ML20237K612

Mit Research Reactor Annual Rept to NRC for Jul 1986 - June 1987

ML20237K612
Person / Time
Site:	MIT Nuclear Research Reactor
Issue date:	06/30/1987
From:	Lisa Clark, Kwok K NUCLEAR REACTOR LABORATORY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8709040446
Download: ML20237K612 (27)

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MIT RESEARCH REACTOR -

l ANNUAL REPORT TO i

UNITED STATES HUCLEAR REGULATORY COMMISSION FOR TIIE PERIOD JULY 1, 1986 - JUNE 30, 1987 BY REACTOR STAFF August 29, 1987

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9-TABLE OF CONTENTS Page Section Number Introduction.................................................... 1 A. Summ a r y o f Ope r a t i n g Ex pe r ie nc e . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 B. Reactor Operation......................................... 11 C. Sh u t d o wn s a n d Sc r a m s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 D. Major Maintenance......................................... 14 E. Sec tion 50. 59 Changes , Te s t s a n d . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Experiments F. Env i r o nme n t a l Su rv e y s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 G. Rad ia t ion Ex po s ure s and Su rve ys . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 0 H. Ra d i o a c t i v e E f f l ue n t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 l

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MIT RESEARCH REACTOR ANNUAL REPORT TO UNITED STATES NUCIE.AR REGULATORY COMMISSION FOR THE PERIOD JULY 1, 1986 - JUNE 30, 1987 Introduction This report has been prepared by the staff of the Massachusetts Institute of Technology Research Reactor for submission to the Admin-istrator of Region 1, United States Nuclear Regulatory Commission, in compliance wi th the requirements of the Tec hnic al Speci fica t ions to Facility Operating License No. R-37 (Docket No. 50-20), Paragraph 7.13.5, which requires an annual re po r t following the 30th of June of each year.

The MIT Research Reac tor (MITR), as originally constructed, con-sisted of a core of MTR-type fuel, fully enriched in uranium-235 and cooled and moderated by heavy water in a four-foot diameter core tank, surrounded by a graphite reflector. After initial criticality on July 21, 1958, the first year was devoted to startup experiments , calibra-tion and a gradual rise to one megawatt, the initially licensed maxi-mum powe r . Rout ine three-shift operation (Monday-Friday) commenced in July 1959. The authorized power level was increased to two megawatts in 1962 and five megawatts (the design power level) in 1965.

Studies of an improved design were first undertaken in 1967. The concept 9hich was finally adopted consisted of a more compact core, cooled by light water, and surrounded laterally and at the bottom by a he avy wa t e r re flec to r . It is unde rmode ra ted for the purpose of maxi-mizing the peak of thermal neutrons in the heavy water at the ends o f the beam po r t re-entrant thimbles and fo r enhancement of the neutron flux, particularly the fast c ompone n t , at i n-c o re irradiation facili-ties. The core is hexagonal in sha pe , 15 inches across, and utilizes l fuel elements which are rhomboid al in cross section and which contain UALx intermetallic fuel in the fo rm of plates clad in al umin um and i fully enriched in uranium-235. Much of the original fac ili ty , e.g. ,

graphite re flec tor , biological and t he rmal shields, secondary cooling l systems, containment, etc., has been retained.  !

After Construction Pe rmit No. CPRR-118 was issued by the fo rme r U.S. Atomic Energy Commission in April 1973, major components for the modified reactor were procured and the MITR-I was shut down on May 24, 1974, having logged 250,445 megawatt hours during nc arly 16 years of operation.

The old core tank, associated piping, top shielding, control rods and d ri ves , and some experimental facilities were disassembled, re-moved and subsequently replaced with new equipment. After preopera-tional tests were conducted on all systems, the U.S. Nuclear

a Regulatory Commission issued Amendment No. 10 to Facility Operating License No. R-37 on July 23, 1975. After initial criticality fo r MITR-II on August 14th, 1975, and several months of startup testing, power was raised to 2.5 MW in Decembe r . Routine 5 MW operation was achieved in - December 1976.

This is the twel f t h annual repo rt required by the Technic al Specifications, and it covers the period July 1,1986 through June _30, 1987. Previous reports, along with the "MITR-II Startup Re po r t" (Report No. M ITNE -198, Feb ruary 14, 1977) have covered the startup testing period and the transition to routine reactor operation. This report covers the tenth full year of routine reactor operation at the 5 MW licensed powe r level. It wa s another year in which the sa fe t y and reliability of reactor operation met the requirements of reactor users.

A summary of operating experience and other ac tivities and re-lated statistical data are provided in the following Sec tions A-H o f this report.

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SUMMARY

OF OPERATING EXPERIENCE

1. General During the period covered by this report (July 1, 1986 - June 30, 1987), the MIT Research Reac tor, MITR-II, was operated on a routine, five days per week schedule, normally at a nominal SMW. It was the tenth full year of normal operation for MITR-II.

The reactor averaged 80.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> per week at full power compared to 75.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> pe r week fo r the previous year and 86.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> per week two years ago. The reactor is no rmally at power 90-100 hours / week, l

but holid ays , major maintenance , long experiment changes, waste ship-l ping, etc., reduce the average. During the past year it was red uc ed more than usual as the result of two week-long shut down s for major maintenance activities (described later), one of them occurring at New Year's and one later in April. %e reactor routinely operates from late Monday a f ternoon until late Friday a f ternoon, with maintenance scheduled for Mondays and, as necessary, for Saturdays .

