ML20024B452
| ML20024B452 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/01/1979 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| TASK-*, TASK-GB GPU-2524, IEB-79-05-01, IEB-79-5-1, NUDOCS 8307080775 | |
| Download: ML20024B452 (3) | |
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spd 25zy UNITED STATES NUCLEAR REGULATORY CCMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555
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IE Bulletin No. 79-05 Date: April.1,1979 Page 1 of 3 i
NUCLEAR INCIDENT AT THREE MILE ISLAND 1
Description of Circumstances:
28, 1979 the Three Mile Island Nuclear Power Plant, Unit 2 On March experienced core damage which resulted from a series of events which t
Several aspects of the were initiated by a loss of feedwater transient.
incident may have general applicability in addition to apparent generic This bulletin applicability at operating Babecck and Wilcox reactors.
is provided to infom you of the riuclear incident and to request certain actions.
Actions To Be Taken By Licensees:
(Although the specific causes have not been determined for individual sequences in the Three Mile Island event, some of the following may have contributed).
- -For-Babcock and Wilcox pressartzed Watar reacYo77acilities with an operating ifcense:
1.
Review the description (Enclosure 1) of the initiating events and subsequent course of the incident. Also review the evaluatien by the NRC staff of a postulated severe feedwater transient related to Babcock and Wilcox PWRs as described in Enclosure 2.
These reviews should be directed at assessing the adequacy of your reactor systems to safely sustain cocidewn transients such as these.
2.
Review any transients of a similar nature which have occurred at your facility and determine whether any significant deviations frem expected perfomance occurred. If any significant deviations-are found, provide the details and an analysis of the significance and any corrective actions taken. This material may be identified by reference if previously submitted to the NRC.
I 8307000775 790401 PDR ADOCK 05000289 G
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j IE Bulletin No. 79-05 Date: April 1, 1979 P. age 2 of 2 3.
Review the actions required by your operating procedures for coping with transients. The items that should be addressed include:
Recognition of the possibility of feming voids in the primary a.
coolant system large enough to comprcmise the core cooling capability.
b.
Operator action required to prevent the formation 'of such voids.
Operator action required to ensure continued core cooling in c.
the event that such voids are formed.
4.
Review the actions requested by the operating procedures and the training instructions to assure that operators do not override automatic actions of engineered safety features without sufficient cause for doing so.
5.
Review all safety related valve positions and positioning require-ments to assure that engineered safety features and r' elated equip-ment such as the auxiliary feedwater system, can perform their intended functions. Also review related procedures, such as those for maintenance and testing, to assure that such valves are returned to their correct positions following necessary manipulations.
6.
Review your operating modes and procedures for all systems designed to transfer potentially radioactive gases and liquids out of the containment to assure that undesired pumping of radioactive liquids and gases will not occur inadvertently.
In particular assure that such ar$ occurrence would not be caused by the resetting of engineered safety features instrumentation.
List all such systems and indicate:
l a.
Whether interlocks exist to prevent transfer when high I
radiation indication exists and, b.
Whether such systems are isolated by the containment isolation signal.
7.
Review your prompt reporting procedures for NRC notification to assure very early notification of serious e' vents.
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1 IE Bulletin No. 79-05 Date: April 1, 1979
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The detailed results of these reviews shall be submitted within tan (10) days of the receipt of this Bulletin.
Reports should be submitted to the Director of the appropriate NRC l
Regional Office and a copy should be forwarded to the NRC Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, D.C.
20555.
For all other operating reactors or reactors under construction, this Bulletin is for information purposes and no report is requested.
Approved by GAO, B180225 (R0072); clearance expires 7-31-80. Approval Was given under a blanket clearance specifically for identified generic problems.
Enclosures:
1.
Preliminary Notifications
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Three Mile Island -
PNO-67 and 67A, B, C, D, E,F G 2.
Evaluation of Feedwater I
Transients w/ attachment 3.
List of IE Bulletins issued i
in last 12 months l
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