IR 05000264/1973001

Insp Rept 50-264/73-01 on 730920 & 21.Violations Noted: Reactor Operated W/Greater than 1.5% Delta K/K Excess Reactivity on 730125 Change to Operating Procedure Inserted in Operating Log,W/O Formal Approval

ML20137G846
Person / Time
Site:	Dow Chemical Company, 05000000
Issue date:	10/24/1973
From:	Charles Brown, Dance H, Fishbaugher J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20136D183	List: IA-85-256, Requests That Encl Form Be Completed & Submitted by 760915 & Facility Emergency Plan & Implementing Procedures by 761007 in Order for NRC to Prepare Info Packets for Use in Responding to Incidents or Emergencies IA-85-258, Amend 3 Renewing License R-108 & Incorporating Security Plan as License Condition IA-85-261, Documents That Appropriate Corrective Actions Taken by Dow Chemical Co in Response to 780113 Immediate Action Ltr,Per 780207 Enforcement Conference at Facility IR 05000264/1973001 IR 05000264/1975001 IR 05000264/1977002 IR 05000264/1979003 ML20137G383 ML20137G390 ML20137G402 ML20137G410 ML20137G417 ML20137G432 ML20137G437 ML20137G446 ML20137G450 ML20137G460 ML20137G467 ML20137G472 ML20137G478 ML20137G487 ML20137G507 ML20137G524 ML20137G586 ML20137G600 ML20137G614 ML20137G637 ML20137G653 ML20137G750 ML20137G793 ML20137G816 ML20137G854 ML20137G875 ML20137G888 ML20137G896 ML20137G903 ML20137G908 ML20137G916 ML20137G921 ML20137G926 ML20137G931 ML20137G940 ML20137G951 ML20137G972 ML20137G976 ML20137G983 ML20137G990 ML20137G997 ML20137H003 ML20137H022 ... further results
References
FOIA-85-256, FOIA-85-258, FOIA-85-259, FOIA-85-261 50-264-73-01, 50-264-73-1, NUDOCS 8508280001
Download: ML20137G846 (12)

Text

r

.

. .

'

.

U. S. ATOMIC ENERGY COMMISSION DIRECTORATE OF REGULATORY OPERATIONS

REGION III

RO Inspection Report No. 050-264/73-01 Licensee: The Dow Chemical Company 1701 Building Midland, Michigan 48640 TRIGA Reactor License No. R-108 Midland, Michigan Category: F Type of Licensee: 100 Kw, TRIGA (Non Pulsing)

Type of Inspection: Routine, Announced Dates of Inspection: September 20 and 21, 1973 Date of Previous Inspection: June 2, 1971 geda ~ x Principal Inspector: J. R. Fishbaugher /c 4!73

'(Datd)

Accompanying Inspector: C. H. Brown /O/S r/8 (bate 6 '

Other Accompanying Personnel: None Reviewed By:

kT.NLw_

H. C. Dance, Senior Reactor Inspector /d/2 73 BWR Seetion ' (Da t &)

8508280001 850712 PDR FOIA KOHN85-256 PDR t

.

. .

.

SUMMARY OF FINDINGS

.

Enforcement Action Violation considered to be of Category II severity is as follows:

Technical Specifications Section E.3 states that the maximum available excess reactivity above cold critical shall be 1.5 percent delta k/k with experiments in plac Contrary to the above, the reactor was operated with greater than percent delta k/k excess reactivity on January 25, 197 (Paragraph 7.a) Violation considered to be of Category III severity is as follows:

Technical Specifications Section I.3 requires that the Reactor Operations Committee approve proposed changes in operating procedures and be responsible for determining whether the proposed change constitutes an unreviewed safety question or a change in the Technical Specification Contrary to the above, a change to an operating procedure was inserted in the Operating Log for use on July 23, 1971, without formal review and approval by the Committee. (Paragraph 5.a)

Licensee Action on Previously Identified Enforcement Matters No enforcement items were identified on the previous inspection repor Unusual Occurrences On October 22, 1971, the operator placed the reactor in automatic control mode while the reactor was suberitical, which caused the regulating rod to withdraw at maximum rate. The operator manually scrammed the rods when he noted the rod withdrawing. The manual scram was initiated before reaching the safety circuit trip point (Paragraph 7.b)

l On January 25, 1973, following a fuel inspection, the reactor was operated with greater than 1.50 percent delta k/k excess reactivit (Paragraph 7.a)

Other Significant Findings Current Findings The reactor is being operated on short term runs for activation analysis.