The reactor was operated throughout the year with 25 elements in the core. We remaining positions were occupied by irradiation facil-ities used for materials testing and the production of medical iso-topes and/or by a solid alumhum dummy. Compensation for reactivity lost d ue to burnup was achieved through seven refuelings of several elements each. The first of these entailed the introduction of three low burnup elements to the core's in t etwed ia te fuel ring (the B-ring) .

The others involved a continuation of the prac tice begun in previous years in which partially spent elements that had been originally ,

removed from the B-ring were gradually introduced to the C-ring to replace fully spent elements. The se procedures were combined with many element rotations / inversions, the objective of which was to mini-mize the e f fects of radial / axial flux gradients and thus achieve higher average burnups. An additional re fueling wa s per fo rmed fo r removal of the one inch in-core facility so as to f ac ili ta te the design and installation of a new loop research project.

l The M ITR-II fuel management program remains quite successful. ,

All of the original MITR-II elements (445 grams U-235) have been per- I manently discharged. The average overall burnup for the discharged elements wa s 42%. The maximum overall burnup achieved wa s 48%.

Thirty-six of the newer, higher loaded elements (506 grams U-235) have been introduced to the core. Of them, three have attained the maximum allowed fission density. However, these may be reused if that limit is increased as would seem warranted based on metallurgical studies by DOE. As for the other thirty-three new elements, they are either cur-  ;

rently in the reactor core or have been partially depleted and are l awaiting reuse in the C-ring.  !

j The availability of a licensed spent fuel shipping cask fr om DOE is again delayed this year. Although the cask is expected to be licensed later on this year, the delay has thus far caused our total fuel inventory to approach the authorized possession limit and con-l t inue s to force us to deviate from our normal fuel management practice .

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-s-(1) The inventory of partially spent elements is now s ub s t an t i-ally below normal. This is making it difficult to convert fron. one core configuration to another.

(2) Inability to bring in fresh fue l and to place it in the A and B-Rings of the core may necessitate premature C-Ring re-fuelings in order to ob ta in suf ficient reactivity for con-tinued operation. This will resuit in lower overall burneps and ultimately increase our need for additional fuel.

Finally, it should be recognized that if casks continue to be unavail-able, we will have to request a reinstatement of part or all of our previous license limit for possession of U-235 in order to continue operation.

l Protective system s surveillance tests are conducted on Friday evenings a f ter shutdown (ab out 1800), on Mondays , and on Saturdays as necessary.

As in previous ye ar s , the reactor was operated throughout the period without the fixed ha fnium absorbers, which ' were designed to

~ achieve a maximum pe aking of the thermal neutron flux in the he avy i water re flec tor beneath the core. These had been removed in November l 1976 in order to gain the reac tivity necessary to support more in-co re f ac ilities .

2. Experiments l The MITR-II was used throughout the year for experiments and irradiations in support of research and training programs at MIT and elsewhere.

Experiments and irradiations of the following types were conduc ted :

i a) Neutron dif frac tion spec trome ter alignment and studies (3 ports).

In pa r tic ul ar , the study of the use of pendel18 sung oscillations )

in the scattering of neutrons inside perfect crystals to greatly j l enhance the e f fec t of s pin-orb it contribution to high-energy l neutron-nuclear scattering is being carried out by the neutron diffraction group, b) The production of M8ssbauer sources by the irradiation of Gd-160 and Pc-196 for studies of nuclear relaxation of Dy-161 in Gd and for the investigation of the chemistry and structure of gold com-pounds.  ;

l c) Irradiation of archaeological, environmental, engineering materi-als, biological, geological, oceanographic, and medical specimens for neutron activation analysis purposes.

d) Production of gold-198, dysprosium-165, and holmium-166 for medi-cal research, diagnostic and therapeutic purposes.

I e) Irradiation of tissue specimens on particle track detectors fo r l

plutonium radiobiology, f) Irradiation of semi-conductors to determine resistance to high doses of fast neutrons, g) Use of the facility for reactor operator training.

h) Irradiation of geological caterials to determine quantities and' distribution of fissile materials using solid state nuclear track detectors.

i) Fault detection analysis of the output of control and process channels from the MIT Reactor as part of a study le ading to control of reactors by ne of fault-tolerant , digital computers. 1 This ef fort recently resulted in the demonstration of techniques for reconfigurable control.

j) Closed-loop direct digital control of reactor power using a shim blade as well as the regulating rod during some steady-state and transient c ond i t ions . A new relation, the alternate dynamic period equation, was developed and used as the basis of a reactor controller, k) Experimental s c ud ie s of various closed-loop control techniques including rule-based control and the use of reactivity con-straints.

1) Development and experimental evaluation of several new techniques for the measurement of reactivity.

m) Measurements of the energy spectrum of leakage neutrons using a mechanical chopper in a radial beam port (4DHl). Measurements of the neutron wavelength by Bragg re flec tion then permits demon-stration of the DeFroglie relationship for physics courses at MIT and other universities.  !

