- t. s . .. . . . .c... ... .. w. 2..
.r .--;.:.r
. . . .. . . . .... r.
s... . . . . .
- . .e. ':.:::
- g. :.: 7,=m ,
- g...iv
~
- . 2 .::. < ,q*.,
.- . , p:= e a s , .:ure hounda. .e,c,.
= .: .:e . . ::. .:.% w , . . ~., ?.~1, -z.g. .
=e- 2 :'
- . . ,.. - i
-~.~.; :;,,- -.. ~ ~;.:-
. :. - a . -., . .
- .~ . , . ..,.:.. . .-.= -.: ,
. -. ..r . a -.. :-
.:. n - --- -., -:: = .. . . - p- . w-- -;.;.g
..... . . . , . . m.; . :
- ....2:x.-- -. : gm
_r- w. .:
=-- u --- - .
3.- : - .e .-.: ;a .m: -, =_g:::. . .
=BQ::,::
=(=;2w .y.. n.
5.:.r%;g.e.m.;;:i:c:: :.;". - c.;g
=c.m:.,y-:
.u .
.o v .. -r
.m w . . :-
. : .wi~ -
.s .~ . n m;;=?;y -o.a. : .
- ' . It shou 1Ube? e:;coghi2hd that. calculations ~~ included -in this~-l~F s '
. = . .- >-:-~ - - . .m-W
- v .: p: \
[N=. .t+ ; :-a-?: r:.t=%.=-@: .r.:..
. a.L ~-m?:+14;;;-;5.:--i f.'i x. . v:: g.: n.r a.*i -,. pw:w- u-l g =-:
cons.:iderataons - of,;. ener
. . .- i
.u.n- .= g.,-u 3 -n. .- . .
a..- '
- n. d n.,as:st .:,. .
. .:: .: sectio.n are-bas.-m.ed -on7.cenera w
, . . ..-.....,....,.:..;~'.a..,..
%. _. .:::. .w :
.a .:r-
...- s .. 1
. . ., ,.. .. .:. .; . ..- , ;w . . . .
.. . . . . . . .. -. ,. .._ . .. .:nw ,. . ..w. ,--
. : -. w : . -. _.
r-.- m u . c .o
. ..; . e... ,.:.ccons.e:va , : .. . : . .tio.ns.under,-i de..al".f..i .r.. e..... i
...d.s.c ..e n .. .v.. n:.
,.e.dit1cri
- s. ..:: a-Fin ei. ,.e... ..structure w t.a...:.
_ - . ... ... .. =,, a:... . -. .-,.w . . .: . .. . n
... . . -.:3.-.n l
.. .w.. . . .
cts'have;mbeen2i .:
,~~ -
E .!, nor c I
. . . = . -
3.::
- . -c
- . X.ef5. :- . . f e..
= -- g.u . :q A.s s. tsi ..
.'ed.;m-s.'tof.fa. .m--= __
. . . .ilitate g..g-43. '.stmple. g. .% . a.. -
hand.- . i. p :.. .
~
m .calc .-
.: --- o - : .. - : .- -
. .=.
.- ..i - M...jpwever,'the~results.shouldJtill'be -. ..z -: . : -
us eful.;>for . ..
general-guidance.
.s. +,. . . . . . ; .. a .,-. ; . :..
.-. w .- s . . .. .
e.......
_ . . y .- e ....c . . v.q . , , . . - . .- y . ___:
2~ - - I - 'tif- th e , sirelif vine -a ssum.stions .'.and . . .
- ~
. ca.l cu.lat. ion..a..l .l,imitatih .s are . .
1 s u- o..s asea en . . . .
a s4e. c..,a a4,e...
u
.r ~ .. . r-- a ..a
. De - ..
. w.
.: v
. g...
~
. r.
H..topriate syste.t heat transfer, and, fluid flow models 'and* core
. t nal-hydraulic models are required to pui these cencepts on a
,: s .
. n as s. .
I
- g. 2.1 .!.h .:.==- es._M : .ow .at_.a .=e 7%- ::=c c5- 3 A=a< .= - ,
( - . ;
.The mass flow rate .through a. break assuming saturated water er . .
. steen upstream .. , .
of..the br eak. is , shown'. in. Tigure 2. . The sa urated 7'-"-
.a'e
. a.n 2 a'=a.m c"-v es a e '~= -
. s e .'. c.1 P~odvis2 . --, =- 3 for stagnation pressures of.,127 0 . psia and 2 500. psia with s .
saturated , liquid and, va'por eht :*ance pro.b. erties. Moody discharc.e l
.. . . e .
1 co efficie,n.ts , (Cp = actual flev::oc:3.y calculated flow) of 0.6 anf
- . ' 1(0 vere. ..e selected for. calculating, the saturated water case. ,
The
.' .. - ~ .. ... .
v ..
.- r ..
5:7 . ', actual .ccef ficien* rhight be ,senewhere. betyeen as cetermi .ed bv -
. :a:.-..
. . . . . . ., 5. . . ..
. +. . . - . - .
~
........... .~,...
.. n ~ n,. - ... . . .. . , . . . .:.. . -
.t- e
,..,. su ch. a, .. c..on.sid.e$t,.i. en.s..~a s'. .th e:.b.reak' . . . . c.onficur. a tio.n and .wh.etN. - - - --
-' in, a la r. . ... ..ge;,.:,..... ... i p e '.... .. .?The : d,.ischarg e coef ficieht, f c: st or small? . ,p . ,
~ assu=ed to be 's.0. . . . .
. :.d. .'r ,
- - ..~.
. 1' . .
P .
,. . . . .: y , u ..%. -.. .. :. ..
... . . . . virys . . E *. *. o .#,. a 5 4 ..3 ' e C onp- ....c .. ,, , . -
~ *? 7,. .= **x- **
- E
. . , =. %.--. s s .? y*. .-. . * .* g a ft *r *::.: . . -
. .a.g ?a =.::. u *2.=p. =.:: . .t. = = u $ =S =>= =J... z. :. . g ..:.: :. : ._ . . s
- -g!-g t ., J . .- -r * *2 - b a . 4 .
- *. : .. J 2, =, c .
1,
. .. . ; : :.= -. ==.--.===n
= u = = u --- :.:-.:. .. .
. .- . ...- .u .:.:..:..:.u
- .... 4
l l
.-. . .. . . . - .:: . . .. ::. .w
.... - _. -=~.-: - . ::._,.-=... .- ..:.. =
. . - . . . . . . .1.a:
- .. .. -t~.. .- _. ..
.e._-
. -e - . . . . . -
" .2*. cc.: ,6e~dsato f or .dass. lost.'.thi c..u-h:".t.hd..po.. stulated,Tb.,sreak i...s . s. ho. .wn. _.2 n r* .
, a ,=..n. : : .,, = ..~. %. g.u._,
..- .. ..sy_ a.
. a3. _.. ... .- . _%. . =,__ :_. - .
- p- - . _.-
. ; .,. .:....m.
- - . . . . . . r. .-. ,=. ~.. r.
- . . .7 ..:.,,: . . __; .n= . r2.; ::. 2 w--%_3,r,
=-.....
o.m?. . ,,h:,rggpres,sur.s.en.n-)ec.t:. .cn .. =_ _2. ,c e., . 3_= ..gi c ur e.,.'. 2s....-
- _ at s'; .,
avail th.a.n. a ble...
.~ - . ... . . . .. u
. .'. . ' 1. i-~.<.-.
.r-. '
r . .. - , . :. -?c.-
' .-=-^:==^==-A.., .
5 C & Q N;::..,cnet.
- v. . - ...r.. . w ',. - . . .
"? -:r~ * -?'2 <
. . . - = ~~
- ~~L' I
s ". Q .i'*~'TO~;% ; = .R
~
o.
-J: -
.-:- ., f 1; ------Iat' . thek in. dica.t.ed..sy
......._... p 2 ,- . . .-r.,g. . v.c.::-e._,,.,,.:_;,,. ...a ,
g.,x.se,t.em ..; ; ...
.-condition.~
.a. ; -. . . . . .2. ..g.=. -; .r..
_ ., _:il f. .. .The, .; . _ . y.. water r._.
.- . a .a._. av 1
. - - . . p!: ::. .;
.. .. .v.
w -
,s r . ~, .,--- . : ._-.
., . 3
- .
- . ; . g;;g _ q
"," ' ^. L 7. . ma.t.e uw. i s a.s. s u.m ed ..to e.b s e ,e at47. 0., C.t. F,.,n . JL.,:=~w:
._ .?.s.W:.-s
- - - .e ,s ... . .
. * - . , . - s- . .:. - . . - . - . . .
,~. . r.-: - - w . . -- '.1. E,; *e. -y' .'.a..+ . ..g'a.. . .a . , ^
2- .* . , . .
.;':.*.a. :.....,,s."..:m.s.....
-r. ,m : ...e:s-- r- . . ::.2.:. ..--.--.-.v
- .~.- -- - .
a~5*. '7'::.,._.:. ~- : ;,, . _ . .;._.~..e
- ,a
' *" pn.d*
. . .. - - r.
'- .. . * : . . ' ;'.. v. .,.-l .'. ;.t-
- r c.,e.: ~.:g . -:; .=:,,c :< . &% ' . ;
.-- %: : " ::. f &~n? .'
.- -. ' .z as g- .:-ee
.'.h. .\. *..
e.e -' = .'-% -
n.
',-z.,,
, - . . a. ... . * . _ . g. ..,,j
.s.-...,,3. m
- w. .e.*:.< .s,,,.,....,- b
-. n.-
.K*.,.
.a..... e -.~..-...:'..'Ll.n.-
.. ..w
-.....-"t.
-~ -- . -: . .;-- ...4 . &.: ~~~. -h .~.... , .- 's
=. .
.,- y - I
=-= .-
,...,.:._ . =- . .. .
_.. ; .w I
-- +.
.=;r- .9-.
. a - T .-. ,
2 2 _Decav r ..-c.
r :
-.e. at;,:A emev e5. Throu u =- = Wc. \hU.c:
~.
"3re aT;hk< ',--.:- :.. G.-
. . ~. +
,s. .: .v~d .i %. i-l..-b.
a... _ _ -
~'.:-.-+
~. %-.. -%.. %. , .. , X,.,.t
. n; .- % .. ~.. - . . .: .-- .y.. _ . . , . . .... .. . ... .:
,. r .,
N' ^
- -The ce'cif'h'ent. which)i. - .. .
s remo'.id.d Jby" mass ' flow through a postulatei
_ _.- > . ~ . . . - -- - . . .- -
- .. . .briak .at 1270 psii~(issuming saturated water or steam upstreah of . . .
l e,
The heat removed is based en the break is shown in Fieure - 2. ,
l th e ma ss f1'ow rate given in Tigure 2 and a s'.acnation enthale..v cor esponding. to c..e ces .gnated upstream conc:.t:.cn, '.e.,
s
.o. ._ .. ... .. . . e . . ._ . e . . . e .. s *. e .=. . u . e', ... _4 . ..* . . .".~m v a l_ u e "o - C > ( O . c.). ss - c N selected to yield a ec .servative -(mini:.um) value for the heat .
l 1
. .. .. I O i removed. .
The decay heat re=cved is shown as a perc.ent of total l
1
.u.. ,. c *. n'e.'. a ' e .^ a ' "- . e . * ~. .. ^. *. .a ' e '. *_ _* ...e *. 0.1 ou _n g t. e .E - a_ a '.e. .
.. 1 c -. .
- m
. '. s '. . c " _' d. b a n c '- eA. ..%..". s a ' " . _s ' = A s s. c- *_ . ... ."-s'_a_ .
f.
- ,#_ * * .=.
, s .. , a .u o. eu,. . . .-,... .- e..~.e- 3 .: w.-Y e , a .. , e '-p a .- c a.. 6. a ~ 3 = o.e ~ .'. e m .
41.,.
This will not' be the case for
...- de' cay heat . than saturatc-d water. . .
__ . . .- .v a 3_ a e ., c." C i'h.
-- e., o- *s. a ' d - wc-'a- "%. s . e a ...
. . .%. e _1 _2_ ~ =.. -
.... . . . . . 2.
r :.a s s flew r.. ate f.o.r..'_ a. t,er . can acre than , compensate f or the
~
s ..-.._.. .. .~.
. ,.-. .... ... m .. .. ~..y .
..-_a..
n .- .
- . . , . .. = . . . ..- :. - . ._ .
. .. . ,c
- r. .--.-: dif.f erance indsatu,ri-t. ien enthalpy. at the. indicatec 'upstrean.
'- ~
.. .. ; =. . .. ..
. .. -.-. =
. . . . , .w. :. . , ;; ... :.. ~... . .r. . :.. ...- . . . . . . . ...
. .. .--- _. _ , . ..g..
..,g..-._,...
... ~ , , . . . ~n .s
... ..-. ~. m. . . . . . .. ..s. > ..y . .-. .., . . .... ....i.,.
.s . - . ._.4..c.,,..,.,3.....
- 3. - .
. ~. . .
. . = . .. . .
.he ti.e after a break before all decay' heat can be removed- .
~
through the brcch .(with sattrated upstream concitions) is .
g i .iicaced in Figure t.. ,
'-his is the time recnired f or the braa:,
-. .: e. .
enere.v. equilibrium with the deca"2 heat. 'h'h e e .e < . - -. e...
e 6
.m..- . . .
.- -e ... . ~... - e -=.: . , w .. , . .. , = .=. 1 , u , .... . . . .. . . ..~ .
- - ~ .. ..
" . 2. . co.-5e3satc f3 ~55ss3c'5E..thr.oughith6.. postulated,.'b,reak :.s .shown;3.n .
?.- ....y: . --;, - .z4.3.. .::,=- ..
. . .e; s . .a:,e,.:. .m-- e . ..:_ . > -=.+ .=;;k.
... +w.
- %u.=- =_,.
.-.-e. :. . :+% . : ,n%. ..,.:f a.x._n .c. e. 3
=y:c-+,.-2 % :m.n. =u. ._..:.m.3. - - , . , f.
n,g.(=' ..)-
.. . .e. .72. ._ cu. . r e. .as
- th o
_hi.gh. pre ssn. eein.)=_ct ;
- , -.,. ._ . _._". 2 .:.m , .. .at.,_. ava1.1able::
. .._ y ..:..._.cf.r.. _.a. .,m-m w on e. s. , .:. . . . ,. _m . :..;
- 1. .a.e.. . .a _,. ......m.#r.+......_. ..e._...
. - - .-.:..=--
- :-~ ~ y:....,._ < .o ._1.-a.-r--.-
"=.;.s.
- at"er -
.availab+ y
.s "; .
' ~
e -
e-
-.n.. .-:- . N. . .u ps.W. . ^-a..a t' t. he- in,- ca.t..ed .-sy stem -cond:.;<.:. _t tone- .,di:.---g:...=
.c-.. . . - .xj;n e ,y9.. a- ; ::..m.n. = .< s.:. n. .: :,,.:.e .. o r g;.s. , .
.n. g. icy;w: q .= .=- ,+._ : -- _. - _ .w:--- 6
.m . . . 2%. .-t.-:.r.+:
?. ._.".. '.:;.- .:. m - w _,; . w y . g ::d f. m .. w g g.;;;.:. _ _ s.
+7 O e,:: '
.. '= mat. _ .._.ee..'.,s. p.i a
..s. s u.m.ed ..to {b. e .. . at' g.9.';,$,, t r. . . .,.. .n_G.
, .f. .F : .P: ._. .W :
. . __..". .,A . . v. _w.. . . ._r.
9m.
. . ._.=,h.
. . .. ..g.. *y.~_. -..,_..;
,.~.. f: . - :. . ,,_. . t. . .
.=.. ..r...,_.=;. :r-
,,.. .;- **.. ..-. _. . . ... . .., -. ,. -. .%.=.;. T .;,-}, . .,:;4 .
r
.. .x-
.w; ..::. ::::.
=,.3. c._p3 . .
.. .:. . .:. . . # .. . - . 4. g : .
_..FS, c.r .
.c -daM::. ,P: + SN..a J. _,.. ... _ : ,.. . c.- - :..-;~_ .- @:,:
- ., . n .=.t. .- z . 4* u. .. .r.
's .;g
. ._ g . .i.
3- . .--~ 5.%. 5i:y.. .:.,w r
. - . ,,. .n..:9.,id <
.. s .
1 r e a k._.,.. . :. .. , ; . .. . . . ..
. .,. 2 2 o=.ca v .-
,s,t.=at,R emcvec Throu
. e. -.- --
= .: e - . -
.- a..r,-=. .:.. a.
--- y
.- i r,; _:-:,. - -
.n m.~. : . . ;. ._.,...::.......
.. m ,. . . . .
- .y.v. . :, s. -
_ .m .
v
. ;--.~.*.__..L.:._=~...
a:, ~.:\
..,........,.2...._..:..t-.a.m
. 7
. . ..-~_.
- m. :_= ..,.
'?' " _.-The ce'es+;h'5at:4hich2is remo.v'ed /by' mass-flow .. . . .
th:= ugh ,.
,a. .postulated
.. .- . . . .. . t i
.-i_.' .:'br eak .a:J .127 0. .esia (a.ssumine saturatec. water or steam upstrean o:
. \
the break) is s hown ' in Figure 3. The heat removed :. s basai en the mass f1'ow rat e diken in Ficure 2 'and a sh.acnation enthale..v -
. cc :espondi.ng. to the cesignated upstream condition, i.e.,
saturated wat'er o= steam. A minimum value for CD (0 0 was E selected to ' yield a cc .servative (minimu=) e value for the heat
.; . 2 . . . . ... .
removed. The' deciy heat re=cved is shown as a percent of total
~
- w. . . . . . . .s. .
^
. de cat' h'e at'"geher'ated a t the indic.ated time following the $reak.
u.
a u s..o..,
u . d , e n o ed.
u . w s a m., _, u_a_ s .e ,_... ... s m- amc< s. e e ...ove- ' s. 1.* 'w d e' .'. a -"= e. ' e, ~ c e.4. . a ~,
. ., s .'.- u' a' s . ' .- a.- .=.'t. . . w'11 .
o_'.%m. -
. . . .w
.. . .. o .
. i.. ,
' de' cay hiat 't.han sat $r.ated wat'er. Th'is will not' be the case fo:
- -- la:ce:- valu es' .. .. .of D C ' w.ith satura ted ..
water upstream.The .
larce -
2.. ..
~. .
h for the
. ---:-a. .
. . ..,;.s .s. .flo -. ,...w... r._. :,.. . a.y, t. e,. ....f..~.3-p. o.r. +s. .'. a t er .. can, .more t an .-
.. .c, ompen sa ,
.. te..
. ....__..am...r.
- c. . :,.w
~~
'ef. , _ . . - . ~. . ." di f.f er.'ence in>s.atu,ra-t. ion enthalpy. at the. ..- indicated upst:aam . . ,
-r-ew ., . . . . . .
- . s.. :m a ..
. . -.-- .- . . s s ....s e .. .... .. . :..u.-.,. . ._.._ u :., x._
..,..ca. _ .. ...
~.. ... .
..,.v...,... .:.,...... .. .
~: .. .
. . .n. : s.,- r. ....._....................,.s......
. w . .. , . ..
-he ti:.e af ter a break:before all cecay ' heat can be removed. .
- 2. :: .
through the b cnk (with saturated upstream concitiens) is .._. .
t*
i .dicate'c in rigure l., , This is the time recuired f or the b sa*.:
[ .
g he in energy eenilibriun with 'the decay heat. The eff.ect of
- - .. . .n.; ,a.- . .- . ..
,. ~: ...;; . . : : .
~
~ -.
. .' - . . - . . r... x wate:J1ev.el-is assumed to,be . .
sid..e D. .-~- h. .1
. . ,'. br ~-. '. .., .e ak . . -. . . . .
Th.e. seFon. .dary.'g .-
. , w.:..:_.. -.:s %....- c.
.. t
,n - = c.. -m. .. . . . . . . .-e........
'.i' . -; . .
..=
~ ... . .-. s.. .. . _. m.u.- .- a . ,.:.- ... ,
. ::~ .
. . . ~
4 T~linc easing 'at..w~rai..r. at,e.Yc. .-..w~.--.u... ifG.1.75 f.t/.-fi.n _Uh.ich,is',f,aYtr.ib. z .:-Q.9:a.r
. m .: .