I-2-l l

.

. .

. The nuclear instrumentation has been upgraded and the modernization of the period circuitry has reduced the number of period scrams significantl Status of Previously Reported Unresolved Items No unresolved items were identified in the previous inspection repor Management Interview The management interview was conducted with Drs. Turley and Anders at the conclusion of the inspection on September 21, 1973. The interview was concluded by telephone on October 2, 1973. The following items were discussed: The scope of the inspection was explained by the inspector and the general findings were related to the license The inspector stated that operation of the reactor with excess reactivity greater than allowed was a violation of Technical Specifications. The licensee was informed that a no-response citation would be issued in that appropriate actions to prevent recurrence had been taken at the time of the even (Paragraph 7.a)

The licensee was also informed that a response type citation would be issued for the lack of formal review of a procedure change resulting when the shim rod was functionally changed to the regulating ro (Paragraph 5.a) The number of scrams occurring from the period circuit was discusse The licenset was informed that his attention to the problem, as shown by the nuclear instrument modification and upgrading, had alleviated the inspector's concern. The suggestion was made to the licensee that he monitor the performance to assure that the expected improvement was realized. The licensee concurred with the suggestio (Paragraph 5.h) The inspector informed the licensee of the AEC policy on failed fuel elements for pool-type reactors. The licensee stated their policy conformed and there were no plans to chang (Paragraph 4.c) The inspector explained the revised procedure for forwarding inspection reports to the licensee. The inspector stated that after the licensee reviews the inspection report for proprietary information, the report will be placed in the Public Document Roo The inspector noted that Dr. Turley was not on the list of members for the Reactor Operations Committee, and he suggested that the list be kept up to date. The licensee agreed and stated that he would correct the lis .

.

.

REPORT DETAILS 1. Persons Contacted Dr. O. U. Anders, Reactor Supervisor Dr. J. Turley, Laboratory Director 2. General Information The facility is being used primarily for activation analysis and no change in the utilization is planned. Approximately 2100 runs were conducted from June 1971 to the present with a typical run being 10 minutes long. The reactor had experienced approximately 75 scrams over the same time span, the majority being period trips attributed to antiquated instrumentation. The nuclear instrumentation has been upgraded with modern solid-state equipment, which has reduced the number of scrams from the period tri . Facility Administration Staffing The reactor operating staff is essentially unchanged since the previous inspection. There are four licensed operators with SRO licenses. Four trainees had taken the licensing examination for SRO just prior to the inspection, but the results had not been receive Reactor Operations Committee The inspector examined the meeting minutes for the period since July 1971, for scope of topics, recording and reporting of minutes, membership, frequency of meetings, and the committee procedures and judged that they were satisfactory, with respect to the Technical Specifications requirements and the committee procedure, 3.2.2 of the Operating Manual. There were 13 meetings held during this perio Control of Experiments The inspector examined (spot check from July 1971 to present) the experiment records and no deficiencies were note The experiments are classified into three categories - routine, modified routine, and special. The "special" tests are reviewed by the Reactor Operations Committee in conformance with Section I.2 of the Technical Specification _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ - _ _ _

.

. .

The inspector noted that the bulk of the testing activity was represented by sample irradiation in the reflector " lazy susan" with occasional use of a " rabbit" that is located in the F ring of the core. The " lazy susan" rotates during reactor operation and the " rabbit" capsules are inserted and withdrawn with the reactor operating. These movements typically have a measurable effect on reactor power. The magnitude of this effect is being adequately controlled by established experiment review and approval practices. The licensee stated that the reactor is generally operated in the manual mode when samples are in the " lazy susan" due to the amount of regulating rod motion in the automatic mode of contro d. Operating Records The following records were reviewed:

(1) Reactor Operating Log, 6/71-9/17/73 (2) Radioactivity released or discharged, 2/73 to present (3) Scram Log, 7/71-9/17/73 (4) Maintenance Log, 6/72 to present (5) Experimental Log, 2/73 to present (6) Daily Check Sheet, 6/15/73-7/20/73 (7) Weekly Check Sheet, 6/15/73-9/14/73 (8) Monthly Check Sheet, 6/29/73-9/17/73 (9) Semi-Annual Check Sheet, 3/73 and 9/73 The above records fulfill the requirements of the license, Section e. Operating Procedures Technical Specification Section 1.7 enumerates certain procedures that are required to be written for operations involving the reacto These procedures were found to be available and were spot checked with no deficiencies noted, i-5-

i l

t

r e

. . Security Facility security has been improved by the addition of a large sliding bolt to the reactor room outside door and an expandable grating secured with two padlocks on the doorway between the reactor and console rooms. The skylight in the reactor room has had a metal grate added beneath i In response to a question, the licensee stated that RO:III would be notified in the event of civil disturbanc . Core Status Current Loading The current core status board was examined and showed 76 fueled elements and nine graphite elements installed. The graphite elements were installed in E and F locations around the core. The source was installed in F-17. The status board also indicates the positions of the control elements, three neutron detectors, and the rabbit transfer tube core position, all of which are consistent with the Safety Analysis Report. The core loading data are recorded on the monthly check list, Fuel Element Examination Technical Specifications Section E.4 requires that fuel elements be visually inspected once per year. The requirement is being met with the last inspection having been conducted on February 9. 197 The elements are examined by removing each one from the core, lifting it to approximately six feet below the surface of the water. The element is then brought to the horizontal and rotated to check for bowing, bulges or cladding failur If the trueness is suspect the element is checked by inserting it into a "go" gage which is built to manufacturing tolerances. During the February 9 examination all the elements had the normal oxide coating per the licensee. No fuel element has been replaced as a result of the visual examinatio The core loading status is maintained in the operating log by element serial number, with any notes of anomalies and corrective action, Policy for Failed Fuel Elements The inspector stated that the AEC considers continued operation of pool type reactors with a failed fuel element to be an unreviewed safety question. The licensee stated that the Dow policy is to replace a failed fuel element as soon as it can be located. The one failure that has occurred at the facility was during initial startup and could not be located visually, so the reactor was operated and by process of elimination the failure was located and remove u .

.

. .

. Reactivity and Power Control Rod Calibration Technical Specifications Section 7.11.d requires a rod worth calibra-tion for each control rod be done at least semi-annually. The method used to perform the calibration utilizes a rising period measurement at six increments per rod for the shim and regulating rod. The safety rod is then calibrated against the regulating rod. The six points are plotted and curve extrapolated with the assumption that the rod worth is symmetrical. No deficiencies were noted. The latest test was performed on September 18, 1973, with the following recorded results:

safety rod worth $2.90, sbim $0.84, and the regulating rod $2.9 The drive mechanisms and associated circuitry for the shim and regulating rods were interchanged in July 1971.1/ A note was added in the Reactor Operating Log on July 23, 1971, stating, in effect, that the regulating rod (a smaller worth rod) was now the shim rod and was to be withdrawn to approximately 400 on the rod position indicator and then the reactor was to be taken critical with shim rod (which was now the regulating rod) and to maintain the reactor in the manual mode of control until the reactor was at the desired power level before shifting control to the automatic mode. This change to the operating procedure was not formally reviewed until August 13, 1971, by the Reactor Operations Committe Satisfactory operation has been experienced from both rod Excess Reactivity Technical Specifications Section E.3 requires that the excess reactivity above cold critical with no xenon be maintained less than 1.50 percent &K/K($2.143I=.007).

3 The excess is checked at cold critical on the first startup of the day and recorded on the Daily Startup Checks. For the last six months, excess reactivity has been approximately $1.70. On one occasion, the reactor was operated with excess reactivity greater than the limit (Paragraph 7.a); otherwise, no deficiencies were note Shutdown Margin Technical Specifications Section F.3 requires a shutdown margin of 0.35 percent ($0.50) with the strongest rod withdrawn. The shutdown margin is checked and recorded on the Semi-Annual Check List as follows:

1/ Letter, Dow to DRL, dtd 4-30-71, and letter, DRL to Dow, dtd 7-20-7 . - - .- , _--_ -

r

.

