Hanford Safety Fuse Production Test Preliminary Proposal

Page 1

r NORTH AMERICAN AVIATION Atomic Energy Research Department COVER SHEET AND ROUTE-SLIP FOR CLASSIFIED DOCUMENTS Do not remove This document contains M_____ pages This is copy 3 of series Clas sifi cation NAA-SR-MEMOS are working papers and maybe expanded, modified, or withdrawn at any time, and are intended for internal use only. Further dissemination is not permitted and distribution to abstracting agencies is not authorized. Each person who receives this document must sign the cover sheet in the space below. Route to Noted by Date Route to Noted by Date

Page 2

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency Portions of this document may be illegible in electronic image products. Images are produced from the best available

Page 3

■nFPABTMENY OF ENERGY DECLASSIFICATION REVIEW HAHFCRD SAFETY FUSE Page 1 of Hi B QDUCTIOH TEST FRELIMIITARY PROPOSAL This document ia Du® to the expected variation in thermal neutron fins along the asia of the safety dement the required uranium loading is difficult to predict0 It is the objective of this test to determine the exact uranium 235 loading in the safety element fuse as per NAA-SRIX-967005„ A secondary objective of these tests is to develop a means of The third objective is to determine the effects of pile irradiation on the gas pressure in the stored state due to heating and BF^ daccmpositiono It is expected that this pressure increase will be slight, but operational data are required due to the effect of pressure on solder ereep0 The tests will be conducted in throe consecutive reactor loadings a One process fuel tut*® will be required for the tests. The test element will be loaded in the flattened region of the reactor and will bo located on the axial center line0 The test element will be preceded by two hollow natural uranium slugs and followed by two normal Hanford fuel elements c The two hollow uranium slugs will be preceded by a sufficient number of hollow aluminum dtnries to simulate the normal Hanford process tube pressure drop.. This is necessary in order that as near the normal heat transfer coefficient as possible will prevail at the test elament 0 As indicated on HAA-SR1>-9670Q5 an alminum tube will extend from the test element to the front face of the reactor. This tube will carry thermocouple leads, a pressure transmitting tube and a power lead to the fuse heating element. The tests will be performed in three consecutive loadings in the same process tube with the safety element loaded in the same position.

Page 4

The first element to be tested will contain one third the calculated amount of U-235 required ia the final safety element* The temperature of the solder fuse will be measured at two points along its axis with chromelaltnael thermocouples. One additional thermocouple will be mounted at the can wall to monitor the ambient water temperature* The pressure of the stored chamber will be transmitted by means of a stainless steel hypodermic tube which will extend through the quarter inch aluminum tube to the front face where the pressure will be measured by means of a WiancJ o pressure transducer, A small nichrome resistance heater will be mounted on the solder fuse to melt the solder at the desired time* During the first test the temperature of the solder and the pressure of the BF^ chamber will be monitored while the pile comes up t© full power* At least one solder temperature and the BF^ chamber pressure will be recorded continuously during the test. Immediately preceding shut down while still at full power the solder fuse will be melted by the nichrome heater element* Any change in control rod setting and any change in ionization chamber signal will be noted at that time* The outlet water temperature of the test tube will be monitored continuously during the test* The outlet water terperature of the four nearest process tubes will be noted immediately before and after th® safety element trip* The second test will be similar to the first except th© pressure measurement will be deleted and the BF^ chamber temperature will be The uranium loading will be increased to 2/3 or 3/3 of the calculated full loading, dependant upon the results of the first test. Two thermocouples will be located at two points along the solder will be soldered to the can wall to determine the ambient water tempera-® Immediately before shutdown the nichrcaae heater will be used to malt the solder and repeat the ^^^^S^l^^rocedure with such refinements as

Page 5

the first test may deem necessaryc fta the basis of the first two test loadings the exact amount of ^235 needed in the solder fuse plug will be determined. The third element will be loaded with the exact full U-235 loading. Temperatures of the fuse plug will be measured as on the two preceding tests. This element should remain in the pile through at least two successive shut downs in order to determine the effects of shutdown on the element9 and to determine theceffect of U-235 burn-out on the solder temperature. The trip detection experiment may be repeated, if necessary, as dictated by the results of the first two experiments.

Page 6

Drawing 3RD 967005 which is pufr^kt-^bhe memo can be obtained from the