ML19296B855
| ML19296B855 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/11/1980 |
| From: | Wilson B Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19296B831 | List: |
| References | |
| NUDOCS 8002220264 | |
| Download: ML19296B855 (6) | |
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of SACRAMENTO MUNICIPAL UTILITY
)
Docket No. 50-312 (SP)
DISTRICT
)
)
(Rancho Seco Nuclear Generating
)
Station)
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NRC STAFF TESTIMONY OF BRUCE A. WILSON ON INSTRUMENTATION FOR DIAGNOSIS AND CONTROL OF 0FF-NORMAL CONDITIONS (CEC Issue 5-3a)
Q.
Please state your name and your position with the NRC.
A.
My name is Bruce A. Wilson.
I am an employee of the U.S. Nuclear Regualtory Commission assigned to the Operator Licensing Branch. From May 1979 until December 1979 I was with the Systems Group of the Bulletins and Orders Task Force.
Q.
Have you prepared a statement of professional qualifications:
A.
Yes. A copy of this statement is attached to this testimony.
Q.
Please state the nature of the responsibilities that you have had with respect to the Rancho Seco Nuclear Generating Station.
8002220 2b
A.
I was respensible for reviewing part of SMUD's responses to the Commission Order of May 7, 1979. Specifically, I reviewed their procedures to ensure that their revised procedures were in accordance with the requirements of the Order and complied with the Small Break Loss-of-Coolant Accident Guide-lines that were developed by B&W.
I also conducted an addit of some of Rancho Seco's operators and senior operators to evaluate the training they had received concerning the TMI-2 iccident and the resulting impact at Rancho Seco.
Q.
What issues are you addressing in this testimony?
A.
I am addressing CEC Issue 5-3a, which states:
CEC Issue 5-3a Are the special features and instruments installed at Rancho Seco adequate to aid in diagnosis and control after an off-normal condition engendered by a loss-of-feedwater transient?
Q.
What is generally meant by a loss-of-feedwater transient?
A.
A loss-of-feedwater (LOFW) transient is usually regarded as a partial or total loss of main feedwater flow to one or both steam generators.
~
Q.
What conditions could cause or initiate a LOFW transient?
A.
A wide variety of conditions could cause a LOFW transient. One of the more common causes is tripping of one or both main feedwater pumps as an equipment protective measure for the pumps. Usually the motive force for the pumps are steam turbines which have a number of devices to initiate shutdown of the turbines. Some of the automatic trips for Turbine protection are loss of lubricating oil, loss of condenser vacuum, thrust bearing wear, and overspeed. The pumps also are protected against abnormal conditions, such as the case at TMI-2 where inadequate suction pressure was sensed by the pumps causing them to trip.
Instrumentation malfunctions can also cause LOFW transients. For example, the pressure transmitter that senses inadequate suction pressure may fail causing a pump trip when one is in fact not needed. A failure of the main feedwater flow transmitter may cause the Integrated Control System (ICS) to close the feedwater control values, thus initiating a partial LOFW even though the pumps are still running.
Q.
How is the plant designed to handle safely a LOFW transient?
A.
The plant is designed to handle safely a LOFW basically by means of three systems: the I.C.S., the Reactor Protective System (RPS) and the Auxiliary Feedwater (AFW) System. The ICS is designed to initiate a runback (i.e.,
a reduction in power) of the reactor and turbine to within the capacity of the remaining feeNater in the event of a partial LOFW.
The RPS will shut down the reactor in the event of a loss of both feed-water pumps or a partial LOFW with which the ICS, for some reason, is unable to cope.
The auxiliary feedwater system is designed to automatically start and deliver water to the steam genertors for decay heat removal following the loss of main feedwater and reactor shutdown.
Q.
What information or data is necessary for the operators to diagnose and respond to a LOFW transient?
A.
The operators need information with respect to the following:
a.