,.af.:
uted .- to. .a.+600,t.. c...-
..r W:.
-=a... su E ;>. .- :E v- ..-.
t=n e c- v....:. .: s. m seconcary.s:.ce wate:.s.
.. -- .. = M. . . . . ?" e.S=. .
f, . P. _-. -- ..
edwa e:Eflow;=-
2.m t.:.a l.. , .-: r-7 . ~. .g.: -.-
Ma.g=m.uauxi'I:pary..f e.. .;:. s.sc. ; .; a.a _:. .s - .;. i aa:-:s m ..3 - 4 l
- A. -.
= . .
nr * %*=..T -.=-n h e. .
a:; :..a2 ;q:.y ..:
- y. .. .
.c---;.:.
. - -:a - c. e.:.=
s
.. w. .lev. el :i..s. .assungd..'to .b..e. .T2.6. f t.e.a.,bove .. : ..;.t. . v.he.. ,.b. ott. .om . - ., . tube .
.. -. -_..,........,..,..s-
,,;....~...
. .. r ...--
. . v_. : . . ._i....,...-.:
.. r. . .. .
- ...,.: . . . .v .:e
... i..
v.,. u. .. . . . .
. . d ..- *: :=.1.^
w
' ~
'the
- st.eam". gena:at.o: t.4.. . %.l . . , n,.. s..wY . .=. m
. .=,
. ...;7. ::"t=
m_e 6raln i. s st.at.t.ed."..a=~.V.
..,.w., .... -__.:. + ...
~- .- . . . . . . . .
..,.:.m......_-c._.....--.,_3.. .. , . . .
.-.__+..,...-o...__.~._....x,,..,,y.,....~-,z.
.. .v. ,..
. . .wr m. .. ,, .. .._s.. . .,.,..-
. .s .:. - - i w. ,x
. . s.. .
......n..,-
. . .. . ::: ..< - . a. -
_- r..- .- . - - .
. . . . .. s.
.. .. . . 2 -
v Th.e ..ef fect.-o f. . ucs'tr.ea.mT". res . . _sur.. . . - .e. and .;.init.ia.l. sec.o. ncary.sice. wate= . . , . . .-
- . - m :m . - ., ;.. . ,. .. --g . . a An i6itial . .'
. . .. level on steap eenerater drain time 'is also shesn.
=, - - .- .
. 7 . .
is the normal ausiliary f eedwater '
secondary.. side leve...l o.f.- 6 f t.- . ..
- r. . -. .=w.-- . ..
. . , - p .
centrol, point untti an engineered safety features actuatien.'-
s --.a v. H.. . = ' ' 5, . =-
.. -~ 'i' si gn a' '. p.s. r.s) i s n':'.'-i .* ~ e.' a' 14 0 0 .esi a - i -
level'wil'1 be in the range of 6 to 2 6 f t. at the steam generato: .
time natural circulation is lost. The eff ect' of an ini.tial level This is an upper of 4 8. 5. f t (top of SG shroud) is included.
limit for piactical consideration since the overficV enters the
- r.a in. .s'e a'm. lin eT . .T.
~ - - .
. .. m. ,
he' e f f ect .of. 2 5 0 0 9. .sia -ea cto l.,c oolant .
is included fe pressure (set point ,of pressu:izer safety valves) _
.,a c
e-..n.e. . .
.. . . .s .
- , ,f:..,.. .
N " "-e . .-
.,2,5 Steah_ Gen.erator 7ef i11 ' T_h.e- -
.. . - gen's:stor, refill time is 'the,l tide required to
.... s m ~
~
ef 5.11
'The steam'. - - .e. .
r.. . .- . .
'~ . '.the inl.et':>ic. e '..ah d tie.nu.ni .and '..s.teain..... eehe'rato=, .
.. tubes ;if a leva'
. . ,;;. . . ,. . . . , s - . . .:.. , . . _ . . . . . . . . ,
.u . ,.
y . . .
..<.,~..,..:
turnaroun*. should c=gt:, when th ~e , prit.a ry sid e water, . level first
.. .. .g. . . ... . : .., :-v ;.., - . . . .
. - . . . . . . . q. .
a--. ;. .. . . ..s.... Typ:. . . .. cal t:..mes'are levelshe , .
~ . . . - ..
r e a ch e s+ th e. . . . . . , , .; .., q.s.ecencar.y s:.ca water.,
.,:e2 .. c.. .. .
r",'-c -e a .. o e -..e s a'-" ,.t- '. a c wa' e - a' T > 7 0 - es i a
- e e -
_: n ..:.4 3.--. -.
/ ..
break.
~
The initial)' steam generated level is that level which.
i.e., when.
~
existed when the steam generator drain started,
.atural cir culation was icst. c is like'.v. th-t tha :..: :a._3 e
. Y .
--..+._.,--.g.e. e - ,r..w -
1 flev.el~is assumed, to.bc . ,_ g. .: p. !
Th sec'ondary'.si6e wat er
~~
~~
' br.e'ak.. .. .;...e - :. : c." m,,.n
._.- . . ; . :. :p. . v. . .x..
- . 2. . w... . - \
z.
.. ._%i ch rdis?aY,@;-a.. . . . . ..ute5 l
... ~-
. w ..
h,,. /~~ Ec:Teis~5 @. .* =:.:-.~ aN3at,eTof4.1 ft'Mii~~1.. -e , r .
... . u,--"c. :
u:. - ..n . 75 ~,.=r. ~ =.w ..
- m. . s.
= m -.e-..~ . . .. w ... .. \
,... . . . g. ,;., ....=w . .. .
. . . . .x.
m s. . . . .. . z. _= 3. _ .n z seconc e:r;
.em. .iuxi'li'a .
rv!..f. e'e'.dwa er7 flow;a=. T.he. ...-~.~..=.7 _im. tz. l. .
a
.';.-" 9.,
.. a;; .s : uc. ....g . g- r*~s :- w. .;...,..... : -x . n
- ~. =.
- m. .
~ ...
- 2. . . - :.
.- .7.---~~.-~---~-=..
. :. .. . a-. . . .;: :e ,
l l . d;'e.,f.<d.6.' ft.;..a.bove r..the - ~ bottom,
- tube .. .. .. sheet ..~ .-when~.:.f m ..u .
' i s d. ?._t. b..
- n. -r. -..a c... : _.
'.:.:.. .. . . .:=. . ... .. :.r. s
- .
- : . i. ..u. 4,.g :x. :
..g
.u. .mlevel-:is. . ass ~ .. . . - ...... . . . ... ..... .. , . . - . . . : .. : a ......
. . . .u _
_,E=.
- ' t h ..
..r.,.
e s.-.te . , a m~c., e.n_e : n.,. at_ c: .6:a .. . . . ,. . x. .,.c. :
.~ ~
.c s.
- . :,.r. . s ;x.::.M. .y=s . . Q
'
- y.a 9.y---2.R-. .t- % . M :.=.+- ;T:;: mig; ,=%$.&.z. ..C- >.'.t.:%;. . M .' .'. L.C.s.:..:-s. . . . t.
y.;Qm.. . . . art.
. ::.- -p.:=
._. e-
.....r..- -
...=_.
..a. w .: . ... e.
g;_m .. .,; .... ,a. ... -
.- .: a. . . . . . . .
. a.m'pressur. .. -: . ne,:and i. .initial seconcary.szce wate ..
4 Th,e ef fe et.-o f . upstre.-.,. w--
. . .- . .m . .. .
- - - . .-.c - . , . . m -.,: a, . . ..= ::: . .,. :- o : . . r - .
- ; . 7-.
An 16itial .
s- .- . level on steam gener.at.or, crain"_ i.imefis lalso shown. ._ .. . _
. ..v. .. .
seconca.:y. side level. of.- 6. f t. is the normal ausiliary f eedwater -
.~. - r- ~ .. . 5+ . . ;.- . , .- ,
control, point until' an engineered . safety features actuatio.-0 .
4 s n-. 8 ~8***..d a' M.00 r-s4a. . ~ : s _' _4*i.=.'..v * 's n '. ". . =. -
s ' g n a l '. (:.a'.- .s) a
'. steam generato level wil'1 be in the range of 6 to 26 f t. .
at the o = a .,. .: ,. ..: : a , ,,_ .__
u m. .. . ,. o _s_ e n. u. - _
+ : e , , a u. .._a _, c__cu, a u _:on : s 1os..
This is an upper
~ of 4 3. 5 f t (top of SG shroud) is incinded.
a for piacti,c.a1 con. sideration since the overflow enters the l
I limit . .
.? . -
.of . 2 5 0 -"6 e f f e.eb 0., sia :d ea .s c t. orf.c oolant-
~
r.a in. ste am. lin eT... .The' .. g .s. ..
I s '.... '>e .. e. eo .-
-.. e s s ...-*- (s='. co8 n. .o'. .
~
.ess".. e- sa#.=.tv. v a N. . = s ) .
1
-,e
- - . e -., n.. . -e.,.
L
..... , v.. ,. .. ..
r.- .. . . . 1 .: : . ,:: . -: p .
__m W .a'o. ..v "i.'T mi". ~ '~ *".:-
.. ,5 s_'.ea%._
")
..*7 '. i. e is th* ' *,i...=. - =. 2 ,ud_ = 4
- o dee . .s n,3
- . . . } . .
s ' e a . . .:. =_ ..=. a o,.. .-e #. 8.1_'
.. w. . ,. a
.y heratoE, tubes if a level r .
i L'- .'e-. . ith a ' i.nlet" pip . .(1,a'n , , . . d plenup~i _ . . .and 'ste m. ge . _ . .
< . , . . , e. . . . . . 7:n . - . . ._3. . . r , . u.~ . . . ,. e i'_ -
ide water, .' evel first turnaround should oc . c-
. y. .:.. . ,,: w. . :p:.:.?h.a-;r.?gtr, reaches the. s.e c e n c.
y s?ca wate: level. Typ:.when p M... . . . f. ;. ...7. . '. . . :, ;.: .p cal t:..nes'are
.theshe.e. .
, pr r
- p , .
in Figure 7 f or' saturated water at T270 psia upstrear of the - ,.. .
. 2 breahl The initial". .
. steam generato . lavel is that level which -
i.e., when. .
e>:isted when the steam generator drain started,
- s ' ...:: -_ )' . . ~ . . ~ ' . ~.. . a ~s. . . . : .. a .;
...,:- ~- -
..a tur a,. c . - -- - - -n .
'.a s 1 o s~-- - A- .
- l
. i j
l
JJ s.ig nificant ~ system. vo.:.u . . .
.etr.:.c
- ..w cvm c.~ a - . . . ..;
- .. . - - - , . . . . - - ..m. n.- .
- . . - . ,s . -
.c. : . m.. . . . . . . - . - . . .
trip is ' " if._; .
'. .~- ..
. =r'essuri-er .bdbbaci.'exp'ans' ion edcurs, whon.creactor u=.g.u W . . . . .
- +.. :..+. . . . . . .:. . . . , :;:+ -
- a. . x_..:.::.....-....... :: :.o. m.u..+..u- .r- 4, . n=_. m. =:w
. initiated '..atii.9.45; esi.al_-Whe* b,ubbleisup.erheats to .,the p,,resstrizer ~
f_;.; 9.-";..a . ... . .;,.. . . . ~.
. . .-. . : -- .. . .m
....:....?..'.~-... ~J**
-- ..,~'
. . . . . . _. _ .-.e - ...
~ ;.. f.;'n
. . - . .. . :-i~ ...- :;
. . u.e. .
. . . .. ..: L. n-es_ -_ v .
u- ., ..-
T. . ,
~- " " '~ ef f ect'ive '.m. e..%,- a'1'.he:Wpei.,.aturs'Wh.e]5ubblei. na~y , expan 4 s..
c.,,.,.
. .. .g . , -;. .
.a t
- . ~: .
... ,.:.u. ,,,. Q ., ... .. .. ..._.,..,:
s.
.3
_~..,.;r.-
-..~.s,-.
v.
~
.,..? .
. . . .. . . e. .m-, .
sup erEeated. :.; .-
. . . ~ - - . s.trea.m .i'sivoiding ..ahd.'.,c' odd
. : . ,. : ehs. ing'.in ,the. vertica..l.. . . . - .. .. . . ..'h..o
-- C .... -
._. . . . .. . . . .n...w. . . ;,>;.
e j .- . :. n.,,..~-
. . - w.-.. :.
. ~ . . . -
- c. . - ; -.. . .. . . . . . _ .
.- . :-- . : n -.--. .
". ='.
- - le~g ' .ein . ?~.e of: ...._.4..,...s,_.._.._... the.Hre..a. c.t*6. r Tcoolant!s9ste-i.: <.The ~..y..
- w. .
eng:neered .:
. - , ., .. safetv&
.. . m--.--a...- .
- a. : ,.,.,,;..
~ ~
-. f: e. .,a .tud - . . - . . .. ...
s .ictua tiion .
v
. , s Ga5a'1'. (ISTAS)'_1.initia
,.~.,, .. ::-......+. .
. . .n . .
tes .. .at'
.-1600 . . . . -
3.
as sur2.ng mar . nun ava:.A.ab:.1:. t y. e ,..one . gh ..:..- press.ure :.n-)ect:.on -
- ,, ;. . .-.~- .- -- .
. . a . . . .- . .. . .
e p.. c c,. u o , , . a ."~. i s o ' a (- c.n o -' -" h. e ' e 'm.~~~ n u , ,
.. p.. p -. ) r.. p . 4 3
.u .
e.s A new stean bubble forms at the highest tenperature/ lowest pressure locatien in the reacter coola'nt systemiuhen the . .
.cressurirer pressure beccmes ,ess .. a n . u. , . .a?c
. - - : m.
- -,- . .c.
.u. ,-
licuid phase at the .new locatien. Since ;here is no significant . . .&
P'% . . ..
heat sink in the het_,' leg pipes between the, reactor' vessel.and s
U ..
i . .
. .. .a . . . .
ste. am c.enerators,. the hi. c. hest te=ceratur e/lowes t' pressure
~
locatien could be in the U-benc pipe at the top of each stea=
-t-..
- . r ga .=.. a o.. s.-3-e..
7 .. .
M. . a - -" ' s n a ' " a 3
~'*.- a s %. a h".bk. l e . .'o ...s - i.n.the U ba...d .
. . i l
circulation.
Hater in the re'act'cr vessel starts to boil - l 1
i
. .. agressi.v'..ly e du'e 'to. . . . . loss of'. circulating flo.w.. , The reactor core
- . . . .- .m...
- s. ..... . _ .. . .
j
- -= . ,.. . .
ex:.t -temperature anc corresponcing ;eaper pressure increase u .til
- v. . r. >. . . .. : . . . .:. :. w , :.; .... . . : .n .: - -. :. . . u . ~.~ . . . . , .
hif.i e
. the r'cactor '.ve 's'sel. tce' cienum. tecomes the . co.ntro11in..
s- . .
- 2 .- - _ . .
te mperature location. .f or stean bubble f ormation. . ?.is c::urs.
uhen the top plenum. temperature. is 'about - 1 to 20 7 above the U-n %. . . . = 'e...a a~"-e. -
< e l
s .
- . e
E 's ic nifict.a t ' system VoJ.'.: e T. J.C CUn bJ.c.b w*va* ***=.-----4-..--. -
- . . *. ~ . . ..-- x .::u:.~ -~ ::.59. . :.: - . l . .-;. . . . .y. M .
. . . . .4=:.:. .....
. ..--t. ...u_-..- ..
actc:. .tr:.,.p : s
.?
h %;.m ....
i: ~.'-= ..p:essu:i:e: .bdbb1e"c>ip ans' ion. occu:s. w en.;r.e.
~.- ..::c,.-m .w:.~. 3.:-i : .+. m.- #,.-. ~.,-W - .
~ ~ ... .= -: ~.-=w
'.- , w;e .. : .z.
a.r. ... w : . '.-.mvewc s . .w. n.~- 7 - .-. -
initiated 'at31.9>ii5;~usiaW Ths'.b~ubbis. fsup.e..rheats .-- '. . = n to .. #.he presscr:. . . . er; '
?" ' -
%j*.s. -. .:. . . ,.
%f
.: . e .L. . .. . % :&;,,, .W.I,,, .. : ., . : .'",.Q'. 9 55" 7. .,m**; .-:..~n.--.=*=e.;...,,,'t.'..
n ay .-- .~ 'G. .; .,_ .
- e. .. e.59.and.~3' *;m *; .;.,.un
...w., . . .
p* ". "w ":w..ef f. .e etive ' meta'l- tei-peiature.'s.che;.ibubbl . . .Q.
.: . -t .
. :+:.,, -
- .v ...d y ,* .
- c. . -
. . .<a.
, . ..w. ....
1-- .. ?.. ; .
. . z .. . supe ea
' v.
.- iding -and . ..-. .:. : ~. . g .c onc e..,n ca sin. g,..otg ,: n
. . .. . vert.
.~~- '
,t. e.i . .
. . r h u. . . c. .<.. . ..,u..,:.. . . . . .. , w .......,..:..?..
.;.. ... ted. stream is ivo.. . _ .. . . .,. ;,.._ :.,;. .. .....
n..
- v. .
... . ._. w.
u , :: .
-.'of:,.the.h. re'ac.t~c3r fccol. ant.!s'yst.e.m..s .T.. h. e eng n. ee red saf.ety U. .;
~..
W, : :. le'-= c. . ide. s..... .. . .
- g. 4 . ,. .. y :.:y ; . w; .
- .: ...y. 7...:z..
3 .. . _,..~.. .
= =p.;5 4 .. g 3.;;.Q.. .
- fuatu: des.actuatien. signal. (ESTAS)2.ini,tiates. at .+~,.-....a..,:.-
.1600 ps:..a.. therg.by '.
1,
. . .:- a
...,r. .
. c.
_.. \
. ... . .,,.........:.,.s.
~ .. ...
~
as surin.: ~ maximum availabi. .n lit. y. o. .f one .high. .. pres sure".
injection. ~ ". . - ,.
..n..-
eithout flos:1 centr'ol, .
..an'd isolation of the letf o n.
~'.-- (H P.I) oum .- . . .. . .- ... . . . .
.h -.- .
. . = r: . q v. s. ,
. svstem. .
I
.A new steam bubble forms at the highest temperature / lowest .
p sssure locatien in the reactor coola'nt system'. .: hen the . .
~
pr e s surize: pressure becomes less than the vapor pressure of -he ,
licuid phase at the.new locatien. , since ..
.t. here is n-o significant e . .
r heat cink. in 5h'e het leg pipIs betWeen the reactor
- vessel .
.a.b.d . .
.s.<...
.. ... . . . . . . . ... .. . . .a .
.... ..e.. .
steam generators,.the high. .est temp'erature/ low.es t' p essdre , . . . .
locatica could be in the U-ben'd pipe at the top sof each stea:
.- r . .
ga ... a.o,. ..
(- a..
. 3 el .1) ..
..v..., ..-. .
s.
.. . . . . . : . . i. . . . . . . .. ..
. y
'If a stea: bubble . forms in, the. U-bend, it interrupts natural circulati6n. Water in the'reacto: vassel' starts to boil." -
agres si.y'.e. ,ly du'e
'to.'. losse.. of._.s circulating
. ..y . . . . . . . . .. . . .. . . .. ..flo.w. .. , The reactor .,ec:e e:::ii. e. .emeeratu. r.e and.. co.. :e,spon.. din.g..ya por pr.es.sur e..n.in cre.a se ..
, u..t: 1
. 9. ~ ,:. . . .a .~. : . ,.: r.: - :.. .. ...a.~:..u
. ::. . r. >
. . :?
.n.
g hi.' h
. th e ic a.. .; . . :. :.;,ctor '.ve ssel, top'. plenum,'bec < om. .es .the contr tem.:erature location.,for,stean buhble formation. .This c5:urs- ..
uhen the top plenum. temperature.is 'about i to 2 7 above the p-
- u. ,. . . .a. u e... . . . n ~ u -- e , .
i
pqes,suro a..d is .d.ostly likely ,elc'wly. con tracting' as steam frc=.~ .
