ML20072P240

Pulstar Reactor Annual Rept for Period Jul 1993 - June 1994

ML20072P240
Person / Time
Site:	North Carolina State University
Issue date:	06/30/1994
From:	North Carolina State University, RALEIGH, NC
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ML20072P229	List: ML20072P227 ML20072P240 ML20072P254
References
NUDOCS 9409070146
Download: ML20072P240 (10)

Text

4 PULSTAR REACTOR ANNUAL REPORT TO i UNITED STATES NUCLEAR REGULATORY COMMISSION ,

for the 1 Period 01 July 1993 - 30 June 1994 i

NCSU NUCLEAR REACTOR PROGRAM i

24 August 1994

Reference:

PULSTAR Technical Specifications Section 6.7.5 Docket No. 50-297 Department of Nuclear Engineering l North Carolina State University i Raleigh, North Carolina 27695

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I DEPARTMENT OF NUCLEAR ENGINEERING PULSTAR REACTOR ANNUAL REPORT For the Period: 01 July 1993 - 30 June 1994 The following report is submitted in accordance with Section 6.7.5 of the -

PULSTAR Technical Specifications 1

6.7.5.a Brief Summary In November of 1993 the PULSTAR Reactor was placed in a shutdown status when primary water inventory calculations showed a slight increase in unaccountable water loss. After extensive testing and data collection, it was i determined that the most probable location for the leak was at a gasketed I flange in the buried primary piping. Isolation valves were closed and the buried portion of the piping was drained. Reactor operations, limited to 10 percent power and natural convection cooling mode, resumed in January 1994 after approval was granted by the Radiation Protection Committee while repairs are being made.

(1) Reactor Operating Experience:

The NCSU PULSTAR Reactor has been utilized for the following:

a. Teaching and Short Courses 119.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />

b. Faculty and Graduate Student Research 252.1

c. Isotope Production 1.9

d. Neutron Activation Analysis 1,278.5

e. Beam Tube Facilities 0.0

f. Nuclear Training (Utilities) 203.1

g. PULSTAR Reactor Training 8.9

h. Reactor Cal / Measurements & Surveillance 50.5

i. Reactor Ilealth Physics Surveillance 11.9

j. Reactor Sharing 10.3 TOTAL 1,936.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> Same reporting period 1992-1993 2,664.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> s

PUISrAR REACroR ANNUA!, REPoKr 2

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01 July 1993 - 30 June 1994 l

l A cross section of experiments nerformed in the reactor- l 1

a. Neutron Activation Analysis of filters, tissue, bone, protein solutions, hair, sediments / soil, rain / river water, vegetation, wood pulp, dyes, paper, electronic components, fibers, plastics, resins, polyfoam, coal, fly ash, graphite, steel, titanium, steam turbine residue, etc.

b. Reactor thermal power measurements for teaching laboratories.

c. Neutron diffusion length measurements in graphite.

d. Neutron Radiography of carbon cloth.

e. Prompt gamma analysis of silicon wafers.

f. Neutron fluence and spectral measurements.

g. Transmutation of silicon for semiconductor research.

(2) _ Changes in Performance Chara.sieristics Related to Reactor Safety:

None (3) Results of Surveillance. Tests. and Inspections:

The reactor surveillance program has revealed no significant or unexpected trends in reactor systems performance during this report period.

6.7.5.b Total Enerev Outpm:

357.7 Megawatt hours 14.9 Megawatt days Pulse Operations:

None Reactor was Critical:

740.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> Cumulative Total Enerev Outout since Initial Criticality:

18,822.6 Megawatt hours 739.4 Megawatt days

4 PU15FAR Rl! ACTOR ANNUAL RiiPoRT 3

. 01 July 1993 30 June 1994 6.7.5.c Number of Emergency and Unscheduled Shutdowns:

Unscheduled shutdowns - 3 total (1) Safety #2 Drive stalled during startup.

(2) Safety #1 Drive stalled during startup.

(3) No Intermediate Range period information during Source Range / Intermediate Range overlap.

Inadvertent SCRAMS - 9 total (4) Operator error - 1 (5) Spurious signals - 8 Explanation of (1) and (2) above:

The upper and lower sealed bearings of Safety #1 and #2 Control Rod Drive Mechanisms failed. See 6.7.5.d later in this report.

Explanation of (3) above:

The Intermediate Range INFINITY CK switch failed open during a routine startup and subsequent power increase. This failure prevented rate information from being displayed on the period meter. A new switch was installed and the channel was returned to service after calibration.

Explanation of (4) above:

Operator downranged the Linear Channel range switch instead of l upranging causing an instantaneous reactor SCRAM.  !

