My locales_source table grows on each request

I understood the problem. The problem is not i18n, but a problem in Drupal modules locales
I found strings in module locales.module which translation cached

// If we have the translation cached, skip checking the database
if (!isset($locale_t[$langcode][$string])) {

// We do not have this translation cached, so get it from the DB.
$translation = db_fetch_object(db_query("SELECT s.lid, t.translation, s.version FROM {locales_source} s LEFT JOIN {locales_target} t ON s.lid = t.lid AND t.language = '%s' WHERE s.source = '%s' AND s.textgroup = 'default'", $langcode, $string));
if ($translation) {
// We have the source string at least.
// Cache translation string or TRUE if no translation exists.
$locale_t[$langcode][$string] = (empty($translation->translation) ? TRUE : $translation->translation);

if ($translation->version != VERSION) {
// This is the first use of this string under current Drupal version. Save version
// and clear cache, to include the string into caching next time. Saved version is
// also a string-history information for later pruning of the tables.
db_query("UPDATE {locales_source} SET version = '%s' WHERE lid = %d", VERSION, $translation->lid);
cache_clear_all('locale:', 'cache', TRUE);
}
}
else {
// We don't have the source string, cache this as untranslated.
//db_query("INSERT INTO {locales_source} (location, source, textgroup, version) VALUES ('%s', '%s', 'default', '%s')", request_uri(), $string, VERSION);
$locale_t[$langcode][$string] = TRUE;
// Clear locale cache so this string can be added in a later request.
cache_clear_all('locale:', 'cache', TRUE);
}
}

An i delete strings db_query("INSERT INTO {locales_source} (location, source, textgroup, version) VALUES ('%s', '%s', 'default', '%s')", request_uri(), $string, VERSION); I base locales_source no grown)))