NRC-87-0105, Part 21 Rept Re Failures of Hydrogen/Oxygen Sampling Sys Supplied by Exo Sensor,Inc.Initially Reported on 870630. Sensors to Be Replaced at 6-month Intervals & Tested Every 30 Days to Ensure Operability
| ML20235E807 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 07/06/1987 |
| From: | Agosti F DETROIT EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CON-NRC-87-0105, CON-NRC-87-105, REF-PT21-87, REF-PT21-87-128-000 PT21-87-128, PT21-87-128-000, NUDOCS 8707130099 | |
| Download: ML20235E807 (4) | |
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Detroit re,mi2 Edison EEES n=.
July 6,1987 NBC-87-0105 i
l U. S. Nuclear Regulatory Conanission l
Attn Document Control Desk i
Washington, D. C. 20555 i
References:
- 1) Fermi 2 NFC Docket No. 50-341 NFC License No. NPF-43
- 2) Telephone conversation from Mr. F. E. Agosti (Detroit M ison) to Mr. C. Paperiello (Region III), on June 30, l
1987 (PBC-87-001) l
Subject:
Part 21 Notification - Exo Sensor Pursuant to the requirements of 10CFR21.21(b)(2), Detroit Elson notified Mr. C. Paperiello (Reference 2) of a Part 21 condition at Fermi 2.
The specific condition involved the failures of a hydrogen / oxygen sanpling system supplied by Exo Sensor, Incorporated.
j Attached information is being submitted in accordance with 10CFR21.21(b) (2) and 10CFR21.21(b) (3). If you have any additional questions, please contact Mr. Steven Frost at (313) 586-4210.
Sincerely, F. E. Agosti, Vice President Nuclear Operations Attachment cc:
A. B. Davis E. G. Greermian W. G. Rogers J. J. Stefano USNBC Region III b
ti 8707130099 870706 ADOCK0500g1
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Attachnent to NBC-87-0105 Page 1 10CFR21.21(b) (3) -
The written report required by this paragrgh shall include, but need not be limited to, the following information, to the extent known.
Name and address of the individual or individuals informing the Commission.
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Messrs:
F. E. Agosti (V. P. thiclear Operations) and 1
S. R. Frost (Licensing) 6400 N. Dixie Highway Newport, Michigan 48166 10CFR21.21(b) (3) (ii) - Identification of the facility, the activity, or the basic couponent supplied for such facility or such activity within the Uhited States which fails to comply or contains a defect.
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Facility:
Detroit B31 son Fermi 2 Nuclear Power Plant Basic Conponent - Hydrogen / Oxygen Monitor Sensors Model Nunbers - H -ll4-D001-G1 0 -ll4-D001-G2 10CFR21.21(b)(3)(iii) - Identification of the firm constructing the facility or supplying the basic couponent which fails to couply or contains a defect.
i Supplier of Basic Conponent - Exo Sensor, Inc.
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10CFR21.21(b) (3) (iv) - Nature of the defect or failure to comply and the safety hazard which is created or could be created by such defect or failure to comply.
This defect involved the evaporation of the hydrogen / oxygen sensor electrolyte volune under conditions where this nonitoring system was to operate as identified by the Purchase Specification.
The evaporation of the electrolyte is caused by:
1)
The heat tracing at the panelg (upstream of the sensors) was operating at 130 F.
At this temperature a high permeability of the sensor nenbrane apparently occurred.
Attachnent to IEC-87-0105 Page 2 I
l 2)
During startup conditions, the drywell has been opened and closed a number of times thus the humidity is low.
Under these conditions the sensor menbrane becones perneable thus allowing the electrolyte fluid to evaporate through the nenbrane. The vaporization of the electrolyte causes the l
hydrogen / oxygen sensors to fail.
The drywell oxygen and hydrogen sensors are passive devices which provide data'to the control room operators on oxygen and hydrogen concentrations in the primary containment. In the event of a i
LOCA and the concentration of oxygen / hydrogen exceeds their l
acceptable levels, these sensors initiate an alarm in the control I
room. However, they do not provide any automatic isolation or i
actuation functions. The Fermi alarm response procedures instruct the operator to initiate various actions to mitigate the i
likelihood of an explosive mixture of mycen/hvdrogen inside the primary containment in the event of receiving this alarm. In the event that the sensor failed, the alarm in the control room may l
not function which could result in the inability to mitigate the j
hydrogen build up in the primary containment if it were to occur.
l It should be noted that in the event that the subject sensors I
fail, the information provided by these monitors is also available through analysis of grab samples of the drywell atmosphere. Information from the Radchem Engineer confirms that l
grab samples of containment atnosphere can be obtained and analyzed for oxygen and hydrogen content within 1 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following a Loss-of-Coolant Accident by use of the Post Accident Sampling System. This provides further assurance that information needed by the plant operators to assess the post-accident environment inside containment is available in a tirrely tranner.
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The date on which the information of such defect or failure to comply was obtained.
Date - The date of the first sensor failure at Fermi 2 was January 1986. A report containing the evaluation of the sensor failures involving loss of electrolyte was submitted on March 20, 1987 to Detroit &lison by Exo Sensor, Inc. Detroit Fdison then evaluated the report and all Exo Sensor failures at Fermi which resulted in the submittal of this report.
10CFR21.21(b) (3) (vi) - In the case of a basic couponent which contains a defect or fails to comply, the nunber and location of all such
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conpanents in use at, supplied for, or being supplied for one or more facilities or activities subject to the regulations in this part.
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Attachment to NBC-87-0105 Page 3 l
As required by Fermi Technical Specification Table 3/4 3.3.7.5-1, there are two hydrogen sensors and two oxygen sensors installed.
In addition, there are at least 2 oxygen and 2 hydrogen sensors stocked as spares.
For information as to other utilities using this sensor, Exo Sensor, Inc. should be contacted.
'the corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to couplete the action.
The following corrective actions have been/or will be taken:
1)
Replace sensors at 6-month intervals - This is implemented. The responsible organization is Nuclear Production 2)
Test the sensors every 30 days to ensure operability -
The responsible organization is Nuclear Production -
I&C.
3)
Red g e temperature of heat tracing from 130 F to 110 F.
This is implemented. The responsible organization (s) are Engineering and Nuclear Production.
These corrective actions are in place and will continue to be implemented until a final fix to resolve the evaporation issue is identified and appropriate steps taken.
10CFR21.21(b) (B) (viii) -
Any advice related to the defect or failure to comply about the facility, activity, or basic couponent that has been, is being, or will be given to purchasers or licensees.
Any advice is expected to come from Exo Sensor as a result of the correction taken to resolve this issue.
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