ML20081C923
| ML20081C923 | |
| Person / Time | |
|---|---|
| Site: | Vallecitos Nuclear Center |
| Issue date: | 12/31/1983 |
| From: | Cunningham G, Reed L GENERAL ELECTRIC CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8403150072 | |
| Download: ML20081C923 (7) | |
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GENERAL ELECTRIC NUCLEAR TEST REACTOR ANNUAL REPORT NO. 24 LICENSE R-33 DOCKET 50-73 NUCLEAR FUEL ENGINEERING DEPARTMENT e GENERAL ELECTRIC COMPANY j
VALLECITOS NUCLEAR CENTER, PLEASANTON, CALIFORNIA 94566 GENERAL $ ELECTRIC l
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General Electric Nuclear Test Reactor Annual Report No. 24 I.
INTRODUCTION This report summarizes the operation, changes, tests and experiments at the Nuclear Test Reactor (NTR) which were cuthorized pursuant to License R-33 and 10CFR50, Section 50.59, for the period January 1,1983, through December 31, 1983.
II. GENERAL A.
The reactor was operated at or above critical for 635.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. A total of 368 startups were made.
Eleven (11) scrams occurred during this period.
There were no unscheduled shutdowns.
B.
The average annual whole body
'diation exposure to facility personnel was 1.37 Rem.
C.
There was one occurrence that required the notification of the NRC.
During routire maintenance the Safety Rod #4 magnet failed to disengage upon initiation of a scram signal on January 31, 1983.
A scram of only one of the four safety rods is sufficient to safely shut down the reactor. All magnets were replaced by ones of an improved design.
III. ORGANIZATION One change was made to the NTR organization in 1983.
The NTR Analyst position was eliminated.
(See IV.A.I. below.)
IV. CHANGES, TESTS, AND EXPERIMENTS APPROVED BY THE MANAGER, ADVANCED NUCLEAR APPLICATIONS A.
Changes Pursuant to 10CFR50.59(a), the Manager, Advanced Nuclear Applications, authorized six (6) changes during 1983.
The changes are described briefly below.
1.
Reactor Analyst Position
==
Description:==
The Reactor Analyst position was eliminated.
Safety Analysis:
There are no license or regulatory requirements for a Reactor Analyst position.
The Nuclear Safety subsection performs similar reviews.
The Nuclear Safety reviews also provide the independent review function required by the license..
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i it NTR Annual Report No. 24 A.
Changes (Continued) f 2.
Manual Poison Sheet Modification i
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Description:==
Two Manual Poison Sheets were modified by replacing the single strip
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of cadmium in each of the sheets with approximately the same amount of cadmium cut into five smaller strips.
Excess reactivity of the reactor was measured before and after the removal of each cadmium strip to measure reactor excess reactivity as a function of cadmium in the modified Manual Poison Sheets.
Enough cadmium was removed to i
decrease the worth of each sheet by approximately 20 cents.
I Safety Analysis:
All-pieces of cadmium were weighed and identified.
Before pulling critical, the total excess reactivity was estimated and determined to be below Tech Spec limits.
During each pull to critical, a 1/c plot was made to estimate the critical position.
Spacers were used to prevent relative movement between cadmium strips.
The total excess reactivity of the reactor never exceeded the Technical Specification limit (76 cents). during the experiment, j
3.
Picoammeter Replacement
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Description:==
Existing picoammeters for the three linear neutron monitor channels were replaced with newer picoammeters.
Safety Analysis:
4 The replacement picoammeters were designed and manufactured for neutron flux monitoring of a nuclear reactor.
Each unit was calibrated, response time tested and functionally checked before accepting it for use in the safety circuit.
l 4.
High Radiation Door Alarm
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Description:==
An audible alarm system that actuates when anyone passes through the i
east access door while the North Room is a high radiation area was-installed.
Safety Analysis:
A system failure can be identified quickly and remedied lby lockitig the access door.
The alann system is consistent with the require-ments of 10CFR20.
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NTR Annual Report No. 24 A.
Changes (Continued) 5.
