ML19290A238
| ML19290A238 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/31/1979 |
| From: | Lanning W NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Mattson R Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19290A225 | List: |
| References | |
| NUDOCS 7910240193 | |
| Download: ML19290A238 (4) | |
Text
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UNITED STATES I ' i ),, c, i
NUCLEAR REGULATORY COMMISSION s 4.7 )3 - y WASHINGTON, D. C. 20555
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AUG 311979 MEMORANDUM FOR:
Roger J. Mattson, Director Lessons Learned Task Force FROM:
Wayne D. Lanning NRC/TMI Special Inquiry Group
SUBJECT:
COMMENTS ON CHRON0 LOGY OF TMI-2 HYDROGEN BUBBLE I have reviewed the chronology dated August 30, 1979. My revisions are enclosed.
$tLt '
Wa ne D. Lanning NRC/TMI Special iry Group
Enclosure:
As stated above 2226 182 791024014 3
CORRECTIONS TO 8/30/79 CHRONOLOGY OF HYDROGEN BUBBLE P-2, 3/30, 1600:
- Lanning (memory) - requested by Ron Scroggins to join himself, Stan Fabic, and Pete Anderson to go to MNBB concerning accident at TMI-2.
Briefed by R. Budnitz concerning existence of bubble in reactor vessel.
Presented data of pressure versus change in pressurizer level and change in incore temperature measurements. Bubble size was approximately 1000 cubic feet 0 1000 psi and 2800F and increasing.
Concerned that core would uncover due to growth.
Participated in per-fonning heat-up and boil off calculations for core.
P-2, 3/30, 2000: - T. Murley (INEL notes) requested L. Ybarrondo and others at EG&G, Idaho to ascertain the detonation potential of hydrogen gas in reactor vessel (details of request unknown).
P-4, 3/30, after 2000:
- W. Lanning and T. Murley initiated Semiscale Test to explore venting of bubble through pressurizer relief valve. Obtained system volumes and pipe sizes from Ed Kane at B&W/Lynchburg.
Obtained current TMI-2 conditions jrom Tad Marsh at IRC.
Bubble volume in TMI-2 was 1000 ft, pressurized pressure 1100 psi and hot leg temperature 2800F. Noted that pressure surge line had potential for water seal due to geometry layout provided by B d.
Recollect there was a lot of uncertainty concerning size of relief valve opening.
After 2200:
- Reviewed system description and piping diagrams concerning ways to vent bubble.
Reviewed make-up and purification system in attempt to resolve blockage of letdown line.
P-6, 3/31, 0200:
- Received call from W. Minners who requested a calvulation
'of the explosive force of a stoichiometric mixture of hydrogen and oxygen inside vessel.
Assume mixture con-tents for a 1000 cubic foot bubble at 1000 psi which would produce the largest force.
P-6, 3/31 After 0200:
- W. Lanning (memory) requested L. Ybarrondo (EG&G) to perfom calculation requested by Minners.
P-6, 3/31 After 0800:
- W. Lanning (memory) assisted R. Budnitz in evaluating various methods for scavenging hydrogen from primary coolant system.
Discussed Minner's request with S. Levine, R. Budnitz, and T. Murley.
2226 183
2 P-6, 3/31, 1100:
- Monitored progress of Semiscale test.
V. Noonan contacted B. Saffel (EG&G) requesting hydrogen detonation calculation (notes from EG&G details unknown).
P-6, After 1100:
- Transmitted preliminary results of Semiscale Test to B&W (BobJones).
I recall S. Levine discussing results with someone at IRC.
Discussed results of test with J. Cudlin (B&W) and calcula-tion performed by B&W.
P-17, 4/1, a.m.:
- Bob Jones (B&W) requested second test in Semiscale.
Suggested doubling size of bubble and include HPI flow based on B&W's contingency plan for depressurization.
Remainder of day spent primarily on coordinating Semiscale test results and second test.
Provided answers to various Labs and individuals who were working on hydroger typlosion, degassing, radiolysis and recombination of : ' ogen and oxygen (no notes available).
P-26, 4/2 Midday:
- Coordinated results of second semiscale tests to B&W and IRC.
B&W indicated that they were going to revise HPI flow rates in contingency emergency plan to vent the bubble as the results of tests.
Discussed analytical predictions of time period to vent bubble in comparison to Semiscale results.
Relocated from MNBB to East-West Towers.
Performed calcu-lations of time period to degas using pressurizer spray.
- A lot of uncertainty existed concerning flow rates in pressurizer surge and spray lines and makeup and purifi-cation system (coordinated with K. Parzewski).
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30 wv NOTE T0: Roger Mattson
SUBJECT:
HYDROGEN BUBBLE CHRONOLOGY Saturday, March 31 1800 hrs. - Berlinger (Recollection) - Lauben and Berlinger were asked by Stello to provide Stello and Matt Taylor with general information on hydrogen / air flammability and detonation limits.
Information was transmitted to Taylor and Stello including 4% flammability limit and 8% detonation limit (most probably 16% at TMI conditions).
These figures were off the top of the head best estimates based on our previous experience in combustion processes.
Stello was advised to contact Dr. Bernard Lewis (oittsburgh, Pa.)
as a 2nown authority in this acea.
2200 hrs. - Berlinger (Recollection) - Lauben and Berlinger (at dinner) discussed the possibility for a hydrogen explosion in the Reactor Vessel. We concluded, based on available information, that the probability of a hydrogen explosion in the Reactor Vessel was very remote since oxygen levels in the RV would have been depleted during cladding oxidation. The effects of radiolysis were unknown at that time.
Sunday, April 1 0900 hrs.
Serlinger (Recollection) - Berlinger was asked by Stello/Vollmer to calculate the change in containment hydrogen concentration which would occur jf the RCS bubble, assumed to be all hydrogen at 1000 to 1500 ft, 875 psia and 300*F, was vented to containment.
The analysis results were transmitted to Stelic/Vollmer and left in the NRR Trailer / files. The results indicated a change in hydrogen containment concentration from sl.9% to $3.5%.
Since the hydrogen concentration in containment was stabilizing at s2% the possibility of a hydrogen explosion appeared remote, unless conditions changed dramatically due to radiolysis.
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