J o) De tec tion of trace quantities of fissile nuclides in geological )

material using a delayed neut ron detec tor. I 1

Two research projec ts that will make major use of the reactor in the next and subsequent years have been f und ed and are in various stages of design and development . They did not actually make use of the reactor during the year, although reactor support services, e.g.,

electrical powe r supply, were augmented in preparation for installa- l tion of experiments on the reac tor in the coming year. The first pro- I ject is a dose reduction study for the light wa te r reactor industry l j

which will involve the installation of pressurized loops in the reac- l l tor core to investigate the chemistry of corrosion and . the transport l of radioac tive crud with systems that simulate PWR's and BWR's. The  !

sec ond project is an extension of previous research to develop the boron ne ut ron capture method of therapy for brain c anc er (glio-blastoma). 'Ihi s 's a collaborative ef fort with the Tufts Universi ty i New England Medical Center. I l

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3. Changes to Facility Design Except for minor changes reported in Section E, no changes in the facility design were made during the year. As indica ted in past reports the uranium loading of MITR-II fuel was inc reased from 29.7 grams of U-235 per plate and 445 grams per element (as made by Gulf United tbelear Fue l s , Inc., New Haven, Connec t ic ut ) to a nominal 34 and 510 grams respectively (made by the Atomics International Division of Rockwell International , Canoga Pa r k , Cali fo rnia ) . With the excep-tion of five elements that were found to be outgassing excessively, pe r fo rmanc e has been good . (Please see Re po r t abl e Occ ur renc e Repo rt s Nos. 50-20/79-4, 50-20/83-2, 50-20/85-2, 50-20/86-1, and 50-20/86-2.)

The heavier loading re sul t s in 41. 2 w/o U in the core, based 'on 7%

voids, and corresponds to the maximum loading in Advanced Test Reactor (ATR) fuel. Atomics International completed the produc tion of 41 of the more highly loaded elements in 1982, 36 of whi:h have been used to some degree. Three with about 37% burnup we re in operation in the core starting in January 1980 and were discharged in 1985, since they had attained the burnup limit. Additional elements are now being fabricated by Babcock & Wilcox, Navy Nuclear Fuel Division, Lynchburg, Virginia. Three of these have been received at MIT and are scheduled for use early in the coming year.

t The MITR staf f has been following wi th interest the work of the Reduced Enrichment for Re se a rch and Test Reactors (RERTR) Progr am at Argonne Na tional Lab o ra to ry , particularly the development of advanced fuels that will permit uranium loadings up to eeveral times the recent  !

upper limit of 1. 6 grams total uranium / cubic centimeter. Considera-tion of the thermal-hydraulics and reactor physics of the MITR-II core design show that conversion of MITR-II fuel to lower enrichment must j await the successful demonstration of the proposed advanced fuels.

4. Changes in Performance Characteristics Pe r fo rmance characteristics of the MITR-II were repor ted in the "MITR-II Startup Re po r t" . Minor changes have been described in pre-vious reports. There were no changes during the past year.

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5. Changes in Operating Procedures Related to Safety i

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There were no amendments to the Facility Operating License during j the last ye ar .

i Quality Assurance Program Approval for Radioactive Material Pack- l a ge s No . 164, Re v . 1, was renewed on June 20, 1986 (Rev. 3). This Ap-proval is required for the shipment of (1) Type B quantities of radio- j active material and (2) fissile material above exempt quantities. In 1 order to renew the Approval, it was necessary to update SAR Chapter )

11, " Quality Assurance Program", which supports Approval No. 164. The I changes to Chapter 11 were minor and were described in laet year's Annual Re po r t . Chapt e r 11, as revised, was submitted to USNRC on April 7, 1987 as Sa fety Analysis Report Revision No. 33 for ' the pur-pose of updating that document.

.4 With respect to operating procedures subject only to . MITR inter-nal review and approval, a summary of those related to safety is given below; a) Evacuation maps .for the ' reactor of fice building .(NW12) were up-dated and improved to include clearer and more directievacuation paths:

as. well as .a desc ription of the sound of evacuation ' signals.

(SR #0-85-24) b) In an ef fort ' to improve. scheduling and bookkeeping of routine

. preventive maintenance, a - set' of thirteen checklists were established to cover the. routine maintenance. performed year round. The weekly checklist covers items that need ' to . be . checked' frequently and the twelve monthly ' checklists cover items that need to be serviced at a longer but regul ar in te rv al' (SR #0-86-10) c) Procedure 4.4.5.1, "In s t ruc tions fo r Use -of Utility Room Emergency Gauge s", was revised to change ' the valve designation pre fix f rom XTV to XV. This was done to simplify the valve numbers as well as matching those on the valve' tags. (SR #0-86-12) d) Procedures 4.4.4.3, " Reactor Fire", 5.7.8, " Smoke ' De tec to r System", and 6.6.2.2, "Self-Contained Breathing Devices", were revised to re flec t recent changes to OSHA requirements. OSHA ' regulations (C PL2-2. 20A) prohibit the use of the ten minute sling self-contained breathing devices for entry to a building. Accc.-dingly , the storage loca tion o f - the MITR's self-contained breathing devices. were changed so that the thirty minute units are outside the reac tor containment for reentry purposes and the ten minute units are kept in the c'ontain-

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ment for use in exiting . (SR #0-86-14) e) A new combustible gas meter was purchased to ' replace an old unit which was used for detection of hydrogren buildup in both the medical water shutter system and the air space on top of the core tank under the lid (core purge), and deuterium buildup' -in tha heavy water re flec tor system in the event of isolation in any of these systems.

