ML20215B936
| ML20215B936 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/10/1987 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Butler W Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8706170517 | |
| Download: ML20215B936 (5) | |
Text
_ _ _ _ _ _
1 PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA PA.19101 (als) ads soto m.. 1^,,".^$ '."....,
June 10, 1987 Docket Nos. 50-277 50-278 Mr. W. R. Butler,-Director Project Directorate I-2 Division of Reactor Projects I/II ATTN: Document Control-Desk D.S. Nuclear Regulatory Commission Washington', D.C.
20555
SUBJECT:
Philadelphia Electric Company In-House Reload Licensing
References:
(1)
Telephone Conference on May 12, 1987 between R. E. Martin, NRC, and W. G. Lee, PECo (2)
Topical Report, PECO-FMS-002, " Methods.for Transient Critical Power Ratios for Boiling Water Reactors'(RETRAN-TCPPECO)",
submitted to NRC by letter dated August 29, 1986
. Dear Mr. Butler-In the referenced telephone conference, the NRC.
l requested additional information regarding the methods described in the referenced topical report for predicting the time of transition boiling.
In particular, information was requested on the predicted time of transition boiling for test runs 112, 229 and 231.
The following information is provided to clarify the results for these three test runs.
Run 112:
As discussed in section 3.1,
" Steady-State Comparisons", of the topical report, the PECo thermal margins method was used to predict the minimum critical power ratio (MCPR) for fifty test g 61 g y 87 P
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i Mr. W. R. Butler June 10, 1987 Page 2 cases in transition boiling.
The MCPR predictions _ ranged from i
0.973 to 1.053.
The mean MCPR was 1.007 with a standard deviation of 0.019.
This leads to the conclusion that the method predicts transition boiling to occur at an upper bound of MCPR =
{
1.026 with.a high degree of confidence.
Applying this result to run 112 (see topical report page 24), transition boiling is predicted to occur at 6.25 seconds.
This compares well with the experimentally observed time of 6.29 seconds.
Run 229:
The topical report lists the experimentally observed time of transition boiling for this test case as 4.17 seconds (see page 1
25).
We have enclosed a figure which shows the actual
)
thermocouple temperature response for the run and serves to further explain and clarify the 4.17 second time of transition boiling.
Although transition boiling is indicated to occur at approximately 4 seconds, the transition occurs only temporarily, followed by a return to nucleate boiling.
This trend occurs several times until approximately 15.5 seconds when transition boiling is observed to occur and remain until the transient is terminated by a reduction in power.
Applying the upper bound of MCPR, as discussed for Run 112, the PECo methods predict transition boiling to occur at 15.6 seconds.
This compares well with the experimentally observed time of 15.5 seconds.
Run 231:
The topical report erroneously lists on page 25 the experimentally observed time of transition boiling as 13.67 seconds.
The actual observed time is 17.55 seconds.
Applying the upper bound of MCPR, as discussed for Run 112, the PECo methods predict transition boiling to occur at 19.5 seconds.
This compares well with the experimentally observed time of 17.55 seconds.
We have enclosed forty copies of a revised page 25, correcting the error, for insertion into the reports previously submitted to the NRC.
It should be noted that the PECo thermal margins methods apply a conservative MCPR upper bound of 1.07 for licensing calculations.
]
Mr. W. R.
Butler June 10, 1987 Page 3 If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, 7?
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T. P. Johnson, Resident Site Inspector R. E. Martin, NRC Peach Bottom Project Manager j
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.,V Table 4 - PLOW AND POWER DECAY RESULTS
' EXPERIMENTALLY OBSERVED PREDICTED PREDICTED TIME ICPR
-ICPR TIME TO BT*
TIME TO BT*
- OBSERVED TIME l
RUN f, (GE)
(PE)
(SEC)
(SEC)
(SEC)
J 201 1.045 1.044 4.59 3.00
-1.59 I
d 202 1.029 1.027 6.00 3.25
-2.75 1
203 1.009 1.007 4.18 2.20
-1.98 i
206 1.160 1.160 3.84 3.20
-0.64 207 1.190 1.200 4.53 3.55
-0.98 208 1.400 1.410 2.56 2.70 0.14
[
211 1.060 1.060 2.68 2.75 0.07 215 1.140' 1.150 3.65 3.60
-0.05 216 1.170 1.170 3.88 3.45
-0.43 217 1.220 1.220 3.06 3.20 0.14 218 1.280 1.290 5.00 5.45 0.45 219 1.335 3.47 4.20 0.73 Table 5 - FLOW AND POWER INCREASE RESULTS EXPERIMENTALLY OBSERVED PREDICTED PREDICTED TIME ICPR ICPR TIME TO BT*
TIME TO BT*
- OBSERVED TIME RUN #
(GE)
(PE)
(SEC)
(SEC)
(SEC)
=_
229 1.073 4.17 18.20 (1)
'231.
1.383 17.55 20.00 (2) l BT -- Boiling Transition Data was not reported by G.E.
1 Boiling Transition was not predicted. MCPR = 1.008 at 18.2 sec 2
Boiling Transition was not predicted. MCPR = 1.022 at 20.0 sec This page revised 6/10/87