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Explanation of (5) above: l l

A trip circuit in the Intermediate Range Channel and the Safety Chr.nnel )

will generate a SCRAM upon loss of forced primary flow or if the safety flapper valve opens when power is above 15 percent. Recently the PULSTAR Reactor has been operating up to 10 percent power in natural convection cooling mode and with the safety flapper valve open in accordance with Section 3.9 of the l PULSTAR Operations Manual. Electrical noise spikes generated within the I console electrical system may instantaneously exceed the trip circuit setpoint and l generate a SCRAM. This was verified by testing several combinations of switch actuations and causing a SCRAM signal to happen. The Intermediate Range i

PUI5rAR REACroR ANNUAL REPORT 4 01 July 1993 - 30 June 1994 Channel was tested or calibrated after each occurrence and found to be operational. Only one Intermediate Range SCRAM occurred since April when an administrative limit of 8.5 percent power for routine operations was established. Since initial criticality most reactor operations were conducted at or near full power. During that time these circuits were always in their enabled state and as long as forced primary flow was present and the safety flapper valve was shut no SCRAM would occur. New Intermediate and Power Ranges instruments have been purchased and are undergoing acceptance testing. It is expected that these new instruments will greatly reduce the number of spurious SCRAMS.

6.7.5.d Major Maintenance Operations:

All of the Control Rod Drive Mechanisms (CRDM) were disassembled and inspected due to two of the units inability to withdraw control rods full travel. Several of the upper and/or lower bearings were starting to fail due to age. Because of the problems experienced with two of the CRDMs, the bearings in all of the drives were replaced. All drives were returned to service after post-maintenance testing.

An approximate 0.7 gallons per hour leak was suspected to have developed at a flange on the buried N-16 Delay Tank in the primary piping. As of this report a contractor has been selected to excavate the tank, build an underground vault enclosing the tank and the primary piping, make any repairs and return the primary system to service. Work is expected to take five months.

6.7.5.e Changes in Facility. Procedures. Tests. and Experiments:

1. Design Changes (a) DC 93-1 installed a new temperature measuring recorder with digital display in the PULSTAR control console.

(b) DC 94-1 authorized the installation of new Linear Power, Safety Power, and Intermediate Range instruments. Installation and testing should be completed by the end of this calendar year.

2. Procedure Changes (a) PC 32-93 was Revision 11 to the PULSTAR Operations Manual.

These documented changes were required by the necessity to operate

PUISrAR REACrOR ANNUAL REPORT 5 01 July 1993 30 June 1994 in natural convection cooling mode due to pending repairs in the primary piping.

(b) PC 1-94 was Revision 12 to the PULSTAR Operations Manual. This revision documented changes required by the implementation 10 CFR 20 which went into effect in January 1994.

(c) A total of twenty-one procedures have been revised (most minor editorial changes) and twelve new procedures (ten Health Physics and two purification system special procedures) have been submitted or have already been reviewed and approved by the Radiation Protection Committee.

6.7.5.f Radioactive Effluent:

Liquid Waste (summarized by quarters)

1. Radioactivity released during the reporting period:

(a) (b) (c) (d) (e)

No. of Total Tot. Vol. Diluent Tritium Period Batches Ci Liters Liters Ci 01 Jul - 30 Sep 93 2 33 539 2.4 x 10' 23 4

01 Oct - 31 Dec 93 5 198 1488 6.3 x 10 173 01 Jan - 31 Mar 94 4 125 1121 8.2 x 104 117 01 Apr - 30 Jun 94 2 25 537 2.6 x 104 22 NOTE: Increases in the total volume discharged from 01 Oct 93 to 30 Mar 94 was due to water loss testing and draining of the N-16 Tank and buried piping. The entire Primary System was isolated within the Reactor Building following the discovery of the leak.

(f) 381 pCi total activity released during this reporting period.

(g) 335 pCi of tritium were released during this reporting period.

2. Identification of Fission and Activation Products:

The gross alpha-beta-gamma activity of the batches in (a) above were less than 2 x 10 4 Ci/ml. An isotopic analysis of these batches indicated low levels of typical corrosion and activation products.

PU15rAR REACIDR ANNUAL REPORT $

. 01 July 1993 - 30 June 1994 (b) PC 1-94 was Revision 12 to the PULSTAR Operations Manual. This revision documented changes required by the implementation 10 CFR 20 which went into effect in January 1994.

(c) A total of twenty-one procedures have been revised (most minor editorial changes) and twelve new procedures (ten Health Physics and two purification system special procedures) have been submitted or

... se already been reviewed and approved by the Radiation Protection Committee.

