ML20041E151
| ML20041E151 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 03/02/1982 |
| From: | Dale L MISSISSIPPI POWER & LIGHT CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| AECM-82-60, NUDOCS 8203100193 | |
| Download: ML20041E151 (12) | |
Text
{{#Wiki_filter:. J MISSISSIPPI POWER & LIGHT COMPANY R Helping Build Mississippo EmikkihadiddA P. O. B O X 16 4 0, JACKSON, MISSISSIPPI 39205 arch 2, 6 NUCLEAR PRODUCTON DE PARTMENT U. S. Nuclear Regulatory Commission j' C ' Office of Nuclear Reactor Regulation [- \\\\ f_ .g, Washington, D. C. 20555 Attention: Mr. Ilarold R. Denton, Dir ector \\. ~ /
Dear Mr. Denton:
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SUBJECT:
Grand Gulf'h'ucichilStation Units I and 2 Docket Nos. 50-416 and 50-417 File: L-860/0756 Hydrogen Test Program AECM-82/60 Attached is a prelininary test program to resolve hydrogen control issues for the Grand Gulf Nuclear Station Mark III Containment in the following areas: 1. Hydrogen combestion in hydrogen rich / steam rich environmente such as night occur in the drywell following a small break LOCA. 2. Burn testing above the suppression pool. This program has been jointly developed by EPRI and the Hydrogen Control Owners Group (llCOG) with Mississippi Power & Light Company (MP&L) taking an active role. This test program has not been endorsed or approved by the ECOG. Upon HCOG approval and submittal of the final version of this plan it is MP&L's intent to endorse and participate in the HCOG plan. In any event, MP&L is committed to assure that this test program as finalized.is carried out so that the CGNS Mark III Containment combustion phenomena issues can be resolved. Yours truly, / L. F. Dale Manager of Nuclear Services SHH/JDR:rg Attachment S cc: See next page j f 8203100193 820302 PDR ADOCK 05000416 A PDR Member Middle South Utilities System
MIE :IT71PPI POWER O Ll'ZHT COMPANY AECM-82/60 Page 2 cc: Mr. N. L. Stampley (w/a) Mr. T.11. Cloninger (w/a) Mr. J. P. McCaughy (w/a) Mr. G. B. Rogers (w/a) Mr. T. E. Reaves (w/a) Mr. C. K. McCoy (w/a) Mr. J. F. Pinto (w/ai File (w/a)
Hydrogen Combustion and Control Research For Mark Ill Containments 1.0 Introduction During 1981 EPRI conducted an extensive research program on hydrogen combustion and control in degraded core environments. The work was largely of generic interest, and the results have contributed favorably to the licensing process. In addition, several other tect programs were also completed. While the present emphasis is on the study of generic issues, the specific needs of the Mark III design must be addressed. The overall test program (EPRI and others) as well as the proposed testing by COMBEX* has been reviewed for possible modifications which would help achieve that end. Modeling and analyses of combustion would continue rince the results will be of interest to all situations including that of Mark III BWRs. The proposed NRC rule for Mark III hydrogen control raises many controversial issues including the control of hydrogen from 75 and 100% metal-water reaction and equipment survivability during a burn. The only planned large scale test will l be performed in the NRC program at Sandia where there is a heavy emphasis on flame acceleration and transition to detonation studies. A utility sponsored large scale test should provide convincing evidence that deliberate combustion is an effective control method and that fears for an early containment failure due to hydrogen combustion can be put aside. Schedule requirements for this work are influenced, both by the proposed rule and by current NRC requirements being imposed on Mark III applicants for either a construction permit or an operating license.
- Combustion and Explosives Research, Inc.
C19rg r 2.0 BWR Mark III Hydrogen Research This program lists two options for investigating hydrogen phenomena that are specifically BWR Mark Ill-related. One of these options utilizes the testing experience gained during 1981 and could be implemented by amendment of an existing program. The two research areas are: 1. Hydrogen-rich steam / air environments (combustion in a small volume with glow plug ignition device and oxygen-lean, hydrogen-rich steam atmospheres); and, 2. Burn Testing above the suppression pool (hydrogen / steam injection into pool, measurement of flame location, pressure, and water spray effects). Sections 3.0 and 4.0 discuss each of the above areas in acre detail. C19rg T 4 3.0 liydrogen-Rich Environment A bench-scale vessel can provide most of the information needed to investigate combustion in potential drywell environments. It may be desirabic to also perform a few confirmatory tests in an intermediate-size volume. Tentative plans call for the use of the AECL Whiteshell facility. This facility is modern and sophisticated and has an excellent capability for measurement of steam and post-test hydrogen concentrations. In addition, this facility offers a highly trained staff of combustion scientists, and several years of experience devoted to the hydrogen combustion problem in nuclear reactors. Both bench scale and intermediate volume tests can be conducted there in the relatively near term. Figure I shows a schematic of the 17 liter veseel with a standard glow plug in place. Many experiments have been done to define the lower flamma-bility limits as a function of steam concentration, for both static and turbulent conditions, and using both 12 and 14V igniter operation. Figure 2 shows much of the data obtained in previous hydrogen tests. The vessel could be used to define the hydrogen-rich flammability limits in the region indicated in Figure 3. Tests near the inerting limit are difficult and require very careful preparations. More than 50 tests will be required in order to fill in the curve of Figure 3 due to the difficulties of detecting marginal ignition, j Whiteshell has a 7.6-foot diameter sphere (220 ft.S volume) which they have used for many utility-funded tests to investigate combustion behavior for hydrogen concentrations from 5 to 42%. The design pressure is 1500 psi and the hichest pressure seen to date is less than 70 psi, for a dry mixture of about 28% hydrogen. This facility (220 ft. ) will be utilized for limited testing to confirm the 17 liter tests and for compatibility with the balance C19rg.__
of hydrogen tests being performed for the nuclear industry. The number of tests for the 220 ft'3 vessel will be determined on an as needed basis based upon results from previous tests. C19rg _.
