ML19224D199
| ML19224D199 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/02/1979 |
| From: | Muller R Advisory Committee on Reactor Safeguards |
| To: | Carbon M, Etherington H, Plesset M Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-SM-0134, ACRS-SM-134, NUDOCS 7907110071 | |
| Download: ML19224D199 (4) | |
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UNITED STATES
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r-NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS
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W ASHINGTON, D. C. 20555 June 2, 1979 H. Etherington M. Plesset M. Carbon P. Shewmon M. Bender S. Lawroski W. Mathis H. Lewis
'l. Lipinski I. Catton C. Michelson
SUBJECT:
'IMI-2 BLOCK VALVE OPERATIOJ Item IV 2(c)ii on the schedule for the June 6th meeting at Harrisburg concerns the 'IMI-2 chronology discussion of operation of the block valves between 4 hrs.
6 mins. and 4 hrs. 54 mins.
GPU has provided the attached discussion of this matter.
Mr. Michelson feels he hcs an equally logical but different explanation.
This will be discussed during the meeting.
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Ragnwald 4311er Senior Waff Engineer cc: ACRS R. Fraley M. Libarkin T. McCreless J. McKinley H. Voress H. Aldermn 260 10!M b
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/ RECDvED CRmowevrAs e,pyts OcvAnTmtsy 2
Date: May 24, 1979 MAY 2 51979 Rm.1e to.
Subject:
Sequence of Events W/R Block Valve RC-V2 Operation To:
E. Wallace Location: TM1
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t Per our telecon, the sequence of events has been' reviewed with respect to Block Valve RC-V2 operation. The attachment represents a sequence of Block Valve operations that has been extracted from the Preliminary Annotated Sequence of Events, Rev, O that was issued on May 10, 1979. The paragraphs below are offered as explanation of the differences between this sequence and that of the earlier April 16, 1979 sequence with respect to RC-V2 operation.
It should be noted that each of the sequences that have been issued (i.e. the 4/16/79 and 5/10/79 versions) is considered preliminary and that updates and changes to the report are expected to continue as the investigation proceeds. The two versions have been compared. Between the 4/16/79 version and the 5/10/79 version, the folicwing items were deleted:
- 1) 04:06:00 RC-V2 shut
- 2) 04:18:30 RC-V2 opened
- 3) 04:30:00 RC-V2 shut
- 4) 04:54:00 RC-V2 opened The 4/16/79 sequence with respect to RC-V2 operation was developed based only upon considerations of Reactor Coolant System (RCS) pressure responses.
Between that time and the 5/10/79 issue date a correlation between RCS pressures and Reactor Building (RB) te=perature and pressure and other aystete operation was made.
It was decided that, based upon the comparison el RCS pressure and RB teaperature and pceasure changeo, th2 occucreace of tha actions noted above could not be supported.
In point of fact, it is believed that the RCS pressure decrease at 04:18:30 can possibly be attributed to Reactor Coolant Makeup Pump actions occurring at about 04:17.
In summary, a more detailed examination of available data, particularly RB te=perature and pressure responses, led to the judgement that changes with respect to RC-V2 operation should be made.
k-Bruce M. Center BMC:clk Attachcent cc:
R. L. Long J. Putnam
,2' t3 0 l ! 00 T. L. VanWitbeck
- 3. M. Center / File
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Attachment Extract f rom Preliminary Annotated Sequence of Events (May 16, 1979, Rev. 0) showing Block Valve (RC-V2) Operations 02:22:00 The Electromatic Relief Block Valve (RC-V2) was shut, stopping (0622:37)
Approximate reactor c,olant leakage through the Electromatic Relief Valve (RC-RV~).
The operator noted that the reactor building pressure t
started to decrease rapidly.
03:12:28 The operator opened the Electromatic Relief Block Valve (RC-V2)
(0713:05)
Approximate in an attempt to establish a normal operating pressurizer level.
The reactor out-of-core and Intermediate Range Channel NI-3 indication decreased sharply indicating flow was established thru the reactor core.
03:30:00 The operator shut the Electromatic Relief Block Valve (RC-V2).
(0730:37)
Approximate The pressurizer level was 220 inches and the Reactor Coolant System pressure was 1480 psig.
03:51:00 The operator cpened the Electromatic Relief Block Valve (RC-V2)
(0751:37)
Approximate in an attempt to decrease pressurizer level, which had increased to 395 inches.
05:18:00 The operator shi.t the Electromatic Relief Block Valve (RC-V2)
(0918:37) in an attempt to compress the reactor coolant and collapse the superheated steam / gas.
260 ii0
6 07:30:00 The Station Manager directed the operator to open the Electromatic (1130:37)
Approximate Relief Block Valve (RC-V2) and the Pressurizer Spray Valve (RC-V1) to rapidly depressurize the Reactor Coolant System and actuate the Core Flood System while High Pressure Injection was maintained (Figure 12). This was done after the operator ebserved no evidence of natural circulation while the Reactor Coolant System pressure was above 2000 psig. The reduction in Reactor Coolant System pressure was also done to ap9 roach conditions which would allow the Decay Heat Removat Pumps 1A and IB (D H-P-1 A and DH-P-1E) to be put into se rvice.
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