Safety Rod Magnet Test Jack
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Description:==
A switch and test jack installation in the safety rod magnet circuit was authorized.
This change permits magnets to be tested outside the reactor cell while temporarily connected into the safety circuit in the same manner as the safety rod magnets.
Safety Analysis:
There are no new hazards introduced by this change.
Leaving the switch in the " test" position with or without a test magnet, and turning the switch to the " test" position during reactor operation either shuts down the reactor or prevents the reactor from startup.
6.
Safety Rod Magnets
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Description:==
The Safety Rod Magnets were changed as follows:
a.
The use of nicaloi and other 50% nickel-50% iron alloys as alternate magnet materials was permitted.
b.
An improved method of attaching the two magnet poles was specified.
c.
Recessing the center pole 0.006 inches in relation to the outer pole was specified to provide an air gap between the center pole and the anvil.
d.
Specifying a perpendicularity requirement on the magnet face.
Safety Analysis:
Alloys of 50% nickel-50% fron are used as scram rod magnets in other reactors.
A magnet was fabricated for the NTR and bench-tested satisfactorily prior to use.
It also was tested on the rod prior to reactor startup.
This taethod of attaching the two poles of the magnet was specified to assure consistency.
The air gap and perpendicularity specifications resulted from measurements and testing of existing magnets.
The properties and performance of the magnets after incorporating these changes caused the residual magnet force (force opposing scram separation) to be considerably reduced.
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NTR Annual Report No. 24 8.
Experiments There was a total of 583 individual experiments reviewed, approved and performed in 1983.
New types of experiments different f rom those already described in Section 7.0 of the Summary Safeguards Report for the General Electric Nuclear Test Reactor, APED-4444A, cr as specified in annual reports submitted since the submittal of APED-4444A were authorized as follows:
1.
Irradiated Fuel Neutrography Experiment Type Approval
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Description:==
The authorization to perform neutron radiography on irradiated fuel samples in the North Room was updated.
Safety Analysis:
Potential hazards from radiation, encapsulation failure, and capsule heating were evaluated and the potential consequences determbed to be acceptable.
2.
Topaz Irradiation
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Description:==
The irradiation of pieces of topaz on the top face, east face, and horizontal cavity of the reactor was authorized.
Safety Analysis:
The potential hazards of activation, interference with safety equipment, and reactivity effects were evaluated and determined to be acceptable.
3.
Iodine Irradiation
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Description:==
Minute quantities of iodine were irradiated for tests at the Analytical Chemistry Laboratory.
Safety Analysis:
The consequences of handling the iodine and failure of the containers were determined to be insignificant.
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NTR Annual Report No. 24 i
C.
Tests Pursuant to 10CFR50.59(a), one test was authorized by the Manager, Advanced Nuclear Applications.
Stack Gas Kanne Chamber Descriation:
This c1ange authorized a special test setup to calibrate the stack Kanne chamber using known concentrations of Xe-133 gas and concurrently establishing a base line response to a specific Cobalt-60 check source.
Safety Analysis:
The radiation hazards associated with the Kanne chamber calibration were determined t7 be inconsequential.
The calibration procedure was determined to be acceptable.
V.
CONCLUSION The overall operating experience of the Nuclear Test Reactor reflects another year of safe, efficient operations.
We anticipate the operation of the reactor will continue on this basis.
GENERAL ELECTRIC COMPANY Irradiation Processing Operation By k.k i h.o o b L. L R~eec ~, ManagW Advanced Nuclear Applications
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GENER AL $ ELECTRIC NUCLEAR ENERGY BuslNEss OPERATIONS GENERAL ELECTRIC LOMPANY e VALLECITOs NUCLEAR CENTER
- PLE A3ANTON, CAUFORNIA 94566 March 5, 1984 Dr. H. R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Reference:
License R-33, Docket 50-73
Dear Dr. Denton:
Enclosed are three signed and forty conformed copies of Annual Report No. 24 for the General Electric Nuclear Test Reactor.
Sincerely,
,l dlf f G. E. Cunni gham Senior Licensing Engineer
/ca Encls.
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