Procedures 6.5.20.1, "Calib ration of Combustible Gas Meter", and 6.5.20.2, "Co6 ustible Gas Meter Use", were modified to incorporate changes pu.:inent to the use of this new meter. Calibration and con-version charts were included in the proceduree to preclude any ambiguity on interpretation of the meter readings. (SR #0-86-15) f) The administrative procedures, Chapter 1 of the Procedure Manual, were revised to update the lists of names and committee memberships .

This does not involve any change. to the procedures . (SR #0-87-1)

. g) Procedure 6. 3.4, " Fan Interlocks and Alarms", was revised to in-clude separate s te ps for opening. the auxiliary damp.ers and stack base damper, and fo r starting the auxiliary f an s . and pneumatic blower.

This change refined the existing' procedure by making explicit several steps that had previously been . implicitly assumed by the original pro-cedure. (SR #0-87-2)

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h) Procedures 3.1.1.1, " Full Power Startup Checklist - Mechanical",

3.1.1.2, " Full Powe r Startup Checklist - In s t r umen ta t ion" , 3.1.1.3,

" Full ' Power Startup Chec kli s t - . Cooling Tower Operation", 3.2.1,

" Shutdown 'from Operation at Po we r" , 3.5, " Surveillance Check for Con-tinuous Opera tion" , were updated . to incorporate ' changes -to ~ various systems., ; Mode of operation is . changed from using all . three heat-exchangers simultaneously to using ' two at a time. Provisions 'are inc orpo rated to alternate the two on-line he at exchangers so as to preclude fouling resulting from stagnation 'of water. This new mode of operation provides better flow charac teristics and standby assurance of a heat exchanger. (SR #0-87-3)

! i)' Procedures 1.16.2, "MITR Operations Qualification Program fo r Senior Operators / Shift Supervisors", and 1.16.3, "MITR Operations' Qualification Prog ram fo'r Operato rs", were updated. to reflect fo rma t i

changes of the page layout and correction of typographical errors . ,

I There were no changes to the procedure.. (SR #0-87-4) l 4

j) The graphite . stringers in the graphite region of the reactor have been in use since startup of the original reactor, MITR-I. As a means of inspecting the conditions of the graphite reflector region and the outside surface of the re flec tor - tank, three procedures . were devel-oped. The first procedure 7.6.1, "Special . Procedure for Graphite Region' Inspection", outlines the steps necessary for . removal of a ver-tic al irradiation f acility (3GV2) in ~ the graphite region, L insertion of a periscope for visual inspec t ion , acquisition of- graphite specimens from the high flux region, acquisition of helium samples from the' graphite region, and finally reassembly of the irradiation fac ili ty .

The second proc ed ure 7.6.2, " Meas uremen t of Wigner Stored Energy in Graphi te ', outlines the steps necessary for ' determination of the Wigner stored ' energy, if any, in the specimens taken . from the graphite reflector. The third procedure , 7. 6. 3,' " Graphite Combus tion Test",

outlines a proc ed ure for. conducting c omb us t ion tests on samples of irradiated and unir rad ia ted graphite. Precautionary information was incorporated whenever appropriate throughout the'se procedures .

(SR # 0-87-5 and 0-87-6) k) Procedures 3.2.4, "Re s oonse to Weekend Alarms", 3.7.1, ." Weekly l Security Checklist", 3.7.2, " Daily Security Checklist", were revised to re flect the installation of a remo te s surveillance system for ' t he control room and remote indic ation panel for alarms and radiation levels. The daily and weekly security checklists were updated to implement new procedure to control access to the parking lot after normal business hours . ( S". #0-87-7 )

- 1) Procedures 5.6.1, "High Radiation Set-Up Area Va ul t" , 5.6.4,-

" Trouble NW12 Gamma Monitor", were updated to - re flect the location change of the reactor fuel . vault which is no longer the sma11' vault in

. the se t-up area in NW12. (SR #0-87-8)

I i m) Nine sets - of boron stainless steel control blades were procured .!

in FY 1987. As part of the quality assurance program requirements,  !

neutron transmission te s t s were necessary fo r final verification of .l l i 1

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the materials used for fabrication. Procedure 7.6.4, " Shim Blade Neutron Transmission Tests", was established for this purpose. 'Ihi s procedure represents a consolidation of all previously used procedures as documented by individual memos to the appropriate Q/A files.

(SR #0-87-9) n) The " Waste Storage Tank Dump Proc ed ur e" , procedure 3.6, was revised (1) to add a step to require verification of the operability of the sewer rionitor prior to use, (2) to add RRPG fo rm 2005 which shows the details of the ef fluent c alc ula t ion. This form had been in use since July 1985 and is incorporated here as part of the procedure.

(SR #0-87-10) o) Procedures 6.5.9.1, " Area Moni to r Calib ra tion Procedure", . and

6. 5. 9. 3, " Cal ib ra t ion Procedure for Fuel Vault Mo ni to r" , were revised to re flec t the fol lowing changes: (1) the log N-16 monitor is no longer in use (because of the existence of the linear N-16 monitor which provides the same functions) and thua deleted from the proce-dure, (2) the new auxiliary core purge monitor has been installed and is added to the procedure, (3) the distances at which the calibration measurements are taken were changed to give better results. (SR

1. 0-87-12) p) The equipment room sump tank was replaced by a stainless unit.