.

.

(1) On September 18, 1973, the rod calibration showed rod worths

'to be: shim $0.84, safety $2.90, and regulating $2.94. The excess reactivity on that date, from the daily startup checks, was $1.62; therefore, Safety rod $2.90 Shim rod .84 Total $3 74 Excess -1.62 Shutdown $2.12 Margin (2) On April 5, 1973, the shutdown margin was $2.23 No deficiencies were note d. Reactivity Insertion Rate Technical Specifications Section F.4 requires that the reactivity insertion rate be less than 0.15 percent tsK/K per secon The monthly check list provides for checking and recording the following:

(1) Rod position indicator operational check (2) Rod withdrawal timing check (by stopwatch)

The withdrawal time for the strongest rod (regulating rod) was 4 seconds on June 29, 1973; 46.3 seconds on August 31, 1973; and 5 seconds on September 17, 1973. The withdrawal times for the other rods were longer than the above time Examination of the rod calibration curve showed that the maximum rod worth per increcent can vary as much as 1.5 times the averag From the above information, the following insertion rate is cal-culated for the regulating rod (strongest)

0.7% 4 K % 4 K/second = $2.94 = 0.066% A K/sec 45.3 sec $

No deficiencies were note !

-8-i

_ _ _ _

,

.

.

.

. Rod Scram Time Technical Specifications Section F.11.6 requires that the control rod drop time be less than one second and verified by test semiannuall O The test is conducted weekly by raising one rod at a time to the full out and pushing the scram button for that rod and simultaneously starting a stopwatch. The watch is stopped when the rod indicates full insertion as indicated by rod bottom light. The inspector judged ,

this method adequate for the purpose. The review of the weekly, check lists for June 15 to September 14, 1973, showed the drop time to be less than one second, varying from 0.6 to 0.8 secon Rod Inspection Technical Specifications Section F.2 requires that the control rods be visually inspected at least once every two years. The control rods were being inspected on a twice a year frequency until January 1973, when the Reactor Operations Committee approved a once per year inspection. The inspections have not found any significant distortion or deterioration of the rods and all rods appear to have the normal oxide coating per the licensee. The last inspection was completed on January 25, 197 Power Calibration Technical Specifications Section F.12 requires that the linear power level channel reading be calibrated at least annually by a thermal power calibratio The calibration is accomplished by holding the reactor at some arbitrary power level and measuring the pool heatup rate. The licensee stated that the heat capacity of the pool was determined by Gulf Atomics using electrical heaters. Minor calibration changes for the channel are accomplished by repositioning the chambe During the most recent test, conducted on February 8, 1973, actual power was calculated to be 80 percent, with the linear channel reading 90 percent and the log channel reading 72 percent. Both'

channels were reset to read 80 percent power. No deficiencies were noted in this are Upgrading Nuclear Instrumentation The licensee described the new instrumentation that has been installed at the facility. The tube type instruments were replaced with solid state, one chamber was replaced and a recorder was added.2/ The 2/ Dow letters to DRL dtd April 30, 1971, and March 1973; DRL letters to Dow, dtd July 20, 1971, and April 16, 197 , m -

.

..

t

. 1 f,

a .

. /- modification was accomplished in two stages; the first in mid-1971 and _the second in June 1973. The modification completed in June 1973 included a modernization of the period -circuit which appears to have made the period trip more reliable as the number of scrams, during startup from instrument noise, has.been reduce t

'

The inspector discussed 10 CFR 50.59 with the licensee and he dis-

<

- played an understanding of the requirement. To date the licensee has informed DRL of proposed changes before the changes are performe . Reactor Pool ' Surveillance

,

,-

.,

Technical Specifications Section D.1 requires that action be taken if either the pool temperature exceeds 120*F or the pool level is j 'less than 15 feet above the top grid plate while the reactor.is

,

operating. The review of the Operating Log from June 1971 to

,

September 17, 1973, showed that the water temperature is recorded for every startup and power change with the highest reading noted

., being 90'F. The licensee stated that no problem had been experienced

"