. .. .= .. . -: . . . . .; z.
. a:;,.
. . .w
., ..a. . .... ,. ,. . :,_ .... :.~ - .... . ..
. . . . .. .., ....~.. .
-.: ~. : m....
~
j-. .-. ... . + V.the
.. .. ,. bu. ...--..b.bl.e .=.:.. . con.d_en.ses<on.
. - - .,- .w,- .w,:--. er u'. . .the?.p.r.es.su. ,.,.. . . i. iz.e.rM. . a.ll. s: cur.in .
.. . g.w c. ool.d_ow .
.: . ._. z. .. ... . .e.. . ..m_ . w,. . . . ,. w-....m,....._..-..m...
.: - . , .: . . . . ., .: -_,m ..w. -.
..._...~., .::.w. . . . ,- . , ..
. . ._u..,..,..
. -... w .. . ..
_,.e. _,1
. : n. .m.,.m .. _
-,,~. .
...... x.. .n. .:_
- ' ~
f....... .. :J;g. Jer. a 'stea=-sid :.. . : ,. . :-s uch. a s;.:at:. the pr.~essuri z e.r. .to i.n p,- .. .:.,w. .. the- .-. break
- . -. .n. , n .e.y.-. bre .. ak...:_:: .. .. _w a.:. .. .s..,r... . . s..
,2-;.
.n. _ . . .
- n. . . , . .
.c . .. . ,.
. vents.the ove.
. rp:ressure and .flashe. , _. .-s any..sa'turat. .ed 11euid in. ..
t he "
.._ ' .- ._.. . .: ;..s w.
. . : . .u.z......,....--......u.......u....,,... . . .
...m.....
... . . . . . . . . . . . . ..3 .. . c. ... . . . -.......w.-. --.....
.~
.. , , 9.
. - _. r. _. :. .
- *: 'a' wateE-sice:br'eak,ibuti Ehe
- r- . .: : . ..:'.. - +. .. .r:-
.'.-c;; n .. -
& .:...:1.- .
pressurirer;in h .- .:.=.rx-
- .a =.-;._.;
'a "similar
. . . - . n. w .i,: ~. . . ~; .. .v
. ..fEshi'on w k- :q to
.,v.2 ..; ...,
u n -
- 7. ~
.. level'1 css ra.2 .te . Vill be. 'loder.s.-,fueto a l'cwer mass flew rate
.for
..=..
u...... m ,-
. .i v.
s .
.r
... . n
.n._
. i s. ... ..
. . stean. through th. e. break (Figure 2) .' When the; pressurirer ste'am
... . .. .- .- . .~. . . . .
- bble 'rearhes pressu,r.e e=uilibrium with the reactor vessel stem.
..= ,
- f. - .- -
bubble,'it starts to contract rapicly as steam continues to be l e ...o ". e d "w... ~., % S..
. 'k.e wear..
. .C -# d e.*..*.-4 n e. ' . . ' . = -e- - e s s "w-.1. . e 4 s a ,,,
. s.v stems aturation conditions , but some pressurizer metal heat
- i
. . . .f . . . . e..: --. .s *o .edu~- th.e . ,c- =, .s s u -8 - - ..*. ~ 1 a. v a .' --.#.se
. - . ate. -he 2 -
e n . ~ e s ' =. = . ". " ' b. '. *. # s . .- ..a....,ve- '
c" c'.A...v ~ .5. . c " y 'n *-.h e e 'ma. a ...- s 4 4--=
break anc it b'econes a water-side breth. The react.or vessel r .
. drain .t.ime,.
should be. . u. .ch shc:ter than given in Figure 5' because :
. . .. . , . _ , . .. e. . . ,. . .
. . . . ~ ...
.. . . .a .... . . . .
.. ..: s #.. 8; -"- e .i s. .'. = ..= a. c'. ' o n a ' c o= r. . - - . . . ' .. . =.- -. = "--.e-w.'. 'c.. w s a
.'e"e.
.,., 1.:~a eg - .. .:
c .1 ..' ", '.' .'.
- '.s. e . =. a..c-- ' * =. '...-=.a'.
- s .. '- .. +.,,=.
- - . . .-.,:... . . .o- .
-...t..,.. .-. ..=
- ..- ., . . , c , ...x . . ..: .
4.
.. , s =.
J
' .2 . e'a g -i 24.=, z..r. s.a- *3. :.3 -- i -sP :s..*%. - 4' -
0 " N 1 C r.I .m -
a ".:Lr._a .'.:.I
' a.:%.; r .a +" O N-* ..m 1 V I v+ 8 '.l.-. 4 *. '*
s... . - . . ..
g.
. .- ' : . .s, s .. .
c==s s 8'
"= t . al" c - - .'. a.'. '. o.. c .' e a ' v. .
' S. e .- a - ' o - v .". a. .i - e .e1
..z.... a "a .s. ... .. . . . . . 1 .a. .s . .. :r . . :- - .s . . .
reaches thejop of the. hot le pipes and reactor steam starts to .
- y. .. .
3..... .
. -s . .. . .. ..
s...s. s.. s.u .e.. s...o.u ,.. .%..a. -:..=s'a..d *
. - . - . a. . r. . . ...c.--...
n~ .
- e. . a. ~- ....u' a. 's e a . '. . .
. . . .. ... . .a.
-. ..x.
- s. .. :.. . .. _ - - . :-n. s. - (. ,.s.. r : c. .s .
. e -
- s. .e 7 .- =. . ' s ) . . ' . ' . . = . . - - 'n . e s e -- -- - ~. ._ s s e s .. s~ ~.o
-- ag.>ss'v=-'y 'um - - o .~. s o ' ci --u' -- - a -d .
.e.
~,.
. reactor core exit tempc sture and cc: responding tcp p'e .u stea:
.- s. , .:
..u..,
, - - . . .. a - .: . -- c.
.. , g , . - . . . . . . . . -. -.- =- .-e e -n sg...e . ... :.s es.n .:a.... .. --;. ,-..g.: .A..:. --- .
.k.
- . . .-. b.r s e 4.S - -- t r-r.
- a .....ae..,,
-- .. - s. .. . t.
sa . u. -
I i.
f t
. ~ , . . . , . . , . , - , , ..n...
. . i
..' pr,eg s, sura . and is; :.ostly likely. sic. ly.~ con tracting' i as steam .f cm. ~ 1
. . , ..~.
. :. _ _: ., : .=.. ..:
. : ., ...=,.
!.,_ .. c.~
. . . . . , 7
.c :. .
...=:.... -.,. ...
ses"o
/,- .
. . -. . '6.
i.t.h......-..:....-.-...,.
a...,,..
e bu. .
b... .blew . con. den.x&,:.
.. u. . . .. m_n :th e'. ".::m,:.e..s.su.
-m:..-..,,,..._.-.
.w . . .r. ize.r -
- r. . 3 .0a_ll .-. ,
.g_.._..._..r._.
- n. -a. .- :.
m_ .,.z. . w: . ,- . v. i ..
....m,
.:...r...-_.: . eak......w_ . --. m . ~-
._,....._.,...a.... . w. . :
.. . ,.y m. .
,v . . . ._,a. . ... ::.u-..m::. . . _ .w.w w.-ata..the .-
- 3. ?o r, a s te a=- si..
..r . -.. .
's . -.
uch.
a s;,. .. - . . .
top, the. break ~ pr.'e (f.." .... ... d.e '1:r. -
.. ..~. .. ,
- n. ... .: . .. m . . .
. . .. . .u. . . _ .. z
. _.-.:.: . . . yu , . .. 1. ..- :_.=
. . s.
. .w s iturat'ed'.'licuid
...--.........w-w..-
in'.the m
- ". ; vents'.'the eve'r..ereiside hes' and' fl5s... a. -...
and s
~".
. ... .x_ . . .w.;. . y .. . . .. z. .: .: ;., . -
.n. . .. _ -...... w .,
... .- - .. .,...... .... ,.. . . _ = . , . .
,,' pressurizer.f.inf a similar fashion to 'aDiatei. ,..-sid e.;br.e ak. ,. ,.. ...the. 9 ,_ _:
.r(.--
-~
. ,.but .~
. r. . :.:
... .- ,' + . ...,e.. {. :- . . . : .
._ -! .-- .:.- :.::,1..y_ _ ; , : . . :, : ,s-.-
c
.1.
- 2. u* ... .... .
A * ;; ;
2.. ..< . s. . . ~: ..-:.~ .vY .
- 7. ~ level' loss.. rate ui11 be. LoJer due to' a'1'cwer mass ficw rate for -
. . . . , .m
... -.<-:._. . .... - :. .v _n. ..
.w ..
.- .. v..
'stea.m th'rodgh the. break (Figure 2) .' " When the; pressurizer sts'am
.u..
.. =.
subble ' reaches pressu.re equili*:rium with the reactor vessel stea:
~
--; -.- bubble,.it starts to: contract ranidiv. i as steam continues to be e _.. 3... e . 4 c... ..
w.. .. k.e hreak. *
- ..': e . . '.=. - ' n g '..". ._= p e s s o _i _ e
- _ _ _4 s a*.
sy stem ~ saturation conditions , but some pressurizer metal heat
- . . .e . . e ..._= _#. . s o . e d u . e t.h e .- >. s su 4 .. =. .- .'a.ve,' _ se . ate.
"2 ha.
en _i e _ s '. .= .=. . '. ". .* '. a. _i s . e... ..,v e .'.
c.". .: c k. ..' /- ".. o ". y- .5 e_ ' a. a ...- s _2 3 =
m5.= .
~
break anc it b'econes a water-side break. The reactor vessel r drain. .t. ime. should, . ,be.. ,.
. u. .ch shorter than given in Tigure 5 because
. .s. .
.....s.
.. w . . :. s .c
.- i. a, . e i.s. .'. = b.
. e. ' o n a ' co . . . .- . ., ' . . =. d_ " . 8 _ e_- .
.. 1 e'". a 4. 4_ c %.. sa
. .. .a .5. .:. .a. a g .e .. . . . . : c n ~. . '_ , ' .' .' ~m.%. . * . =. 1.._c .' '. =_ '. . - .=. a '.s- .'.s ..o'_ .~.. .,
e.h.=.
~. . .. .. ... . . .
- = = s " ' ~ = -* o c . -
..: * .- L : " = = .s ;,t= .s
. .s .. .s., ..: 4. ,.-
. . . . ., .. 5. . ... .
1w-
.' 2 ~ ~ = . . s i a 4 m. .-z , v u=.'..o.-s.1
- - c' r.a.u_s.a --
.'=.' c.,u - *o 4.~ c a . a..a - - oo. xa.
.... .s . .
- g. ~
"..=. e.e_1
. a1. ' c.2..- . ~' a '. 2 c.. c ' e a ' v. c =_ = _"_ s 8 _ - .
'
- 5. e- .- . a .' o. v .* =. e .1, ..
.. . v. t. . . . ... .. . . . . . , .
= . .
. reaches thegop of th.e .het leg pipes. and reactor steam starts to
. a .n......- ...a, .. 2 s__.__...
......s...
-e... 2 .:, s ' a. a. . a.
,. o. u s s- " .u' a. 'na . a .
. . . .s... s.w. ~i e. . .. . .
. . . - ~u%.. . .
,.._ : ._.. e, . .,_: n s. . . ,.s. . e . .tc.u. a e - - s..e .... -..a.. e . .'. . , . -.----:-n .s... .ec.c. .,.sse.. .
starts to 5:i1 agressively due to 1 css of ci$culating fic . ,. -he i
reactor c: e exit temperature and cc esponding top piene: stee, .
.- s .- . . . e 8... ..- c .= s a. . . ". %. .
..-. -'s. , :" e s _...s . . _ .
, - r .e. s s ". . = . . . .. .: . . s es_i.% .- :a.... --; ,..a c '-'. ' *. = -
'-* ~~=*e"-a r .- - :-- --- - '. ".
c=-- -
i
,g ,, , ..q,,, , . , , , .
l
_.w_. .. _
.* st*. . . = = .
. . . . , . . ._. .,_.._c.....;.,,,...._...._.:.
. . /...>.-...y
. ._. .e. ..,.. a -.. ..._s . .
r?-a .b:je ak. I. .;7h
- . .~..
- . . .. , .
a- .fte etu al,.'
- .. . -. . . c.
'i, g- h :. .-.ghar pressure. .- -
-- . .< . -i-'=Tc topip'l~enY.-f_to
+-
d~ran, r.=
,_._m.. e ,. . , ;
... _~ __s ,.... .=.
. _, _- .~- = _: :. ... -.
. . <, . :.z..=
..c.. . u. --4. , ._. ~ .,.,,_. . ..
4_._c. . .
2_., ._ :: . . . . _ . . . m . m. ~ . ..
~~.e .'m ."=f duridg'MEsch.iod~o~ofu :the ' drain chas e r # 11d acreis e,a-the drain- time.
c--.:. . .7. ..:f..*::;(~-. . . , .z ,_. :._ ..p . _: p_.y. .g , _ 7... <.-_.+_.. _ :: .
. .. yr . - . .-
. _ _ s.. = . =_ ~9-- =. .r.m. w +w.._:..%. ., . n . ;,., m :.,s .r
--o... ... e.. ._
....-.r. ., , _ . .: . . ... . , .
- + . . ,r.
... for.
- m. .M ~ "~. ~.'.Ei, S. .i. gure,.W'shoGM.,
- a. ,. nc.P%_.P. l.oHg=.,.:a. f te. r; a .,.,b r.e.
.~..c.
.,g.,.,;,.,.. 2
, . ,- . . _ . w. m .a g . e . .. .,. . . p ._ , j. . . 4_. .. A. ., p;r.. . . . . , . . .
1.
. ,.r,,..,-f,,.,,q.,.,;.,
+ y. ., m..- .. . . .
- n. n . _ ~
.- - .. - ~ - .....a.
-be=c. .
..r e.-- = o. v,.e. d. >t h.....
r..o.u ch.-th.._e: rbreak._.-. :.For. the .ra. n.c.e o. f - sma. .l. ler. bre aks ,:.:__
= n-
= ,..=. . r .
n 1-....... .: . . . . _ . = ,:
.g_ .
+ .-- _ :. ,:.. .us. .:.: ._~-
....c.-.
., .. 2 r. ._.:e. ...c c- e *c.. .=
~ ..,p..._... ... :&.w,. . :.r-
. . .~ . r .3 . ...=m ..
. . . ,p w.:,-..._.w-.y_._.._....:...;,..
- =
.. .. . . ~ .
.A, .._n .' , :. J; r, e a c.to. r. .v.as s.'e.li~.dra_ i.de;a.y_ t:
- ~
- r gr.y- -;: m.
,.=c e fo.r . .a m:..-.g.: &. .-a.<n ven br.e,a. w- .s.k.: .-e-s1=e.;1s
- .. ;s:. : .u=- -;somew .e
".?1_;. .=r ~.: -re.=~ =. .: ., a .:w% : .--- -*n-*-e.r .::.W._..=.:.m=-- L crb.,: :. _
~
.::r; .:::.
-. o- , ,~ : ? _- -- --
. ~ . " . . . ..F.._.s..h.
- ...-c. ort er. :.. th a.n. . .
.,t _h. .e, ew.e _ . , . _
r gy e qu:.libr:..
--.um .tiae:. -. Ta2.s .
means that.._.;. .
. . .+ .
.-..r-
-- - - . * '. r . g. . -
4 .
~ o* . . - :. : .- :: =n *-. .r,. .:.m*. .,, . .x
. . ;** -=. ,.g. ,. . . - :r . -~ ~ : =- -
~ , . . ..:
na tura% cr;:rcul atief cea s,es te. .r or,e tn e -c r eak c a n,. ---re=o.e cecay a
.. . .- ~
. .- _. .;~
.. - =. 1.
. : i ., .
.c. .g. . - : a ..e,._..
.w.._g. <..p..4 --. . . .. ,. . - -uw.- . . :.- . ~.
. t _. e .; . o -e... ,y.e;
. .. .- ,. _; _ au m: o , z . : ,~,., c c.. . s .. , -. s- -
- e. .. e . .,:....
. u. . e u .. . .is s.,
. _ . . .. . . . . . = . _ . . _ = ..
- . .y....
- . . . - ...___.--.=..::.._...:.
f.: .
'-r- -e .
..the excess' decap heat while vait,ing for. the steam. generators to drain followin g the loss of natural circulation. . :n crea sin g the
- t. re s sure. _: n cr eas es n. ow tu..rou en the .crea.r. anc t.ne re o.v. cecre as e s e
en, 3 f. ,._ ._. u. , .' b . ._i u.T. _ _4 ..e '. o.. a c. 4 v e n % ---
--=ks4e. _
_ ' .s k. . o " '. a % =.
o u.a ..- c cm.. .:._gt. ;
-..c -. . ;. -2 e. a. .- ,_ _ . a s . . _ : ._ _. _ w, : ,,.
. . ._ ,o- . . _
. u
,.o c.s.0 .
s_:
' o ".". . e . .:. c .w. . o .'. ". n =.
a q. .=. .=. .. s u n .' .' .s =. -' v. .A.....*. a - o '_*. s. _ ~.~..".=.e.-=.
. n .
2 2 0 0 . s ; a c'. */ e. ,. 'o.-
. n.- 1 . O a .*.*. _* c n'
- s.e .
.%. '.'., ". .-'. ' _* .'. g c. '.'... ' _' '.. _* c n .
. ..' .-.i, .
n.. . . .
e.
3 wwuob,.h . 4_.n._ . 6:s..
6 : a:. c.
.nwi.. u. u.. .
i
- c. 3J3 .
.. . _.d.su ....a..
- .. :on .:.a, su .o. ..~2 <..=..u..=. e u' .~ > - . . , . ' . . = . . .:= '_ *
. . . 1__t. ' . a_ _s . ,
,. _t _ . . o ~ . = '- a. . "e n -5 e _ ..
. , ._ ,; a s su r 4. . a .
. oa.n
%. ...g. . . ., .. o *. k .. s c.n.
e.ya 1..a.. e A _ n
.2 .... ..s "o e ~..4 . . : . . ... . - m , . C ,,
.' =., ~,, e 1 an d o = a >. c.' .= >. w =. . y e. a ~. . e '. .',=. c .s .
~
. . . ' " . = . ca_' C"..' a'..:
. . .s s.... _ C .s wa e, e .-6 o.. - ..= . ... =. . e .3 v. . c o n , '..- - .m. .. .. .=. . . .=. p .- = .e. s ".. .. ... a..c., '
... v, . . , . , , , . , . , , ,
- j . . .
o . __ ,_ . . . ,, e _ ..e .. .. .,. .*. .*_a
_ .c c.__ .. "'. ~.. . u = . a ' c _i _ c ". _' a ~ 4_ on. ' s 3_ co - -. g .
. ; r ..
s 4---
' " k a .. .* - -- .
'w.% *- ~ ' - = _--o. . ~.= n. . e
~ n..,. ... .
- a as' . i. ~. ; , ... . . . , . .
- s. 2..vs ' ed '-- =_ d su ..., . e .- .d. =
. = e =a s a s * ' ' .. o ".3. '.h .
...a,,c-une .c.- o e- w.u ,- w c , .. ;, a s ,. s .. ; 9. ,_ ., a g . s,:
,gg2 , 4 .y:, , c . _ . . f
.__ .. c .u. -
u _ -
This will probably result .in a lower ultir. ate core level and a ,
higher pea.x c.,ac. te..perature :.. t.ne core is uncovered.-
.t_ . I:cs e tv. e. e ahalysis based on an appropriate : odel for the ver.. small-
, : e a.. .< ., . 0 . n s --,. ,.: .
...: y . ,. 3, , a _: ......_...e.,. . ._. ..u . s .
. _ _ . _ _~..-s-r- -
u ... . - . . _ .. . .
&..~. , _ . .., . , . .y.-,.. s..... .e... .:....,. -,t .in.f .._. .. .,. . ...
3 s ~.
~-
~1. '. - s. 7. .-' top"plend='_to diaih"a'fter?-a br.e ak.p.7he. actual . . ..-nigher pressure.. -.