An " Equipment Room Sump Tank" procedure was established to outline the necessary steps in removing the old unit and installing and plumbing in the new one. (SR M-86-1) q) The checklist used for procedure 6.1.2.1, " Building Pressure Test", was revised to reflec t the fac t that the leak on the outer door of the truck lock had been repaired, and that both doors should be tested independently. (QA #0-87-1) r) Miscellaneous minor changes to operating procedures and to equip-ment were approved and implemented througbout the year .

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6. Surveillance Tests and Inspections There are many written procedures in use fo r surveillance tests and inspections required by the Technical Specifications. These pro-cedures provide a detailed method for conducting each test or in s pec-tion and specify an acc e pt anc e criterion which must be met in o rd e r fo r the equipment or system to comply with the requirements of the Technical Spec i fica t ione . -The tests and inspections are scheduled throughout the ye ar with a frequency at least equal to that required by the Technical Specifications. Twenty-seven such tests and calibra-tions are conducted on an annual, semi-annual or quarterly basis.

Other surveillance tests are done each time before startup of the reactor if shut down for more than 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />, before startup if a chan-nel has been repaired or de-energized, and at least monthly; a few are on dif ferent schedules. Procedures for such surveillance are incor-porated into daily or weekly startup, shutdown or other checklists.

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, During the reporting pe r iod , the surveillance frequency has been at least equal to that required by t he Technical Speci fica tions , and the results of tests and inspec tions ware sa tis fac tory throughout the year for Feaility Operating License N7. R-37.

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B. REACTOR OPERATION Information on energy generated and on reactor operating hours is tabulated below:

Quarter Total 1 2 3 4

1. Energy Generated (MWD):

a) MITR-II (MIT FY87) 190.1 185.9 203.4 182.6 762.0 (normally at 4.9 MW) j b) MITR-II (MIT FY76-86) 8,430.8 c) MITR-I (MIT FY59-74) 10,435.2 d) Cumulative , MITR-I 19,628.0 F MITR-II i

2. Hours of MITR-II Operation (MIT FY87) a) At Powe r 1,097.7 1,000.5 1,087.7 977.0 4,162.9

(>0.5 MW) for research b) Iow Power 56.9 30.4 19.8 30.9 138.0

(<0.5 MW) for trainingII) and test c) Total critical 1,154. 6 1,030.9 1,107.5 1,007.9 4,300.9 Note: These hours do not include re ac to r ope r ato r and other t raining conducted while the reactor is at full power fo r research purposes (spectrometer, etc.) or fo r isotope production. Such hours are included in the previous line.

4 C. SHUTDOWN AND SCRAMS During the period of this report there were 10 inadvertent sc rams and 11 unscheduled power reductions.

The te rm "sc ram" re fe r s to shut t ing down of the reactor through pro tec tive system action when the reactor is at power or at least c ritic al , while the term " reduction" or " sh u t d own" re fe r s to an unscheduled power reduction to low power or to sube ritic al by the reac tor operator in response to an abnormal condition ind ic a tion . Rod d rops and elec t ric power loss without pro t ec t ive system action are included in shutdowns .

The following summary of scrams a nd shu tdowns is provided in approximately the same fo rma t as fo r previous years in o rder to facilitate a comparison.

I. Nuclear Safety System Scrams Total a) Channel 3 noise resulting f rom technician failure to adequately secure chassis in rack 1 b) Channel 3 due to faulty coaxial connector 1 c) Channel 3 noise due to cold solder joint 1 d) Low voltage on detector power supply due to failure of the A.C. constant voltage power supply 1 Sub to tal 4 II. Process System Scrams a) Primary pump circuit breaker opened on thermal overload due to a defective heater 2 b) High temperature reactor outlet sc r am due to operator inadvertently slamming closed the door of temperature indicator 1 c) High temperature reactor outlet scram due to technician investigating sticky recorder 1 d) Low flow secondary coolant due to operator ,

tripping pump by mistake 1 !

e) Simultaneous deflation of both gaskets on main l personnel lock due to trainee error 1

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Subtotal 6

e III. Unscheduled Shutdowns or Power Reductions a) Shutdowns due to Elec tric Company power loss 5 b) Operator shut reac tor down due to:

i) High plenum particulate activity resulting from trainee f ailure to secure core purge -

filter housing adequately 1 ii) Low oil pressure in exhaust damper due to hydraulic pump failure 1 iii) Oil leak in intake damper 1 iv) Winds greater than 60 mph I c) Opera tor lowered power to investigate: ]

i) Low pressure in the helium supply at an irradia tion thimble 1 ii) Tripping of a cooling tower fan due to vibration switch 1 Sub to t al 11 Total 21 Experience during recent years has been as fol lows for sc rams and unscheduled shutdowns :

Fiscal Year Number 83 25 84 19 85 10 86 27 87 21 h

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4 D. MAJOR MAINTENANCE Major maintenance projec ts during FY87, including the ef fec t , if any, on safe operation of the reactor are described in this section.

Many major maintenance items were pe r fo rmed in FY87 in an tic ipa-tion of supporting the necessary requirements of the upc oming dose red uc tio n project for light wa te r reactors. In order to support the projec ted electrical loads for the loop experiments , a new three phase electrical penetration through the containment shell was installed and leak tested. Appropriately sized electrical cables were installed to bring the powe r from the pene t ra t ion to the notor control center in the equipment room where the main switch gear is located. Additional

! cables wre b rought from this loc a tion to the reactor top there the instrumentation for the experiment is located. This new three phase system wi th a neutral ground is designed to operate at 480'V with a peak current of 400 A. )

In addition to enhancing the high voltage electrical service capability, heat removal capability was also increased by installation of a new heat exchanger for experimental coolant. This heat exchanger is capable of rejecting 50 kW of heat at 120*F. This heat exchanger is located in the equipment room together with the other processing components. Piping was installed from the heat exchanger to the f reactor floor where the out-of pile experimental coolant tank will be located.