The magnitude of the loss of feedwater, i.e. whether one or both pumps have been lost or whether control of feedwater flow has been lost; b.
whether the ICS is responding as required; c.
whether the RPS has been called upon to shut the plant down, and d.
whether the auxiliary feedwater system, if required, is functioning as desigged.
Q. As a result of the NRC review of the Licensee's response to the May 7, 1979 Commission Order, have you identified any areas where there was insufficient instrumentation and capability to immediately retrieve necessary information or data during a LOFW transient at Rancho Seco?
A.
Yes.
In order to verify or perform the actions described in the previous answer, we found that Rancho Seco, as all B&W operating reactors, did not have suitable indication of auxiliary feedwater flow. Therefore, flow detectors were installed on each of the auxiliary feedwater headers and flow indicators were installed in the control room. When required to verify feedwater flow, as, for example, in emergency procedure D.14,
" Loss of Steam Generator Feed," the operator must:
1.
Verify auto start of both auxiliary pumps and operation of auxiliary feedwater valves.
2.
Verify auxiliary feedwater flow indicated on FI-31801 and FI-31901 located on H2PSA to both once-through steam generators (OTSG's) and levels maintained at 224 inches on the Startup Range (~107,on the Operate Range).
We found the instrumentation and capability for information retrieval suffi-cient for the operators to perform all of the other actions as described in the previous answer.
Q.
In your opinion, are the instruments described in this testimony r.dequate to aid in diagnosis and control after an off-normal condition engendered by a LOFW transient?
A.
Yes.
BRUCE A. WILSON PROFESSIONAL QUALIFICATIONS I am a Reactor Engineer in the Operator Licensing Branch, Division of Project Management, Office of Nuclear Reactor Regulation.
I am responsible for developing, preparing and adminishring examinations for applicants for reactor operator and senior reactor operator licenses.
I am assigned to the Power and Research Reactor Group, which is primarily responsible for administering examinations on Combustion Engineering and Babcock & Wilcox designed reactors in addition to research reactors.
I reseived a Bachelor of Science Degree in Mechanical Engineering in 1966 from Syracuse University and a Master of Science in Nuclear Engineering in 1967 from the IJniversity of Washington.
In 1967 I entered active duty with the United States Air Force and was assigned to the 10 Megawatt Nuclear Engineering Test Facility (NETF), Wright Patterson AFB, Dayton, Ohio.
From 1967 to 1968, I was a Project Engineer in the Experimental Branch where my primary function was to design and perform safety analyses of in-core irradiation test experiments.
From 1968 to early 1970, I was Chief, Reactor Engineering Section, where I perfomed safety analyses for reactor modifications and safety limit bases for technical specifications. During this period, I was certified as a Reactor Operator and Shift Supervisor at the NETF by the Air Force Directorate of Nuclear Safety.
From 1970 to 1971. I was assistant to the Chief, Operations and Maintenance Division during the final decommissioning and entombment of the facility.
In 1971, I was transferred. to the Amed Forces Radiological Research Institute in Bethesda, Maryland. For eight months, I was Project Manager in the Accelerator Division and then transferred to the Reactor Division, where I was Assistant Physicist-in-Charge of a TRIGA Mark F reactor.
I received a Senior Reactor Operator's License for this facility from the U.S. Atomic Energy Comission (AEC) and was primarily responsible for experiment safety review, technical specification revision and training.
In October 1973, I resigned my comission with the Air Force and joined the Operator Licensing Branch of the AEC. From May to December 1979, I was assigned to the Systems Group of the Bulletins & Orders Task Force.
My functions on this Task Force were to review and approve the Small Break Loss-of-Coolant Accident (SBLOCA) Guidelines developed by Westinghouse and B&W, and to insure that the applicable facilities have developed emergency pro-cedures incorporating these Guidelines. Finally, I audited the operators and training records to determine that sufficient training had been conducted regarding the SBLOCA phenomenon and the revised emergency procedures.