- .-- .. . . . _ . c:+., . . .~. , :
~ , . n __ ..._.n_,..., __-._ r =. .. _ e.. . .. ;. w. . _s :-- n._ ,,.__._... - _ ~.. .. .,.=....=.:.. :
. x.~. __.. n. ... ._w . .. . . .. . ~ ... . . . a 92 'N .%:Gduri~.-igHti. r_. ch.i.o6~of; the ~ drain ._. _,,.. _::dhe phas e%~. .a._
drain- t1=e.
._ a= a .yw..w-u:.a.:., . .=._,. .: =;. p.. :. .n.c :.a, -r~ -
. . t :. : . .-
e . ..
. v
.. m.,.=,- ;r =.=.._.;; + . -
-5.=. - ~w. a. - . --.,.a.- .~
, : 'M. . - . =i Ti~. .u___. ..rFhoW 1dHg=:.after?.a'=treak: be.for:e call .deea'y. h. eat:cana w,e. _ .,. y.:w gure
_.a-- s.Wsh - .oW,. .e g._ . -- .f2s, , a. . , . . . . .c ;. . .a. . ., ., u . . .c. . f. g . 7. _ .,y. . . ...4#. ,,s,,e.
. : , ._ ,s.. ,._q y.
_.--=...._sc=. *.
pa ...
.. -- '
- e .; .:
- _ ., w..n.....- ,
2 th;e r.bre s.~..
a'k.-
.>. - + =. -- - ,-..,
- .c.7c
the.
ran
-%=- .o :e- .:.'" b. e:;;. r,. ..a-e=ov ed.th.roueb' .,a..
- u. . _:.w:.. ,. . ? . = .. ._ . ; :.g e of s: . aller. hreaks
...n.-:- - ,.J
-: - .::- : , v...:..
. m. . . . ....._.
. .._..=.a :. . a.
- r. - -.s . **;.=s f,.a. < t. :. .: .v . . . e. ..c.- ~a.r . w~4 - ~ .,J-. e-. 3_. x. /. -.,: wm. .s -; .. .
ak s1ce.;1s 7somewhat-=a..._--
. ~ . . . .. . ..
W
. ;; reactor
__vass elv Ara: ,.. ;=.vn ..
stime for . ._.:. - ;-
g,.-.r__n- 49.* wt; a.
=
a .:
.5_:.,.:.af..,.sa:.u:.4.+=-v. .=:dN,ii[: +_.v.c._p::.i_..l.::ce . ~~..-+g
= .x .a= _ _.w. ..n .-..-,..:. - :.- .2-- ,
- ..-. .;= c 5 5. c.;e J 2 l ,
- . ..
.F. . ? .s.h. .. o r. t e,.r. . c a n t_h e .'.
- .. . . ewe.r gy e ;~ . sf.:e :-;g-se- 32. t : g,. hi.s me quilib
- .;_._. riu m t = e . T
., , 1 ,
. = . . _ . . -
w a .. .-.c .. ~.
... .- , . . - .e : _;. . :. ,. ;, . . :..,n.:..=..-:.=...=..,...r all...=,e..
- a. . - .
. u. ;. - ..
." 7. 2.atura1 c:.;rc:lation .n.~.. cea s,es -be. :.. ore .tn e cr eak can . remove --..;
cecay l
'1-"
- =. := . .:.x. --.sc = . -:-. ,..- -:
.. ,. c. . f . - w. 4w . :.,' _+ . ,.e H...s.:.:.- - ,.... =. .. . . ~ . ..
a,_._<-_-
. ..sne_o u. -, - .u .. . .
.4 _ _ _ o. 1,._ .:11'.c . c". s .. a v-".i. e d . o e...-. v.a.
,u4 ,
_os . e. .
e .- _.. .. = s.. .
. : _:. ._. ..,:.. .~.
.w . . .
.::...:......__r__._-.:c.._..._r.. ..
' 7-~. ..the exesss' decay heat while. vaiting for. the steam generators to
. drain following the loss of natural circulation. . In crea si.I.g the
__-._ s s _.e . _: ._. .c-, a s e s .ov.
.. '.h..o#..;.C. "m . a_ ", _- a_ : P. a . . d _ '. . =. .- a. .,k, v, d e c =_ _ a _= =_ s en ... cy ,. .@, : ,_-: 3_ _4 ..-... ._ : _. . ,. _. o,c a e, _ v a.d n b - =_ _= >. s _i .a. .
-e
. - ' . s k. . o " ' ' %
~.
- a _. .-,_ :.__ _ ,. s ._. _. __: . _. ._: u. ,,.-nm 0 ,s_4
.. , o . n.a.
_c_-- m ._ : 13 ,.- . . . - e. .a , :> s.
. s n .
a s r _= .=. _ s " , .' .# k = ' v. . = . .. ' . ~ . . . a. ' .' o '_. e _-
". .. ". =. , . .- =. '.. th. . e _ .:., c,. k. . '.- o.' '.h. a_
y -
25 0 0 esia cu.r.ve, s.
for C.n = 1 0.uhich is.the bounding cendition.
. . . . . ...s.s
,.._ 3.w s. . o t.,. _; h u_-n ._ e s..,_ .. .,. : n o 2_: w a. , u.s. . 4 , , , 3 3_ ._ . .__.=su a._
._on _s
..,4..__3.,, ,
w s..ou..u.
2 3_.._ .m. n 4__,e . ._, o a s.... . . . . . ee.e e . v_. _,_.. _:,, .
- a. _'. e s su .. 4 .. .- '. _i o n. '. . a ". =. . .o . .k., e .a_n
- a va .' " a .e d.. .* 7.
". _ _ . .. s o '. . . ..4 . . . .." = .o_. .
3.ye_, an .8 c_= a . __ -'.=.A * *-..., e. a " ". =. e #. .# =. c _ .s . '-. .~". a c' a _' cu _' a '. _i .s t<.._ e.s.
wae ,.a e . . o. ...*. ~ ...=. _ e. _' v. . c o n .# .1 .9. . . . ._ * . . .=. g _- =_ _= s _ _- . . a .. on . . .a v, .. .- u .
~
"f. .-'. order'.to. remov . . . . e _d.e:a.y heat. whe.n. natural circulati.on. is icst. s
. . . . s . . , .
' __ =_ s su. e i r - a_ _a s a_._s sw '.h. o u z ..k ' %.. =_ '-=._=t.. .2 ,. 2
~., n..., e a .s. ,C_ . . . .g. . .., .s.. . y s '._4..e.< .
- s. n e~-
c- e . se.,.
c e c ,.e a s , s. _...; . . g, _ . ., p...c- c.. . :a- ,. a:__.
n._s_.u.- r ,gg
. . .. ,. ....:,c..
. . ., _y , .
This will prcbably result in a lower ultir. ate core level and a ,
s "- , c ~. . e . e _e .
w : '.. a. ..
- c. a k c.' a c. 6_ e. .. _ =_ _ a ."
a- . . _ -. ... . _ cs * .
.. . r_ e .:,
r ..
tv. e. e analysis based on an appropriate .odel for the very small-
- .'. . =. . . ". .. =*.. s .
u e a .<
, . ,. 9 .n . :
s _ c "'. . e .' . ., d *. . e ... . . =. . . . . ,
- m. - ,- ,
. ... ._ .. . . . .. . . . . . _. .......,..w.... _ ...,.. .
J.., ~
. * -, ..: leg pipes; :. .(e>:ce .. . - . ~t.s.for a.T deh. sit'yTdiff erence correction) .
A m., ..: .-===.r .-
=_.,,a. . = = =* .~.a.*....on---.* :.=. v. - s. 1 . .
.. . - . . - .._.. ... . .;. . .:. . .,= . w ..w __ ===:. a :..= ,=+ .. .
. :- ._r ., : -. -.. ,
istehm. : .a w.. -.
whichc . ..s,-
c_- - .r -2:'. p ert:. on ..ofi th,e _... . . .. .. '.. g.-en. .era :- .a.ted_s;1 . - =. . =thi n-.-. . -
t
....._-n..-.
....~..:..,.m..
- .-a, see s
. , . .u-n.- :.
-. - w-.
---=-.;,-~.y. . =. ..;a z_~- .. _
.a t.m.rert,icalc hot- .,:.e g s. a nm und ergo _,u c=
. . ...,n
...-=.w
.:.+ .c.m
- .th et g
r-
- ea e tor
. . v: :.
co re...
. m, le.-
e
.:m.111 :., - b,.;
- - t_ sp, u . eay=- x ... 2 n to rth e=
,.. w . ..-.- - .. -n.u -.
.....~..w.
.f.c.s- -.- .
- , . . --. .-, _ v. :w :. .-...:=. .. :. .,: . -:.- ~_..e_ ... _ .:. ..w. w=+ : =
n - : - : . . :~...
.ci s en g.a g e. =ens. t 4 at;.C. .e.i wa.. t er-s te. .a.r.: m .:cnter., ace
. . .?. '
m: Th is.:.?. .- steam. t-..s then.- . 1 .
. .. u . _ . : : :. .. w . .: - .. -. .. w c-.
.=. : _ v=:.- e :. :. .- m .=a.-.:- -_ u :- .. -:. :. ..
_ _ . . :. . . . _2 .
....,.c.. .
%~ _ F . ~.j. - --
C. : : . .. '. -fre e -t'o cond en s~eliEsid'e that?.po,=rti~on '... =.:-.o u,f ' th
. . .,+
..?:- .+. . :. . ....n...~-... -
- --. .a.;.
- . -- . .. -.. ... .i .
..w: y, u - w .=. =.
._...-r...
- n. . e= w. .=.o - ,n ;. ./_;, w.. . ~.: .
. - . . .: __ . ,: .. . :. .. . = .
.wh ich___ s ar. .ov . .n. ..
_ r..-pr.ima ry . s e_wa , .:. er; evep:ani3.be ow the,-.
y ..
- e. t..ne . ' _ n. .. ....
...u .- , ' . . .=.,.
. 2,.- a.. .w
....~n :. ........--c...:.....,a .: - .-..:
.=.
_ c. .... .
seconc a y sa ce gater: level.b:: Conc. ~ensate. ;nsa.ce the' steam.
= * .d . . * * ~ . .* _ . . _ , * -.
J .. ,.
.t.
. . .-. ....-- - - . ..- ,_ .. z-_ .
.. . : .a, . .
- ' c
. gen.-era tor d. ube s is..: fetu ned ,-io the reac tor vessel,'by c.rav' tv fic.
~
... . a. . .
throligh . th e 6. :=5. 1cco rs e al s an d c,ol d l e c. .ci =s. . .
= . . .. ., . . c.. ;. .= .. . .
. 'he reac c: vessel level (tu c - pha se) fluctuates above an e.'a~.a__4o.. - o_-_ x__ o..d_'.., ,
- , '- o 'm%. a_ ' c o o ' ' ...k.a. h. o
. .4 . o n ta _i h o "- 2' e ,, .
,_e_su.--: -a .i' '-h e l a_ v a. ' . ' . . , 'mh e v e'.. '-4 w e. _' -
'ms. ._
.'.c '- . a : y4y -as.c' ors *- o
%. , _ _: _ , .. _3
. - . .9 _ . %. . i. a. ., 9,eva'# C ". .
_ . n' '- " " a " *- # . .. a- ' .b. a- _-*__C*--
- . . -_ "y a _ s. e s_ _"
, 3.r .... _1 a
- .s . e.- .: e .
. ' . . . _ - . , . . , .*. b.. . . s. uo'-
b
_a.;e.
- 6. %..s. n C m.. .. o. p. s m. s- . n 4. ._:
s b
- c. no. .
A
.n_ . .- a d _' .., - _ - .". o u c.i . . .%. . . k_, . e a k. . . o _' c. . c =_ _-
. o_ .s . a a. d 2- m n e _' _i t. _4 d ...a'... =. e..
capability. For certain s:.all' brea? LCO.;'s , the rea Ctor vessel
'_n ' :..
.... 2.
_ . . ._ _.- - u . . # ' .- .. .= . .
. .v x =. . . c .' . .%. d "-. . . # '
. _ y ,= _- . ,~ . . . . _o,, .e t.a core .has been .uncove:ed f or a pro'.cnged time.
For certain
.s.. > __=__ ". .. a a ' . s , '. " . . . _= _ c "s . . . d ,. . _43- k. '- %- =_ .. =. a . .u. . .d
. - A u _ _'. .. , . h. a. . .a , _ _ c ;-
s__ c_ _ . .. . , u_ _:_., -. ,. .". a .. a_
~_ '._ a..a _i ' _8
- . . ."o ... . . ' '. "
a ' - - '_- -" a ' m n _ s. , pc e.. ',
u
.._a._n ,, ; . .; . , . . .. ... . .
.- ... #_ e.; ee _ < e.. __n. .c_c.. n_e,s _ 0 ,- ~- .- o n,. m. - . 3. ,- __ my 2 4 .
c ' - w_u 1 > - : e n
=
- .r. . ..
- u..
9 4
. _ _ m. . . :. .: .- s. ._ a' &.o __ o.p e 3 o. _1
. 1 c_ V e l 'm" _- . . a . o u .# , '-.' . * . ' esf e .'
. _ .&. . ,. . '_ s ' c
.. . .s .s .e. , 2.... A .
c..g._. ... _7 _3 y . 3. --- ,
.....g s .o i n , . ,, ., ,., :,.g.
- y. - . . .
g
,,0
- ,, c ,_ g 3 ., ;,g ,
. . .,.r c a
., _: - . . .n c. f r. E a ' s # n * *. . =. '.' a. **. ' . 4 Cea* *
- ,. y.,s. n _-c_ -
.. . 3 .. ;
\
r i J ..a: :
e.:----~: -->a_.
- 'a.,- :.. :. .. ..
.::.:. e s. ..
--- _.a . . . . _
v= ^ e. _-r- -E -=,s .
. . c.:. :. = : e n ; e
,.,. .._:. = . , , .... ,. - c. :. 7u-. - _ s '-
- . . ~ ."* . . ~. . .~. . . .; s n. e c----m., - - "*as ^"=. .. -
. .= , ;- ., g
.. . ... ..,. , . _ . > ...t .. .
lec cit 6 Efor aT c e.hs it'yT,. .... . . .... .diff erence correction) . .A
. .., . ~ : e-.: s .... ( e .. xc e, ..
. .=u.: :e- e,.=. -y: ....
- z. : .=m . =. ~ =. :.w .. .. . .. <. .n.. . .. . .:...r
... . .. .. _, . . . . - . ..e r
-. - :n.=..a
- g. -.- -
".r.-
_:.- -er per i. cn .of; the isteam *whichri_s*sen_ er.
- *
- e.1^..~. s ,
- w . e' s,. a : a. .s .. .,_ . ===.=. . . . * .. m..a ;=.#-w ated_Vith.. t : .y
. ,;.. .a.S ;.-- .. .a:.n the!. reactor. core.t r? . *.,.
- :.:..,e <.m.c.r .. .
. >>.. . ..-. -s. ..:.:.:~. . . . .. . a c.-v. t.:
a ..,~. . w - . . ...u --~ .s . me.e. a.. -- . . - . . - .: . % :,e .:. . y 1 c
..s, . he mertical.:~h:ot-legs. and und ergo. uncle.-
- . -see
&<.- ' '.-.: br. ts,o ay:u .-ntort ..;~a, .
. .4.:-m- _.., .i.11
. - . . . .. .: .:.c . - .-, .....2.
- g. . g . .w ,. . .
- :. . . . r .... . . -
..me ..:- ..
... - . r.,:.- m c......~.c.....-. a=. ,
s----q, -.- ,._
e - . . .:=. : v::, .
- r. s.=+ . ::.; . . ::: m . v: ,_ :. . : :. .. :. -
. - - di.s. e.n .:- .r c.a .e. =. en e ,.t=- at,. t .a. n.
- .m : : .
.. m-.. ..- u
. . .-- ....:.=.. .:. :.- :. - . ... .:.
- .- .:- . -a.-=
u.n.'h.e - - :: v;w.--:t .:er_
w :.: -s_te. .
.,-.: :.:: .a... -.. m... ? -.
.- . : = ...
n .terf
.. .. ac.e p.
. .: This . .s.u.t eam
- i. ,M . Z.v-fr e e ..t'o con d en s.~e ..i3...s. i..d.:-.e. :th.a.t?.po. w . .rti~cn ':of' . the . st. :
..;.._,...a.~.....,. . ? c ';. .. ;. . . n. >,
~
..n.: ;. .
. u. . ..c:9,.. .. ... e _ ,. .:.y: ....:.
--~.... . ,.L ". yhi. ch- is_ ab. ov.ef th.. e 1pr.p' m. 3 .:. .w.c-.: ,- ..
.. . i ary
.'sidef_. water _-lev e l ;, . . _-. . . .zan6.below c... th'e _.
. . - . . . u,:. . . . .. .:< :. = ~. . a ..
- .: ,a.: .- ...
.a.
,n.. ...c.. _... .. a...n.......-.-
. , .: --= . . . <
. . . . = . . ., . .
second . . .
a y. sics : .
water; level.M. :. Condensate .
.tns: de the' steam - d.. : .
. . . . . . . ...-. . . _ _ ., . . ... ,c.. . ...
.. . ,z. , .
2..,
generator .tuOes is returned .to tge r eac tor ves se3,'.g.-y gra V:.ty f1C'.
J . "*. ..
.-.I throl:ch'.the d.u - 6' 16corseals and c,old leg .eines. '
T- -
n . r.: - .
. .o . . ..
The reactor vessel' level (two-pha se) f,1uctuates above an
. elevati'on corresponding to the top of _the ho:fizontal hot leg .
pipes u.N.il the level in the ve'rti' cal hot leg pipes . drops to the g e_ _:_
- '. a.' 1. o '. a.., e'eva_'cn. _ A ' ' ". a * ' 4 . . . =. 9-.e
. _-a_=c
- .- yesssi
- ,, e .y. . e .,. a : . s . ,.
, ....3 . . . . . . . .. . , . . . .u. c . . 4 ,. .; ,. . . - u. n. .. =. n d a. .... a. a. s = =- . . r'.
- 'c.n; fluid. lost thro.uch the break no longer exceeds the lic' idu make ap
~
. n . : .- ...,
i c.4,-.,
.. .-;. . : o . c a..+.a #. .sh s . .a. l '_ "- e. .d. . . -~ o ^.'. ' s , ~-.5 e . e. a c .. .- ". e .e.r _ ' .
. 1
, e..,,
. I a,
..- -.......,__n...; v u- . a_-u.._c g..-_- . . :. . -- _a ,.. .. .a
. ....v,. .. m .
. . e. c.. ,=..- ....e i
.s e a _- =_ /. .aa. - ' e. e.. "s.. ." o v e . =. .^
. #_a .. a ..-e c n c. =_- A -:-... e .
r c- -=_--ain~
. s.._,_ _ =_ _
-'-e a r.s , a. ..=- ot.. .d M. .e h. w %_ - - -
. . & _ e o ..k.=. .d A " - 4 ., -- -- - , ~ 5. ._ n a .- a t' s . .: .- _ ...-. 4_. _; ,.. ,. .S. a .e. =
a.- '
__ a.. .i -8 ..
'- c.
a' --- #-- _a--_n 4- ~.~.
..e_o'-
b.c i'i. in g. . '. . . .s.
. ,- _, 2 0 4,_ .c ,.
3, m ,, ... s. s. 4m- 4 e. ,. .c. c.., cy.o., .- o n ,. . - 3 ,_ cu- i 1, 4en
. w... .p *. ::
. ~.......; * -
- - ?' . .
,., , 4 'avel 'u_na.cu.d, " . . - =_ 9- eve _1 .e '. a . . s _o
. _ _ ..e ...- .- =. a- w '. c % e e s = 9 -
. inercase and e /enhually returns to the top of the heritental het
.r 2 _
.__1_. . ,. s .
- c. .._,.a.
- - . - , _ . <. e., .- 3. .. .
ure a. _ -. . . _
.. .. ... -_: c a. ,..... .. .
=
...e.,..._..._a:. _n_.,.=... .. :-
p!. e s .
-..: p:v. .- . g f . .so .. g
-e..g..-;.c_ : .: :.
- .=:ence
- .. :. .... :-_.,, e: n....g
...s.. .. e,,...
- - - - -,.e-
.; ,. . . - o_- ~< es ..,. a .. ..,-..:_.
