ML18113A270

Forwards Non-Routine Radioactive Effluent Report

ML18113A270
Person / Time
Site:	Saint Lucie
Issue date:	02/25/1977
From:	Schmidt A Florida Power & Light Co
To:	Moseley N NRC/IE, NRC/RGN-II
References
Download: ML18113A270 (10)

Text

FLORIDA POWER & LIGHT COMPANY February 25, 1977 PRN-LI-77-42 Mr. Norman C. Moseley, Director, Region Office of Inspection and Enforcement II U. S. Nuclear Regulatory Commission 230 Peachtree Street, N. W., Suite 1217 Atlanta Georgia 30303

Dear Mr. Moseley:

REPORTABLE OCCURRENCE 335-B-77-02 ST. LUCIE UNIT 1 DATE OF OCCURRENCE: Januar 26, 1977 WASTE GAS SYSTEM The attached Non-Routine Radioactive Effluent Report is being submitted in accordance with Environmental Technical Specification (Appendix B) 2.4.3.f to pro'vide 30-day noti-fication of the subject occurrence.

Very truly yours, A. D. Schmidt

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Vice President Power Resources MAS/cmp Attachment cc: Robert Lowenstein, Esquire Director, Office of Inspection and Enforcement (20)

Director, Office of Management Information and Program,,Control (2)

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A. Descri tion'.

During the period of 1-6-77 8 2300 to 1;26-77 8 0800, on seven separate occasions, greater than 5 curies of activity (primarily Noble Gases) was vented to the Reactor Auxiliary 'Buil'ding and'ubsequently discharged via the plant vent. All seven releases were in excess of the reporting level specified in Environmental Technical Specifications (Appendix B) 2.4.3.f. Pathways were various vents and drains on waste gas surge header, relief valve on gas supply to volume control tank (exceeded setpoint) and ruptured, diaphragm on Beckman Gas analyzer sample pump. (See Attached Table I).

B. ~Anal aia:

1. A gas sample was taken on the plant vent just after the first abnormal release of greater than 5 curies. 'The was reading 175 cpm at the time of sampling and the gaseous'onitor highest reading during all subsequent discharges was 20,000 cpm.

2. Analytical results

a. Iodine 2.331 x 10 uc/cc x 1.109 x 10 cc collected x 70 000 cfm x 3 releases = 10.8 uc I-131 5 cfm (collection rate)

No iodine detected on Plant vent, charcoals after 1st (3) releases

b. Particulates Rb-88 was only particulate detected on Plant vent filter on all releases a

c. Noble gases Sample taken after 1st release

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Xe-133 4.409 E-06 uc/cc Xe-135 . 4.206 E-07 uc/cc Kr-85m 1.53 E-07 uc/cc

• Kr-88 2 '1 E-07 uc/cc

• based on Kr-88/Kr-85m ratio of 1.446 on,RCS gas sample

3. Total Release

a. Noble gases 113.856 Curies over a 71 1/3 hr time span

b. Iodines 10.8 uc

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4. K, L, M, and N calculations were performed per specification 2.4.3 for the highest .release (20000 cpm,~ 175 cpm x analyzed activities).

The results for M were the most conservative and showed that the release rate was 68% of the allowable avera e release rate during any 12 consecutive months.

5. To validify the 'use of sample taken after 1st release for ratios!

A gas decay tank released on 1/12/77 was analyzed fox total curies Xe-133 released using plant vent monitor ratio of 6000 c m durin release 175 cpm during analysis of B.2.C Ratio Results were 53.9 curies Xe-133 released where actual results from release permit was 52.7 Curies Xe-133 C. Evaluation:

No release limits were exceeded. The highest release rate of the discharge periods was only 68% of the allowable average release rate during any 12 consecutive months. The releases were properly monitored and accounted for by sampling the plant vent. The total released', activity was derived by relating the sample results to the plant vent monitor readings and checked as stated in B.5 above.

Efforts to identify and isolate these various leaks in a timely manner were hampered because of the apparent random starting and stopping of the releases and slight imbalances in the ventilation system masking the true sources of leaks. The randomness of the leaks were later correlated to conditions when hot sources such as the Volume Control Tank were vented excessively to the waste gas surge header for short periods at .a xate greater than the capacity of the waste gas compressors. This caused higher than normal gas surge header pressures which initiated leaks that were not occurring at lower pressures or not detected under lower activity conditions.

D. Corrective Action:

1. All vents and drains on the gas surge header have been capped.

2. Lowered operating pressure on Volume Control Tank and reduced setpoint on H2 xegulator.

3. Changed operating level band of Volume Control Tank to reduce press'ure surges caused by excessive level fluctuations.

4. Repaired gas analyzer pumps.

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RECU..ATORZ Ot'"RATIONS REC!ON P ATLANTA CA.

MAR 2 9 aottH'77

TABLE I RELEASE f/ DATE TIME TOTAL ACTIVITY PATHWAY r '

DISCHARGED 1/6/77 2300-0140 7+i ci leaking gas header vent valve

.1/8/77 2030-2300 24.1 ci leaking vent valve on 1B evaporator and'CT venting 1/9/77 1220-1700 11.09 ci 'leaking vent valve on gas surge header 1/12/77 1430-2300 17.7 ci VCT N2/H2 relief valve

5. 1/16/77 0200-1000 10,74 ci FCT N2/H2 relief valve" e

1/20/77 2100-2400 '5.3 ci Gas analyzer pump leak 1/24/77 1430-0900 37.85 ci leaking union fitting on 1/25/77 1030-0800 evaporator and VCT venting

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i-'EA4 GASEOOS EFFLUEN1'fELEASE CALCULATIOiVS

- Highest peak 20,000 cpm 1=8-77'030 2300 20000 ~ 114.28 175 Ci/sec M N Xe 133 1.66 E-02 3.65 E-02 7.47 E-03 Xe 135 1.59 E-03 8.27 E-03 2.54 E-03 Kr 85M 5.75'E-04 '.36 E-03 5.29 E-04 Kr 88 8.35 E-04 5.18 E-03 5.26 E-03 E Q.M. E Q.N 5.23 E-02 1.58 E-02 1> QTU X ~EN x 13 1> QTU x ~EN x 25 QW QTV 1> .68 1> .395 68% of yearly. limit

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