<

'

in maintaining the temperature less than the 120*F limit. The temperature is monitored at the console,with a monthly check of the RTD readout by a lab type thermometer. The monthly check list for

,

,

June 29, 1973 - September 17, 1973, showed good agreement of the

<. ,

,

two temperature devices. The pool level is checked daily for reactor startup. The loss in level amounts to approximately one half inch per week (approximately 500 gallons per year), and is made up once-a-week. The evaporative loss has been the same since the startup of the facility, based on a spot check of the startup check sheets, and indicates that the level has been maintained greater than 15 feet

[

/ '

, above the cor >

/

'

, The pool water conductivity is measured by conductivity cells before and after the ion exchange column. Both cells are read out on the console and checked monthly with an independent meter. The pH is also measuredlat this time. The Technical Specifications Section '

conductivity limit is 5 micromhos per centimeter. The normal reading is approximately 0.3 micronhos. When the ion exchange resin (H0H)

starts to deplete the resin is changed out and disposed of as solid waste per the licensee. The column read 2 mram/hr on contact per the September 17, 1973, monthly checklis , '

Pool activity is measured by a chamber monitoring the purification flow, with backup of a CAM sampling the air in the reactor room and an area monitor. The surveillance on these instruments conforms to

- 10 -

t

.Ir

>

(

.

. .

.

Section G of the Technical Specifications as noted from the weekly checklists June 16, 1973 - September 14, 1973, and semi-annual

. checklists March 1973 and September 1973. The pool activity monitor chamber reads out on the console and the reading is recorded on the daily checklis Containment The pool water heat exchanger represents a containment boundary between pool water and river water. The flow paths and the pressure control valving for both primary and secondary sides of the heat exchanger were traced. The licensee demonstrated the control of river water pressure en the heat exchanger, and described the administrative control on river water outlet pressure so that it is higher than the pool water inlet pressure. Consequently any leak would be into the pool. The two pressure gages are located in the console room next to the heat exchanger river water outlet isolation valve, which is used to maintain a back pressure on the heat exchange Pool water flow through the heat exchanger is sufficient so that the pool temperature is maintained with the reactor operating at full power. The purification piping bypasses the heat exchanger and the flow is maintained at approximately 5 spm. The licensee indicated that with this flow rate all the pool water G--5000 gallons) will go through the ion exchange column at least once per da . Unusual Occurrences Reactivity in Excess of Limit Technical Specifications Section E.3 requires that the excess reactivity be less than 1.5% f K/K. On January 25, 1973, following a fuel inspection and other anndal checks, the core excess reactivity was found to be $2.22 (approximately 1.56 percent delta k). The licensee then performed a rod calibration. Using the recalibration data the excess reactivity was found to ba $2.28. The reactor was then shut down and the core loading changed. The postmortum by the licensee attributed the change in reactivity to cumulative effects of random rotation of fuel rods resulting from the fuel inspectio The licensee also recognized the fact that no operation of the reactor should have proceded until the excess reactivity was reduce The licensee was informed that the condition was considered to have been a Technical Specifications violation but that in view of his report 3/ and actions taken to prevent recurrence no response would ;

be require l 3/ Dow letter to DRL, dtd February 16, 197 l

.. - - _ _ ._ . ..

O

, .

,

s Erroneous Use of Autcmatic Controller On October 22, 1971, the reactor was placed in automatic control while the reactor was still suberitical. With no signal to the controller the regulating rod withdrew at the maximum rate and produced a fast power rise. Upon noting the above the operator manually scrammed the reactor. The manual scram was accomplished before any of the safety trip points were reached. This was an operator error and the licensee indicated that personnel involved were contacted. The procedural controls were clarified and re-emphasized to the operating personnel. The licensee stated that the capability exists for automatic control on a period signal, but is not used. The inspector examined the procedure (Section 3. of the Operations Manual) and verified that the requirement was available to operate in manual until the power is in the desired range before shifting automatic mode. No deficiencies were noted in the licensee's review, report, or corrective action taken on this event.

i

,

.

l'

I

,

.

- 12 -

,

. . . , - . _ . . --_ _ - - . - , ,,. . . . _ . , - . - .-

- - --. .. .