In FY87, nine sets of control blade absorbers and six electro-l magnets were fabricated in our own machine shop. These included the l armature assembly and the pieces to fo rm the connecting rod. All the l

installed control blade ab so rb e r s (6) , magnets (6), and the regulating rod ab so rber( l) we re replac ed wi th new ones. The control rod drive mechanisms (7) were rebuilt and replaced. New calibration curves were generated with the standard calibration procedures. The old set of I ab so rbe rs was in service since 1981 and had accumulated over 100,000 MWH of exposure.

l The graphite region was last inspected during the modification in /

1974 and 1975. A procedure and tools we re developed to inspect the l conditions of the graphite stringers in the graphite re flec tor. Ac-cess was gained by the removal of a graphite vertical fac ility (3GV2) .

A periscope was inserted into the graphite region a nd inspected both the graphite stringers in the vicinity and the surface of the reflec-tor tank. Graphite samples were taken and tests were per fo rmed to determine their stored Wigner energy and combustibility. The results showed no signs of any stored energy in the graphite nor any ability  ;

l to support combustion, even at tempe ra t ure s in excess of 1200*C. The i I

physical appearance of the graphite stringers was the same as when installed. A film presumably oxides, however, was found on the re flec tor tank. A subsequent vis ual inspection is scheduled to be performed early in the coming year. l I

l The equipment room sump Lank and pumps were replaced because of excessive corrosion accumulated over the years. The new sump tank was l

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.made of stainless . steel so as to inhibit oxidation of . ttie. tank. The two old submersible pumps were replaced by a. self-priming gear pump which has more than the ' combined capacity o f t he two- submersible -

pumps.

The leak on the truck lock outer, door was found and' repaired. It passed , the annual '. containment' pressure te s t with adequate margin. An old PCB trans former, ~ which developed a very small leak, was removed and ' disposed of . in . accordance with the environmental sa fety require-ments. The trans former had been .used ' for . operating the helium refrig-eration plant for the cryogenic system. This experiment has not'been ac t ive for many years and will be dismantled; - therefore, the trans-former need not be.-replaced .

Two new electrodes for. cathodic protection of the steel contain-ment shell . were installed to inc rease protection coverage near the-truck lock - and cooling tower area where the secondary pipes are located. The se- two additional electrodes replenish the decrease of electrical potential in the soil due to deterioration of . the older units. The condensers in the air conditioning units fo r the contain-ment building' were completely flushed and . cleaned. Good i,ize leaks' in the cooling coils in ' the in take plenum were fo und and repaired . This restored the capacities of these -two units.

j The leak checking on one of the main beat exchangers , HE-1A, is l still .in progress. Various methods of loca ting leaks in the approxi-mately 1000 tubes have been tried. The helium leak detection method was found to be the most sensitive and is being used. One 'of the cool-ing tower booster pumps developed a leak on the sha f t seal which was subsequently replaced.

To provide improved surveillance of reactor status prior to entry under emergency conditions, a TV camera system comple te ' with pan and tilt capabilities wa s installed in the control room for remote moni-toring the reactor instrumentation. The TV monitor and 'the movement controls for -the camera are located . in the operation office. A remote zoom lens allows reading of almost all indications in the control room J from the operations of fice. An annunciator alarm on the alarm panel in the control room is actuated whenever the remote viewing system is turned on. 1 Facility security has been enhanced by the installation of addi-tional closed circuit surveillance equipment.

1 Many other routine main tenance and preventive maintenance j obs were per formed throughout the year .

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E. SECTION 50.59 CHANGES, TESTS AND EXPERIMENTS d'

ThisLsection.contains a description of each -change to the fac il i-ty or procedures and of the conduct of tests and ' experiments carried

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out under the conditions of Sec tion 50.59 of 10. CFR 50,' together with a summary of.the sai'ety evaluation'in each case.

The review and L approval'. of' changes in the facility and in .. the procedures as described in the . SAR are ' d oc umen t ed in 't he MITR reco rd s

.by means of "Sa fe ty Rev iew ' Fo rms" . -These have been paraphrased fo r.

this report and are ident'ified on the following pages for ready re fer-ence. if further information should be required with regard to . any item. Pertinent pages in the SAR hsve been .or are being revised to reflect . these changes , ' and the y willt .be forwarded to' the Director, Standardization and Non-Power Re ac tor Project Directorate, Office of Nuclear Reac tor Regulation, US NRC .

The conduc t of tests and experiments on the reactor are .'normally documented in the experiments . and irradiation files., For experiments carried out. under the . provisions of 10 CFR 50.59, the review and ap-proval : is' documented by means of.the Safety Review Form. All other experiments have been done in accordance with the descriptions pro-vided in Section 10 of 'the SAR, " Experimental Fac ilities" .

