ML20086F470
| ML20086F470 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, 05000000 |
| Issue date: | 01/27/1976 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML19289B554 | List: |
| References | |
| NUDOCS 8312270082 | |
| Download: ML20086F470 (2) | |
Text
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I January 27, II/6 Re: Docket Nos. 50-277 50-278 d5Uh Mr. J. P. O'Reilly Director, Re<jlon 1
[.h h Q Office of Inspection and Enforcement f
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U.S. Nuclear Regulatory Comission Ol-
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631 Park Avenue C
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g@y[N King of Prussia, PA 19406 ut
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Subject:
Technical Specification 3 8.C.5 4L' Jnique Reporting ReqJIrCrmnts k
e Plant Gaseous Activity Release Rate Exceeded N
E Foar Percent of Technical Specification 3 8.C.I for.'iore than 48 tlours
Dear Mr. O' Reil ly:
In accordance with the subject technical specification reporting requirement s, this is to advise yo.J that the yiscous activity release rate exceeded four percent of allowable for M hours at 5:00 p.m., on January 17, i 176 On January 17, 1376, the release rate was 7.lf, of the technical specification limit. The off-las flow rate was 156 5 cfm and the of f-jas activity at the steam jet air ejector (sum of six Kr-85m, Kr-u/, Kr-d8, Xe-133, (e-135, xe-13d) was 102,000 C1/sec. The release rate from the holdup pipe to the main stack was approximately 10,000 pCI/sec.
Apparent Causes The cause of the increase in the gaseous release rate was an increase in off-gas activity due to fuel cladding perforations.
Preliminary analysis of data taken imediately following the observed increase in off-gas activity indicates that approximately 10 to 20 lenker fuel assemblies exist in the core. Although the in-core locations of the affected assemblies are not presently known, Type 1 fuel assemblies may contain the majority of defects. These assedlies were fabricated prior to the availability of pellets having design improvements which decrease local pellet cladding interaction.
In addition, the Type 1 assedlies do not contain hydrogen getters and may have contained fuel rods fabricated with a moisture level above that currently being fabricated.
8312270082 761220 DRADOCK05000; 1047
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tir. J. P. O'Rollly January 27, 1976 Page 2
Analysi s of Occurrence:
On January 13, Unit 2 was at about 95% power and increasing power at 5 t%e per hour via core flow. The off-gas was about 2,000 to 4,000 Ci/sec (at the SJAE) as indicated by the off-gas radiation monitor.
At 12:32 p.m.,
load was dropped via core flow 240 the because of a turbine generator trouble alarm. At 12:35 p.m., power was returned to the prior level. At 7: 10 p.m. on the 13th, load was dropped 40 t%e via core flow due to a condensate flow problem. Twenty-three minutes later power was returned to the prior level. These transients were the only unusual power changes made bef ore a change was noticed in off-gas.
An off-gas isotopic sample taken the morning of January 14 showed the activity at the SJAE was 23,000 Ci/sec. Iodine done equivalent increased from 7 0 x 10-3 to 3 75 x 10-3 pCi/gm. No unusual power changes ensued, however, at about 8:00 a.m. on January 15, a step change increase occurred at the of f-gas radiation monitor. An off-gas isotopic showed the act at the SJAE was 65,000 pCi/sec.
Iodine dose equivalent was6.02x10'{vity/gm.
showed a peak at 7 8 x 10"jditional iodine dose egalvalent samplespC1/gm an C1 A
pCi/gm and. decreased slowly thereaf ter.
The jascoas activity release rate, estimated from the main stack and roof vont radiation monitors, increased to 44 of allowable at about 5:00 p.m. on JanJary 15. On January 18, Jnit 2 cane of f-line to repair a drywell leak with the reactor maintained at pressure. The gaseous release rato peaked at 23 to 25/> of allowable darin] the shutdown.
Subse g nt to returnin] the anit to service, the gascous release rete decreascJ to 5.S'. on Janar.ry 22.
The off-Jas activity at the SJAE on January 22 was 68,000 Ct/sec ' decreased fro i a peak of 102,000 pCi/sce mensared on January 17). The off-jas activity shoald stabilize at the lower level and the steady state release rate (as now estimated) from the holdJp pipe should be less than i?.
t Corrective Action:
1.
Fuel assemblics will be sipped to determine leaker fuel assemblies during the refueling outage presently scheduled for March 27, 1976 and appropriate corrective action will be undertaken.
2.
Operating procedures maintain post shutdown reactor pressure so as to minimi::o gaseous releases.
Very truly yours, A-M.
Cooney Superintandent Generation Division - Nuclear cca Mr. J. G. Davi s, NR C Mr. W. G. Mcdonald, IRC