. , . .u
' clodly . com.rirds'sedi. a.n.d . 'co. nd.e.n.s.ed. 'b.y.. th.e . higher r ea ctor ve rs ea
-: . .....:. = ,.s
. > . ..:.t.r v.r u-. u..
. . .r.
'; i
. . < . .n .p._.pre sp- sur. e, -- E.ed.e.ver., j'.th.e.. ..'.l.,tF-b e. n...wd. . nay:. . . , ~ .~.
,.. . . a
......,..:.,,o,,..:...,.v..
..v.-..
. ;, a. :. ..~, -c.._.- .n,:
. . =. ... . a. , . . .. . m. . + .. v._a. ~.- . ::. ..
m ..-.a..--
....u
. ...c > .- . . .. . . . . ~ . . . . .. .. . , , . ...
.1g poi n e. . _ , su.,.,.:.clen -.:. -
,J . v::> .
I ut.ula ,te d- a t '-th1-s > system
- a. w. . .: -.., n... -..u.~....c.<..,,:,.~...,.
x.,.w:=hich~ w
,. - . - * . ,h. .-..,.av.e.T.a.:e..c.
. .n. .. z. _.....n,,m.,. ._ u.s . . . . - . , . . . . . - .c ...
- ,w, j .-,-..._1..
=. .,. . .
. 1 m p.e.s ,_ ,.
- .?.nonconcen.sibl,e... .. gas es i, it .w1 . e. . , _.
.w. . >.,. ..e a r e..pre s o.e_.. nt . p .a.,.1, . ,
v . .j: . .. .
- g. . :. . : <:.. . _.u;, ,
..u:
. .... ,.x... .
v._...
.<.. .e. . _ . - , ... . .e .. . . .
. . . . .r. .t.:.on.
/ '; .-th e U -ban,d 'vith fluid: a6 6 .,&s tablish'.'na.tural
.-... ..c1rcu
- a. sr.; . -
.:.. .. :.=. . :- . <. .-p.
. > :q:. ._. .: .n :.L.,::v::.w .... -: . y. . . .= .
< y :. . . . ...
.- m..:. w
~ . .Y...... . ..- . ..,
..us. e.
?;,,,.
a,a. .:mx.
. .._ . .s
- .r. ,,.;
..-r.:, w:
.a v...
v -w..
g: as.J-q._..;w4.+:
,j
..m. ' , ,y.. . .?,,;..?.._,
',: ., z .: .. ..,a........y<, . :. .
.. . -. . .. .e._.-. .. . .
W 22f.F. na'tur.s.1.2c. .ir c.uli.ti6E -ii c,..re.. established , the :eactor vessel..i ~. _
F
.. .; \.2.v .:+- . =.y: .m = . g... . .. .. . :. , . w . .:.
. . , . .., :- - -. . . : ,...:. ; ;.. > y. e;w . .;.- ..-
,s. ..
'~
- . -1 .'..'.1'evel'.;is7above'-the g -. . .:. - c .. ho-izon.tal' _ n .
hot"le'g' pipes, and . incr
.. ea sing ;:'. .- and
. . . . . . . . '. . :.? : ..-
. .n: .:. .
.v: -
. . . .'th's Feacio' r co ~olant' .
=.i.cin.
v .and .. . . .
- steam generators are full of -
.: .- : . .. . m. .. . .: . .. .. ..
water.. The reactor vessel level. cont. nues :o increase unt 1 operator ' action is taken to trin back on the nakeup rate. , If
' ~
~
natural ' circulation _ is 'not re-establish'ed and the . break cann remove suf ficient decay heat, the reactor. coolant system pressur i increases until ade'quate heat removal can be achie"ed th:: ugh t;.
break cr. the pr.essuri.zer. saf etv. valves o.can. . .
r . . .
At'som. e" coint; . .
,op.er.i. .:. . tor..ae. tion.,, .. .
may:be' invoked to ocen
. . . . . : the . .
e ..es*..i . . .
a-
-- e ' e c ' . ....= . i .
- k a. '. ' 6 .' v _= '.v =
- o a s s "-- e c c.. . s _4 . ." > '. .' . . . e.
w e ... , -. - _ s . ., a ... e - e. c . .=. pc 1 a__
. . ~ , - . , ; , : n. :,. , o . c -.-: . .. .. . ......_..a,_,_ .e..... .
provide,'lsuf'ficient' depressuriza tion ,to go.,on shudddwn coolf.n - . .
.this valvehas,not been qualified (cl.a ss II po.:er; etc.
-Io .te v e r , .
.to.per:orn.....
an essent- al nitigating , unction and can .se m .
'._ .: a c. . '-. : .a.:.";'... e . ".ve.s'v".
- e v
- .. a : . .' a' a d s . n .'.: .=, ' a
- _1 ". e .
. . . . . u .m .. . . . . . . .
.. . . . . . + . . .. .
6.: ring . . . . ~ . ,;
.the *transiti.en . : ..~ :
.'f:en. .
Pool w:. . .
boiling v . . ... . .. :
, to natu'::a1.ci culati:n , . .
... .2- .-<:.,.,
... .. .r.. . . , .
the Te:tieni hot
- 1eg "gipe sta:;ts to refill'and cover the s. urge 1:..ne conne: sen +o ^ e e--=ss" - ~_ e . .- w. . e' v . e s c u- - - - ... .
.=. t,. .
,:,.3
( ..,.. .. .. _~ .
e.
. - ,. . . ~ ,. . . e . .: s' -' *e c a s a e ) a s
-- .. '. - a , f d
..,,,....:=..-
. . . . . . s . a. . .. ' ^. '- -.' -. e. . c . ~A s ... =. s o - ' s ". - . . . =. A ~. .s..-... - . .s - . u- . .
I I
g.
g - S
.- - h- * -S - S .* -- ..
t l
l 1
e
. slodly co:-ires' sed.d. .d 'cond.en. sed. by . the .. higher reactor ve:se).
.- .. .. . ..,.~.:..,~-:.=,........w.. . :, < . . - . ..
t.
i :..-.~..
.. . - , . . . . . .m.
- - - - ~
'.. 1 - =. .. i. .. pre ,.
s sur - e., .
p _ _m :. S. m. .o. lever o
..c w 7t.h e'..a._ .,U-b.
. .z:a e. n...:d., ,.,.', ,_...
- y. . : ,z ,,...
.nav
, , . = -..,.u.--
. conta
. .g . . .in .n on co,n,d w. - . . . en c
.. ... . . . -. u. . _ u.c e. .a_ .=g%,
. u .s. .- . ..
_% ~
cs j m. .
Y '~ ' ..... .J_wh.;.,.s ich have. : accumulated- :n . , v w .-~. . at.-this.:.mvsten . .u .- -,~.'hich
. <.. point. ... :If suffi.c:,.e.n
. . . ,- .. . w.u<< r. :.n..~,.*-.x ,-...s.
-t ..w
..n.
~.r-...e
... ..~ .. - . . ~:... .
.w . . ~.
,. c
. . . rn. . . a . ... - ..~= - .
. ~ . ..
~ .a
.. c .nonconc s .3.-c ..cas es ar e Pr. e.s e nt c. :.t. 21,1.. be. ... .w ..c..o. .s .sei s.,
. . ....... to .ra.r.: _., ,_
._ .. en.y..icle..
.~ .
~ - :. -. .. : . r. . . .. :...
. . . . ..:y..n. . . . ...,.v ~ . ..>.,...~
. -th e U- b an, .. --, . -.d with fluid' a6a :,6stablishIna.tural ci.. . -..rcula.tlen. .f. .,;. ~
~ .. . .. . .
- . ~
..= x < .a. : . . ; c w. .;...... :.... ; ,. ;. .,.... . ,< , . ;;; .
- m w .:. . .m. , .n. . ::.. .m. ~.>...w....... . . . .m. . . . .. = . ... . . . . = .
,a... 2. . 4:> .. . .. v. 2._; :. r. -w- w . :.c. . .u. . ..;- . = n . :. . :. .. ..
-- .:..-.:. ..:. .=....:; ..v . ,. . . .:> w . -
1.:~f_:.. l.;c. .e. stablished, ,.is there eac'ior vesse19. . -
>' .n.n,u-e ..= . ,.....If- na'tur.a. irc.ula..tio'5.
. . . .. - . -. . . . . , . .... .,.....,. :. p ..._..
u... ....::... .
.. .a .. . .
E. '.leve1~ isabove';the....horitordal' hot' .legipipes and incr ea sing ,. and
. -. . ._ .:..4y .- .: :.._ .- .
coo'an' e s ' a s n. c aa-..'.eo s =- e
._ o .doin . . .a . i d ' --. - '_ ' o =
. th a..-aa
. k.. . .- . , .
.- . water..; The raactor vessel level . continues to increase until.
- u, < o ,. en, ... a . e , - a. ,- .
o-u. e a o -
a.c._;ans 1c a .,1...- , n o -- :n .. . .
_a
.m. - s. t,. _,. a _, _
- .c t,. ,. a .. : o n _: s n o e - e s a b.3 s '.' .i a _* - a.. - . ' k. . a. '- a a ' . c 3 . .. .
renove suf ficient de' cay heat, the reactor coolant system pressun 4 . . . .. a. a s a. s " . . ~ -4 ' a-.v".=.--
a P, e .=. t .- * . ..o". a .' c a .n ' e a .Y a".. a. .... * ' ' . - . -.. .
- b
.". . a. a 'n. c- . %.,- -
y- ees" a - ---8 s a ' e',, " a .'. ". a. s o :- =.n .
k c ,;
At' so e point;' op,e:ator. action nay be' invoked to o,:en the e-e s c. . :-- .. e
. s ye.-.,.. -o,:u e u , , y ,- ..-o a s s "-- e c c. . 4 . ." > '- r .- -e
%. .. . . . . . ,--. . - s.,..,.,....:.c. .
=
. 7.~1
. , - 3,-; - :n 3 .:,
c.m- :- ..a-
- ... ...a provide' sufficient depressurization co go on shut'd:iwn cooli..:. . . .
-Io ue ve r, this valve 'has not bien cualified (C1.a ss II po.:er , etc.;
to. per:orn an essent:a A natigating , unction and can .me
- - . u:
-..ac-
.a - e.= w_ .y a pas' -
'a'aA s4 n. ' .a.
- - - .' a .t _1 _e. .
c .. a = : n ,
o i .~-#-"-
w..-.. < n , .u. s. ~ a n a :s 4 .c... - c~.....- :c
~ -u -. . .s. ... o. . i. = ~.u .a l . - -
~
.e . > . . . , . .
the vertical hot' leg .:ipe starts to refill and covar the s-. :: e . -
s o -.*e e-- 55.,-4 evescu 11..e conne; :.on - --
e- . -- - - . ..
. = . =. ... .
,4,.s
( ,... . r- -
e ,- -
-- .... _ ,. --q--- 2 . .: s --i " ' e : a s a e ) --
- e. s '- . . . ' - a r= 2 .
-) ^^.. ".-
i
..u...--.-
. .. ., , ,.., -s g.,..,.. . - u w .3 e. c ... -,.... . ,. s w.
- . . -- : s ". a . . ~. ~. A. .. .
a.... u .
- p. g -O -SI .
f I
i l
-~ .. - . - . - -, - _- . . .- - .
~-
to in C. IO Es.e. C ha s.s,. : ).C. W.. . Tat net e : C- C 15 T na r. v. a.:. y ,, w. . . c - --
..:.. . . .- : .. .. . . . . ....-....,....m....a
. . s. ;
w,.
w-w . %:idne breah. s le..s.s,. t.haiEO.'02 r~.., . f..t2 ' .wit..~h.
c . .w, , . c.3. . . n . = _L.,.O.-kili reaetor: drain
..-x-=,-....-.
. . .w
. :..-.u.....
- -- - - -: . .+
-r..... n,.
.-a. .- . a .
. :..::a. ~. ..
.v: . ".:- --- .
- . . e. -: n-.:: . n.==- e - -
~
. w - -. - .--..n-..~...--...c-. 1 .
~7 .: - -e . . - ..i tame fc: d.a given,-breat . sire.w.'
.w be 'semewhat. ,,....x.:...
shorter. .than . en
. ::. ,.. - .. .:_.-. .---w.,..,.:
. .= =- . .n.e. .-= rrm .m. w=- e . r. ~. .s . : . . .
Y .
Ar. .z.... -. .
.m. :t= u 7 . .r..=..
r - . . . . . . .. .- . .
- w. -..r...u.. . .-- . : . .-wc
.. .,.equilibr.ium
- ;;. 1 . . _ n ....-
. ..t1.me.,~.:e.For:,chis
=. . -
v.~. y .,-<n.
.e. . ;
case,.. ..natural
. circula. . t.io.. . n. .c.eas.
. . . e.. w..
- . . . , .; .
- n ' . b e f o r. . . . . . . .. .em.. .. .. , .:.. ove~ ,:. .. , allT. ,.. .:. -decay' . heat and: some system .
- e. r., -the br e.a. Y..,.,c_an .- . a. ..._ .; ...:a, ..;.......n-.. :. J..:..
. , ... ,u. .p
....- .+.:,.
. i
- n. . :. .. .p .:.g y.~.a. . ;e.
. .:r . ..; .. 1. . ....
. -: 4. .- :.;-- . . . , ;
. . n.
J
.w -
. =..
...,..s
. _ . .. -. ~ .r .r.e . ores.,. u r..iza.tio,.n,. oi::cu_.r. s._. -..o
.. . ~. . :.v. y.. x. .. .-, -... .,. _. ... , ..- . v w
.,c. . -e. . .n.. .a.
. ,n . ..n .
. ,wa.
t e. r,-si 6 e _br e.a, k wit h cp = 0. 5.l ..
1
. . . .the eomear.able. :.s. itda. ti,on '.dev el.ob. s. .f breaks' or .. which are less1 than n..,...,.-
. .. :.. s.. . - , ..
0.035 ft2.- ' I n ..b u...oth ca'.ses, th.e dif ference between' drain time and
. . - .... . . . . .. s..,.. .. . .
e.7 e g.v e . 8 '. i b i u- . ' " # . e' ' e a *--, ' h. = s = .. =. .
. ..c.m
- *..=. k
"'=..,"~.'..'#
. .p t r .
6 ,
'. ~
-a ac~o ' h.'=sse' d. a t n *4 ..=.
. an A e.v-' c. y e .:, n --- t ' .'. % .. * "w ~... "- .,e "c a - * ~. e. .
break area, , the conservative choice byer the range exanined ,
. a y ~ =- = - s ' o h a Cy = 0. <~ . . .
Figure 6 inci=ates that a Moody coefficient of 1.0 instead cf 0.f
<o- .. ....e
- - -s: 2 - - .s- .. . , ,. g 5 c ;ag ,..g - -
g y .. . .-a.. ., c. .. e. ,. . ..e. .
u
.ac.g ,-:n .:.,_
n- .
u"Y s' a a s"
- e s ' = .* p. .a 1 #- *- -
F- so "
a 9..#. V .". . -"~ e ak. . s .# .. e . .
u =.* ~. =- -- .) o#
.~cchdedsin: sur f ace .in' sic e .the' sr.eam 9'enera tor tuSes ; theref c e ,
n, e ' c o n , . . a : .>-.z . . . ,. s o ,. -. - ,y e - u . -,,.s.
...:- -, <. . -. v. - ~ : .-, 2 a=at, u. -r:---> - . , - . -,
% i~-y. = 0. e . .,
s . . ..,. .
. .r . . .
7.4.c" as 3 a.,d 4
- o ae s ~. c.8. ." ' c k - = = .>. , .--
. :r. ao. , V .r . . -
4' s.5o 1A - .. ..
.., .. .--4 ., .~... a -. 3. ,.
-.. s. ,
. -e.-. :. c.-
lo ss .
c... om e.>...'. e b - =- = W.. .e
. ..a G.s
' represent'ative of the fluid at, the core" . exit.- .
An a :ange: art fe:
au .. -~ a ~, = . .~7 s s. ~ .. m. c - ~. -
= . t wa ' = , . s ' = a.. ,* ,,
~ ~<. . ,. . *. n s e ', _',..,_ue
.,,e .n... ..
. J..- ,. -~ ...c. . . .. . .. . . v.?. . . .
s .. .
c . , g ..:
... .- - o .a. . e u , d. ', c' a '- i ~.i . .~is~- - . ' =.--a s su ..= 4 . -
'4 -
, ". . . s. . e. t. . - 2 . . s.. a 1.--:
- %,- -,-- e e e t -s,--: --. e m y... s> . . %. - .w. _a. . . r
. e .. - - mu .: . . . . , . . -
.s .o- - - . . . - - - -.- --- . . . . . . -
a-'o..s, s4, . w ea..u
- - o k..=- 5 ' ^:.. : - >- e s u -. =- - .a.adec 4c.,
- (".: ,s
. e.' -
.my bypass the core and hny decay heat ganerate d wi-hin .he' c:re ,
-3 v . . , .
, ,..., , w, - . ._2 ... -. . .y c . . .. . . .- . n 4 .. a . e . .--d .". - .". a. s " '-..=. .. : e d. .*, u .;. .- 3 .. _-
.O
_ - _ - - - , y,. ., , _ , _ . _ , _ _ , . , , . , _ _ _ _ , , , _ , , _ , ,
- t o 1.n cre.... z.s e d ma ss. t.}.o. Tao ne: c:: ect a s sna r. wu.y x ..c,.--
. - _ ..e.
- .- a.. u v... ._ _z.__ .a. .. ...e .: .- : - v-
- ; - . . ' ,.%__..16 e br.e.aks. _les E s,. t.h.:a.__,O._'_0,2 f. tu w t. h . cD_. =__1 i 0 ill reactor dL ai.n v.
.s.-
v . -:.~i. w- . .:......>,r......n.._..,
_. w:. c-.. ,m,
. - - -- - . . .e ., . _ . . ,s
- v. .
rq '
-. t:.
.. me f ori,a g v.en. -br._eaY s i=e .be semewhat sh or... --- . . . - .t e r .ergy, .th a n- e n. . . . .
- . . .. - .. n. _ . . - - ..
- ?. . . ..._-..
- ...
./: _ . :. v.::=.
u . --
, . m . .
~=. .a. .~ :
. . . . .- . m. . =._ ..
.s _. . _- -. . c. ,
_ : ._..u_ eq uil . c.,r.ium. t.,im.e., . Tor . t.h. .is,.ca _s..e , . n. a tu .rcu, ral_. c_:. . .yn c.eas.e.
c.
. .. a._t..io. s ._.- ....
.....,...,.-....:.u..g.,..,
.. . . . . . .. .. .....,, .m c.: . , : f. - b e :_ o r. ... ... . . . .e. th e b. .r e.a.K. a c,. . __.. .
. . _ . ._ . rem.. ove" allT decay' he.at ans: s ome system c. . : . .
. .-s....... ...n. ww u .~ . a. . - . . . . =. . - . 2. . :... .:- :-
...- . . _. :. . .n. r. n .1.._.r. .n:=.=.
.. . .. . . . , 1- ~ . .:. . .
._... iza = 0 75.'
. c_ r.e pres __s. _y ur. . n. tion . .o_ces,rs._" _ r..oi.
.. . .a.".wa.ter.,-si d e .bre.a. k with C3
- ... , .. . . ..w.
.. w
._.- ... m_ ... .= . _. ; , :. .
.r...,., . . , _ _ . _ .
.. the cc=carable . : s.
...itfa. ;- ti.on.'.d.evel.ob. s. for b.reaks' which are less than -- ...
- v. .. . . . .
8.... . . . . 2- . -
0 . 0 ' 5 *. ~. z .*. . ~ a...-.--'. .-""
. . ca'.s e s , - '. '. ., e 6 *. .'. " =- c . . c e * =. . = = = n. ' d _ _= .'. . '..' ~. .. s c. . . = .
.. .2... .. .
43 v * '
e.n e _3 - .v ", e " i 9 _*
- - . b., _it.. ... -. .e' .i .e a_.~.-'h=.=..=....=. . ._c..-..=.._a..,.--..'. ' -
_ e a c .o _- n. a s s e ' ?_. a t n ~ _; .. e a n 6 e . =__~ cv e 1 " _'
, - -.% . .* " ... *- * . *. " ~, _~ a ~ .' . e .-
' --a. =. *r. a _- a_ _= , '- .k. e ".o. .s a_ _ va *-
- v e c h. - -4_ c e 6". =_ _ " .b. a.
a n c e e. x. a.. 4 n=_ ^
a r -=__=_s 'o ba_ Cp = 0. c. . . .
