ML18004B754
| ML18004B754 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 04/03/1987 |
| From: | Watson R CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| HO-870396-(O), NUDOCS 8704130347 | |
| Download: ML18004B754 (5) | |
Text
REGULA INFORMATION DISTR IBUTI YSTEM
( R IDS)
ACCESSION NBR: 8704130347 DOC. DATE: 87/04/03 NOTARIZED:
NO FACIL: 50-400 Shearon Harris Nuclear Pouer Plant>
Unit 1> Carolina AUTH. NAME AUTHOR AFFILIATION WATSON> R. A.
Carolina Poliler 8c Light.Co.
REC IP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desi
)
DOCKET 05000400
SUBJECT:
Special rept: on 870305> util notiFied bg Sorrento Electronics oF environ qualiFication problem e/interconnecting cable on digital high-range radiation monitors. Caused bg misapplication oF cable bg vendor. Alternate monitor used.
DISTRIBUTION CODE:
IE22D COPIES RECEIVED: LTR g ENCL J SIZE:
TITLE: 50. 73 Licensee Event Report (LER) > Incident Rpt>
etc.
NOTES: Application For permit reneual bailed.
05000400 RECIPIENT ID CODE/NAME PD2-1 LA BUCKLEY> B INTERNAL: ACRS MICHELSON ACRS WYLIE AEOD/DSP/ROAB NRR/ADT NRR/DEST/ADS NRR/DEST/ELB NRR/DEST/MEB NRR/DEST/PSB NRR/DEST/SGB NRR/DLPG/GAB NRR/DREP/EPB NR
.P-MAS/
RB Q. FIL 02 GN FILE 01 EXTERNAl:
EQSQ QROH> M LPDR NSIC 'ARRIS> J COPIES LTTR ENCL 1
1 1
1 1
1 1
1 2
2 1
1 0
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 5
5 1
1 RECIPIENT ID CODE/NAMF PD2-1 PD
- CRS MOELLER AEOD/DOA AEOD/DSP/TAPB NRR/DEST/ADE NRR/DEST/CEB NRR/DEST/ ICSB NRR/DEST/MTB NRR/DEST/RSB NRR/DLPG/HFB NRR/DOE*/EAB h!RR/DREP/RAB NRR/PMAS/PTSB RES SPEIS> T H ST LOBBY WARD NRC PDR NSIC MAYS> Q COP IES LTTR ENCL 1
1 1
1 1
1 1
0 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 41 ENCL 39
CARL Carolina Power & Light Company HARRIS NUCLEAR PROJECT APR 0 5 198'ile Number:
SHF/10-13510C Letter Number:
HO-870396 (0)
United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 HARRIS NUCLEAR PROJECT UNIT 1
DOCKET NO. 50-400 LICENSE NO. NPF-63 NRC 14-DAY SPECIAL REPORT Gentlemen'.
In accordance with Technical Specifications 3.3.3.6 and 6.9.2 for the Shearon Harris Nuclear Po~er Plant, Unit No.
1, Carolina Power 6 Light Company hereby submits this Special Report.
This Special Report concerns the operability of the Containment High Range Radiation Monitors.
Very truly yours, RAW/RS/sdg Enclosure R. A. Watson Vice President Harris Nuclear Project cc'Dr. J.
N. Grace (NRC-RII)
Mr. G. Maxwell (NRC-SHNPP) 8704130347 870403 PDR ADOCK 05000400 S
PDR MEM/HO-8703960/PAGE 1/OS1
ACCIDENT RADIATION MONITOR SPECIAL REPORT Back round:
Shearon Harris Technical Specification 3.3.3.6 (Table 3.3-10) requires at least 1 channel for the Containment High Range Radiation Monitor to be operable or initiate an alternate method of monitoring within 72'ours, and either restore the inoperable channel to operable status within 7 days or prepare and submit a
Special Report to the Commission within 14 days.
The SHNPP design includes 2 Digital High Range Radiation Monitors (DHRMs) RM-1CR-3589SA and RM-1CR-3590SB.
These monitors are manufactured by Sorrento Electronics (SE).
On March 5,
- 1987, CPGL received initial notification from SE of an environmental qualification problem with the interconnecting coaxial cable on these monitors.
SE has discovered that when, the interconnecting coaxial cable is exposed to the high temperature LOCA environment, the cable dielectric insulation resistance decreases causing the monitor to not respond within a factor of two accuracy as required by Reg.
Guide 1.97.
Descri tion of Problem.'he monitor consists of an ion chamber located inside containment and monitor electronics outside containment.
These two devices are connected by coxial cable.
The cause of the problem is due to misapplication of the subject cable by SE.
While the cable was qualified by its manufacturer, Rockbestos, in the LOCA environment per IEEE 383-1984, SE recently found that the dielectric insulation resistance is not high enough at high temperatures
("350'F) for the ion chamber and its associated electronics to operate properly.
Th~
DHRM detects radiation in Containment for the ranges of 10 to 10 R/HR.
As a result loss of the interconnecting cable insulation resistance could cause the detectors (o read lower than actual radiation levels in the range from 10 to 5.0 x 10 R/HR during a
LOCA/MSLB event.
The effect is projected to exist for approximately 2 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> or until the containment temperature returns to below 200'F.
After this interval the cable temperature is reduced to the point where the response of the detectors is acceptable.
MEM/HO-8703960/PAGE 2/OS1
Corrective Action:
These detectors are used to assess the consequences of an accident and classify th~ accident.
The SHNPP design also includes four lower range (10 to 10 mR/HR) radiation detectors installed in the Containment.
These are qualified to the, same environmental criteria as the high range detectors and their range encompasses the radiation level used for classifying an accident in containment.
To mitigate the loss of detector accuracy, the following actions were taken pursuant of Technical Specification 3.3.3.6 Action c'.
1.
Calculations were performed to support the use of an alternate radiation monitor (RM-1CR-3561ASA) as a backup means for classifying an accident in containment.
2.
PEP-101 "Emergency Classification and Initial Emergency Actions" has been revised to reflect the use of the alternate radiation monitor as a backup means of determining emergency classification.
SE continues to pursue a solution to this matter.
SE has informed CPGL that additional data will be provided which will allow a plant specific analysis to be performed to determine acceptabi.lity of the SHNPP installation.
The above actions will remain in effect until the present installation is found acceptable by plant specific analysis or the present cable is replaced with an approved cable.
MEM/HO-8703960/PAGE 3/Osl
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