6.7.5.f Radioactive Effluent:

Liuuid Waste (summarized by quarters)

1. Radioactivity released during the reporting period:

(a) (b) (c) (d) (e)

No. of Total Tot. W1. Diluent Tritium Period Batches pCi Liters Liters Ci 01 Jul - 30 Sep 93 2 33 539 2.4 x 10' 23 01 Oct - 31 Dec 93 5 198 1488 6.3 x 104 173 01 Jan - 31 Mar 94 4 125 1121 8.2 x 104 117 01 Apr - 30 Jun 94 2 25 537 2.6 x lod 22 NOTE: Increases in the total volume discharged from 01 Oct 93 to 30 Mar 94 was due to water loss testing and draining of the N-16 Tank and buried piping. The entire Primary System was isolated within the Reactor Building following the discovery of the leak.

i (f) 381 Ci total activity released during this reporting period.

(g) 335 pCi of tritium were released during this reporting period.

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2. Identification of Fission and Activation Products. i l

The gross alpha-beta-gamma activity of the batches in (a) above were less than 2 x 104 pCi/ml An isotopic analysis of these batches indicated low levels of typical corrosion and activation products.

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PULSTAR REACTOR ANNUAL REPORT 6 l 01 July 1993 30 June 1994 l

3. Disposition of liquid effluent not releasable to Sanitary Sewer System:  ;

All batches of 1(a) above when diluted by campus water (2.80 x 106 liters; the minimum daily campus intake) resulted in activity j considerably less than 1 x 10-7 pCi/ml (10 CFR 20 limit). Therefore, all  !

batches were released to the sanitary sewer system. l Gaseous Waste (summarized monthly)

1. Radioactivity discharged during the reporting period (in Curies) for:

(a) Gases:

Total Time Year Period In Hours Curies 1993 01 Jul - 30 Jul 720 0.192 31 Jul - 31 Aug 744 0.127 01 Sep - 28 Sep 696 0.046 29 Sep - 27 Oct 690 0.040 28 Oct - 26 Nov 713 0.082  ;

27 Nov - 31 Dec 852 0.000 i 1994 01 Jan - 31 Jan 744 0.015 01 Feb - 28 Feb 672 0.082 ,

01 Mar - 31 Mar 744 0.074 i 01 Apr - 30 Apr 720 0.071 01 May - 31 May 744 0.039 i 01 Jun - 30 Jun 720 0.023 Totals 8,759 0.791 (b) Particulates with a half-life of greater than eight days:  ;

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Filters from the particulate monitoring channel were analyzed upon removal and again the following week. There was no particulate activity ((b) above) indicated on any filter during this reporting period.

PU15rAR REACroR ANNUAL REPORT 7 01 July 1993 - 30 June 1994

2. Gases and particulates discharged during this reporting period:

(a) Gases:

The yearly average concentration of Argon-41 released from the PULSTAR reactor facility exhaust stack during this period was 5.27 x 10* pCi/cc. This is below the regulatory limit of 1 x 10-8 Ci/cc. (10 CFR 20 Appendix B)

(b) Particulates:

See gaseous waste 1.(b) above.

Solid Waste from Reactor

1. Total volume of solid waste - 2.9 m' (102 ft.')

2. Total activity of solid waste - 0.1 mci

3. Dates of shipments and disposal:

03 Jun 93 Chem-Nuclear Systems Inc. (CNSI) 06 Oct 93 Chem-Nuclear Systems Inc. (CNSI)

• 24 Nov 93 Chem-Nuclear Systems Inc. (CNSI) 14 Mar 94 Chem-Nuclear Systems Inc. (CNSI) 6.7.5.g Personnel Radiation Exoosu.e Report' Twenty-three members of the faculty and staff were monitored for external radiation exposure during the reporting period. Fourteen of the twenty-three received measurable exposure which ranged from 0.010 to 0.120 Rem. Total person-Rem for the faculty and staff was 0.810.

Approximately 18 film badges were issued to graduate students and temporary staff,216 for short courses, and 225 film badges were issued for visitors. No significant radiation exposures were reported. The majority of these exposures were in the "no measurable exposure" range.

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' Compiled and prepared by the Radiation Protection office.

PUISrAR REACIOR ANNUAL RilPoRT g

• 01 July 1993 - 30 June 1994 ,

6.7.5.h Summary of Radiation and Contamination Surveys Within the Facility Neither the radiation nor the contamination surveys indicated any trend or shift of data from past experience or surveys.

6.7.5.i Descrintion of Environmental Surveys Outside of the Facility '

See Attachment A b

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