. _ . . . c., _
- ,: : . a '. e. ..
. 'k..=~. a F.co.' v c e # ".1 . .' a_ .'. c .# .
. . 1.0 .' ..s c.-Ac . c .: vn . :.
.' c ". .=. . e - s _' '_ =_ ' -..a_ .o. ,. s 4. - c.. e a s a.. s
_ 'w h a. *. = . ~ . . -=..=.='c.
c' _- _=_ 3. . _: . =_
.,m x
) for a given break. size. .
This~ ~ assures 'an earlier unecvery of a.
-c x . ..2. , : s .i . . s " .c # c e . ' .. .l. ic e "..e. .e.
- e .= ~. v =. 7 = a '.o - _ "', e s .
. _ .'.a..-=..".c_-=.,
... -, e ,. .,. n .._.._ , . . . , _ _: . .. ,_
- s. . o :_ .- ~., , u. .... __. ..:
-=. =. .<.. ..._. .: ._. .: a:a_: , . u-_,
__,_2 .
_o
. I u n.
. e._u =0.c.. - .
1 j
as 3 a.6 4 t o a s ~:. =_ c .' .= _' c '_'_- = =. .>. ,
. .. ~ .. a ,_;_ ,
n_n ; . . ... v5c - . .
. - s.bo"_nA. .. . _
. a ._.. e _ _ < , ._ .2. .. . w-.
. . . _ ...s. a- .e._..: c ,.. o .e.t w : o._. : >..
..u. e .c a_ = k ' _ e _. . ..a _C . . s represent'ative of the' fluid at.,the core . exit.- - .
'.n a r ra n g e- a- fe.
- a. .e. ._::. _, ~., _ '._ t,wa ' =. , . s '.a c..,' . o _ <
. a . a. . . ...= s s _- _= .n .e . _ . a. .
- w. a s a '._m _ _- . .. _s. e
. n.c .s . .. . .
.o ..
...~r.
- c. =_ e-._*' '.o .~,.k.e. " =_ = >.. 1 c -a ~ '.~.. ..." s " '...=. a s s o ....=. =- ,' .
....~.n. c. e. .a.. . n -
t
~ .
. ..a. . . ... .
. . .- a. .. ... ". e #. e .' .'. e.-.". * ". e '2" b > ". a.. . ." .. = _ _ = > . . T.. .- o .- . a_.: ,
.: s '. *, ** . . . . . . - .
side break locati5ns, the high pressure injection ( ) pump e' -.
,3 y byp3 r.s the core and any decay heat ganera e d withi.. the c:re O 2 .v ..
=.te. .._.. 2..e y ,. _ ... ,. _4 .= . a. " . . _ . . ' . .". a s".'...=_ -=c....a=:. .: g . u.
t h.e n at. u ral . ci c. ulation p.,as e. appears .
y
. c, w. . . . . , .,.:. . . ... ~ ....r,.,.
y .
-.m.itig a.t...ien
. l ..;.:.
.:. Note . ..t,ha't v.. . .-. :: . v- .
= .. . ' . . . . . > ..w.: ..-. ~.-=.
- n. .
. . . . .=:. ..
. - . . - =
..-~...-.r......
,....ws,.-- . ...s.--^.
. ,:... - =,. .= . y: ....
- w. . -
- ::j. v.~ ..,:. .
au c.s s
=.-a mt..n.
gs.. .s. s u ---
4 a .-,s.
c.s
.. . p , j. .-.: ; i7. .:.aepL:... q .,c,&w.
s <:.s . . -.
. .:w %. ,. .a.m ' . ..> * .
m
,95, . :m .. a,- .c.
p'.g.<GG . a . .c. ., g. . . ,.. ..
. g:r. .. :.. n.. e=.~
r-* . -- - y 5., a.e-55. ....- ,.- :.-= . - u,..
.:. :;... . ry,
~
.s, . .:.a. :.a . .
%.=. ...?..u . - : = . . . ,.:.:w
. - , - ~ -
..: .-~.:.:.
.:; - ...m_ ;,?,.s.
- . .u.
.n . m ~ : .. n.
. .~:-::r:
v :. .:r :. .* ,
n : ? n.:;. re . w -
- . -. , . . ...:.......~
. . . c.4. 3 .Le ve P-Turn ._ ..,arou n d . a.hu. ilt ib.~rrinn ~=- .c..:-?_.
. . . .. . ...,.s..,..
n
_.. _d . . .rnerev . .; . :-.
.c.. g.O..
.w
< v.,. : n . - =. = .;.~.- . ~.e. :- - =.ww.:..t n::,s .. . .. ....
a.- e.
x ~ .: r=;; .
. ' ...::;v >V - n %.;.::.4.'.:. .y) . .= . ..n,.o. ... .-:. .
- i. w ':.n < .7 -T -3:1.~ .
- (- .:. -
. ... . . : . . ., w .
. n .. .
..*;,1 ...n..- - .- . ..:.L.r e v.e 1. ~..tu..rn a. rou. nd. z'. .-curs o,c . ; when ma t 2
,. r. .: . . . ._ . ; :* . .,.,.
- = . ..
... ~.c.n.
. =. =. u =.
.. .=. ..keuo. available from.
,e--
.,~. .
.=.. .
, . . . . :...: .he hi h . ... .- *
.w .:.:. ? 'l-~~'.ptes sure~~in jeictio@. (F.?I) Epum,op er.ceeds mass flow rate. through th
. s.. .
. . ..:. .w =.. . . . . ,: . a.
.x.~. . . - .
.. ..:.,..,... . a..
- a. .. x.. .:- . .
r - break. at the '.existingsys. za.. u..,tem . pres Figure 2 'shows that at-.
.v - -
- z. .. s sure.
=.:.-... .;. ...: .
-:.:. cu +; .
- s- -
t .-
s.n . .
. . . ... .....25 ... 0 0~ o si a .th e . .ficw .
- f. rom c'n e 9?f,r-u=.o er.c e e d s . th e .r.a s s fl o .: _- a e
)
. . th rou c. h a . 0. 0.0 4. 'f t 2 water-side break (Cp =,1.0) or a 0.008 fta 1
.. , 1 cteam4 side break. Level turnaround should be immediate fe.: the
~ ~
break sizes. If the break is larger but less than 0.01 ft.2 f or water-side break or 0. 035 ftz f or a s, team-side break, level
. . \
turnaround occurs before the system pressure' reaches 1270 pri a . i g .
Breaks exceeding this range lead to a prolong 2d icss of fluid
- through the. break wif.h pool boiling at 1270 psia until a12. decc l r.-
. .. l heat. can be re=oved through the break (energy ecuilibriu.-. ti .e)
. l
. 1 a .. d 'w'.e-- a".
- . .- ' " - . ' . e . . e . e s s - ' .. e ' ' '. .+. .=; " s '. a. . . .s .' e a...
g a.s. .s.-- = u. .. s
.<....,,,,u.
4.,...-s.
.; ,ge :.. -. a...-,. . . . :.-.y,.,..-n.... ..
..o .. se,. s. y. ,.u.a ..,.:..
the secondary side lcafety valve,unless ' operator action is i .veh -
. to oc.en a's_ :s.cherie dume. . Jalves.
The delavini, . ..
eff e cts of reve.-< .
hea: transf ar from the stea= generators nust be a<:: counted fer
. . . 1 when depressurizing through a break at belo'w 1270' psia. vigure I
i sho.es the ener gy e uilibrium time. .for a 0.01 ft2 wa:er-side bre:. .. -..
wi th C~,) = 1.0 c: a 0.02 ft2 water-side break with C-s -
= C.5 is -
cver 30 minutes. .
- 0.025 ft2 steam-side bro 5.k reaches
- .._ .. a.%.... . .c ... :....~. e s . Ma u-=' c '--
. . - u ' a '- - - . . .- ". .- . . =
m -
2 . t ..
. a . .u. . : . . E.. -. ,.- :- ..: -- n- . --T.
. .. .. v n ,"a* n - -t -u- -- :* .. * ' : <. --:------..:
,:, - - a e . . : .
to e a . . . : :-=. . .. :
9
!I l
tr.' tigation.-/ note that th.e n atu ral . cir,c.ulat:..cn phas e. appears . .
. . . ~ ~ . .. .
1
- _. c -. :_ . .:.
. .a
-. ... . . .. ..:. .:~ ... . ., :, .: .. ,a_ .na. . . u. ,-
, m. _... . . .
. .. = : . .,.::.. . = ... . '~::. ..=...--u
. . _ . _-: - .: .. 7.:..~.:-
. -:e .
r: .
. _ , . e n %. _'..=..."..a'- . =.. - .- M_. . . ;.-' 'S
~
- - _m -o-
. c . e s s =_ .~.t
- a .2. W.
r- :. .- . 3 . - %.::_s. s s ;. e. # f r, . ;_7
=M.w. ge. . .,;r.w
. , n=,. ;,s.:. %_
a .:w:.:.j".
.J. ., :g: .::.1 g .r...*.U. ,7 ,==.
2 pp< /A.c
- s. .g"..
.: : 2:s. . ..
.:. . . ._- : :-- . .. .:r
~
.-e-..
_. .: - ... .. _. . :.:. . ,,,..=p 4 _ :a 2::g _-
,----;,_ . - - w _ _ ..r..,,
.: - .-=r.~.,..,
.a......
- .~a ; . -e . . r.: . .. ,.:r-
- m. . ...e ... - e,r.: 7. ;:. .,.; .c: ... .
T ._.5 . . ..+. g, g.
co ,r w. , , _a g_ .
.y o._. . y. .
..~.:. =r. ar
_ r=
- y. .
, .: ,
- g .- ; ,,,,,..
s, k ._. :.; ,/. ; 4. 3 "L.eVel'" Turn Mround . An d Tne TOV
,CM.
l l 1. h r.~y itm .. == , ,, ~_, ,;;_f,,,
.T~.. M., .7fJC
... ,f ,. . l . , , ". ..
,. - :: v.2 3 . -: _--- ,-1,...._. e =.. c.- n s;._w. o. ..
. . < .. y,, ....s .
. _ c:: _.., ..
f: y .,. . . _ . _ ,7.q ::..,a.<. q - ..;: 9:.....:.: :r_.:-
. __._. . . ..y... v:. , - :. .
s ,- .s ... -: . n.: .. . . , . :.~:- : .. ::: :~.: -
ava::.lable from. .. he high SL , . -7 Lev. e 2f..tu.rn
~. .=a.
.;. : - ,. .;.m rou n,d oc., .. .;; . curs w.... _ : . : . . .- .m. . =
. wh.en_
t
. makeu_
i/ -1.
M-i.tes'sure~in jesticifS.F.PI) Epi 9ip ed.ce5ds mass flow rate through the
- .... .. .- .:. e.~. n..~. . r . c.,.. w.
. . =_.. .. . . . .
.-~. 7.,. . . . _.. ,
= . . - ... . . .
.a .,
- .=.tin e
< . break. at the
., . , = . . - .-.
'exis.
- 1. : ..g-.sy stem . pres sure. -
.~.
n.gure 2 shows that a-/
. .:. :- . - - .. .: :=. .L+.:h:_ ^- i.
. ..~: . . -
.250 0~ __esia
.the . fica f ~cm o'ne E?I .s, s 'u=e.. . er.ceeds .the .ma ss flow ra te ;
throueh a .0. 0.0 4 'f t2' - . . .dater-side break (C.D = 1.C) or a 0.008 ft t
. . - . .. . . l n .. .. .
cteam side break. Level turnaround should be immediate fc.: thes
. i break sizes. If the break is larger but less than 0.01 fez f e:
water-side hreak or 0. 035 ftz f or a s, team-side break, level turnarcund occurs before the system pressure' reaches 1270 psi a .
s
,. Breaks ex:eeding this range lead to a p:ciong2d 1,ess of fluid r e_. . . o u :: h ' h. e . .'. c a"
. u w i u...
, o ' ~.. .o.i
.' .i i ., a . 12 7 0 ,,s .d a t . * *_.'. a '__'.
- 3. c m-.- ;
- .. o u e i
- k. = a '.. c a . . ~ w. .
. . e . ~, .r e d_ 4. ., .. ' S a b.
.. es >.. ( e v. . _ e,, y e c.u -- i ' 4 % 4 ..-,. ' . . . _ - .
and ther eby further depressurice'the system. Steam generat::s
.,....,,.,m. ,=
. . . ._ . ,s u . ..*. ' . *_ ,.- : *_ v . . ..
. . . .. ' *. o M_ m c 'mk. e. .
.m. . , . . , _ * . ,... :
1 the secondary s.ide .'c. afety val. ve, unl. ess operator action is i .voke . . .
to oc.en ats__:scherie 6ume. valves. The d el'avinh, effects of r.ve-,- .,
heau transfer from the stea: generators must be ace:n.ted f :
when depressurizing through a break at belo'w 1270' psia. Fig- re sl:ows the energy e:nilibrium .. _. .
tim..e,for a 0.01 ft.2 wa:er-side brez
..,. ... m. . . .
with C~,) = 1.0 or a 0.02 ft2 water-side b.reak' with C, =
- .5 is .
over 3 0 minutes. . A 0.035 ft2 stea=.-side bredk ren hes .
,_,..:.,.i__:....
.. . . . . : a.%. -... . .= .. .... .c. " . e s . Ma "_=' c i c " ' a '. . .. .. ...- _ .. e
. 2 _ .,. a,_c... ....u. . _: __ , a..._t - _:
. . _ .n- ._. a_ _..:- y. a -u _t a_ _t ---s - . a - _- ,. :. . a. . ,~.: _. _ :.... . . .: _.. _ . . p f
.,._.,a.._..._e_...
I t>
b
(
. .? s. .. ).. m.... 4 d ; . Cn1..s Cha.n5O e ,.. C.,.,. a...: es . . . .e. n. .D 3 a t. - os e--~ c .- --
c, . - . .. ... .-..., o - w, ...;
l 2 .. . O w w. ;,. ....r . ..u...,..a.,. .
. - . . ~. n .
m.:. . :: . .,a. .. . .
. s. .
... .si c e ibr. . . .. ..e ak,s:(ori t he acc.g.c.
. pt'he. .a c~enverse)+-s.o.m. etim.e. .cu.m ri. ng..s ent . . ..
.. ..-s .4...... :. . .-. . .
.-m..-.......:.=......,.=:,~,,.==~.r~.-
. ~+ .s
. s s. . .:m. . .
...:.:......'.. ..2
..:a
. . . . . u.a n .,. x.v. .n: .
v....... ..c . .... . - - - . ..
kater sica . break'chanc',ng to a '.
ca s,.e .o f ..E.~.
. For ,. i;th.:.e .-.,<.~::. m:.. ,.
- m. . .;
.. -.:. sc en ..a.ri.o.,.:::.. ,..mc:
..w~=
w --
...,..s-.m_..m>....-..._ ._. .
e....-::..
.-: .-- . . ... -. s =. '- -
Lw:.2..-:--, - . st e ..
~ - . -
a-5-s~ic,e . bre ah"9 Ficure .5.. -. s ih. dicates the . reactor drain_ .time. ... ..
......s...<m
.: . . , . . . , ,.= . . . ...
.~ ::-
- - .increases considerab1)v. if thep change
) . . , , . . ; , .: . : -.: _._= C_. ~, ... _ :.. . ..:.
. .. occurs while - .... 'the . too elencr.
....... . .. ... ... . t. ...s.,....
- u. ..:.
.=.. . . .. . .. . ,. . . . ..- ~ . . . . . . .. . , . . .
J. . . 6.isu 's , .
till .d rainin. g. /j. 7,ieure . .; , ,
.. . 4 .'shows the d ecreas ed .' mass flow rate .
, . , . .. a,,,... ...:
. . c .. x. . . ...,.
.a throu.gh the b.r...ea.k.... when..--steam
.~
- . .:.s-.
. . . sta rts to. elow does not ha ee a.
da .e ctable. . e-.f ect..'on' t. ne energy ecui,:.. -c rium t.1:e :: the revious
.s .
.. . m s e- e, a.. -- ..
"- o-. C9
.0. 6- -*
x -5e
.- w.=. =-- -- '1 - w i s 'o - C = $..',
. . . e e ....;., . . e :t, 4 , : w..: 1 n : .. e a " e s '- e.=. .. s' a - .s '.o ' ' c ' 4 .. a- -- :.. =-
- . - - . . . . - - - =
- c-- .u .v., w s
.. m~ ,. , a e c.,. ea - s cn o ' '
.: c. "--- - s e a..d 5 .4 nA - 4 . '. .,-
e, e - ., .v e c.". 4 i 4 b .. .i " . - : ... e d - : n , ~-,5 e s .ae.
- 6. e n = s =- 4 s a ...'- .=.p--
- .t s
vary s..or . whe n cc=parec. to reactor ves se.; cra:.n t:.ne so no
-- =.. . e s - .' .. .=. . i c . t e. .' ". e ' 4 -aa n" 4 - ,-- .= '. a.' . . .
s
, , s ,.,n, a ._. = d 5 .a . a. s # c.
4 -
y -
r .,. . , .
. . . - a. a '.s- c. . - a s . e a ...- s .' # e '... e = k. - o =.
. e.
- v. -g - .s.#c. 5 . e a .' . d ".a .. 4. 7. ..,
- 'sha. u-
- de t. . s e.,a.*..' o , z 4c". . e 5 e.
.. ' . c . ,
.. .s. a'. -o - v = s s e 'i. '. = .3.n '. .. . . .. e d e c .- =. a s e e ...=.->..=.v.. 4' ^..'. a. '= .. a 'r.
. '. . . . a .-d 5. . . r . m. . +. . o .. . r. . .u W.. 7. . =. 3- "v.' '>
. - a- .e.. . - e.e '.s.
. '--=>
.= - - .- . e s
~
and sc=e system repressurization may occur. . This is the type :-
a < .. a = n ~
~
. -- e.= . . e w%. .i c h.. d av= - 1 e s c"-: .. . a .".-==.'
...r a '. 'e -
pressurizer top. It initially vents fr.e stGa= overpressure and eventuallv. . asses water. .
. ,.. =.=. s s s t.t .,n 4 o . rm. 3.9..s. .
e 1.3 A.-ns . . .
., 0.05-ft2 break at the pump discharge is th'e smallest 5 eah 1.1, y. e c a .. 2 c . . .- c.---.y a u -
= c u g: ., ~.~ , :
...~n g....,... ---.: . ,--
m (
- :: n,
- ,. g--8 g ,. --,
v 4
- .e...... - ... . . e. t -
.n. -
-..--...e ...-- -..- .... ~... .
, e.. -c.c: ,.-c... : -
.c..- ,
- u. e,.. .a. s.
.. s. . :. . ,- g; ,.. . , . .
._....,....,,u,3 . _ ,
s
. F.iny postulated breahs change 'frem..a f.:ater-s:.co crear. to a staa -
=.. , .. . . . .
- -e
. . : . . a .. .. c... . m . ,. . e .. ... . ... . .
. . .. , .. c.. .
~
...'. ,-5 ... ..."". .si.d..d.i.br. i af5, +-
. { ori.~th.. : . ._.m . .rd. o'nv~erse).& W om'etim.e. uu. c r.in~g ~.th_e _ accident. . Z ._
..a._
_.. . .. .z.r..- _ . - +-. m . ..c. . .. . .. n .
, .a. m.. . . . ._.s
..- ,_._.o. . : -Tor th..e_.x.
.._ . _ . . .. \
n.. w ,..- cas e. ' o f .,.. .n
- m. .,. . . -
., sc ena.r.i .
, .-. - ~-...;..
- a. : w..a._t
.,.,. . e._ g. .- .
er; sic a. _.. .,.... r.ea :......a -r.
_._...c .,a n g,
- .n g to . e. . ...
t e.reaetor c.ra:n ta.~= e. ..,._ .. . .
.i .
+ : . . . - -.-.:.