In recent annual reports, the only facility changes . and experi-ments carried out ' under Sec tion 50. 59 were in connec tion with the digital closed-loop computer control proj ec t . No change made' in FY87 in connection with this experiment involves an unreviewed safe ty question. The current status of this computer control project and the tests performed during~ the reporting period are as follows :

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17 Digital Computer Control of Reactors Under Steady-State and Transient Conditions SR#-M-81-3 (11/17/81), M-81-4 (12/10/81), E-82-2 (01/08/82),

E-82-3 (02/24/82), E-82-4 (03/03/82), E-82-5 (04/14/82), E-82-6 (07/13/82), 0-83-5 (02/03/83), E-83-1 (02/08/83), 0-83-12 (04/23/83),

0-83-20 (07/20/83), 0-84-11 (06/25/84), 0-84-12 (07/12/84), 0-84-16 (12/6/84), 0-84-21 (11/1/84), 0-85-11 (5/9/85), 0-85-13 (6/28/85),

0-85-16 (7/12/85), 0-85-20 (8/16/85), 0-85-25 (12/1/85), 0-85-26 12/1/85), 0-86-11 (10/17/86), 0-86-13 (11/28/86).

The projec t involving computer analysis, signal validation of data from reactor instruments, and closed-loop control of the MIT Reactor by digital comput e r wa s continued. A non-linear supervisory algorithm has been developed and demonstrated. It functions by rest ric ting the net reactivity so that the reactor period can be rapidly made infinite by reversing the direction of control rod motion. It, combined with the signal validation proc ed ures , insures that there will not be any challenge to the reactor sa fe ty system while testing closed-loop control methods. Several such methods, including decision analysis, rule-based control, and modern control theory, continue to be experimentally evaluated. The eventual goal of this program is to use f aul t-tol e ran t computers coupled with closed-loop digital control and signal validation methods to demonstrate the improvements that can be achieved in reac tor control .

Each new step in the program is evaluated for safety in ac c o r-d ance with s t and a rd rev iew p roc ed ure s ( Sa fe ty Review numbers listed above) and approved as necessary by the MIT Reactor Safeguards Commit-tee.

Initial tests of this digital closed-loop controller were con-l d uc t ed in 1983-1984 using the f ac ilit y 's regulating rod which was of relatively low reactivity worth (0.2% AK/K). Following the successful completion of these tests, facility operating license amendment No. 24 was ob tained from NRC ( April 2, 1985). It pe rmi t s :

(1) closed-loop control of one or more shim blades and/or the regulating rod provided that no more than 1.8% AK/K could be inserted were all the connected con t rol ele-ments to be withdrawn, (2) closed-loop control of one or more shim blades and/or the regulating rod provided that the overall controller is de signed so that reactivity is constrained suffi-ciently to pe rmit control of reactor power within desired or authorized limits.

A success ful experimentation program is now continuing under the provisions of this license amendment. A protocol is observed in which this controller is used to monitor , and if necessary override, other novel controllers that are still in d evelo pment . Tests pe r fo rmed during this reporting period include:

4 a) Completion of the tests in which one of the re ac tor's shim blades was moved at hal f-s peed . (Note: The initia tion of -

these tests was described in last year's report.) The tim-ing-chain sprocket of the blade used for these tests has now been returned to its normal. configuration.

b) Tests of a controller designed using state analysis methods.

In addition , the MIT Reac tor Sa feguards Commit tee approved use of reactivity constraints derived from the alternate dynamic period equa-tion at satisfying the provisions of Tec hnical Specification #6.4.

This approval did not involve an unreviewed safety question because the alternate constraints are always bounded by the standard ones on which the reactivity constraint concept was originally based.

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F. ENVIRONMENTAL SURVEYS Environmental surveys , out side the fac ili ty , we r e pe r fo rmed us ing area monitors. The systems (located approximately in a 1/4-mile radius from the reactor site) consist of calibrated G.M. detectors with associa ted elec t ronics and recorders .

The detectable radiation levels due to argon-41 are listed below:

Site July 1, 1986 - June 30, 1987 North 0.4 mR/ year South 0.7 mR/ year East 4. 3 mR/ ye a r West 0.3 mR/ year Green (East) 0.2 mR/ year Fiscal Yearly Averages:

1978 1. 9 mP/ year 1979 1.5 mR/ year 1980 1.9 mR/ year 1981 1.9 mR/ year 1082 2.5 mR/ year 1983 2.3 mR/ tear 1984 2.1 mR/ year 1985 2.2 mR/ year i l

1986 1. 8 mR/ ye ar i i

1987 1.2 mR/ year

G. RADIATION EXPOSURES AND SURVEYS WITHIN THE FACILITY A summary of radiation exposures received by facility personnel and experimenters is given below:

Period 7/01/86 - 6/30/87 Whole Body Exposure Range (Rems) No. of Personnel N o Me a s u r a b l e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Measurable - Exposure less than 0.1.............. 91 0.1 -

0.25....................................... 9 0.25 - 0.5........................................ 7 0.5 -

0.75....................................... 6 0.75-1.0........................................1 j Total Personnel = 145 Total Man Rem = 11.4 Summary of the results of rad ia t ion and contamination s u rve ys from July 1986 to June 1987:

During the 1986-1987 period, the Re ac tor Radiation Pro t ec t ion Of fice continued to provide radia tion protec tion services neces-sary far full power (5 megawatt) operation of the reactor. Such services ( per fo rmed on a daily, weekly, or monthly schedule) include, but are not limited to, the following:

1. Collection and analysis of air samples taken within the con-tainment shell, and in the exhaus t-ventila tion system.

2. Collection and analysis of air samples taken from the cool-ing towers, D20 sys tem, waste storage tanks, shield coolant ,

heat exchangers, fuel storage facility, and the primary system.

