ML20052H971
| ML20052H971 | |
| Person / Time | |
|---|---|
| Issue date: | 04/05/1982 |
| From: | Catton I Advisory Committee on Reactor Safeguards |
| To: | Boehnert P Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1434, NUDOCS 8205240263 | |
| Download: ML20052H971 (3) | |
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~ T. .I aul Boehnert gb S g.wiel' / : f y- .FROM: 2 van Catton an .g- [ SU,BJECT: Smiscale Review Group Meeting, 9 March 1982, Bethesda NN ' Q.* An interesting fact to start my report is that Seniscale costs 7._q%.' _ ~ y $35,000 per day whether productive or not. A number of topics were co'vered.. c, durin,g the meeting. Each is summarized below. The M005 version of Semi c
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scale presents several alternatives. The currently defined research program b would be completed and Semiscale could be phased out during FY 84/85 or i. MOD 5 and its research program could be added and Seniscale could be extend N m beyond FY 85. There is now no money in the NRC budget to augment the FY # O 83/84 budget to develop MOD 5. A decision must be made now if MOD 5 is 9 i interest. 8 REChiVED 4-1 Semiscale has been a very useful tool during the past ten years c -M&2019825: 4 ff Most thermal hydraulic behavior that is of importance in nuclear 7 can be investigated with the facility. Further, in that most inciden's-have been thermal / hydraulic in nature, Serniscale is a valuable asset. 1 SP" // 7 Serious consideration should be given before it is allowed to phase out 0 nv 't ~ No better testing ground for a wide variety of phenomena and ideas (SPDS. (3 ..o. produces etc.) exists. g ,2 RELAP5. RELAPS is not a part of the advanced code effort in the ~ usual sense. It is totally within the Semiscale program. Agnumber of utilities are beginning to use RELAP5 to develop their own computational capability. It is beginning to see use as a tool by some who supply. technical assistance to the staff. There is direct support given to MRR .4. ' o-y by INEL. An interim release of MOD 2 has been made (whatever that means) that is verified and suitable for NRR use. It will deal with PWR large s snd small breaks, some transients and BWR ATWS. Centinued support is being given both LOFT and Semiscale programs. A BWR version will be com-pleted during 1983 with release planned for 1984 b, RELAPS is being used in an interactive mode. Thb code runs faster than real time interactively. One can make mistakes and follow the effect of the mistake. During a show-and-tell, a number of errors were deliberate-ly made and we were able to watch a LOF evolve into a near disaster then recover it. An engineering simulator now exists. The computitional objectives of the RELAP5 program appear to be F nearly achieved. An effort focusing on " User Services" has been inigiated. l It is interesting to note that the cost of RELAPS is about $2.5 x 10. Of course this doesn't count the many early codes like SCOOP that were diss.'q = continued. Nevertheless, it seems to have been a successful pro ect. a Saistale Heat loss Study. The heat loss from the Semisca e appara MJ tus is roughly eqW I to the nominal decay energy. The solution has been. YC l to use heater bands and tapes. Heaters have been installed everywhere-- l all pipes and the vessel. By controlling the heaters, an almost zero ' % t net loss is achieved. Analysis can then be done with an adiabatic boundary L assumption. 0205240263 820405 ~ 4MC EN PDR ACRS .,~ CT-1434 PDR ([-. ~ I' Certified By N* UNIVEASITY OF CA1.IFOEN!.A-(tetierhead for talardepartanestal ama) 7 4 >l,,.., E
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t. + ..p,. v Semiscale Review Group Me: ting-ceint'd.:p..... g. q. 7;*.7ame m uunsomous. gPagef;;g.v.;<:',a ~ f,J Less of pump suction and other strange ~ behavio ..s ~u .'=.,c J.y*&$ f- .,.1 tion. There seems to be little effect on core inventory. lt fr1m heat addf-bg is important and uncompensated losses must be modeled if good result E at less andel- ; are to be obtained. small scale facility users (in particular HSTS).The Semiscale experienc !.MNI Test Series. A series of six experiments were conducted to-M *c of break sizes and to assess code performance (RELAPS) e.., ; Y l more upper herd by pass, which is a result of the change The tests showed ?- This plug causes water to be pushed down into the core yielding a lower 'd collapsed liquid level than anticipated and correspondingly 11onger dryout ? period. The W licensing calculations do not show quite as much core level D$ depr'es s ion. The calculated dryout period, however, is much longer with the net result being conservative rpedictions of clad temperature