- ' " st e am-sr-.
c..e__ -re .e ai:r
.am. F:..c,ure m:._ , . p .a..ncicates - .. . ,
~-
... .. , - . . . . ~
r .../ . e. . ,:.... . . . . .. .. . .#._.
. . .,~.. .. < . - - .>-
1.
. . = . .. + -. i.ncreases.consid.
. . . .i.. . . nn..: . : a : m. :.
era.b1.v.-. if. -th.. .e. chance occurs while- .... the to.o .e.:.ennn l g: e. .. . .. . ..... .. . w; . :. _, . . . .~ . . , n, . -.
. :. ,. 1
. .:. . . r- is 'still .d raining. @. .. . -igure 4 Cshows the d ecre's ed. mass flew rate. ) a s-
- 2 < -. n, through
. m. a . ...-a_...
. a. . .. x...
he break when steam starts to. flow does not have a
.2 . . . . ..- . . .
l
. . l.
u 4a- le,4339e,'e. Ject..Cn 4 4
.nn e n e ---y**y e ""*
s I 9 --. I b. .*. .# "w .1 *. 4. ... o_ '
. -.J. *
- .b. o. ,.'=e*._I.o *
- a*
.g,*g C,.. --." . "a e . .=. ~ = _- _" _' c s '. _-- -- ' . . . ' . ' ,
.. _ -- 4 3 o. . _ s . _:o 0.6 . .
v C.., i
'.e e..a-,"2 4. .. u _i _3 _*. k, i n .2 . ' .. e a .'. ' e
- - . - s ' e _= ... s '. a .. s ' o # --' c ., 4_ . . .. =. .- e. =. .-
..~. ~ .ic = k' .v. , _ '.o -a.e_, a c c.,. , a . 2. s n o .' ". ' c " .- s 4 a .. d
. . .C, ##
-o _3 m_ 'a.-
d .#
.- ' $. #n 4
s a _'*.
e.l e . ., V. e ',-"- 4 S. _i b _ _# * * *-
- - I -
... - -... e d u .m . " - *_ a' e s * .*_ e 7.
e.=. s a. .s. ;. - .,
very short when compared to reactor vessel drain time so no
_- =_ .. e s s . .' _ ...=. . _- m. e ..' " e c . _4 s a. n . 4 ' , _= ' _ ' . ,
m,
~J If the postulated break chan es frc= a stea .-side break to a
=
y-- ,- k :. 's ' '. =..- .e'a .*.
. 6"a-- A_1 . W. . =_ u.-
?.>n' s ena.'o, .
- c. . . e 5 . .. . c.. ,
.- ,.as.u -
--..-.. .., g g e , . 2. ,:n .: ... e . es c _- =. c s o..c .._= . '.. =. _= _1 v, . ..'~.a_ '.-. e a *r.
. u...,._ , . ,
-. a. .r... : c s *.. w. .m. ." ~ . . - . > . .
- r. .n w- .. ;. c. . =. = _ .' .'_'- *. .=. 'v. c, _ o.. . - c .' .4. . '.-s.>..*.
and sc.-e system repressurization may'. occur. . This is the type c'
. r. e ' c' a_ n ..__ . -r". . = .a. e w "...' '.5.. d ev a. s. oes d "w . _: . . a .b.,..- =. 6. 'u- a ".. . .. = .
eesu =-
. - - - '- o .. _'- - .(* ,_ . 4 a .' ' v .
v a n 'a- ,... a. s ' =- _= ... c v e-_, . e a s -a. a..>
eventuallv. . tasses water.
.... . . .ees . _ y,.2o
.. .,,,s.1_.
- . . . . - - m _: ens .
- 4 ' - 4 s '-.'.'a s ..aP a_ '. " _ =_ a .
. . O. C .:. _' ' 2 . . =. a P. c- '. ' 'a e eu r..o. - s
. ..a..:= -
a . a _, ), _ ,., c c .. .;
c .. . .
,a uy a c u - - .ze ....:
- ~- .. . _- ." = . - a.-....: . ......a _.
m .
v
) :
.. . _ . _. _ . _ . . _ _ . _ . 2 . ._3
. u. . . . s "u'. . e
_ -- .=..e ..=-
s e . . s. .e.: C .:. .=.. _. .. . ,. . a . 3 8. ,. . a~w~ u_ -
...s.:
"- = st. =-- 1. _1 "- " - ~' . r "~ a~
O
1 1
)
~ , h Gak becaUs3 the. ce:av tr.a a*. rate :.. _
- S 2 n c'g uJ.a A .se e w.- - *..4 . . . s. 4...
1: .. 6.
r, . .. _.i. . : a .:. * . .
.,. . e . _...~,..; :' ,o
- 0. ,
.-. - . . . ... .rou .
gh. the'_ br. eak.~<. i_n
- l. e..s. s;. _than . 5. m. .i.n. u.t. e. s' f ol.l.
... :.. .. ,. . : .. _ ' _. ; 1o. .s. t .t_h_. . .
s= f: . :
i
. :2 g:.;,.ci;m,.r = .jp q' - . .:;. :. r;.; .g . .:. t . . .. . .cc. **..-
e c ..:3 . a .- . ,; v .3-~ < .e ,;; --
. .?
- . =:.. r* '4**.
_ ,% m:3..,,, : .;% ;.g ,,,
- . 4., yM ' " .. .- ** -~:*'-'.-'=,,;;,=* .
- =- -
M, ;re .-_J ":.
- M. q. ?igure ,-,r ,3) ,-there. afters.,+eli:-inating the . steam .. ;.generator as 2.a'.c-; .
. . . . _ . n... m_. . .s,._._c k;:.E__,- 7.. :. .. .3.. ... ..__. ..:e - .. s. _ . ..:. 2 . ,.a ,..E
- ..e.
. _. ~. ..... ..
_.) .mall . .b're..ak_si. .- the loss. of 'this Heat- . .. -
. . .. .; .c~; equ. ired , . , h.e. eat. _ -._. _c_in . _ _. ..- .e.r. -r
. :sr. .;..... .. .. ..
.r .w .c. . .. ... .
' ' ~ ~
. _u. .
- v
.._" sin)P. a. dd i.di.; ult'imaYe'.e.ffact~on -
..: :.... fuel'.cla dding'. 6mperature :ies.e_s z
. . . . :. v. ..:. w. . ::, 2. 3......t.
x.; n. ...at-.. . . . _. e v. , - =-- _=_ :+s. . .: - . ;-
a to be .co.n. si_6eted..W::..-y.-. . .'.a.". =..r.w.-.V ..2: p:.: . A..-h - . :......,--
~ - a .-
~
..s e:# :..:. x
.- . ~ -- ;;.. .- --
z . , .._ . . - .c . . . .z.m :. ....-.n yr. . :.:- . ., . .-a. ; . .:. . - - - .
~. ..:_.
...; . .s : *
.-.v.. ;. . - , ..
._ a- - .
. . v,._n.p . .; . ..
w .- . . .u .. u. . .. .. .
. . . ...?. . . .
- 4. 5 . Break' T sol ation Xr,_d .v_uee .shutof f I.'.'.ects
.r . .__ . .. . . . . . ..
s e . . . . . .:.
_ .=. --. . .;
. ..m. .
.....*'*:='* : l.._ . . s. . _ ; ., ,.; ,. *
- ,jt, . . ,
. . = w. - .
, It,'may be a natural t'edcency f or ,the plant operater t: . isolate a This a:
very s=all break it it can be located and valved out.
evan be a recuirement of the emergency operating ' procedure .
c:
. plan. In s'ome. cases, such as for a letdown .
l 'ine, the is:latien r.a v. " e ,a . . .='. e _ c ..._',_=_+
.~ y b a.
a . a ".'. o .._= t _4 e .
. _ _- =_ a P. *_ s o_' a '_ _' o.". .
==
c e t e r c :..n e c s y , o ca t:.cn c:. t. ne :.s o,.a t:.n g ceve ce , nur. e a .c size h _ ;
o .' ~ '. .' ou . _= ~.*.. s '.o .. . _-_ e a k , .r .~. ' , o ..a-'. *. .' *. ".a_*._.*'*c-~..'a'_=.=...'.>_
a .. , .
P '. .
'.. e a k. ,a . e a b v. o ,. ..'.. , 'v a ' v .a_ _e s ". -.%.. a s _ v.. a. , . e s .e ". . i z a. . s< e . . . a_%. .. .
p.: . ..- ... .
e
.,..a, _n... . . _as o _
n u._t o., ..
_ : ._. s s . a. .,.
u.. ._.e s y. a ._ e _. . o __ _ .. a. .- e
. . . . .. a ..
_9. .. W. . c.. , .* .a ?. ". e -.~ u~ ~. =. .^ . '..:" ~.*. =. o .:m _ n .=.'s u. e a',
..,, + e . . . u- . c a a . .=. ...-
time after break before isolation is achieved. For instance, if the orie.i-=1 break. area is.0.05 ft2 and CD = 1. 0 , en er e. .v.
e:iuilibrium and loss of . natural circulatien; occur in 'ess t'.a . : .
- rinutes (Figures .4.and 5) . . At this time , the break can ra:.: e all decay heat, but @ e reacter coolant system continues to irai
.s . . .. .
. .. .e, ,,<
.. s. . - i _ a .o..
- . %.=.'ow M O ,s4a s'.a .s ... _:s
{ ..: g.. ,. .
ev e . s e '.. e n' *. .. a,. s '._ . . #_- -
_ . ... . k. . .. s .s _=- u. c'a. . e .= c . e .
,__ e -
- s. _
_. . ,, e e .4 y, _
- .i .utes af ter the breck, the stea . ge..e:s tor tubes a re drai .3 d 6:y-; to the se:c.dary side water level. -f at this ti.e 5e 5:cak sh 1d' be is: lated, there is ne ef factive heat si: '.; <c.ca te:
a.
~..*. , br e ak be c a u s Q th3. c.e a. .v .' .".t a .
- - ~
- r. a to.. ? s in . tr@.:. A A 3 4 4 w.
w -. 4 . . . c . 4.. .
.. .- s . .:.:.: .-. .
- C. ..
..3... .a."..
16.,s.~t .tF.r...ougli .Tthe.- br eak-in
- a. le ss'i.han 5 m.i. nut. e. s f ol. lowing the.. break
~, . .
q-. g ._; :5 y .:.,4. p ..:.u.a..__::..g
...?.;..
- ,w .. .. . x,.. . .
=. _3 1 . .;.
. ,,, .:.g.:: .. .
...: (Figure 3) , thereafter:' eli:-inating;.the . steam generat.or as a' -r ~ .-
' _n;. . ".:..~,.s.
- - . . m .~
. :-t .- + - - ..+.q.
~ .. -- -
= x.. .. .-. . .y.:.. 3, ..+ ..u f? - -ie=u. ~. ired. , . .- heaE." . sinh
.:-- ;=.'G ror..--r.- :s'ri. llir breaksi the loss cf this 1ieat - =..-.
. v .a;-.=-
U .~ . ' ~ ~ sink and' i. tis;-,ult'imate'effect
. - . . ..: .. on fuel'ela dding .ti.emperature .dee6_s
.o . - .-. ..: .+-. ~ ;
.,:.r.:.- 4. m =.. .u,. . . .1..c. aw c.=r. :.
- p . . . . . . . . ., .
~.
~. :. .: =.. * *'. W: . .y* . *-* -' ' ~ . -l ..
~
' ~
.- .u I *'*
to .' be. co. n. s i.6 zer e d..n,. -le~r.* .
T
~..*~ 5, .. .
- 3. . . n'^ .~.., . .*. - '. m. r 3 * . .:,;.". .*y:.
.n-
- ,.Q . .;. .
.3 -Q ..
.:p}.*-
...-..,.u..-
- .,. v._-. . - .. ,;:. .. . .. .s.
. 2 .
C. 5 . Break Tsol ationJ -a ar.d e_ e cts
.- . .a>u - -a shutof f I.f.a
.- . m .a. .
.. .2 . .. .
. . u. , ..a y --w . a n a".u . ' . s'a. . . c e.~. .v .' . . .5 e p 1 a . *. c -a. -. = ' e- ' .a. -'e-
. . . - - a . =- =
very small break if it can be located and valved out. - .is nay even be a requirement of the energency operating ):ocedure c:
. plan. n s'o me cases, such as for a letdoten 3.ine, the is::la-ica s a' w eya
. ~a y .k.,- = a "'- w .. ..= *- i c . : .. =. a .v. i w a '. i a.n - .
.= v. .= .=. .' o C - . .. . 9 =. .= = =.
. o ' ' *. . e ' s c ' a - ' . . - ?e" c=-, .n"-....-=--a..=
. c' = ~ e _- ".. '-. . =. = b.v 1 c a ..4.
. - . - - e ' _ =-
o s. ' .c .. 1. o. . . .. . - %.. S-* o . b. .. --- w ggg, . . . .. A. g g . ~- . u.. 4 =. Va .*. 4 C .'.' .#. e . #. s. ., ..# '
.* .-i- l O .'.-,_ e a .M ,.a. ea bv ._ o c a . ' . . ., . a ' "v a- e s ". .
. .w. a. = *. %. =- .
e -.ese" - --- = ". e ..'. a ". =..
1 1
l r .
. . ..e l
.. m. .. .p 1 = -- '= s o - - '. t.., . . --='
1 . . .. e s '. . = ".. -. =. 5 Y. a .. e = . o - =o. T. . e .. =. . .. .s .' . . ' . 1 a +. e . 4 . . ~. ~ ~. ". c .. ;~ =- !. = ' e .. L . . =. . ^ . %., . . . " . =m . . .. :n a=' u e a'r.,
-. -- u.ca .... ' - ...
tir.e after break before isolation is achieved- For instance, if the orie.i-".' break area is.0.05 ft2 and cD = 1. 0, e n e:c.v. -
e:- u :.1:. .. : um an d , oss of .natura.A c:.rcu.'.a t en occur . n , e ss t: an :
ninutes (Figures .4 and 5). At this ti:.e , the break can ra:.:ve all decay heat, but.the reacter coolant system continues to irai
. .s . . . .
s 8 a = .. %='ow m o , s'a s'a s .. - s
{. . . , - -
- a. a. ,
D=.,--~. - - .
.. . .,:e a
- u. , .
e y , . g e u.-- . . , . - a--,. . s ' =- - .' - "- . . ~ %. . =. s a .=. n c.'=..~. e = ~ c .- c.- ,- .
-1.utes af ter the brenh, the steam ge..e:a tor tubes are d- ai .3 d n .
m
.. .. a.
- . ,. .c. e. -
w . . .s .. v. s**e :a'.=. 1===1
- -- ~. " a '.%. . . c. -'--..=. ...s. -
- u. c a s.. s . . ,. . . au --- s e -a-.- :--n,. c-, a a.
- g ,, .~ e s : %-- . ..- : n e b. e g - ,:...
--.a
..4. . . .:..
1 behave. ..= :._ a i e., .. Sr.
aller aroc . breaks which are i~solated should a s
.- s. .u.. : . . . . .. - . . . -
. - . .w. p .-. m. - - .. y~. ..r
.. . .. .......u.,
.1 - . .. ...
eEc :ept.'-it
- r. . i ~. . I~2 : f. a shion r.ay take. . . - .. .. . to- los e, natural, ._ ..,7 7 _:..
./
. at ion,.g e r . t.'. me
.~X- - . . . f. '-Q', . .*.". RtW%.' ',.v. QM :- T . z. ; - ' .: ,::. . . .,g --- ',* .- ..5 ~.:w =_~; . .
~5 . ' : :._3. 1: ir culatio.n..i- :ar-- .. - rg e. :'.a.re a br.e..aks. can a s o_; proa.uc e_
. . . . .-. s:.m
,a
. -:: .... s.s .cp.<.: -..... , . -. . . ._a.c. -. -: _. .
. .-. v.. ;.*; :& . x. . .. - . .- . .
. . . .:., . u.m...;: .
Y. r .. .- .c
- cHcu.'mst.a.r. ices: if . thev
' are is51ated.
_ ; s , .;. ,
. . _ , . . , ....___.,..,4.._,:.. . . . . . .. --
.~...~
n .:.--..
-a. ...~
w::. . - m .1.. -.
~. . . .:: -
= ,-:. .e . . .::.sh.c..
- .ll,. pielsBrizer ..:..... . mmay".'co'nvince ,the oper.ator to . trip the EN pu-
-- . fu -
w
- . . =
.s ... ....;--.-..;.--.- . - ..
-... and watch for a subsequent 1 css -of level. If this happens and
- , ..a ..
..c......- ., = . ... ... ..- - : - ..
th e break -has - bee 5 '. isolated, the stan generator tube level star
. . ' - * *.. ou-h. "c_~=-
.-.' o '.a -~. a. s.- e d u e
- o .-a_ ' = a s = o # "'.uid
= - 3 h.e sa'a."; ,
until. an adequate ccn'ensing surface is established.
Ne f u-th s:
level loss is likely and the' safety valves should re .ain ci::ei.
n s -. a a ,- .- w
- - .. , 4 . . .,
. . .e.~ e .--. : , , ,:- - a v a --. ".S a- - e s s "- .. * -- =- -
c- e. k.
. . .. ' c'
. e ... = 4 n "u__ o ' .#1"-.'.d .7 4 ' .5 a c e n t o .'. ' ' ., -, s ' e o-... '"bk.'e
- . ~
i n ..a.
-es. a n. u_ o-- 3.,o s s e 1-
+
i i
t; = 6 p e =e en:.- :j,,x=o --
7 e.e 7 T- .3,= *. =m 4. 3. : e.n
=:.; .
a .
8
- ., i.
...g .1 s g oe C or ,y
.h. a. .n w s -
-. .. . y sl di 3-o.e . o. A. .. 3 e C w. :7 w.... . 7. . g .. .: . , .,
. 4. s. - -.
- n s-c_ ' * *
- b. . a * ' *-
- s s u '.._:w.. *- eva- : -, .:.s.. n o,w a C --^ . .e._.*.*...-'<-='- . . v. . . . . . . - -
. e c.3 - .--". ' 3 . 4w ..
'e"el'o".e *b.a. . M,n-~ > cc a.
- . _ . D"
-( n c, ~ . l a. . . a . u. a 1 .
r.hase, water can he~ draining fron the reactor vessel top .
Is..ur
.'. = . .-
, m, :
. .s e . ~ .s =. s.u - - - .
a '
a . e' .# s " ' w l," . '. .. e .=. e ' . . c. .T. .e
- ' -=__= .. _: s th e top . of th e pre s suriz e r s te am s pa ce , a' rapid pre s suri=e:
re filling cari ' occur.' .During the' transition to pool beilin a..-
s'- =.. M ' - =--c...
' uw g. . ,--o v o , s *.. " T 4-3o, .s 4,
,e.n i , e : n
. - 2 < c.-. _3*n.rr. .
- -- . . w. .~-..- . s. . .
C .- a. .. ..s y km -- .-..'Ce".a-6 w --
- . . . . *-- a- --# o '~ a-r : .. a s s " . .#. a - 1 e". a i 4. s - -.
C...s'A=-='
. - . a ..e
- #'D 1 =-
- - -.'. a a s ". o .c ~w-- = ~ww ~ w~ --
1 ' .. = C..=.'..'...~.s. . c. ,.
c . ' . =. .-. - m
- - .* ..a - > c ' e -
c . o '- -....-
' *'- a~--n '- 's : - o..e=.d.
. ..: - -e - - -
- .s a.
O , , .
g
-lD. .-
..f
.h
.. . ...$- { f. --.--...$..f.II.; - . g
..e .
g M.
. .g..g g ,
h ee
. T... . f, - 3. = . =--= -
- 4
_ - . . : u.s .-
~ -
~ . , .
a .,, .. S:.cliernarea. breaks which are isolated should behave' in a.:. sirila .
.r- .. .. ...:....
- v. :. . ,.- . - w. . .. . . . - . . . . ,,.......,...4-
.a. ... .. . .
.'s.J.:fa shion' er:c e pt -i vt v.i.. - . ..,. . . f ak.e'.a'-l.onger. y- z : . w.::-1. . time'.. Y.o ._..?los . e e na tura 3 .. - - -
.i.....;...a......