3. Pe r fo rmance of radiation and contamination surveys, radio-active waste c ollec t ion , c alibra tion of re ac tor radia tion monitoring systems, and servicing of radiation survey meters.

4. Providing of radiation protection se rvic e s fo r control rod removal, spent-fuel element trans fers , ion column removal, etc.

The results of all s u rve ys de sc ribed above have been within the guidelines established for the fac ili ty .

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H. RADI0 ACTIVE EFFLUENTS This section summarizes the nature and amount of liquid, gaseous and solid radioactive wastes' released or discharged from the facility.

1. Liould Waste Liquid radioac tive wastes 7 generated a t - . t he facility are dis--

charged only ' to the sanitary sewer serving ' the fac ility . There were t wo sources of such vastes during the year: the cooling tower blow-downs , and the liquid waste storege tanks. .All of the liquid volumes; are measured, by far the, largest'being the 6,208,000 liters discharged j

during FY 1987 from the cooling L towers. (Larger quantities of non--

radioactive waste water are discharged to the sanitary sewer system by

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l I other parts of MIT, but no credit for such' dilution is taken since the-volume is not routinely measured.)

All releases were in accordance with Technic al Specification.

3.8-1, including Part 20, Title' 10, - Code of -Federal Regulations.

There are no reportable radionuclides inasmuch as all activities were substantially below the limits specified in 10 CFR 20.303 and 10 CFR 20, Appendix B, No te 5.

2. Gaseous Waste Gaseous radioactivity is discharged to the atmosphere from the containment building exhaust . stack and by evaporation f rom 'the . cooling towers. . All gaseous releases likewise were .in accord ance with the 'j Technical Specifications and Part 20, and all nuclides' were below the l limits of 10 CFR 20.106 af ter the authorized ' dilution fac to r of 3000,-

Also, all were substantially below the limits of 10 CFR 20, Appendix B, Note 5, with the exception of argon-41, which:. is reported . in the following Table H-1. The 4j23 Ci of Ar-41 were ' released at an average concentration o uCi/mi for the ye ar . . This represents 30E of MPC (4 x 10pCi/ml) f 1.20and x 10-

. is slightly more than the previous year's release of 3797 Ci. The inc rease is due to an - imbalance in one com-ponent of the reactor building ventilation system that existed for a .j week during December 1986. i

3. Solid Waste Only one' shipment of solid waste - was made during the year, infor- .l mation on which is provided in the following Table H-2.

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f TABLE H-1 ARCON-41 STACK RELEASES FISCAL YEAR 1987 Ar-41 Average Discharged Concentration (l)

(Curies) '(uCi/ml)

July 1986 304 0.90 x 10-8 August 320 1.16 September 203 0.75 Oc tob er 329 0.96 November 313 1.13 December 663 2.40 January 1987 394 1.14 i

February 394 1.43 J Ma rch 396 1,43 April 317 0.92 May 293 1.06 l June 297 1.08 12 months 4223 1.20 x 10-8 MPC (Table II, Column I) 4 x 10-8 l

% MPC 30%  :

(I) Note: Af ter authorized dilution factor (3000).

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SUMMARY

OF MITR RADIOACTIVE SOLID WASTE SHIPMENTS FISCAL YEAR 1987 l

l Un i t s Shipment #1 To tal

! 1. Solid waste packaged Cubic 112.5 112.5 Fee t

2. Weight Pounds 3489 3489

3. Total ac tivity Ci 0.082 0.082 (irradlated components, ion exchange resins , etc .)

60 SI Cr , 55-59Fe Co, 65 Zn, etc.

4 (a) Date of shipment 06/09/87 (b) Disposition to U.S. Ec ology , Inc.

licensee for burial

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M81 SEP -Lt A 449 i

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.2 NUCLEAR REACTOR LABORATORY l '

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AN INTERDEPARTMENTAL CENTER OF- 'b$;p MASSACHUSETTS INSTITUTE OF TECHNOLOGY O.K. HARLING - 13b Albany Street Cr.mbridge, Mass. 02139 L. Ct. ARK JR,

' Director Director f Reactor Operations (617)253 421 1 August. 29, 1987 l

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washing ton , D. C. 20555 i

Subject:

. Annual Report, Doc ke t No. 50-20, License R-37, Technical Specification 7.13.5

Dear Sirs:

Forwarded he rewi th is the Annual Report for the MIT Research Reac tor ' for the period July _ 1, 1986 to ' June 30 1987, in' compliance with paragraph 7.13. 5 of the Technic al Specifications for Facility Opera ting License R-37.

Sincerely, 1

Kwan S. Kwok -

Assistant. Superintendent, j Reactor Operations l Lincoln Clark, Jr.

1. ' 1 I

Direc tor of Reac tor Operations I l

LC/gw I

Enclosure:

As stated 1

cc: MITRSC <

l- USNRC - Region I 1 l Chief, Reactor Projects Section IB i i USNRC - Region I j l' L.T. Doer flein , Proj ec t . Ins pec to r , Section IB USNRC - Resident Inspector, Pilgrim Nuclear Station t .

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L_________. _ _ _ _ _ - - - -

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