4.0 Burn Tests Above the Suppression Pool The question of burning above the suppression pool is among the most important of Mark III-specific problems, particularly since a full-scale simulation is desired. Construction of a new facility which has appropriate dimensions is in the planning stages. The time schedules for satisfying the proposed NRC rule on hydrogen would allow this plan to be implemented. The construction of a new facility will consist of an essentially full scale segment of the suppression pool /wetwell area open to the atmosphere at the top. Such a new facility will be outfitted with a continuous hydrogen / steam injection system for simulation of degraded core accidents. The hydrogen and steam rates will be actual expected values based on calculated scenarios for these accidents. A flame front detection system will be installed for flame spatial histories and a measure of transient temperatures. A water spray system suitably simulating spray carryover to the wetwell will be installed to verify the mixing and cooling effects that result from the use of sprays. The intent of this plan is to simulate a portion of the suppression pool /wetwell area including the area above the HCU floor to simulate the vent characteristics of that area. C19rg _
1 i l 1 5.0 Schedule All projects discussed can provide data within the timeframe required to support licensing needs or to satisfy proposed NRC regulations. Interim requirements for Mark III hydrogen control were published for comment in the Federal Register on December 23, 1981. The comment period may be extended into March 1982 due to lateness of promised BCL source term calculations-which' are to be open for review. The rule will be effective only after several months (or longer) for NRC review, and 30 days after the rule is published. If the proposed rule stands, Mark III owners would then have one year to install and justify hydrogen control systems (or the date of operation above 5% full power if that is later). Figure 4 shows the tentative schedule for these requirements and the proposed schedule for experiments. The bench-scale Whiteshell facility has been dedicated so far to EPRI-sponsored work. The full scale project is proceeding in the planning phase and these tests would be conducted in the fall of 1982. i C19rg - -.. - - -.. - -.. - - -, _
r ~ 4@ Nx / / / /' \\\\ \\g ~1-h- l f /3 g i, @^'; N c / i 10 cm h .- a ELECTRICAL "r WIRES l l l l N l l v ~ Figure 1. Schematic of Whiteshell vessel for studytag hydrogen-rich steam / air mixtures with glow plug ignition.
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r u $a I ] I l l (T eo IGNITED MARGINALLY NO GAS OPERATING IGNITED IGNITION CONDITION VOLTAGE o e O STATIC 12 VOLTS u a O STATIC 14 VOLTS V V V TURBULENT 14 VOLTS W o
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PROPOSED LIMITS FOR STATIC MIXTURES o
M sim g 15 . PROPOSED LIMITS FOR TURBULENT S MIXTURES \\ m I g E c g 6,7 l ,,[014.3 O s, 5 m is Q 2 G / o / x ,,. n h, F 10'4- =" 3 15' /+' " ga onl Z mi .3 ay/ c sr o a Z 5 2o is 79 A O ".. 2, si 8 n 23 'V 1 n z n a w m O Usia 3 5 # 3 2 22 V-b m 6 u. v Y' o 2. y x5 Tu ,e ~ 9r78 _, 33 V 13 / ~ 0 I I I I I O 10 20 30 40 50 60 STEAM CONCENTRATION (%- BY VOLUME) Figure 2. Effects of steam in lean hydrogen mixtures as determined by Whiteshell for EPRI and utilities. l l
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\\ g = g w eo 40 x ....q e ( ( a>- 9 r . ~_ \\'. t. . _ '. _. _ _ '. _. -l. A F. L}... W.6.t.L_. - (. N, ..RC FICM .../ i- .j._. ... ] - -. _ _ _.h 20 1._._ _._. .___..)... l&. ]. 9 A Fr i.._ 1A41 I AM.. 1 ..-... g - p..... 0 20 40 60 80 0 STEAM CONCENTRATION (v.%) Figure 3. Hydrogen-rich region for proposed investigation.
Figure 4 Schedule for Mark III 11 Control Research and Regulations 2 1/82 7/82 1/83 7/83 1/84 PROJECT H -Rich Phiteshell ~~~ 2 Conbustion Burn Testing Proposed NRC Rule for Mark III Connent Review ? Rule Period Period Effectivef C24rgl}}