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is another example of why one must be carful if pgocedures are based on This f2. vendor codes. The upper head geometry is important. p.i J cipated. The ELAP5 results look very good. No severe heat up is anti ' Natural Circulation Experiments. 7:. A large number of experiments circulation as well as reflux cooling.have been conducted to gai ' r. The results from the tests were used to explain the PXL test results. R Semiscale in a number of respects. The PKL facility is different than ~ Using the results of one facility to explain those of another is a reasonable argument for expressed understand-ing of the phenomena. The RELAP5 predictions compared reasonably we gc tests. when the secondary side was starved. f It was possible toadehuately predict the system response to N using some simple thermodynamic relationships. s Decayheatremovalwasa$equatedownto50%primarysideand8% second side inventory. The non-condensibles had a minimal effect up to 50% of ? the accumulator nitrogen. '? ' Westinghouse Reactor Vessel Level Instrument System (RVLIS) tive experimeWts were conducted. Actual W handware was installed on Sem A valve failed shut and was not found until the test was run.Some operationa [.'.E line leakage required bleeding out of the air. Capillary Sense line flashing occured
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at the highest elevation of the line. ^ the sense line flashing could be circumvented by bleeding through the iB ^ )3- . exchanger pater. 'j blems were considered big problems.None of the operational problems were conside on were off and under quiescent conditions.The RVLIS was shown to give core dryout indicator even though not necessaruly an unambiguous levelIt was indicator under all conditions. to be cprrectable. Most problems encountered were believed, n M005 Feasibility Study. of representing a B&W or CE plant.M005 is to be a 2 x 4 loop design capable ~! wants one and is it worth the money.T-he question is whether or not one '(. design would deal with them.be completed by July that would bring out lic early to come to any conclusions regarding the merits of a MOD 5The study k ~ UMTVER S!TY OF CAtJFO RM1A--(1stterh4 for laterdepartmental use) =
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.-l'. n.,.. ry. - - 2 :,9 ~.., / ', f M.Jberaal Hydraulic Experfaents Tac 111ty (THEF). .. J. O ^. " # ~ ' ~ Ply - g??:.hU.d.1 THEF was used to support the LOFT experimental program. It has y taro facilities: ,s 3 slowdown Loop--2250 psig 550' F.11.4 f t 4,i - -6 j Two-Phase Loop--1000 psig. 55'lbm/sec steam, 9000 GPM unter !., gy, A number of separate effects tests are being proposed for THEF for FYB3J._ - g.. It was proposed that large horizontal pipe flow regimes, candy cane flow J. - ~4 dynamics, pressurizer repressurization and critical flow be studies. J 3. subsequent report will discuss these proposals in more detail. a, Future Efforts at Semiscale. ine balance of FY82 will be devoted to .E analysis of thelfHI and natural circulation experiments Intermediate Breafs (IB), and Steam Line (SL) and Feed Line (FL) breaks. The IB experi-ments will be selected to fill in the data base by choosing a 50% and a 21% break. The 21t break will yield a test that corresponds to a test at LOBI (a much larger facility). The FL break test pill focus on the CE 2'. system 80 licensing issue regarding maximum repressurization rate. Pheno-mena associated with heat transfer from the primary to secondary will be _^ studied. The SL tests will evaluate how well codes can follow a cool down event. Licensing calculations seem to be setting the stage for the experi-ments. It is not clear that this is good as we will be focusing on things s we already are thinking about. Fy 83/84 efforts are to focus on loss of offsite power transients, stear, generator tube ruptures, steam line breaks, pump suction breaks. 't lower vessel breaks (instrument tubes), and ATWS. During FY 84/85 off 1,.. design breaks (hot standby for example) will be looked at. 5.-' g, e.d e-g. W.*. v. Nb'.?:: V. 7:,. v. tx r. n '.
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