.-. _~ . . . . . -.: 2 2. . -
v e.- . . .,:., . .
. ~
m .
.m... .f .
a..:...,.
2 . . ,n
~. .
. ..: c. ,.. . - . . -:-e ?.> . - - .
.: . - circulation #.07_arg er ' are a' br eak_s -can also. J'
~..:); creduce ~
.w..: .; .[: s'im . lar O 5^~l
[ . ? ~;8 ? . T ._.; Wh.N.;5.5-.ip . -lP. *-l :-
-t.; __.
~
ci'feumstanc'es; if they',are isolated. s.:.- * ~
.N '
~
. =.;[i..i i .7_ a "'; ,* .: *
.. . . 'h' !_. . *_ _ ' -
- - . v'
- "- c- * ' _,.....;,.... ^ ..;=*.<; . . .-a;$*' . . : !. 5*i.f% -.# '.3,.W..f :-. r . ~.: . - _ . .b .
^
- 7. - ~ .. ....-;-...........:...,.:., A. full pressurizer mayT 'co'nvin.c e ,th e ope r. -ator to'; trip the ." r pn:-
.i...:.....=...---. .
. .. . . s .. . .
n . ..
- :. . > -: -a. _ .a .
~
.and. watch for a "subseb.uent loss of. level. If this ha.ccens and
~
- 3. _ . :s - . ., . . . . =: . ...
.=.. : .,: ..
,.-. . ~
the break-has-bee ~., ~
iso 1ated, the stan generator tube level star-
. to dec:deas e due to deliase of f1'uid through.the safety valve.s until, an adequate cendensing sur' face is established. Uc furthe:
level loss is likely and the~ safety valves shoulc re.ain c1: sed.
A stable boiling moce will prevail. The pressurizer should
. e...- =4 - .."". '1 -
o . #.. # 1 "- #v 4-.14+5 a cont . *..'., .. s'eam b."~W e 4 n-...
_. _ _. c ._.. o . s, ,. s s ,e .
- i en ,=_. - -u .g e=,ue 9 ..
~o 2 e.en.;-
.- = .a- _
e = ed1 .
The modes of decay heat renoval ciscussed in section 3. o ":i-c ". . a _ .
a s s e.tz _a .._.1 _ e v__e_ n .s.. n.oy__ a c ._
- . _e_- . . .-t. .M_.e >. ~. ~ _ . ~,., #.........s.a._-
., level 'over the murer ce; e. . ,. During the na:vral circulatica ,
phase, water can be~ draining fron the reactor vessel top pienu:- ,
,s,o i.=- u. . e l .3 s ...'. ~ '1 2" 4_.. _ e.=.= .'...;.. 7: . .w. =. s--...
. .. ..i.:,e. r
.. _ . . . -- - - - . - s
~$.= *op.o#
' 5 = 'a . e s s" i . e s ". = a.m s e- - =-. - = , a . a- r i d , ' =. .=. e. ..., _ _i =_ .- .
re filling ca:i ~ cccur. puring the~ transition to poc1 boili.ng an ithile i.n pool bo.ili.n.g,'. the icvel should stabilize even :houc.h - . -
1 j
u -.-. . .... , :. .
- .- . . c ~.'s..- e ' - '. .'. = -. e'. o e .r y. = s s u- 4 . e- l e . e ' 4 .=. ,
c:nsidered a reliable guida as to.. core cooling cc:.diti:ns. Ne o .. ... , ,
.t ... .,. .- ), , .ege <
a.e ,
-..p.-
- _ t- g-
- n -n : g - . o..:
- e. .--_; ,$ .
. ._..:_e :.s a -.
,)
.q. .. : ,
-..2:.
- _ o. . ..
...,. 2. , ;. _._2...
. . . =.. .. . .
- -- . _ _ . _ _ . __m____ . _ _ _ _ _ _ _ _ _ _ . _ _ _
a cCtallCc transient Calculation.s b* seq on accroCralte 'sys is anc a
.. < . . m.- . -
. n --
- -:- . ~ . .
. - e-,. -: - .- ; . .
... .- -.. .. ... .g :
.,A.:.
.,.. . s , ....
. .,,.,~.
. . / **a
_ 30:.r..o ,..t.h
.-- co.:not
- a. .a cappearsto
,c.-. m-e r.ma f.e ., 4. c, .a . . e
..- . l-.h
- a ym yo raulic Pea. a .s.m .. - . ,: . c-% ~ . =. . . = .
ecom:noda f.e, .-Tr..s a e,
,no..s.,el, s.,.~.-.:
te thes,
..m,.,e
- . a Th e.. . . :.n.e. ._.,:.
vf.. y r.. .,4.a very.
.scall
_ ;.s po r to 6 . N SSS. v e n' d e r .o
, . s.+a . . v bre.. ak.
.,. LOCA .
.- J ,...;,,.
-M F,c-:. ._ - . . ;..
s-
."",. ~ ,
- ,.,... -=:..2. ,:... ' . -.. .. v_. .d_? .
. g ;,.
- -r
..'.:;:n.e. .. . U,. .d %..-%, ?..; . ;. . .. wr .. .,;c.j . ,.- . m :p. .
. ..L,.
-f.~~
.~. _.
. Q. si..t. u a ti.ons....Eg;iI.a.m.
..,.......c_. r,.
n.c ea ch
.... y.u._..
. ..:.ca.. s .._.:,c,_.... e,"' ; w; f u..el : p.e.a..k. :. cl.a.d,, tem. .oe ratu. r e. is. the _ . .;_., .
. u . . . _ .....n..
. .. ~ . , ..._.n. .
pa ra::iete' of. p a rti_c.c. ._ .ulariinterest:for e emparison.. with ...
the ICCs ^
- . ..:.;a.. .: r:. : ..m.
~ . .. .
.:s. :,.
= . -. . . . . -: = - ,:s . _ . - .
.i _ . . ._ . _...i..--
.".cr.. .iteria ft.b.ut. . st a.b..i.lity of .th e_. fluid'_ proc ess and . * ._.
. _ . . . . ___..-- a.c c e pt. an. ce..
_:.w. . w_ .p. ..._: .v .. - .:. . . . = . .
.. ..a _
~_e . -
. ade
-...=uacy..of :...nstrume..n..t. at.. ion. an d co. .mponents should also be
.. ...=
. .. .~..._.
. . . . ~...... . - .. .,
. , . = ... . .: ..~
- - ~. -
.c o . . g .a.. _a. ,g... , a. . .
z.
p
..v
- 1. . .
.. .._* .cu-_s' 1 '
c1 ' s **
= n '-' '-' e' o a s a ~.~ .c *"'
- s. - a
- u. . . n '.=. .- * '.. '. e n - n' a'u . a 1 mode of initial decay heat removal following a very s..all break Lo A (section 3.1). The adequacy of this unsta-le mods for decay. heat re= oval needs to be verified.
- 2. ".' k.. a_
- a.. s ' 's. _4 o .n ' c. ,. .. _ ,.u a '_ c _i _ c"- _' a 4 o n .o -e ..'
u a _:. , ; n ,. .,.m . .. ..a-. . . . : . ,. ...., ;
. . . g1. = a. g .u. _; ,. .a. ; :. .--_a.. .: . , .- . , . . . .. :.. .,.-
D ...:n,
.: o
.-. . a' . .. . 4 n _, .4c _.
... . s o. .,. . ..
3,one_~c -o . - -... _ . _,s ., -- 4 -.a4 .
uan _ y 's : .1,
- o s. . h . s e..., .a.._, -. .. .._ . . .- . .
. . s t. < =_ c ~- ; . .. .' . ) . .
, -. u. : g ... .: ..,_, .e ; . s.w. . .. . c,.... . , s . . . :. __- n _;.s ... y;,, -_- e,, . n, .- . . _:: _ , ,
-- a_ e. m.. v he'a t is not being ren ved th' rough the break.
The ef nct and a c c =. c'.W. . l ' '%v c ' ' .b. ' s - a_ ._ _ a s" . .. - _
4 a ~. 4- n .-
' . . e e- # s ' o ba.
d e ' e .-~. ..#. . . *. c~ .*
. ~ .
. . 5 e d a_ h. -y h.e = ' . #- a c t .i o.n. +..._4c5 . is e..n.,v=d ' h. o" p- 5' 's..
. . '_- _ a ak
.o a y-i~ *e s C..ow a'a_ v._-- i "a laes
- sen ...-
~~ .h.an. ,-- a_ . s.u. . .. ' a. '. ..' m .
- -, l, the fluid'enthalpy upstres: of the brec.k is represent 3 ti.e c:
. e co e e.:..
. _ s-. sn..a_ -..
,--; (.e..n..: .
n
. n s, . . .u. e g e._,_ _.- . : ~. :.; ... - o I,
..- ,. _. .. . _.. ... - ..n s. , _,-n , , e,a . '- i c " ' -_a -
_' )- '.>" 5. . era-d- - c _e2"- . a. . .-
n.
- 9) .,...-c....4__.,.:~....,
. .. ,. o = .'. s '. a " e e " = ' " = . =. d " m
. , - r ". 5. . .- e '.
. n. . .
.:.o. .. .. .: .. . .. ..%. - .. c _' ". .. = c . .>. - ~, .- =_ ' ". : = e. s
.-o v. ' - -= . ,:- .e. - -
a . s...
- a. . .
?
L_._______.__ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _. _ _ . _ _ . _ _ _ _ _ _ _ _ _ . . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
cetailec transient calculations asseo on approprcate cystes anc
-. . .n. _:
=...:.-, . ...- , = _ . = . . -. .w . . <.. . .~. .e.n..
_; co r e .th . . .
e rma l -h yd rauli_c __ . . . . .
-=. . . . . .-reported Esss ven' do:
,;.._, ,mof_els.: : Th e. . . .o d e.ls,.
r .r.;:. :. .
y._ ,_ .n. 2 .m +myi.:gm_ s._. i. .v .um...s:g ,.72 7%:q.* .,. .a.s_.gs nim _.. _. ., . . .. :. ..-j. :-
. ....%..,~.
._ e . ..
N, . .- co. . not cappearst ,_o: accommodate thes..m._.,._ne:very.small bre.k..LoCA a ~v=-
- s. .. ....-- :.. c._.. .,.- +m. ,_- .. m. ....__.,.a
,- : :.: 3 t ,. t. 8.',c.., .. . ..
- .. ;._ . . . _ . =.., .
.n .: ._ . .
. ~~. . . _
r.._. r'..-. . ._. .: .. -^ si..tu a..ti_o.ns. 4w-r,_In e. .a c. .htem.ocrature. :.c a s e,f. is. fu.e_l,: pe.
.. the .
._.u..=.._...
~ ._.
n..
pa ra m ete r oparticulara. .....
f . . .. ,.- .z ...._.~.
7 ._ .
nterest -for ccmpar:. son with the ICCS
. . -_ .. -- - . ' , . : 3.-* ::..- .r. ' '. . . .' - L-*.,. :s *::. ,<* -i--. . . _ -.: . ==Z _. . ._ .
. _ _ _ . ... . _ . _ . .. a.cc .. ept. ._ an.ce.._cr..iteria f,t but. _ stabi..lity . . .. of. .th e_. fluid _ process and . ' ._..
. . .n.. .. ,e,. .p, .+ ..a..
~_ . .-
. .. ac ecuacy. o:'.: nstr.ume.ntat.. ion. and co ponents should also be 0.. a 2 e ,, 2 .
. s .. _
- a. .. .
- u
- 1. . n ...
......-- s..s- ..a u u ab_ _ _; - ,..,, ,s.t- - an
- g _;:, _ _ n s.$ _a _: , c a g a _. _,. e s _s u ,_ e mode of initial decay heat re.toval f ollowing a very s..211 break LOCA (section 3.1) . The adequacy of this unsta'le r nrfs for decay. heat removal needs to be verified.
.. ~..k.=_ - _ a ..a_'
- 4 o n .# _ c m ._. = m u _ = '_ c -( . c " ' = _ _4- n so : .. .'
o . n ._ . . ai-1, . .. . ... .. . . . . , . : .. . , o .1.._, a a u ,; :
\
~s _; ...u. 3 :. - a. :. . -.
a . ~ . . ,.
~ . _ ._= ...
j =
.- . _,.m 4 :..n ., : o .- . . a
.._n .._e.o. .._.._,s
_ - ._ .. _ -4 n -,.4c . __... _
- w. s .,_ . . . . . . . . -. , e.a_: .. .
u .- _ o w k. . a _ se--- .. ' =_y's .= .._.=_ "
. . -1=.".=_s. ..r e. . ._ - _:o . . ., . , ) . ..._:._
_- u. . .: g .:_., _e . . . . . . ; . . _ u. . .....
... . g . ., s,:_ . - v -- : .. v,:_ _. _, _ c... :: a.,_,
_ _ __ _e , :...v yea u _<g no -. w,_ ..c . e_......,e s ._...~
.. -s..
3 .s.-. ,
8.,_ =-c ,... 9_ . e e . .cm. . a n c.
a c c = .' a M- --- _ ' i ' v o '
- b. _ s . a_ :._ _ = s . . 4.. a _ _4 n ' . . e e -a
- . A - 'o - be c .--. e .-. . . .. : _... . a .
- 2. The decay heat fraction which is removed throu-h' the reak for a civen mass flow rate vill be less than p: edicte! u..1,3.e the fluid enthalpy upstream of the breck is represent.s tive of the core exit.enthalpy (section u.1) . The sensiti.ity to
.: .u
...e_._. .. e ) ...s. .,. :. . y , -.4 eq-- c~_, , _ _,v, _
c: 5. - ..;
.u a - d- .ce"o..- _; ..
m i .......:...., . v. .= ' s '. ^ b e e ". a ' "_ .=. . =. 4 '+-s-v . , _ - , . . . . .
.. _ - 's.-:a.
o _ ., .. _: .- ._.e. . ..s..s.
. . . _ c.i .. , . c.o_..,. e-... . .v. _- ,e.s
. ...v, '-=_.,.e.=.s...a_.
. .. , . .- ....s ... - . :... ., . . ;. m. ..._...
.s.
..s. . .. . .. .
. - -, - , f._.. .a.;..
. .. g . y% . r :._. 5; ~.
r:.
.. . pp ;a
.',~t ..
. :. -. .. '. .- . . , ,d.. . .n. .
... . ~ . e, .ww,.
... -. . g .:. .. ... .
. .e.~.. .
.~.N. .C._O.R..~_ ..
R..I.S.O. . - C'.G. ,II* G. w~ ~ :
..... ~.. .:. . . _ ,..... .
.- . . ... .....m._=...r...__..._...ru...f'".....,.u..
, gs. . ..
. . _w.g.. ..
- 3. . .
.. . ,.,u... .
.. g .,4 y, . , , y,,
....,>....~.a....
a =g,g,,, ., s g .c . .. .
... , , . . ..2,,.**.,*
s.
a.J ; ,*.
,., ,., .. .,.s.,.
v....-
- - . .- .- -- ... . . ~ . . c.. :n . .e. -
,-.. .- u.
m.. :.=. n v. . .:.
.= . x. :- . .s..
, -< v.- . ... .: ~-
-- ..:...a
.- . . ' .+ -
. ~ . . . .-
,,3... -gg. .
....:,.e
. . n. . . .
. J - N- :is a l "Pic e S i e.:..fis.1 . .
Sch.e dule No. . '. . Flow Area (M M =
--.....r.........-=...
, :.._ -.n. ,.
.. ... . . .a....~..
. - .. . . . . .w. > *l s. .. .-
.. . ~,,. ..-
. , . . . . ~ . . r.
m.
. . . . O u, :> ..
m...,..=.<
. .- -...;.., : .. t . .-
.. =. , -. . - . .r
, : ~.-- '1 1/2. . = ' - . 150 ~ .0098
~ ~
2 - i -
160' .0156 2 1/2 -
160 .0245 .
3 160 .0375 4 160 .0544
,...4,,-
. . . . . - _ s.
. .. . , e _ ....s. e e. ,. 4 --. . .w. ...% -- ...--- . . e s- .ea*aa=.
- v. . .: . .,
3, . .
O
~ ~* '
s e , -T .* ' . ,*
3
' . ; *. 6 *'L .w * ,, S 3. ..
e
.
- e m.
.. . s ,.. m...- .- .
.s w*.- =.. ..r-
. , .. f. ..M=
., , . . . , . . , . . , . . . . .*'. 1
,. L ,., . *: ..-. .-i .. . . . . , ..-. , ..,:'.
.5%y ..
. 4..
-. == . --
. . , ,..~,-- - . . -
.v...,
s ...
7%.
.~4 . 5 .,.,,,A*,m Qs , -.. < c .
. 4,. 5 _y y,,. ..,m.,. .. m ...-....,_.;_.
y s....-, .. .
- . .... . *-, . .. . . . ..... rk .
n, 6 s. ..... . . . -
. .. .,.., GA . . '.' T - *"* * .;
.** '* r.
, ' , . ~~ .
- - g
- * .. ^ * '~ ** * . . , * *-
...=.=.,.;6..*a..,~~.
a *. ~.,4 . . ' . ' " . kl_ ..
. . . .. .. ., , . . =
- , .* . g, g,4 ;.
. . ~4 .. .-. . . .. g g .., g y ; 4 ,, .
- . . , ...s ., _..,,,...a.
..s.
-. a. ,
- .J *,..
...,.a.',* .
....v.......n,.._...
._.. . ~.....
.... : .. ;y *
.*.:= .Y.. .. . ... . *
- a
- . . , = ' - . . .as,._._..,.. n . = -. ..n f - ._....:-...
-. .. a . . .
_........_.s.
. . . , . .. . . = ._ .
~ .. .. .- . .- -. . . - ... .. .. .
. . . . - .. . . - - . . ..~.. ..
Sch.e dule No. Flow Area ( M U '*
?6 :in= 1. . .-'Pice . . ,S .. . ite (i n. , ..11 . . . , . .. . . .. . . .. ..
. - . . ......1...
. - ... . . . . . . . . = . . m ,. . .-- . . . . _... .
..u . . . . .
.- - . :.. . .,. .- a. . a v - -
=. .
-- . . 3. .gf 2 ,
.- n .. .. .: . . . .
. u.. . .
150 * .0098 2
160' .0155 2 1/2 -
150 .C245 .
3 150 .0375 4 160 .C64;
.,,. , . , ...... e, . . _. . .
...~ ...... ...-- ..
j . .
. h g
. .+
M e.
O.
- e e g . .
....,. .. .. . ~... . . .
s g .
\
/
v O
l
/. . s' u. . * . . r.#.h ,s.'M .. ,
- }g ;- . .
. . T. .,c
\. .. .. .. . . : .
, d y ~ *. . . ..r.:.5 r :,;* -. % .. . _ . . .
a.,.~..- .. .:- ~%s
- ..,,.,g.-::. , . . . ._.,...m. - . . . . . * . . . . ; m. m-m. - , . m. . .
, - . ~ ~h. ..e . ? . .. %. . . ' :.w. . - . .
- o. - .
.. . 3 e.
4 4 F. ..:e;. ,. : ;c .,v. m o. 9
.-m.-
. ,; - k .?. .cr,
..s.-
ek. .. C-. , . ., .
r
- ,-$g .
,n... .g .
n..Ji-* . .. ....f,., ..
- ? e.: c: : :- .. _.
.g.a. --s"...g - z:.-:;gg s.,.,. . s%;,a i. .:::2 :;;r.. . .,..,,
- S.
- : . ,. ' y+4
- d. .
- . .c . . e. . t. ;
0 =ca. ray ::: . :* '?
~ - * - * *
- W~..
. . . . .- -. , .y-. .
..t Q 'c. . .a. , %. ..": .- .-,-- >
-....:.- +.u
.. . .__. .; :g. -- ,, . . .
-.- x .n s
~ -
. .s.-....: . ..
,f... .
- c. , . . . .-r
. . r... n9. ,..%. . . ~ .1. ;.. .-.. .-..~t~;
. M
~g Ig ..,. ., .,
s g .
.~vl.. :
.j : .: ::'Y.o
.: . i~ '. :+-: * ,
k ~.. . 4q .
...s.. ?
..- . - q. Q
.: :.s L~;..- 4,..- .:yS?M::iw.:. .,-2. .C p . . y %.-: - .-